pinball repair williams, bally wpc pinball games 1990-1999 part three
pinball repair williams, bally wpc pinball games 1990-1999 part three
support this pinball repair website & phof. please purchase the marvin3m.com/top
repairing williams/bally wpc pinball games from
1990 to 1999, part three.
by cfh@provide.net,
10/02/07.
copyright 1998-2007 all rights reserved.
scope.
this document is a repair guide for williams and bally wpc pinball
games made from 1990 (funhouse) to 1999 (cactus canyon).
internet availability of this document.
updates of this document are available for no cost at
http://marvin3m.com/fix.htm
if you have internet access. this document is part three of three
(part one is here, and part two is
here).
important: before starting!
if you have no experience in circuit board repair,
you should not try to fix your own pinball game!
before you start any pinball circuit board repair,
review the document at http://marvin3m.com/begin,
which goes over the basics of circuit board repair. since
these pinball repair documents have been available, repair facilities are reporting a
dramatic increase in the number of ruined ("hacked") circuit boards sent in for repair.
most repair facilities
will not repair your circuit board after it has been unsuccessfully repaired ("hacked").
if you aren't up to repairing pinball circuit boards yourself or need pinball parts
or just want to buy a restored game, i recommend seeing the
suggested parts & repair sources web page.
table of contents
1. getting started:
experience, what is wpc?, schematics
necessary tools
parts to have on-hand
different wpc generations
game list
lubrication notes
the circuit boards (board differences)
introduction to operation
troubleshooting (quick guide)
2. before turning the game on:
check the fuses and power leds - blown fuses
and what causes them. how to diagnose the "check fuses f114/f115" or
"f106/f101" error messages. and, "why at power-on does my game repeatedly fire a coil".
burnt gi connectors (and wpc-95 gi diodes)
quick and dirty transistor testing
should i leave my game powered on?
3. when things don't work:
removing the driver board
replacing components
checking transistors and coils (stuck on coils and flashlamps)
game resets (bridge rectifiers, diodes and caps)
problems with flippers
the lamp matrix
the switch matrix
infrared optic switches
electronic ball sensors (eddy sensors a magnetic reed switches)
ball trough problems (random multi-ball and bad trough leds)
dot matrix/alphanumeric score displays
power-on leds and sound beeps
"factory settings restored" error (battery problems)
lightning strikes
sound problems
more general illumination (gi) problems
test report & the diagnostic dot, strange game behavior
fixing a dead or non-booting cpu board
game specific & miscellaneous repair tips
4. finishing up:
rebuilding flippers
new coil sleeves
protecting slingshot plastics
cleaning and waxing the playfield
playfield rubber
3h. when things don't work: infrared optic switches
as early as 1982, williams started using infrared optic light emitting diodes (led's)
for switches. this is similar technology to what is used in tv remote controls
today. these optics have two advantages over conventional mechanical switches:
no moving parts, and they can fit in tighter spaces. they also have some
disadvantages. they consist of two parts (instead of one part like a
micro-switch): a transmitter (the led that emits the light), and the
receiver (the led that receives and interprets the light). they can also
get dirty (from that infamous black pinball dust) and not work.
pin leds are always on too. that is, the light emitting half of an
opto switch is always powered on, as long as the game is
powered on (even when not in play mode).
led's aren't much different than light bulbs; they
eventually burn out too.
several different optos used in williams games.
the "u" shaped slot optos are used for fliptronics flippers,
twilight zone clocks, etc. these consist of a transmitter
and receiver in one package. the stand-up optos are two
parts: the green board opto stand-up is the transmitter,
and the blue board opto stand-up is the receiver. the
transmitter led is larger and protrudes further from its
case. the single led shown below is a replacement led
transmitter for the stand-up optos, and for opto boards
used in ball troughs, etc. the specs for this infrared
led replacement are also shown in the picture.
left: type 1 flipper optic board. again note the orientation of the
optics, and how this is different than the type 2 board, and the
vertical metal optic interuptor. this style was seen on games from
addams family to twilight zone.
right: type 2 flipper optic board. note the orientation of the optics,
and the horizontal plastic optic interuptor. this style of flipper optic
board was used on wpc games indy jones to cactus canyon (with only a
minor revision around wpc95, using the 5 pin "u" slot schmitt trigger optic).
the plastic activators can be troublesome, as they often warp and don't
clear the opto, causing a flipper not to work.
note: when purchasing a replacement flipper optic board, be sure
to get the correct style! many times the newer type 2 flipper
optic board is fitted in older games (all versions of the wpc
flipper optic boards are plug compatible)! replacement flipper
opto boards are available from
pinballheaven.co.uk and
pbliz.com.
flipper opto board type list.
if a wpc game is not listed below then the game did not use optic
switches for the flippers. note the type1 and type2 interuptors (either plastic or metal)
are not interchangable between type1 and type2 flipper optic boards.
type 1 (interuptor slot runs vertical). originally used in:
addams family gold (and some regular addams family)
creature from the black lagoon
doctor who
dracula
fish tales
twilight zone
whitewater
type 2 (interuptor slots runs horizontal). originally used in:
attack from mars
cactus canyon
champion pub
cirqus voltaire
congo
corvette
demolition man
dirty harry
flintstones
indiana jones
indianapolis 500
jack*bot
johnny mnemonic
judge dredd
junkyard
medieval madness
monster bash
nba fastbreak
no fear
no good gophers
popeye
roadshow
safecracker
scared stiff
shadow
star trek next generation
tales of the arabian nights
theatre of magic
who?dunnit
world cup soccer 1994
where optos are used.
williams uses optos for lots of applications. wpc fliptronics flipper buttons
are opto activated. these flipper opto boards were implemented on addams family,
mid-production (many addams have them, but early models don't).
often clear ramps have opto ball switches. many pre-1990
williams drop targets use optos (they stopped using them there because
the led's leads would break from vibration, and the optos would fall off).
all wpc-dcs (1993) and later games use optos to sense balls in the
ball trough.
two parts to a opto switch.
each opto switch has two parts; a transmitter, and a receiver.
the transmitter is a infrared led (light emitting diode).
the receiver is a light sensitive photo transistor. the transmitter (led)
is always on when a game is powered on. if the light beam
from the transmitter is interrupted, then this registers the
switch as "open".
because the transmitter is always on and producing light (and
hence heat), the transmitter is the part that fails 98% of the
time in a opto switch. the receiver part rarely fails in comparison.
on non-u shaped optos, usually the transmitter
led is mounted in a white plastic case with a small green printed circuit board.
the receiver
is usually mounted in a black plastic case with a small blue printed circuit board.
cleaning optos.
optos can get dusty from the "black dust" inside a game. to clean
an opto, use a q-tip dipped in glass cleaner. wipe the opto with the
windex-wet q-tip,
then dry the opto with a clean, dry q-tip. do not use canned
air to blow optos clean! the air in these cans is too cold and
can damage an opto.
testing opto switches.
testing infrared optos switches is no different than testing
mechanical switches (to a point). just use the wpc internal test software.
press the "begin test" button inside the coin door, and go to the test menu.
select the "switch edge" test. activate an opto switch by passing something
in front of it to block the light from its corresponding transmitter.
the display will indicate if the switch works. opto switches
that are not activated will be displayed as solid "blocks" in the switch test
on the dot matrix display (which is basically reverse what you would expect,
compared to a micro switch).
12 volts to the optos.
if an opto switch doesn't work, first check that the +12 volts is
working. if you have blown the +12 volt fuse (either the unregulated
12 volts which provides power directly to the optos, or the regulated
18/12 volts which provides power to the entire switch matrix), the
optos won't work. check fuses f115 and f116
(f101 and f109 on wpc-95) on the power driver board. also if the
unregulated +12 volts is below about 11 volts, the optic switches can work
intermittently! if this is the case, usually it indicates a bad
br5 bridge rectifier on the driver board (or bad 12 volt
d3-d6 rectifying diode on wpc-95; see the reset section
of this document for more information on this). br5/d3-d6 is the
unregulated 12 volts (where br1/d11-d14 is the regulated 12 volts, which
could also be the problem since this powers the entire switch matrix, which
ultimately reads the opto switches). remember there is also
a large 10,000 or 15,000 mfd filtering capacitor c30 (c8 on wpc95) associated with
the power driver board's unregulated 12 volt rectifiers. check that too for cracked
solder joints around the capacitor's leads from vibration (often i will
run jumpers to the capacitors and bridges, as shown in the
reset section of this document).
testing the opto transmitter.
on the transmitter led (the one emitting light), you usually can not
check for 12 volts dc right on the opto with a dmm.
unfortunately in most cases the opto voltage will show only
about 1 volt (putting the red dmm lead on
each leg of the transmitting led, and the black dmm lead on ground).
a better way is to remove the connector going to the opto, and
measuring the voltage at the source connector (usually black and gray wires,
where the orange and gray pair go to the receiver).
if there is no 12 volts present (and other optos in the game work),
there is either a break in the ground or 12 volt connection going
to the transmitting led. also sometimes the optos get cold solder
joints (from vibration) on their associated circuit board. resoldering
the opto leads can fix this (assuming the opto lead going to the led itself
hasn't broken). heck vibration often breaks the wire off the opto board too.
if there is +12 volts going to the transmitter opto but the switch does not work,
there is a good chance the transmitter led has failed.
radio shack sells a $5 credit card sized "infrared sensor".
mcm electronics also sells one, #72-6771, for about $7
(800-543-4330 or www.mcmelectronics.com).
if you put this card right in front of an opto transmitter,
the opto's emitting light can be seen; the light will show on the colored
band of the sensor card. also, a digital camera or a camcorder
will usually show infrared light from the transmitting opto,
if the digital camera has a small lcd screen
used to show images "live" (but personally i like using the
opto cards better).
if there is +12 volts (hint: do other optos work?),
and the opto switch doesn't register in the diagnostic test,
your opto transmitter is probably burnt. the receiver
side of an opto switch rarely dies. that's because it
only senses light, and doesn't produce light. the transmitter
will be the offending unit 98% of the time. remember the opto
transmitter is powered-on all the time the game is turned on,
and it can burn out just like a light bulb can burn out.
reversed leads on the transmitter.
another common fault of the led opto transmitters is having the wires
reversed. yes it does matter which wire goes where. and don't think
you are the only one that can make this mistake. i have seen nos
parts right from williams where they have soldered the leads reversed
on the opto transmitter! note usually having the leads reversed does not
blow the transmitter. there is a flat spot on many led transmitters
too, signifying which side to connect ground or 12 volts. but i have
also seen some manufacturers have the flat side reversed! so if in
doubt, try reversing the black and gray leads on a non-working opto transmitter.
testing the opto receiver.
the simplest way to test the opto receiver is to first
put the game into the "switch edge" test. then block the opto
transmitter with a piece of black electrical tape. now shine a penlight flash light
into the opto receiver, or a tv remote control (which is basically
an infrared flashlight). the switch should "close" (go from a solid
block to a small dot on the dmd screen). when you remove
the light, the switch should "open". if the led receiver is working
properly but the switch does not work, often the opto transmitter has burned out.
another way to test the opto receiver is using a dmm.
first block the opto transmitter with a piece of black
electrical tape. put the black dmm lead on ground
(the metal side rail of the game works well). put the red dmm lead on one leg of
the opto receiver (gray wire). one opto receiver leg should show 12 volts dc, and the
other opto leg should show close to zero volts (orange wire). keep the red dmm lead
connected to the "low" (zero volt) opto leg. now shine a flashlight into the opto
receiver. the dmm should now go to 12 volts dc, and when the light is removed,
go back to near zero volts. if this does not happen, the opto receiver is
bad. or if 12 volts is seen on both opto receiver legs, the receiver is bad
(or there is direct light shining into the opto receiver).
testing the infrared opto transmitters on a 7 led ball trough
assembly. the led's can be seen lit in this photo, but you won't
be so lucky with the naked eye. that's why this infrared sensor
card or a digital camera/camcorder is so handy. note in the
digital picture below, the red and blue infrared leds are lit.
with the naked eye, the leds do not look lit. this card is available
from radio shack #276-1099 or mcm electronics #72-6771, about $7.
opto transmitters on newer wpc games.
older wpc games use optos with straight resistive photocells.
some newer wpc95 games use a transistor gate photocell. this means the internal
transistor can die, even if the photocell part of the opto is ok. keep
this in mind; if an opto transmitter tests good (with your radio shack or mcm
test card), the opto could still not function properly. replacing the
opto is the only thing that will fix it. this is rare and hard to diagnose,
but if everything checks out this could be the problem.
opto board (the opto receiver and transmitter tests good, now what)?
if the receiver tests good with the penlight flashlight, and
the transmitter tests good with the infrared sensor card, there
is one more thing that could be wrong. this would be the opto board.
usually before messing with the opto board i make darn sure that
the optos themselves are not the problem.
i typically do this (for non u-shaped optos) by taking a new opto
(receiver or transmitter), and holding its legs to the back of the
opto board. for the transmitter i can check it with a digital camera
or an opto sensor card. for a receiver i can test it with a penlight
(or the other tests given above). unfortunately if the opto board
has a problem, these tests may not work...
most of the newer wpc games have a seperate board mounted under
the playfield called an "opto board". these have some lm339
voltage comparitor chips and diodes and resistors. if this
board fails it can really confuse the game.
there are many different 'flavors' of these opto boards,
so it's hard to give an exact test for the opto board.
but there are some general things that should be looked at:
make sure the cpu board is not the problem. i always
put the game in switch test t1, remove all the connectors
from the bottom of the cpu board, and cross each switch column/row
(this test is described in the switch matrix section). this
rules out the cpu board as the problem. i always start there.
after eliminating the cpu board as a problem (and reinstalling
the cpu board connectors), i remove all
the connectors from the opto board and make sure the switch matrix
test t1 operates cleanly with no errors (other than the missing
optic switches). if problem free, then the optic board is
starting to look like the problem.
opto board led - there's a red led showing the opto
board has power. it should be on.
opto board has many idc connectors. it is not uncommon
for these connectors to get a wire broken/pulled, causing an
opto (or set of optos) to not work. to test this (game off),
pull one female connector just slightly off its male header.
then use a dmm and check for continuity from one male header
pin to where the wire goes. repeat for all pins.
no continuity, and you have an idc connector problem (very common).
check the back of the opto board and make sure all the
male header pins do not have cracks in the solder where they
attach to the circuit board.
using a dmm set to diode function, make sure all the
1n4004 diodes on the opto board test correctly. they should
read .4 to .6 in one direction, null in the other.
check all the resistors with a dmm.
check the traces from the header pins to the resistor/diodes.
it is not uncommon for a trace to be broken on an opto board.
if everything checks out, that only really leaves one thing
left: the lm339 chips on the opto board.
i generally replace all the lm339 chips (and use sockets!) on the
opto board (there are usually two to four of these chips on the opto board).
unfortunately the lm339 chips are not that easy to test,
since they're dealing with voltage levels. but as long as the
voltage levels on the outputs of the lm339 are stable (not pulsing and not
fluctuating), the truth table for the individual comparators can be
tested with a dmm (inputs) and a logic probe (output).
other problems.
often the source of ground for the 12 volts going to the opto
switches can be tricky to find. and if this ground connection
fails, several or all optos will not work.
for example on indiana jones,
the drop target board and flipper opto boards get their ground from the
fliptronics ii board's j905 connector.
if this connector is bad or removed or off by one pin, there would
be no ground optos ground, and none of the optos would work.
wpc fliptronics flipper optos.
flipper opto boards were implemented on addams family, mid-production.
if a wpc fliptronics flipper doesn't work, and it's not a coil, transistor or
wiring related problem, you should suspect the flipper opto board. this board
has two "u" shaped optos that detects the flipper button. these boards are all made
with two optos, even if the game only has two flippers instead of four.
use the infrared sensor card to determine if the opto is working on the
flipper board. if you suspect a problem with this opto (and don't have
a infrared sensor card), swap the left and right flipper opto boards,
and see if the problem moves to the opposite flipper. note:
both flipper opto boards must be plugged in for this test to work!
flipper opto power is run from the backbox, through the left flipper
opto board, to the right flipper opto board. flipper opto ground is run from
the backbox, through the right opto board, then to the left flipper opto
board. hence both opto boards must be plugged in for them to work!
if indeed one of the flipper optos is bad, and the game only has two
flippers, reverse the two optos on the bad flipper opto board.
one of the optos will be unused since the game only has two flippers,
instead of four. mark the bad opto, and its position on the opto board.
as a general rule, the "top" opto on the flipper board (the opto farthest
away from the two resistors) is the lower flipper opto.
unsolder both optos and move the good opto into the marked (upper)
position on the flipper opto board.
the only problem with doing this is a potential switch error with the
bad opto. even though the second flipper board opto is not used,
many williams games check for this switch, and will report it
as "bad" in the game's power-on test report (even though the game may not use it).
also some games use the "unused" flipper opto for scrolling through the high-score
initials. so ideally it is best to just replace a bad opto instead
of swapping.
weak flippers and bad lm339's on the fliptronics board.
on wpc fliptronics to wpc-s board, chips u4 and u6 (lm339) on fliptronics ii
board can fail. on wpc-95, these lm339 chips are on the cpu board
at locations u25 and u26. this will make
the flipper opto boards seem like they are not work. swap the two
flipper boards to test this. if the problem doesn't change, suspect
the lm339 chip(s). these lm339 chips can
also become "leaky". this will make flippers seem very weak.
a bad lm339 can also give the indication that the eos switch is bad.
if there is a marginal flipper switch reading, this causes the high powered side
of the flipper to rapidly oscillate between on and off. the holding side of the flipper
coil never engages. this problem will cause the flipper coil to get
very hot in a short time.
opto wavelength.
optos come in basically two different wavelengths: 880 nm and 940 nm.
the 880 nm optos came first, but the opto industry has largely
moved to the newer 940 nm wavelength in the last few years.
williams used 880 nm in nearly all applications, but this older
wavelength is harder to purchase today. the newer 940 nm standard
minimizes false triggering from sunlight and incandescent light,
and can operate at longer distances from the opto receiver.
also the newer 940 nm wavelength works better in foul air
(high humidity and polution). the only down side to the new
standard is if the application has a newer 940 nm transmitter,
and an older 880 nm receiver, this can cause problems.
replacement infrared led optos.
the infrared led transmitters have the industry part number qed123 (fairchild,
mot and qt brands). these are 5mm sized leds. the color of the led
will range from pink to yellow to blue. they also have one flat size,
which denotes the "k" (cathode) lead, which is the shorter lead.
the flat side of the led is usually marked on the circuit board too.
the other non-flat side lead should be longer, and is the "a" (anode) lead.
typically in a wpc game, the black switch matrix wire goes to the "k" (flat side)
of the infrared led. the gray wire goes to the "a" lead.
radio shack sells the infrared led (transmitter),
part number 276-143 (or 276-143c), $1.69 (replaces williams a-14231).
also mouser sells fairchild qed123 leds.
replacement photo transistors.
the photo transistor (receiver) have the industry part number qsd124 (fairchild,
mot and qt brands). these are 5mm sized leds. the color of these
are usually black. they also have one flat size,
which denotes the "e" (emitter) lead, which is the shorter lead.
the other non-flat side lead should be longer, and is the "c" (collector) lead.
typically in a wpc game, the orange switch matrix wire goes to the "e" (flat side)
of the infrared led. the gray wire goes to the "c" lead.
radio shack also sells an infrared transistor (receiver),
part number 276-145a (or 276-145), $0.99 (replaces williams a-14232).
when mounting these, the flat edge
goes in the hole furthest away from the hole that has the
notch drawn on the circuit board.
mouser sells the fairchild qsd124 photo transistor.
digikey also
sells a receiver, part number pn104-nd. when installing this
photo transistor remove the center pin before installing.
just wiggled the center lead back and forth until it breaks off at the base.
install this part so the notch at the base lines up with the notch drawn on
the circuit board.
radio shack also sells a combo package with both the receiver and transmitter,
part# 276-142, $1.99. this is
essentially the #276-143 and #276-145 parts combined into one package,
at a discounted price. the word from radio shack is part number 276-142
will change. the the old stock led style transmitter/receiver is discontinued,
and replaced by a "u" shape style opto (though the part number is
still the same). this "u" style opto will work on some unique wpc optos (see the
"radio shack 'u' opto" section below), but nothing else. but lately the
u optos have again been replaced with separate led style optics.
lastly, it has been reported that the radio shack #276-145a
photo transistor is not as sensitive as the stock williams part. apparently if
the distance is greater than two inches between the two optos, often the photo transistor will not
register the infrared led. in conclusion the #276-145a photo transmitter is not sensitive enough,
since using a radio shack #276-143 led and a williams photo transmitter does seem to work at greater
distances. your mileage may vary, as radio shack parts can often be inconsistent.
how can i tell a transmitter from a receiver?
in case you have optos laying around and you don't know if they are
transmitters or receivers, a simple diode test with a dmm across the
leads will reveal which led type it is. a transmitter will check
about 1.5 across the leads one way, open (no reading) the other way. a receiver will
check open (no reading) either direction unless you shine a flashlight on it, then it
will check open one way and shorted (0) when the leads are reversed.
wpc-95's five leg "u" shaped slot optos.
starting with wpc-95, williams changed to a "u" shaped
schmitt trigger opto (five legs in total, three legs on the receiver, two on the transmitter).
the schmitt trigger optos will not oscillate (turn on and off quickly) when
the optics gets dirty/old (they either work, or don't work).
the problem with the older 4 legged flipper optos when dirty/failing was the
oscillation. this would cause the flipper coils to get low amounts
of power continuously during game play (like the player was
pressing the flipper button on and off continuously, and very fast). this
would cause the flipper coils to get hot. it would also
make the flippers weak (because when the player really
did press the button, the oscillation would try and turn
the flippers off very quickly too!).
the older 4 legged "u" optos also caused other problems on games
that used the flippers to control playfield toys. for
example on indiana jones, a dirty/failing flipper optic could cause
the mini-playfield path of adventure (poa) to "stutter" when the
player tried to move it right or left with the flipper buttons.
this was a confusing error because in test mode, the poa
would act normally (because the flipper buttons were not
involved in the test - if the poa stutters in both game and
test mode, the two 4 legged optos on the poa board could also
be bad).
because of the oscillation problem, williams changed to a
five leg schmitt trigger "u" shaped opto with wpc-95. this solved
the dirty/failing optic flipper problem, and
made diagnosing flipper related optic problems easier.
the new five leg optos usually either work, or don't work.
replacement 5-leg "u" shaped slot optos.
the williams part number for 5-leg optics is 5490-14575-00 (or qte734, qt724,
qt850, or qt902 has been seen), and is
called "ic opto integ schmitt 10ma".
replacement five legged optos are available from
mouser #512-h22loi,
which is a fairchild semiconductor part #h22loi.
replacement 4-leg "u" shaped slot optos.
unfortunately, "u" optos are fairly expensive (compared to micro-switches).
for example, if you are repairing your twilight zone clock (which means
replacing all eight of the "u" shaped optos), this can get costly.
the industry part number for the pre-wpc95 four leg "u" shaped optos is
qve11233,
with a standard sensitivity of .0110. unfortunately, williams requires
a higher sensitivity opto for their applications. this means
the cheap $1 optos from most electronic supply houses may not work, as their
sensitivity rating isn't high enough. if you
are shopping for these "u" optos, keep this in mind. you should be looking
for part number qve11233.0086, where .0086 is the increased sensitivity rating.
this is the exact part used in twilight zone clocks, one of williams
most sensitive opto applications. this means a qve11233.0086 "u" opto
should work every where else just fine!
as a side note, the original williams optos were made by
motorola. but around about 1996, they split their opto electronics
division into a new company called qt optoelectronics. then in
early 2001, fairchild bought qt. what does this all mean? well it
means the "original" motorola brand "u" optics are all gone, but there
is a fairly good stock of qt brand "u" optics around (which are
identical to the original motorola brand, differing in name only).
fairchild unfortunately has discontinued the older optic line,
and no longer makes an exact duplicate of the original motorola/qt "u" slot
optos. they do make some similar optos, but the leg spacing and specs are slightly
different (but they may work!)
generic "u" shaped slot optos (qt brand) with the lower
.0086 sensitivity are available from
mouser (www.mouser.com,
part number 512-qve11233, $0.90) and
digikey (www.digikey.com,
part number qve11233qt-nd, $0.90). unfortunately, these
most often do not work in williams pinball applications.
a replacement "u" shaped slot opto that works 100% of the time for sure (and mounts
dot on the opto to the dot on the pcb) is available from
dragster_73@hotmail.com,
prestige industries (800-456-7277
www.pinball4u.com) or
competitive products (800-562-7283
www.competitiveproducts.com).
at about $5 each (qt brand, long leads too,
for the twilight zone clock), these are a very good replacement for nearly
every williams pinball application.
the radio shack "u" shaped slot opto.
radio shack used to sells a "u" shaped four leg opto, part# 276-142, $1.99.
the "new stock" of this part number is not a "u" shaped opto, but is
essentially the led style #276-143 and #276-145 receiver/transmitter combined into one package.
the word from radio shack is the "u" style was discontinued,
and replaced by the led shape style opto (though the part number is
still the same). the old r.s. u opto does work in the twilight zone clock and
in the flipper opto boards (four leg variety, prior to wpc-95), with some minor
mounting modifications. the spacing on the bottom part
of the "u" of the opto is slightly different, and some mounting
adjustments are needed to offset this (especially on the twilight
zone clock).
the old radio shack "u" optics is also a perfect replacement for the
indianapolis 500's lighted target. the style of optic used on this
target is exactly like the radio shack part.
installing the old radio shack "u" optic.
installing the radio shack optic is "backwards".
this opto has a "dot" silkscreened or impressed on its side. normally,
this opto dot should line up with the dot silkscreened on the printed
circuit board. but in the case of the radio shack #276-142, this dot goes
opposite of the circuit board dot.
on the indy500 targets, the board does not have a dot.
instead the dot on the radio shack opto goes to the "a" terminal (instead of the
"c" terminal of the original williams opto). if there is any question you
can confirm the orientation using your ddm. testing with the red dmm lead
on "a" and the black dmm lead on "k". this will show a reading of about "1".
all other combinations get a reading of "0".
on the radio shack optos can not be found for an indy500 fix, drill out the
rivets and remove the "r" opto case from the target board. then take a 4-legged
twilight zone opto and pry off the case. this will expose the "guts", which
can be transplanted to the indy 500 opto board. note the cover does not need
to be put back on the opto.
a williams flipper switch opto board. the "top" (lower flipper) opto has
been replaced. note the "dot" markings on the flipper opto board. many
replacement optos will have a corresponding "dot" or "notch" in the opto,
which aligns with the board's dot. if the new opto does not have a
dot/notch, align the "s" and "+" leg of the opto closest to the circuit
board's dot.
installing "u" shaped optics (other than radio shack's "u" optic).
there are two positions that a "u" shaped optic can be installed.
putting the optic in "backwards" usually does not ruin the optic,
but it will prevent the optic switch from working! many replacement
optics have a "dot" or "notch" on one side of the optic. this
dot/notch should align with the dot silkscreened on the circuit board
(there are exceptions to this, such as the radio shack #276-142 "u" optic,
where the optic's dot goes opposite of the board's dot, but this is a
rare exception, see above).
if the new opto does not have a dot/notch, there should be "s", "e" and "+"
markings on the top of the two legs of the optic. in this case, align the
"s/+" leg of the opto closest to the circuit board's dot.
after the new optic is installed and in the game with the power on,
use the radio shack infrared card to
find the transmitter leg of the optic. the newly installed optic should
have its transmitter leg in the same relative position as the other
original adjacent optic(s).
the "u" optic on the left is an original base mounted williams optic (this one
from no good gofers). this style of "u" optic case is sometimes hard to find.
but the case can be pried apart, reused, and new optic guts placed inside.
the optics on the right are the replacement "guts" for the "u" shaped optic
(taken from a regular "u" shaped optic). the original case is then set over
top and snapped into place. alternatively, the plastic case can be discarded,
as shown here!
"u" optic replacment alternative: reusing the "u" optic case.
the u shaped optic's black plastic case can be reused, and just
loaded with new optics "guts". guts can be taken from other new
"u" optics (that use a different style case), or the optic guts
can be purchased separately. the "u" case pries apart from the
bottom, using a small screw driver. the new guts are then placed inside.
when doing this be careful to identify which is the transmitter
*before* taking the original optic apart. this way the new transmitter
and receiver can be inserted in the same positions, and the case
cover installed with the "dot" in the correct location. in some
applications, the black plastic case may not even need to be replaced
(if there is no risk of a pinball hitting the optics, and no risk of
stray ambient light). gregg woodcock sells these individual optic guts at
users.sisna.com/woodcock/wmsoptos.htm.
the transmitter (gregg's are red) goes into the
spots marked "a" and "k". the receiver (gregg's are clear) goes into
the spots marked "c" and "e".
3i. when things don't work: electronic ball sensors (eddy sensors and magnetic
reed switches)
starting in 1993, williams starting using "eddy sensors" to determine
when a pinball rolled under a portion of the playfield. a eddy sensor
is a electronic switch; it has no moving parts. it can sense when a
steel pinball passes over it, and acts like regular mechanical switch. star
trek next generation (stng), road show and theatre of magic (tom) uses these eddy sensors.
these electronic switches are used in playfield areas where a regular
mechanical switch is not practical or visually pleasing.
an under the playfield eddy sensor control board as
used on roadshow, stng, theatre of magic. note the potentiometer
and led. the connector on the left goes to the actual
under-the-playfiled mounted "sensor" (see pictures
below) that tell this board there is a ball above it.
adjusting eddy sensor boards.
often eddy sensors can go out of adjustment and become less
sensitive. this can cause the eddy sensor to not activate
when a ball passes above it on the playfield. to adjust an
eddy sensor do this:
on the under the playfield eddy sensor control board,
turn the potentiometer counter-clockwise until the led just turns on.
now turn the potentiometer back clockwise until the led just turns off.
that is all that is required to adjust an eddy sensor. to test the
sensor, put the game into wpc diagnostic's first switch test. then
move a pinball over the playfield area where the eddy sensor is
located. the switch should activate on display. also from the bottom of
the playfield, the eddy board led should go on as a ball passes in
front of the eddy board's senssor (this can be seen anytime, the game
does not need to be in switch test.)
different r1 eddy sensor values (fine tuning).
because the ball sensors are different on some games, the
value for r1 on the eddy sensor boards can be different.
for example, on star trek next generation and (two of the eddys on)
theatre of magic), r1 is 4.7k ohms (these games uses the small ball sensor).
but on roadshow and the tom trunk, which
uses a much larger ball sensor, r1 is 2k ohms.
so if you switch an eddy board between these games, the eddy r1 resistor may
need to be changed to the correct value.
the purpose of the r1 resistor is to make the adjustment pot "centered"
for the particular ball sensor. for example, if you use a 2k ohm r1 eddy
board in stng, the adjustment pot will be turned almost all the way up
(with very little adjustment range). it still works most of the time,
just the adjustment range is not centered.
with this in mind, i once had a roadshow where i could not get the eddy board's
led to turn off, no matter where the adjustment pot was moved. normally roadshow
uses 2k ohm r1 resistors for all three eddy boards - but in this case i had to
replace the r1 resistor with a jumper wire (0 ohms). this put the adjustment
pot about dead center, and the eddy boards worked great (with the 2k ohm r1 resistor,
the eddy boards would not adjust, and hence would not work.)
left: the actual sensor that senses the ball. this is a smaller sensor as
used on the outlanes of many games.
right: another type of eddy sensor that senses the ball. this sensor is
used in theatre of magic and covers a wider area.
second generation (auto adjust) eddy sensors.
games made in 1996-1998 (like sacred stiff, cirqus voltaire, monster bash)
use a second generation
eddy sensor. instead of having a potentiometer under the playfield
to adjust sensitivity, these are "auto-adjust" eddy sensors.
this style of eddy sensor is better, as they do not go
out of adjustment. but they also use more logic parts, meaning
more electronic parts to potentially fail.
you can buy replacements for these boards at
pinbits.
the new auto-adjust boards are plug compatible with the older manual adjust
eddy boards (generally speaking), but some resistor values may need to be
changed (again r1).
twilight zone eddy sensors.
the eddy sensor that causes the most trouble in
twilight zone is the sensor by the ball trough (switch# 26).
note eddy sensors were used as early as twlight zone. the eddy
sensors in tz are different than the later sensors, and do not have
an adjustment pot and they are not auto-adusting
(they also are called a different name, like
the "trough proximity" board). on the ball trough sensor, it is actually
two boards: the sensor board, and the driver board (the driver board is
the one with the two molex connectors; a picture of the
two boards is here).
the only adjustment you have
on the tz eddy is moving the sensor board closer to the
ball. this can sometimes fix many problems.
another common tz problem are the molex connectors on the driver board.
just taking the two pin molex connector
off and putting it back on its header pins will usually the problem. if not,
this small board often needs to have its molex header pins resoldered.
the solder joints on the board's header pins can crack.
also, it is possible for the tda0161 (williams part number 5370-13452-00)
chip to die on this board. if you don't want to replace just this chip, the whole
proximity driver board is available for under $15.
modifying your twilight zone eddy sensor.
ray johnson (
http://www.aros.net/~rayj/action/tech/tz_prox.htm)
came up with this cool modification.
it adds a small pc-board trimmer pot to the sensor pc board. this
allows you to always be able to adjust the sensitivity of the sensor.
here are the steps:
buy a small pc-mount trimmer pot. get the lowest resistance rating you can find
(something around 100 ohms would be ideal, but the most common "low rated" pots are
about 1k ohms). some of these small pots can be very, very touchy, so it's best to get one that has a
low resistance rating (like 100 ohms), which allows you a good accurate adjustment.
the average amount of resistance you'll want from the pot is around 20 to 30 ohms, so check
your pot with your meter first to make sure it will let you adjust it easily to this value.
with the power off, remove the sensor board from the game. two hex-head screws hold it to the underside of the
playfield.
on the component side of the board, cut the trace between the connector pin and the sensor.
this is the only trace on this side of the board, so you can't miss it. use a sharp knife,
or x-acto blade, to slice through the trace. use multimeter to make sure there is no
continuity after you've made the cut.
scrape some of the insulation off the trace that leads to the sensor (see image above).
remove enough to adequately solder a jumper wire onto the bare metal of the trace.
click here for a picture of this
step and the prior step.
on the solder side of the board, use a small marker to mark the position of the
three legs of the trimmer pot onto the pc board. drill three holes in the
board through which you will mount the pot. use a very small drill bit (1/16" or smaller).
click here for a picture.
install legs of pot through the holes you drilled in the pc board.
bend the legs on the other side of the board to hold the pot on the board.
click here for a picture.
on the component side of the board, connect two small jumper wires to the pot.
the first jumper wire will come from the back side of the pin on the
connector (the one with the trace going away from it). the other jumper
wire will come from the other side of the trace that you cut, where the insulation was
scraped away. connect the other ends of the jumper wires to the pot. one goes to the middle leg,
and the other goes to either side leg (doesn't matter which side leg).
click here for a picture.
the modification is now done. install the sensor board and the cable that
goes between it and the driver board. with the sensor board installed,
the pot should be easily accessible with a small screwdriver. now power on the game.
with no balls in the ball trough, adjust the installed pot
just as described above (for the newer eddy sensors):
turn the potentiometer until the led just turns on.
now turn the potentiometer back until the led just turns off.
test your work by putting a single steel ball in the ball trough.
the led on the proximity driver board should come on. move the ball away from the sensor and the
led on the driver board should turn off.
magnetic reed switches (beyond eddy sensors).
starting with safecracker and nba fastbreak, williams started using a different ball
sensor switch instead of eddy sensors.
this change came about because the eddy sensor had reliability problems.
even the later self-adjusting eddy sensors were not as reliable as needed.
instead, williams changed to a magnetic reed switch (mrs) with safecracker and nba fastbreak.
this style of switch is contained in a black epoxy package, about 2" long,
and 1/2" wide. like an eddy sensor, it can sense when a pinball is near
the switch. games which used this reed switch include
nba fastbreak, safecracker no good goofers, cirqus voltaire, cactus canyon
and star wars episode i. i believe these are the only games that used the
reed switch.
mrs switches uninstalled, williams part number 20-10293
(the "9937" is a manufacturer date code).
the advantage to the mrs is great; there is no additional
circuitry needed for the switch (unlike eddy sensors).
and mrs switches generally do not break, fail or wear out.
this makes a mrs more reliable and cheaper.
a mrs plugs directly into the switch matrix,
just like a micro switch. it doesn't use an additional circuit board,
or even a diode! williams used the mrs under plastic ramps and under
playfields.
a mrs switch under a cactus canyon ramp.
there are some drawbacks to a mrs though.
first, it does not read a really fast moving pinball as
predictably as an eddy switch. for this reason, often williams
puts two mrs switches in parallel to compensate for this.
also the ball must roll directly over the mrs switch. because the switch
is only 1/2" wide, again two switches are often used in parallel to
make sure the pinball is "seen" by the mrs.
finally, a mrs must be very close to the ball. if mounted
under the playfield, they can only sense the ball through the
thickness of a playfield insert or a plastic ramp, and not through wood (which apparently
is too dense). the mounting for the mrs under the playfield is often two rubber grommets.
if a grommet falls off, this will not allow the mrs to be snug against the playfield, making
ball detection difficult.
3j. when things don't work: ball trough problems (random multi-ball
and bad trough leds)
the ball trough is the area where the balls drain and collect when
a game is over.
up to 1993, williams used a conventional ball trough design. this old
style ball trough used mechanical switches to sense the ball's
presence. it also used two coils to move the balls; one to kick the ball from the
outhole to the trough, and another coil to kick the ball from
the trough to the shooter lane.
starting in 1993 with indiana jones, a new ball trough design was used that
instead relied on gravity to feed the balls into the trough. this saved one coil
(the outhole coil was no longer needed). the new design
also used opto switches instead of mechanical switches. this allowed
one ball trough design to be used in all williams games, regardless of
the number of balls used in the game. the ball trough could now
comfortably hold from one to six balls (depending on the game; most used four to six balls).
the two opto boards used on either side of the ball trough to sense
the balls. note the large blue resistors used on the top board. often
these resistors can vibrate and break. this will give the opto board
false ball senses or no ball senses.
ball trough problems (random multi-ball, drained ball not sensed, game won't start).
when the opto ball trough was first used on indiana jones,
star trek next generation, judge dredd, popeye, and demoman,
william bolted the opto boards right to the side of the
trough. the vibrations from the trough often caused
the leads on the large blue two watt resistors and the infra-red led's
on the opto transmitter board to break. this would cause the
game to start random multi-ball at just about anytime
during the game. often the game would never end (because
the trough would not reconize when all the balls had
drained).
to fix this problem, williams redesigned the attachment
points for the two opto boards. instead of being bolted
directly to the trough, the mounting holes on the opto
boards were enlarged (and one hole moved). then
rubber gromets where inserted into the holes, and
short metal tube bushings where inserted through the rubber gromets.
when the opto board bolts where tightened down, they tightened on
the metal tubes. this allowed the opto boards to "float"
on the rubber gromet, reducing vibration considerably.
also be aware that on star trek next generation if
fuse 103 on the power driver board is blown
(3a slow blow), the game will not start and will constantly throw
out balls. fuse 103
powers the solenoid which controls the upper diverter on the
under-the-playfield diverter. without a working diverter, the game can't
load the balls where it wants, and the game will attempt to
load and reload balls continually.
also another tip concerning indiana jones:
check the front right switch on the bottom side of the mini playfield. balls
hit it underneath and mash the wires/diode/switch lugs together creating
a short. since this mini-pf switch is in the same row as the ball trough
jam opto in the switch matrix. this can cause the game to continually kick
out balls because the machine thinks the ball jam opto has a ball in front of it,
and kicks out another.
the front right mini-playfield switch on indy jones. this switch's leads often get
crushed by flying pinballs, shorting them together. this can cause all kinds of switch
matrix problems including continual multi-ball and switch matrix confusion (multiple
switch closures by a single switch closure).
later opto board design.
to make the opto boards more resistant to vibration,
starting with world cup soccer 94, williams moved all the electronics
off the opto boards and onto a separate board. this meant that only
the optics were on the trough opto boards, and no other components.
no longer could the large blue two watt resistors crack from trough vibrations.
unfortunately, indy jones, star trek next generation, judge dredd,
popeye and demoman all use the older ball trough opto boards with the
easy-to-break blue resistors and bad mounting design.
check the shooter lane switch.
though usually not the problem with random multiball (a closed shooter lane switch
does not get the ball to the shooter lane), it's a good idea
on most wpc games to make sure this switch is in good condition
and working. use a ball to test the switch (in switch test t.1).
ball trough divots (indy jones to cactus canyon).
another problem with the new ball trough design is
"divots". as the pinballs fall into the ball trough from the playfield,
they eventually make divots into the metal. this
can cause the balls to hang and not roll the length
of the ball trough and down to the shooter lane upkicker
coil. all sorts of weird game problems can occur from this.
the most common is trying to start a game by pressing the start button, and
the game responds with "pinballs missing", or a game
that doesn't end when the ball drains. random multi balls can
be caused by this problem too.
at first look, where the balls fall from the playfield into the
trough would seem to be the problem. but that really is not the
big problem; where the balls rest in the trough "v" slot can develop very
small divots or nicks in the metal. all these newer game use four to
six balls, and often a pair of nicks in the metal can exist where
each ball rests in the trough!
to fix this, a dremel tool or a hand file can be used to grind
the divots out of the metal. after the nicks are ground out smoothly,
sand the sides of the "v" in the trough smooth with 220 or 320 sandpaper.
if this doesn't work, order a new ball trough, part number a-16809-2. this
newer design of the ball trough should last longer and
divot less.
on the left blue circle is where the balls slam down into the trough.
but the big problem is the two smaller blue circles, center and right.
these very small nicks will stop the balls from rolling down the trough
as a single ball is fed to the shooter lane. these causes all the balls to
hang and not roll the length of the ball trough.
buying a ball trough mounting upgrade kit.
if you want to upgrade your indiana jones to demo man ball trough
to the current board mounting design (which can help solve random multi-ball
problems), order an upgrade kit, part# a-18244.
this includes two new opto boards, and all the mounting
hardware needed (the mounting hardware is absolutely
necessary). at $50, this is an expensive kit!
modifying the existing trough boards mounting instead.
modify the existing trough boards can be done for
much less money. the parts can be ordered from williams:
(6) metal bushings, 3/16" outside diameter and 3/16" long, williams part# 02-4975, $0.28 each.
(6) rubber grommets 3/16" inside diameter and 1/4" to 7/16" outside, williams part# 23-6626, $1.02 each.
(6) trough board mounting screws (same #6 size/thread as the originals, just 3/4" long).
these parts can be bought locally. rubber grommets can be bought at any decent
hardware store in the electrical department. the inside diameter grommet hole
(the important part) is 3/16". the outside diameter can vary from 1/4" to 7/16".
the metal 3/16" bushings can be bought at hobby shop that sells
3/16" brass or aluminum tubing (usally in 12" lengths), used for hobby applications. this
tubing cuts easily with a dremel cut-off tool, or for $5, most hobby shops also
sell small tubing cutters (easier to use than the dremel). buy metal
tubing which fits easily but snuggly inside the 3/16" rubber grommet (3/16" or even 5/32"
outside diameter tubing). the longer 3/4" #6 trough board mounting screws are also required,
and are a standard hardware store item.
the rubber grommets and metal tubing which
goes inside the grommets. three grommets/tubes
are needed for each of the two optic boards.
after buying the above parts (either from williams or elsewhere),
drill or use a hand remer and make the trough optic board
holes bigger, about 1/4" (or up to 7/16", depending on the
outside size of your rubber grommets). be careful you don't drill
through any board traces (this should not be a problem). also, drilling
the center hole is optional;
mounting with just two (outside) of the three holes per board
works fine too. insert the rubber grommets
in the enlarged holes, and put the metal tubing inside the grommet.
the metal bushing should be just very slightly shorter than the width of the
rubber grommet, no longer. this allows the board bolt to tighten down
on the bushing, but leaving a bit of "play" in the board (which the
rubber grommet gives).
more random multiball: the ball trough optic resistors.
on indy jones, star trek next generation, judge dredd, demo man, and popeye,
the ball trough optic boards have several large blue resistors mounted to them.
since these boards get a fair amount of shock and vibration from balls,
often these resistors can crack or break. if this happens, random
(and continual) multiball can result. check these large blue power resistors for
breaks or cracks. usually the resistor leads break right where they
connect to the circuit board.
do not try and repair the resistors; just replace them. they are 270 ohm 2 watt
resistors (do not replace with a version less than 2 watts). these are available
from digikey, part number alsr3j-270-nd,
$1.37 each. nte/ecg sell these too
at many local electronic part houses for about 99 cents a pair.
ball trough optos.
the ball trough optos also commonly break from ball vibration and wear. every optic is
a pair; a transmitter (which gives off infra-red light), and a receiver (or photo transistor, which
sees the infra-red light). the receiver rarely goes bad. the transmitter optics
are on the trough board closest to the coin door (lucky for us, as this board
is easiest to access). the transmitter optic is available from radio shack,
part number 276-143c, $1.69. this replacement optic transmitter is blue in color,
and works fine as a replacement. gregg woodcock also sells yellow trough led infrared transmitters at
users.sisna.com/woodcock/wmsoptos.htm,
for $1 each. in either case,
this part should only be installed one way. printed
on the circuit board is a round circle with a flat side. the optic also has a flat
side, which should match the circuit board.
the receiver optic is also available from radio shack,
part number 276-145a, $0.99. this receiver is clear, unlike the williams
receiver. the flat edge of the receiver needs to be mounted closest
to the top edge of the circuit board. that is, the flat edge
goes in the hole furthest away from the hole that has the
notch drawn on the circuit board. digikey also
sells a receiver, part number pn104-nd. when installing this
photo transistor remove the center pin before installing.
just wiggled the center lead back and forth until it breaks off at the base.
install this part so the notch at the base lines up with the notch drawn on
the circuit board.
the new williams ball trough and the blue resistors.
if using the newer metal trough #a-16809-2, and using all three mounting holes,
it will also be necessary to move one of the large blue
resistors to the back of the board, and drill a new center position mounting hole in the
opto board. another option (and spending $50 is not an issue),
order the upgrade kit from williams, part# a-18244, and get the two
new trough opto boards and the mounting hardware. or use the existing trough boards
with just the two outside mounting holes. if drilling the current
trough boards is not an option, they can always be mounted with two of the three holes instead.
this works fine too.
bad ball trough connectors.
another ball trough problem can be related to the connectors used on
the ball troughs. again, due to vibration, the solder joints for the circuit board header pins
can crack, causing intermittent connections.
to fix this, reflow the solder on the connector pins on both trough boards.
testing the ball trough optos.
after modifying the trough boards and grinding the divots out of the trough,
i connect the transmitter and receiver boards to their connectors. now i
dim the lights to the room, turn the game on, and go to
the first switch test t.1. using a radio shack or mcm
infrared detector card (or a digital video or digital still camera),
check all the transmitter led infrared optos to see if they are working.
after that is done, shine a small pocket flashlight or tv remote control into each of the
receiver board detector optos. they should register in the t.1 switch test
(room needs to be somewhat dim for this; ambient room light can
also activate these). turn the game off and assembly and install the
trough board on the trough, and install the trough back in the game.
now it's time for another test, one that is especially good to verify your
work, or to test the trough if you have not modified it.
with all the balls removed from the game,
turn the game on and go to the first switch edge test t.1.
most switches should show with a dot, indicating the switch as open (a sqaure
indicates a switch is closed). but on optic switches, a blocked opto is a dot,
and an unblocked opto is a square (opposite of what one would expect).
there should be a number of squared switches, indicating the opto trough switches
(check your game manual for exact switch numbers).
if your switch matrix has no squares (all dots),
your playfield has lost the +12 volts powering the optic switches.
check fuses f115 and f116 (f101 and f109 on wpc-95) on the power driver board.
now slowly roll a ball down the trough and watch it cause a square
in the switch matrix to turn into a dot, as the ball rolls past each ball trough optic.
when the ball is resting at ball trough optic one,
physically push up on the ball lane shooter solenoid
(that would kick that ball onto the playfield). this will cause that "trough jam" opto to
turn to a dot. this opto only sees the ball as it gets kicked out,
or if there are two balls jammed so they are sitting on top of each other at the right
end of the trough.
fill up the trough completely with balls, then remove the balls manually,
one by one. try this a few times to see if you can isolate any of the ball
trough squares which are not turning to dots consistently.
lastly, remove all balls from the trough and close the coin door. press the flipper buttons
to activate the flippers while still in switch edges test. look for flickering square-to-dots
on the ball trough column on the display. this tests flipper vibrations
which can cause intermittent
flickering on the opto switches. now continue checking for bad optos by hitting the
playfield with the meat of your fist near the flippers (it's not as bad as it sounds!)
if any of the squares flicker to a dot,
there is some vibration related problem (broken/cracked blue resistor or opto lead, or
cracked header pin solder joints). if nothing has appears, leave the game in
this test mode for 20 minutes (note some games will exit test mode automatically
after 15 minutes) with no balls in the game. be close by, within listening distance.
if you hear the game "bong" that means a switch has opened/closed in the switch test.
go to the game and
check the score display, as the last switch closed will be reported. see if this is a trough
opto switch number. if so, it is a flakey opto or bad opto board resistor or bad
connector. this "time test" allows the game to 'warm up' too,
which often the other tests don't account for.
if all the trough switches change from squares to dots when the optos are blocked
with a ball, and there is no flickering when the
playfield is vibrated, and the game doesn't report any random switches in test
mode for 20 minutes, the opto boards have test good. if there are still random multi ball
problems, there is most likely a divot problem in the ball trough (see above).
here a ball trough transmitter opto board is being tested outside of
the game using an external 12 volt dc power supply. there are seven
infrared leds here, but the one with the red arrow is not lighting. check
for a bad blue power resistor, broken traces, or even a bad opto itself.
note the digital camera this picture was taken with shows the infrared
light quite well.
pic by tx.
testing the ball trough transmitter board outside of the game.
the ball trough transmitter board needs +12 volts dc to operate, and nothing more. because of
this, the ball trough transmitter board can be tested outside of the game
using an external 12 volt dc power supply. also needed is some way to
"see" the infrared light coming from the transmitter leds. a digital camera
with a viewing screen works well, or a radio shack/mcm electronics infrared
card.
3k. when things don't work: dot matrix/alphanumeric score displays
dot matrix displays are one of the coolest features on a wpc game. they
provide the score and graphic animations, and even video games within
the pinball game. note that the first three wpc games (funhouse, harley davidson, the machine)
used the older style alphanumeric displays.
wpc alpha numeric score display problems.
the first three wpc games that used alphanumeric displays have a common
problem. the resistors r48 and r49 (39k ohm) on the alphanumeric display board
often fail and go open, or go out of spec. this can cause all the score displays
in the game to work very weak, or not work at all. before replacing a score
display, replace both of these 39k resistors with "flame proof" 1 or 2 watt
versions. see the williams system 11 repair guide at
http://marvin3m.com/sys11/index3.htm
for more information
on repairing alphanumeric score displays. all the information there applies
to these three wpc games (though the component label numbers will be
different).
a dot matrix display on the way out. notice the absence of
some characters in the display (on the right side).
dot matrix displays and "outgassing".
the unfortunate part about dot matrix displays (dmd) is they wear out.
time will eventually kill these, and the display will "outgas"
and fail. because of the high voltage involved with score displays,
the anode and/or cathode inside the diplay glass breaks down. this results in the "outgassing"
of impurities that eventually change the internal gas properties, so the display
won't glow (the gas must be very pure for the display to work). often the
gaps that don't light up at power-on will gradually come on as the display warms up.
this happens because as the existing gas warms up, it expands.
a new display will solve this problem, and is easy to get and replace (a 5 minute job).
these do cost a bit of money though at about $115 each (complete). there is
no way to fix an old "outgassed" display.
when a dmd starts to get blurry or displays gaps, the rumor is the power requirements
for the display increases. it turns out this rumor is actually incorrect,
at least as far as the high voltage (-120 and +65 volts) is concerned.
the hv (high voltage) power
used by a display is directly proportional to the number of
dots lit on the display. if a display is entirely outgassed and not lighting (even
though the cpu is asking the display to lit), it will
consume no more hv (high voltage) than a working display that is not lit.
kirb did some test of various displays and metered the results, proving this.
but what about the 5 volt consumption? unfortunately we did not do enough
testing of the 5 volts to draw any conclusions. but based on reports of
outgassed displays causing game resets (stressing the 5 volt supply),
it is reasonable to think that an outgassed dmd does consume more 5 volt power.
another interesting fact is that certain dmd makes consume more 5 volt
power than others. the biggest 5 volt power hog is dale/visay, consuming
nearly twice what other dmd displays use.
regardless, i still encourage people to buy a new display if theirs
is outgassed. the 5 volt power stress, particularly on games like
twilight zone, can cause potential game reset problems.
buy an entire dmd display glass and board, or just a new glass?
a new dot matrix glass only can be purchased, which will also solve
the "outgassed" problem. these are available for about $65, which is almost
half the price of buying both the display and its attached circuit board.
but trust me on this, don't be cheap;
just spend the extra money and get both the display and
its attached circuit board. installing a new glass into
the surrounding board is a lot of work. and games produced in 1993 and later
don't have "pin" style glasses, so these display glasses alone are not replacable.
even if a display has the "pin" style glass, it's just not worth the trouble
to unsolder 132+32 pins, install the new glass, and resolder all those
pins again. it's a solid two hours worth of eye straining work, and
it's very easy to make a mistake. it's just not worth the trouble.
are all dot matrix displays the same?
the short answer is "yes". but be aware dmds come in different sizes.
williams always used the 128x32 column/row variety (dataeast for
example used a 128x16 and a 192x64 display, in addition to 128x32).
and yes a 128x32 dot matrix display from a gottlieb, sega, dataeast
or stern game will work in any dmd wpc/wpc-s/wpc-95 game or
vice-versa (but note
that dataeast/sega/stern have an additional controller board bolted
to the back of their 128x32 dmd, which is not used on a williams wpc game).
also it should be stated that some brands of
dot matrix displays (like babcock) require 12 volts to operate, and most others don't.
i have seen problems where a dmd requiring 12 volts won't operate in a game,
but one that does not require 12 volts will work.
can the dot matrix display itself be fixed?
this is a tricky question. sometimes the display itself
fails due to problems other than an "outgassed" score glass.
the controller chips on the display glass' circuit board can die
(they are static sensitive). this usually causes "garbage" to be
displayed. other problems i have seen includes
delamination of the surface mounted parts on the score display glass'
circuit board (often this is fixable). and the power .156" header pins
on the display itself can have cracked solder joints, causing the
display to not work (though sometimes these are nearly impossible
to resolder, because the display glass is in the way!)
example a ribbon cable problem on a wpc game (demo man). can you tell it
says, "game over"? reseating the ribbon cables often fixes this. click on
the picture below for a larger version, and note the dark spots in the corners
of this display - this is an indication the display is starting to outgas.
note it's not just the display ribbon cables, but also the other ribbon cables
like the one between the cpu and driver boards.
another example of dmd garbage that was fixed by reseating the ribbon
cable between the driver and cpu boards.
picture by wil.
blank, strange garbage, or diagonal lines on the dot matrix display
(re-seating ribbon cable connectors).
this problem can be caused by a bad dot matrix ribbon cable. a blank
display (assuming all the fuses are good and voltages are present) is
usually a backwards installed ribbon cable from the dot matrix controller
to the dmd itself. garbage or diagonal lines is typically a problem with
the large cable running from the cpu board to the fliptronics board to the
sound board to the dot matrix controller board.
the ribbon cable connectors are gold plated, and sometimes require
a "reseating" (remove and re-install) of their connectors to "clean" them.
since these are gold plated connectors, reseating is an acceptable means of
cleaning a gold plated connector. (all the non-ribbon cable connectors in the game
are *not* gold, and if reseating "fixes" a problem, that means the connector
board pins and housing pins need to be replaced! see
pinball connector web page for more info on that.)
example a dirty or removed ribbon cable from the dot matrix controller board
to the dot matrix display itself. reseating the ribbon cables often fixes this.
when reseating the ribbon cables, be careful not to re-insert the ribbon
cable one pin off. this is very easy to do, making pins 1,2 hang
off the side of the mail connector (or cable pins 1,2 connected to board pins 3,4).
this will cause additional problems like garbage display (but luckly all
are fixed with the proper reseating of the ribbon cable connector).
also note the red line on the ribbon cable - this indicates pin 1 of the
cable, and it should align with the white arrow or "1 2" silkscreened on the
circuit board. luckily the only ribbon cable connector that can be easily
installed "backwards" is the ribbon going from the dot matrix controller
board to the display. if this cable is installed "backwards", usually the display
is blank, showing nothing (like the display does not work).
here's what happens if the sound board ribbon cable is connected one row
of pins off-center.
also be aware that an over-zealous previous owner may have runined a
ribbon cable connector when it was reseated. it is very easy to rip the
ribbon cable away from the connector,
making the game do some very strange things (usually the
diagonal lines are a symptom of this). so be careful when reseating
ribbon cable connectors.
finally, random vertical or diagnal lines could be caused by
12 volts not getting to the dot matrix display. this voltage
comes directly from the driver board (see "testing dmd voltages"
below for diagnosing this problem further). also some dot matrix
displays (babcock in particular) require 12 volts to operate,
where other brands do not need 12 volts.
missing vertical or horizontal display lines are missing.
another common problem is missing display lines in the dmd score display.
this is very common with the "pin" style dmd display glass. this type
of dmd glass has pins, bent at a right angle, that solder into the
attached dmd circuit board. often these pins break, due to vibration,
right where they attach to the display glass' edge.
because of this problem, all the dmd manufacturers have changed to
a very flat ribbon cable style of connection between the display glass
and the attached circuit board. this largely solved the problem.
if missing some lines, and the score display glass is a "pin" style,
often the pins can be reattached to the display glass using a conductive
silver epoxy. this often works well, but is a difficult repair. it usually
does not work if more than two horizontal and/or two vertical pins are
broken.
diagnosing other dot matrix problems.
if you are sure the display itself is working, there are some
other things to check when a dmd doesn't work.
make sure to check fuses f601 and f602 (all wpc games). f601 is
used for +62 volts, and f602 is used for -113, -125 volts (or -103, -115). on wpc-s
and before, these are 3/8 amp fast-blo 1.25" fuses (originally
williams used slow-blo fuses here, but about 1994 they changed
to fast-blo, so either fast or slow-blo can be used).
on wpc-95, these are t0.315 amp 5x20mm fuses.
the dot matrix display circuit is the same in all wpc generations!
even though there are three different wpc dot matrix controller boards,
the dmd voltage circuit is nearly identical.
click here for the high voltage dot matrix display
controller board schematics (showing part references for all generations of wpc dot matrix display
controller boards).
it's easier to test voltages at the dot matrix display itself than at the
controller board. use the "key" pin for reference to figure out which is
pin 1 and pin 8.
testing dmd voltages.
if the fuses are good on the dot matrix controller board (or audio/visual
board for wpc-95), you should next check the power at
the dmd itself. voltages used are +62, +12, +5, -113 and -125 (or -103 and -115),
or within +/- 10% of these values.
check these voltages at the dot matrix display
with the display connected, or at connector j604
on the controller board. the pin out at the dmd is:
pin 1: -125 volts (-110 to -130 volts); williams lowered this voltage to -115.
pin 2: -113 volts (-98 to -118 volts); williams lowered this voltage to -103.
pin 3: key
pin 4: ground
pin 5: ground
pin 6: +5 volts (4.9 to 5.2 volts)
pin 7: +12 volts (10 to 14 volts)
pin 8: +62 volts (58 to 68 volts)
all voltages should be pretty much right at the above specs,
or within +/- 10%. in regards to the -113, -125 volts (or -103, -115), these two
voltages need to be 12 volts apart - that's the important part.
that is, if -98 and -110 volts are measured, those two voltages
are fine. if -118 volts is measured,
the other voltage should be -106 volts.
if they are not within 12 volts of each other, the dot matrix controller's
high voltage section probably needs to be rebuilt.
if the -125 volts is missing, -113 volts will be missing too.
if the +62 volts is above 70 volts, chances are good someone
jacked up this voltage by changing the dmd controller 1n4759 zener diode to compensate
for an outgassed dot matrix display (very common on games imported
back to north america from other countries).
if any voltage is low, try disconnecting the power connector to the
dmd, and re-measure the voltages. if they return to the correct voltages,
the display is bad or the high voltage section on the dot matrix controller
board is failing and can't handle the power draw of the display.
remember the voltages created by the dmd controller card
are -125, -113 (or -115, -103) and +62. the +5 and +12 volts come from the
driver board. if the 5 volts is
missing yet the game boots, there's a connector problem.
if 12 volts is missing there's either a connector problem,
or the dot matrix display itself is "sinking" the 12 volts
(disconnect the dmd power connector and see if the 12 volts
comes back up, if so the display is bad or maybe the driver board 12 volt
section is failing). or the 12 volt driver board section is failing.
(measure the 12 volts at the driver board, and then at the installed
dmd, if the voltage is different there is a connector problem.
if they are both the same voltage and are below 10 volts,
there is a driver board 12 volt problem).
lowering the -125 and -113 voltages to -115 and -103 volts.
at some point williams lowered the -125 and -113 voltages to
-115 and -103. this was done to increase the life of the score display.
just keep this in mind when measuring these voltages. the important part
is these two voltage must be 12 volts apart.
both the -125 and the -113 volts are the same voltage.
the dot matrix display will not work if both the -125 volts
and -113 volts (or -115 and -103) measure as the same voltage.
these two negative high voltages should be 12 volts apart.
the difference in voltage occurs because of diode d6 (d3 on wpc-95), a 12 volt 1n4742
diode. the failure of this diode also kills
transistor q7 (known as q7 in all wpc generations, a mje15030).
also check resistor r8 (4.7k ohms 5 watts), if this is bad
the two negative voltages will be the same.
the -125 volts and -113 volts must be 12 volts apart, or the dot matrix
display will not work!
the +62 volts drops to +12 volts under load.
when this happens, check transistor q3 (all wpc
generations). this transistor has probably shorted. also check
diode d3.
the +62 volts is not +62 volts.
on wpc-s and earlier games, the positive dc voltage trace that comes from a
very small bridge rectifier br1 is physically routed underneath resistor r9
(1.8k 5 watt resistor).
because of the heat generated by this 5 watt resistor, and the current
drawn from the bridge rectifier, this circuit board trace can become
burnt and break underneath resistor r9. because the trace physically runs under
this resistor, the broken trace can be hard to see. if the +62 volts is
not +62 volts, check this trace.
if the +62 volts is above 70 volts, chances are good someone
jacked up this voltage by changing a dmd controller 1n4759 zener diode to compensate
for an outgassed dot matrix display (very common on games imported
back to north america from other countries).
the -125 volts is too high.
another problem is the -125 volts (or -115) is too high, reading instead -140 volts.
the usual cause of this problem is a broken trace on the
circuit board. these traces are fragile, and the high voltage
section of the dot matrix controller can get very hot, and burn
them. use your dmm set to continuity and check all traces.
negative high voltage low, dmd barely lights.
negative high voltage reads -102 and -93 volts, and the display barely lights.
dmd high voltage controller section was just rebuilt, so that was ruled out.
checked resistor r6 or r26 on wpc95 (47k ohms) and it was open.
also checked resistor r4 or r30 on wpc95 (120 ohms) and it read 1k ohms
(had to unsolder and lift one leg to test them).
after resistors replaced, high voltage went up to -112 and -100 volts,
and the dmd was nice and bright.
rebuilding the dot matrix high voltage (hv) section.
if the fuses are good, and the display itself is
good (tested in another game), it is time to rebuild the high voltage section of the dot matrix
controller board. but before doing that, raise the playfield and inspect
all the connections from the transformer in the bottom of the cabinet.
though a rare problem, one of the connectors may have come apart or became oxidized.
after all else is checked, the best idea is
to just replace everything in the high voltage section
(parts also listed at dmdhv.htm).
note all these parts are also available in kit form from
great plains electronics
for around $6 per kit.
this is a *very* economical way to rebuild the dot matrix high
voltage section. the parts to replace includes:
q6 (mje15031 or nte55): controls the -125 volts (and supplies voltage
to the -113 volts).
q7 (mje15030 or nte54/buv27/buv28): controls the -113 volts.
q3 (q1 on wpc-95, mje15030 or nte54/buv27/buv28):
part of the +62 volt section.
q4,q5 (mpsd52 or 2n5401/nte288): part of the -125 (or -115) volt section.
q2,q10 (q2,q3 on wpc-95, mpsd02 or 2n5551/nte194): part of the +62 volt section.
d4,d5 (d1,d18 on wpc-95, 1n4758 or nte5090, 56 volts): part of the -125 (or -115) volt section.
d6 (d3 on wpc-95, 1n4742 or nte142, 12 volts): part of the -113 (or -103) volt section.
d3 (d2 on wpc-95, 1n4759 or nte149, 62 volts): part of the +62 volt section.
q1 (2n3904, wpc-s and prior only).
r4,r5 (120 ohm 1/2 watt). usually ok, but replace if they look burned.
check/replace the resistors too.
also check the resistor values. resistors either
work or do not work, and are easily tested (unlike the above transistors).
all resistors should be within 10% of spec. replace any
resistors that are out of tolerence or that appear burnt. the 5 watt
resistors take the most abuse; if these are working yet cracked, replace
them! always mount resistors slightly above the board to allow air flow below them.
on all these resistor, replace if they look at all damaged, even if they measure ok.
1.8k ohms, 5 watts: r9 on wpc-s and prior (r44 on wpc-95).
4.7k ohms, 5 watts: r8 on wpc-s and prior (r43 on wpc-95).
120 ohm, 5 watts: r11 on wpc-s and prior (r28 on wpc-95).
120 ohm 1/2 watt resistors at r4, r5 wpc-s and prior (r30, r31 on wpc-95).
47k ohms 1/2 watt at r3, r6, r12, r13 on wpc-s and prior (r25, r26 r27, r29).
an alternative to rebuilding the hv section.
if the inexpensive hv rebuild kit from ed at
www.greatplainselectronics.com
is beyond one's technical skills,
there is an alternative to rebuilding the high voltage section. that is to
purchase a pre-fabricated board which essentially does the same thing. the
dmd-hvp (dot matrix display-high voltage power) board is available from
www.pinball-parts.com
for about $60. this plugs into and overlays the existing dmd controller board,
replacing the original high voltage section on the original dmd controller board.
installs in about five minutes with no soldering. if the original high voltage
section is blown on the original dmd controller board, it does not matter (as this
completely replaces it). a good alternative for those that have more money
than time, or limited soldering skills. only works on pre-wpc95 games though.
i have some minor critisms with the dmd hv board though. for example, they use the
smaller wpc-95 style fuses. now this would be ok if the board worked on wpc-95
games. but since it does not, it puts a mix of fuse sizes into a wpc game
that otherwise don't use this smaller fuse size. this is bad for the end
consumer that may have a supply of stock wpc hv fuses, which now won't work in
their game! also, i feel there should be leds for each of the high voltages
to show at a glace that -125 volts, -113 volts, +62 volts (and perhaps the
+12 volts and +5 volts) were working on the board.
dmd components by voltage.
here are the same list of components, organized by voltage. if only a particular
voltage is missing from your dmd, only these selective components can be replaced
(not recommended):
-125 volts: mje15031 transistor q6 (all wpc versions). mpsd52 transistors q4, q5
(all wpc versions). 1n4758 diodes d4, d5 (d1 and d18 on wpc-95). all these components supply voltage to
the -113 volt section too. hence, replace the -113 volt components too.
-113 volts: mje15030 transistor q7 (all wpc versions). 1n4742 diode d6 (d3 on wpc-95),
which drops the -125 volts down to -113 volts.
+62 volts: mje15030 transistor q3 (q1 on wpc-95). mpsd02 transistors q2, q10
(q2, q3 on wpc-95). 1n4759 diode d3 (d2 on wpc-95).
the biggest tip when fixing the high voltage.
the single biggest tip when fixing the high voltage section on the dmd
controller is this: replace everything. this is a high voltage section.
this means if all parts were replaced except for one bad part, this
bad part can cause all the others just replaced to immediately fail!
it's just not worth the trouble. rebuild the whole high voltage section,
and replace everything. in the long run money and time will be saved.
example of a "cloudy" dot matrix display.
cloudy dot matrix display.
cloudy display problems are strange. the display can test perfectly
in the internal "line" dot matrix test. but when large areas or
inverted graphics are shown, the display is "cloudy".
this is usually caused by heat related problems. fixing this could
be as simple as adding new white heat sink compound to the three heat sinked mje transistors.
also make sure they are tight to their heat sink. check the three large
5 watt resistors too. if they are more than 5% out
of spec, replace them (see above). lastly, cold solder joints in the high voltage
section can also cause cloudiness. try reflowing the solder joints on the
5 watt resistors, the high voltage diodes, and the high voltage mje transistors.
if none of this works, rebuilding the high voltage section should solve this problem
(see above).
wavy hum-bar, bounce, or horizontal roll on the dot matrix display.
the "wavy hum-bar", graphic "bounce, or horizontal roll seen on the dot matrix
display's images can be bad dmd power filter capacitors.
on wpc-95, these are caps c28, c42 on the audio visual board.
on wpc-s and earlier, these are caps c4, c7 on the dot matrix controller
board. these original capacitors were 150 mfd 160 volts. this value is
somewhat hard to find, but can be replaced with the more common 220 mfd
160 volt electrolytic caps (remember going up in value on electrolytic
capacitor's voltage and/or capacitance is ok, but never go down).
if 220 mfd caps are used instead of the 150 mfd, don't get ones
that are too large (due to their weight, vibration can crack the
capicator's solder pads, essentially removing those new capacitors
from the circuit!)
additionally, if there is still a "wavy hum-bar" or horizontal
roll or a display "bounce", try replacing
the smaller high voltage filter capacitors. on wpc-s and earlier, these are
capacitors c6, c9 and c10 (.1 mfd 500 volts) on the dot matrix controller board.
on wpc-95, these are caps c29-c31 (.01 mfd 200 volts).
if these caps fail, hum bars or roll can occur. as the game warms up
the wave, roll or bounce may change (get better or worse).
crystallized solder joints.
if a dmd display is not displaying correctly, and the voltages
seem ok, also check this. it's common for the solder joints
on the zener diodes in the power section to crystallize, causing
heat damage, excessive resistance, and finally a lost of
voltage regulation. this can then lead to a failed dmd and damaged
power circuits. these diodes are d3, d4, d5, d6 (d1, d2, d3, d18 on wpc-95) on the dot matrix
controller board.
a bad 6264 ram chip on the dmd controller board can cause this problem
(verify it's not the dot matrix display itself first though!)
dmd columns stuck "on".
if there is a column or two stuck on (as seen in the picture above), chances
are good the 6264 dot matrix controller card ram at u24 (wpc-s and prior)
has failed. of course
this assumes that the dot matrix display itself is not the problem (try the
display in another game to verify). if not the display itself, replace
u24 (wpc-s and prior) with a new 6264 ram chip, and this should fix the problem.
missing lines on a dmd display.
the first generation of dot matrix displays used pins to connect
the dmd glass to the dmd circuit board. due to vibration, often
these pins would break right where they meet the display glass.
this would give the display a "missing" vertical or horizontal
line (depending on which pin broke). and often more than one pin
would break, making an otherwise good display nearly useless.
this problem was solved with newer dmd score displays that used
a short thin flexible ribbon cable instead of the pins.
on displays with broken pins,
there isn't enough material to solder the pins back to the
display glass. but another technique can be used instead.
this involves "conductive epoxy", and essentially gluing the
broken pin to the score glass. the conductive epoxy has silver
powder in it, so it conducts well. and it's the only way to
get a broken pin attached back to the score glass. usually one
or two broken pins can be repaired in this manner (trying to do
much more than three seems to not work well!) just be careful
not to short two pins together with the epoxy. success rate is
certainly not 100%, but it usually works. the epoxy is expensive
though, because of the silver powder in the glue.
i have also used conductive epoxy to fix the thin ribbon cable
variety of dmd displays with missing lines, where the ribbon
cable has ripped away from the display glass. the success rate is
not as high, but it can work.
using conductive silver epoxy to fix a missing line on a dot matrix display,
where the metal pin broke away from the edge of the display glass. note
this display uses both the ribbon cable (at the circuit board) and the metal
pins (at the display glass). but the conductive epoxy can be used to repair
either style (pins or ribbon), but the success ratio is higher on metal pins.
problem: dot matrix display got blurry.
when i was playing my twilight zone, the dot matrix display
started to become very blurry. within 5 minutes the display became
almost unreadable. the dots to the left and right of the active
ones started to flicker.
answer: the asic chip on the cpu board was not making good contact to
its socket. the asic chip is the large square chip on the cpu board. after removing the chip
and cleaning all of its pins, and reseating the chip in the socket,
the problem went away. another thing to try is reseating the board ribbon
cables in their sockets.
problem: funhouse alphanumeric display, character 16 was mimicking every
segment being displayed in the other 15 characters.
answer: if this is happening in display one, replace chip u8 (6184 anode drive)
on the wpc display driver board. if happening to display two, replace chip u5 (6184).
problem: my twilight zone's dot matrix display shows random vertical
lines. at first it was just occassionally during game play, but now they appear from
the moment i power on the game. the problem has gotten worse, and
now every time i turn on the machine, all four flippers
energize.
answer: the problem was a bad ribbon cable. there is a single ribbon
cable that goes from the cpu board to the fliptronics board to the
sound board to the dot matrix controller. if the ribbon cable was
mis-installed by one pin, or the cable has torn at its connector,
this problem can happen. the ribbon cable houses the address and
data lines to the fliptronics, sound and dot matrix controller.
often the ribbon cable's connectors can just be dirty, so reseating the
connectors sometimes fixes this problem. if the ribbon cable is
damaged, mis-installed or the connectors are dirty,
strange things like this can happen.
another potential cause could be the lack of 12 volts getting to
the dot matrix display controller board.
3l. when things don't work: power-on leds and sound beeps
cpu board led flashes.
a simple diagnostic led (light emitting diode) flash pattern exists on all generations
of wpc cpu boards. these flashes can signify a problem and what
might be causing the trouble. they can be seen immediately when
powering on the game. led's exist on both the cpu and driver
boards, but only the cpu board's led have a diagnostic flash
pattern. on wpc-s and earlier cpu boards, the led's
are labeled d19 to d21. on the driver board and all wpc-95 boards,
they are labeled "ledx" (with "x" being the led number).
cpu board led flash codes, all revisions.
wpc-s and prior uses a "dx" designation for its cpu leds. wpc-95 uses a "led20x" designation.
d19/led201 (blanking): at power-on should be on for about 3 seconds (1 second on wpc-95),
and then turn off and stay off.
when d19/led201 is on, the blanking circuit is disabled (and will not allow any coils to be energized).
d20/led203 (diagnostic): after d19/led201 turns off, d20/led203 should stay flashing permanently while the game
is turned on. this indicates the cpu is "running".
d21/led202 (+5vdc): this led should always be on. it indicates the cpu has +5 volts dc power.
problem power-on cpu d20/led203 (diagnostic) flash codes. if d20 does not flash continually,
here are the flash codes diagnostics:
blinks one time: u6/g11 cpu game rom bad
blinks two times: u8 cmos ram chip bad
blinks three times: u9 wpc custom chip bad (pre wpc-s), or g10 security pic chip bad (wpc-s and later)
wpc-s and prior driver board leds, test points (tp), and fuses.
for reference, tp5 is ground.
led1/tp3: +12 volts dc switch matrix circuit. should be always on. if off,
check fuse f115. this is often caused by a bad cpu board chip u20 (see the switch
matrix section for more details).
the ac power originates at connector j101
pins 4,5 and 6,7. it then goes through fuse f114, bridge br1,
capacitors c6 and c7, led6/tp8 (18 volts dc), diodes d1 and d2, voltage rectifier q2,
fuse f115, led1/tp3 (12 volts dc), then to connector j114 pins 1,2.
also, just before diodes d1 and d2, the circuit splits to the lm339 chip u6,
and led2/led3.
led4/tp2: +5 volts dc digital circuit. should be always on. if off,
game will not boot. check fuse f113 (or bridge br2 and capacitor c5).
though not likely to fail, there is also a voltage regulator lm323 at q1,
a lm339 chip at u6 ("zero cross"), and two 1n4004 diodes at d3 and d38.
the ac power originates at connector j101
pins 1 and 2. it then goes through fuse f113, bridge br2,
capacitor c5, voltage rectifier q1,
led4/tp2 (5 volts dc), then to connector j114 pins 3,4.
note after fuse f113, the ac power also continues to diodes d3 and d38, and to
lm339 chip u6. then this "zero cross" power merges back into the +5 volt line
before hitting connector j114.
led5/tp7: +20 volts dc flashlamp circuit. normally on. twilight zone and later,
this led fades off when the coin door is opened. if off, check coin door and fuse f111
(or bridge br4 and capacitor c11).
the ac power originates at connector j102
pins 1,2 and 3,4. it then goes through fuse f111, bridge br4,
capacitor c11, led5/tp7 (20 volts dc), then to connector j107 pins 5,6 (and j106 and j108).
led6/tp8: +18 volts dc lamp matrix circuit. normally on. if off, check fuse f114
(or bridge br1 and capacitors c6, c7). though not likely to fail, there is also
a voltage regulator lm7812 at q2, a lm339 chip at u6, and two 1n4004 diodes at d1 and d2.
the ac power originates at connector j101
pins 4,5 and 6,7. it then goes through fuse f114, bridge br1,
capacitors c6 and c7, led6/tp8 (18 volts dc), diodes d1 and d2, voltage rectifier q2,
fuse f115, led1/tp3 (12 volts dc), then to connector j114 pins 1,2.
also, just before diodes d1 and d2, the circuit splits to the lm339 chip u6,
and led2/led3.
led7/tp1: +12 volts dc power circuit (motors, relays, etc). should always be on.
if off, check fuse f116 (or bridge br5 and capacitor c30).
the ac power originates at connector j112
pins 1,2 and 3,5. it then goes through fuse f116, bridge br5,
capacitor c30, led7/tp1 (12 volts dc), then to connector j118/j117/j116 pin 2.
tp6 (no led): +50 volts for the coil.
the ac power originates at connector j102
pins 5,6 and 8,9. it then goes through fuse f112, bridge br3,
capacitor c8, tp6 (50-70 volts dc), then fuses f103/f104/f105 (and f102/f102),
then to connector j107, j106 j108, and j109.
led2 (no tp): this led is not always installed.
high/low line voltage sensor. normally on, but flickers with the playfield lamps.
led3 (no tp): this led is not always installed.
high/low line voltage sensor. normally off, but flickers with the playfield lamps.
wpc-95 driver board leds, test points (tp), and fuses.
for reference, tp107 is ground.
led100/tp100: +12 volts dc regulated. should be always on. if off, check
fuses f101 and f106 (or diodes d11-d14 and capacitors c11, c12).
if fuse f101 has failed, this is often caused by a bad cpu board
chip u20 (see the switch
matrix section for more details). though
not likely to fail, there is also a voltage regulator lm7812 at q2,
and two 1n4004 diodes at d1 and d2. if fuse f101 has failed, suspect
the voltage regulator q2. the ac power originates at connector j129
pins 6,7 and 4,5. it then goes through fuse f106, diodes d11-d14,
capacitors c12,c11, led102/tp102 (18 volts dc), diodes d1-d2, voltage rectifier q2,
fuse f101, led100/tp100 (12 volts dc), then to connector j101 pins 1,2.
led101/tp101: +5 volts dc digital. should be always on. if off, game will
not boot. check fuse f105 (or diodes d7-d10 and capacitor c9). though
not likely to fail, there is also a voltage regulator lm317 at q1,
a lm339 chip at u1, and two 1n4004 diodes at d23 and d24.
the ac power originates at connector j129
pins 1 and 2. it then goes through fuse f105, diodes d7-d10,
capacitor c9, voltage rectifier q1,
led101/tp101 (5 volts dc), then to connectors j101 pins 3 and 4,
j138 pin 4, j139 pin 4, j140 pin4, j141 pin 4.
led102/tp102: +18 volts dc lamps. normally on (can flicker with playfield lamps).
if off, check fuse f106 (or diodes d11-d14 and capacitors c11, c12).
the ac power originates at connector j129
pins 6,7 and 4,5. it then goes through fuse f106, diodes d11-d14,
capacitors c12,c11, led102/tp102 (18 volts dc), diodes d1-d2, voltage rectifier q2,
fuse f101, led100/tp100 (12 volts dc), then to connector j101 pins 1,2.
led103/tp103: +12 volts dc un-regulated. should be always on. if off, check fuse f109
(or diodes d3-d6 and capacitor c8).
the ac power originates at connector j127
pins 1,2 and 3,5. it then goes through fuse f109, diodes d3-d6,
capacitors c8, led103/tp103 (12 volts dc), then to connectors
j138 pin 2, j139 pin 2, j140 pin 2, j141 pin 2.
led104/tp104: +20 volts dc flashlamps. normally on. this led fades off when the
coin door is opened. if off, check coin door and fuse f107 (or diodes d15-d18
and capacitor c10).
the ac power originates at connector j128
pins 1,2 and 3,4. it then goes through fuse f107, diodes d15-d18,
capacitors c10, led104/tp104 (20 volts dc), then to connectors j133 pin 5 and 6,
j134 pin 5.
led105/tp105: +50 volts dc coils. normally on. this led fades off when the
coin door is opened. if off, check coin door and fuse f108 (or diodes d19-d22
and capacitor c22).
the ac power originates at connector j128
pins 8,9 and 5,6. it then goes through fuse f108, diodes d19-d22,
capacitors c22, led105/tp105 (50-70 volts dc), fuses f102, f103, f104,
then to connectors j134 pins 1,2,3, j135 pins 1,2,3.
sound board error beeps pre wpc-dcs
(wpc alpha-numeric, wpc dot-matrix and wpc fliptronics.
1 beep: sound board ok
2 beeps: u9 sound rom failure
3 beeps: u18 sound rom failure
4 beeps: u15 sound rom failure
5 beeps: u14 sound rom failure
sound board error beeps wpc-dcs and wpc-s.
1 beep: sound board ok
2 beeps: u2 sound rom failure
3 beeps: u3 sound rom failure
4 beeps: u4 sound rom failure
5 beeps: u5 sound rom failure
6 beeps: u6 sound rom failure
7 beeps: u7 sound rom failure
8 beeps: u8 sound rom failure
9 beeps: u9 sound rom failure
wpc-95 audio/video led.
led501: +5 volts dc, normally flashing (but at a slower rate than cpu led203).
problem power-on audio/visual board beep error codes:
1 beep: audio/visual board ok
2 beeps: s2 sound rom failure
3 beeps: s3 sound rom failure
4 beeps: s4 sound rom failure
5 beeps: s5 sound rom failure
6 beeps: s6 sound rom failure
7 beeps: s7 sound rom failure
10 beeps: audio/visual board's static ram bad
3m. when things don't work: "factory settings restored" error (battery
problems)
often when you buy a used wpc game, upon power up, you'll get an error message
stating, "factory settings restored". this message indicates that the cpu ram chip
at location u8 on the cpu board has forgotten the game's bookkeeping and options settings.
most often, this error occurs because the three "aa" batteries on the cpu board have
died. these batteries should be replaced every year with good quality alkaline batteries
(batteries are cheap, battery damage is expensive).
the three batteries must keep at least +4 volts of power to the u8
ram chip for it to remember. when power goes below +4 volts, memory reset can occur
(and you get the "factory settings restored" error message).
a bad battery holder. at first glace, this holder looks fine.
but the two battery contact points on the left have corroded
and fallen off. the contact on the right is the only one intact.
these contact points are actually rivets, but corrosion will
cause the face of the rivet to break as it goes through the
fiber insulator, and the face of the rivet that contacts the
battery falls off.
changing batteries.
if your game is working, and it's time to replace the batteries, follow
this procedure:
remove the backglass and gain access to the cpu board.
turn the game on.
note the orientation of the installed batteries (all positive terminals up, or
to the right on wpc-s).
remove the old batteries and discard.
check the battery holder's terminals for any corrosion (they can be clean with 220 grit
sandpaper if any corrosion). if damaged, turn game off and replace battery
holder.
using a sharpie pen, write today's date on the new batteries.
install the new batteries.
turn the game off.
if you install new batteries with the game turned on, the machine will not
forget the old option settings or bookkeeping totals.
more on installing batteries and measuring their voltage.
on all flavors of wpc (except wpc-s), the batteries install with the positive
terminal (the terminal with the "tit") up. on wpc-s, batteries
install with the positive terminals to the right. to not lose the
game's memory and firmware settings, new batteries can be
installed with the game powered on (assuming the old batteries
are removed with the game on too). after the new batteries are
installed, turn the game off.
now measure the voltage with a dmm to make sure then are connecting
to the battery holder properly. put the black lead of the dmm on the lower
left battery holder solder point (or on wpc-s the upper left), and the red lead on the upper right
battery holder solder point (or on wpc-s the lower right). about 4.5 to 4.8 volts dc should be seen.
the battery holder: a weak link.
if after replacing the batteries, you still get a "factory setting restored" error
when turning the game on,
suspect the battery holder. use your dmm and check the battery voltage
at the cpu board. with the game off, put your dmm on dc volts and
put the black lead on ground (the grounding strap or on one of the screws
holding the cpu board in place, or the bottom left battery terminal).
put the red lead on each of the cpu board's positive
battery terminal solder points (positive is the "up" side of each battery).
test each of the three batteries' positive leads
individually, starting at the left. you should get about 1.5, 3.0, 4.5 volts at each battery
(note the batteries are additive and the first battery in the chain will
give you 1.5 volts, and the last battery will give you 4.5 volts).
if you don't these positive voltages, suspect damaged battery holder terminals.
these corrode quite often if new batteries aren't installed religiously.
replace the battery holder and re-test to ensure proper repair.
a battery gone bad on a wpc game. note the
white "fur" on the bottom of the battery, and
how it has corroded the chip and socket below it.
the battery holder, chip and socket must all be
replaced. also the board must be washed with a
mixture of 50/50 water and white vinegar (a mild
acid) to neutralize the alkaline battery, and then
rised with water. after drying, the corroded areas are
sanded clean to the bare copper traces, and the
components replaced. if the board isn't washed with
this vinegar solution, the corrosion will return.
the best battery holder to buy for any wpc game is the new black plastic battery
holder used in wpc-s and later games. this is williams part# a-15814. this design
of battery holder is much better than the pre wpc-s design.
remote battery holder.
another excellent solution to potential battery corrosion problems is
to install a remote battery holder. this way if the batteries do fail
and leak, the damage is limited to a $1 battery holder. the cost of
replacing an entire cpu board because batteries have leaked and
corroded the board is too big of a risk for me personally. though
it doesn't happen a lot, if you have ever had to fix battery corrosion,
it's a lesson you will not soon forget. because of this i have
installed remote battery holders in all my wpc games. they cost less
than an original style wpc battery holder, and it's good insurance.
i personally use a four "aa" battery holder, using the fourth battery cell area
for a back-up blocking diode and
as the screw area (to do this i put a 1n4004 or 1n5817 diode
with the band towards the red wire, where the fourth
battery would be located). the four aa battery packs seem to be
easier and cheaper to find, but of course only use
three batteries! install three "aa" batteries, and
then solder the red positive wire of the remote holder to the
cpu board's main positive battery holder trace, and the black
lead of the remote holder to the cpu board's opposite
main negative battery holder trace (see pictures below for
installation in wpc-89, wpc-s, and wpc-95). on wpc-89 and wpc-95,
the main positive battery terminal is at the upper right of the
original battery holder,
and the main negative terminal is at the lower left.
on wpc-s the main positive battery terminal is at the lower right,
and the main negative at the upper left.
some people ask why i put the "blocking diode" in my 4 "aa" battery
holder? well it is not required, but i put the blocking diode
in as a backup diode (which prevents the cpu board from trying
to charge the aa batteries when the game is on). the other
advantage to this is the added blocking diode slightly decreases
the voltage from the batteries. this is like an advance alarm clock
for me, where the game will tell me when the batteries are getting
low (opposed to them totally dying and leaking, and then i find out i need
to replace them!) using a common 1n4004 diode will give
the most voltage drop (about .4 volt). this decreases the battery
voltage just enough that the game will give me a "factory settings
restored" error just before the batteries are totally dead - which
is exactly what i want!
using an inexpensive four aa battery holder, a in4004 or 1n5817 blocking diode,
& three aa batteries as a remote battery holder for the cpu board. on wpc
games the diode is not required, and a wire can be used instead. a 1n5817
diode is used instead of a 1n914 or 1n4001 because of the forward voltage
drop is less with the 1n5817 diode. but i actually prefer a 1n4004 as an
"auto alarm" when the batteries are getting low.
remote battery holder installed in wpc-89 game.
remote battery holder installed in wpc-s game.
remote battery holder installed in wpc-95 game.
is power getting past the battery holder? (bad diode d2 or ram u8)
if the battery holder is ok, next check to see if power it getting
past the battery holder. find cpu board diode d2 (all wpc revisions); this is a small glass diode,
right next to diode d1. on wpc-s and prior, look to the right of the
big square chip u9. on wpc-95, look just below the battery holder.
with your game off and new batteries installed, put your ddm on dc volts and
put the black lead on the backbox ground strap. then put the red lead
on diode d2 on the cpu board. the banded side of the diode should show
about .5 volts less than the non-banded side (which should be about 4.3 volts).
if only one side of the diode shows voltage, or both sides show the same voltage,
this diode is bad. diode d2 is a 1n4148 or 1n914 diode.
next test for voltage at the cpu u8 ram chip (all wpc revisions).
with the game off, you should get about 4.3 volts dc at pins 26, 27 or 28 of
chip u8. if you don't, the battery voltage is not getting to the u8 ram chip,
and the game will boot up with the "factory settings restored" error. note
pin 28 of the 28 pin u8 chip is in the same position as pin 1 of
the chip, but on the opposite row of pins. pin 1 is designated with an
impressed "dot" right on the top of the chip.
there can still be problems even if a new batteries are installed and all the
voltages check out. if the game is still giving "factory setting restored" or
"set time and date" errors, there may be a bad cpu u8 ram chip. this does
happen where a bad u8 ram will suck the life out of new batteries, causing
them to go dead in one to four weeks. but make
sure to double check that battery holder. even minor corrosion can cause
this problem. the voltages may all check out, but the corrosion may be enough
to limit current, and cause this problem. the u8 ram chip is a 6264-l or 2064 ram
chip.
batteries die too quick.
batteries in a wpc game usually last for years. if the batteries in a game
die quickly (a few days or a few weeks), the d1 diode is probably bad.
if the d1 diode has failed, the batteries are trying to power up the
entire cpu board (instead of just the u8 ram). this will drain the
batteries quickly. find diode d1 (all wpc revisions); this is a small glass diode,
right next to diode d2. on wpc-s and prior, look to the right of the
big square chip u9. on wpc-95, look just below the battery holder.
also check and test diode d2.
with your game off and new batteries installed, put your ddm on dc volts and
put the black lead on the backbox ground strap. then put the red lead
on diode d2 on the cpu board. the banded side of the diode should show
about .5 volts less than the non-banded side (which should be about 4.3 volts).
if only one side of the diode shows voltage, or both sides show the same voltage,
this diode is bad. diode d2 is a 1n4148 or 1n914 diode.
batteries are hot!
another problem can occur where the batteries get hot. so hot, they
can melt the covering off of them! if this is not fixed, the batteries will
surely leak, or even explode. this happens when the game tries to charge the batteries,
while the power is on. the problem is usually diode d2 (1n4148).
does the battery power anything else?
actually yes it does! besides the ram chip at u8, the
battery also supplies voltage to the large square asic
(application specific integrated circuit) 84 pin chip at u9
in the plcc (plastic leaded chip carrier) socket.
because the 8-bit 6809 microprocessor (the brain behind
wpc, on the cpu board) is such a bad time keeper, the time information
for the wpc clock is generated in the u9 asic chip.
a dmm can be used to measure the battery voltage on the asic
chip at pins 1,22,43, and 64. if 4 volts dc is not seen at these
pins, suspect the plcc socket for the square u9 asic chip.
these delicate sockets can corrode easily from leaking batteries.
the wpc asic chip pinout.
my game's time clock is slow!
there is an internal time clock that keeps the time and date for the wpc system.
within the game's adjustments, you can turn the clock display on, so it shows
the time and date on the dot matrix display. on twilight zone, this internal time clock
is used during attack mode to set the playfield clock.
if you notice the wpc time clock running slow (losing time), or the game
just won't remember the time (boot up error of "set time and date"),
the batteries are getting weak and need replaced. if you still
have this problem with new batteries, suspect the battery holder's terminals.
they may be corroded enough to cause resistance, and lower the voltage
at cpu chip u8.
3n. when things don't work: lightning strikes
all william's wpc pinball games are very durable commercial devices.
they are well protected against voltage surges from lightning storms.
there are several lines of defense against voltage surges:
excellent grounding
mov (metal oxide varistor)
line fuse
power transformer (all voltage goes through a transformer)
bridge rectifiers
if the power line to your wpc game is struck by
lightning, usually this will take out the line fuse and the mov.
damage beyond this is extremely rare.
to repair your game, you will have to replace both the line fuse
and the mov.
the mov lives inside the "power box".
the mov is the green disc soldered across the
lugs of the radio frequency interference filter.
the mov (metal oxide varistor) is designed to have high resistance.
but when its rated voltage is exceeded, it internally shorts.
this immediately blows the line fuse and halts the power
to the game, saving everything but the line fuse and the mov itself. smaller
voltage surges are absorbed by the mov without total destruction (though
lots of small surges can eventually destroy a mov and make it short).
the mov is located inside the cabinet's metal power box, next to the coin
box. if you need to replace it, here are
the values needed:
north america (115 volt power): 150 volt or 130 volt mov.
europe (220/240 volt power): 275 volt mov.
the rating is the voltage at which the mov will short.
lower voltage ratings will provide more protection. but
remember the power supply circuits have other protections from high
input voltages too. so don't select a voltage too low, or
you'll be replacing the mov often from small voltage surges.
radio shack sell mov's that
work well in wpc games.
3o. when things don't work: sound problems.
the pre-dcs a-12738 sound board.
williams' pre-dcs (pre-indian jones, funhouse to twilight zone)
sound board is part number a-12738.
this is sound board has a 68b09e cpu chip, ym2151/ym3012 8-voice fm sound synthesizer (8-bit sound hardware)
a ad-7524 dac for processing 8-bit digital samples, and a 55536 cvsd chip for speech.
the wpc a-12738 sound board has similar features to the system11 d-11581 sound board,
but with much greater rom memory space (allowing more speech and sound).
the i/o circuitry is improved as well, allowing more control of the sound
board by the cpu board.
line-out.
the pre-dcs a-12738 has "line out", through connector j509.
this is a tap into the mixed analog signal
(from all three sound generating devices) before it going
to the volume control and final output amplifier circuits.
connector j509 pin 1 is the analog ground, and
j509 pin 3 is the analog sound out.
unfortunately a bit more needs to be done then just tapping into
connector j509 to get a usable "line out".
on pre-dcs games on the component side of the sound board,
lift resistor r102 on the side which connects to pin 3 of j509. on the back
of the sound board, connect a jumper wire between the negative
side of capacitor c21 and the plated-thru hole left of resistor r102 (which
connects to pin 1 of j509).
this will give a functional line-out at j509 with the pins indicated above.
the line-out you get from this modification
is a fixed level and does not get changed by the volume control.
to get a line-out on a wpc dcs game (pre-wpc95),
add a two pin .156" molex header to the sound board connector j6
(the left pin is audio and right pin is ground).
on wpc-95, just add a two pin header to sound board connector j509
(left pin is ground and right pin is audio).
note the line-out on dcs and wpc95 sound boards is
directly controlled by the volume control buttons inside the coin door.
volume control.
the pre-dcs a-12738 sound board also features a volume control chip (u5, an electronic z-pot) which allows
software commands for controlling volume. on the sound board an option exists
so the operator can install a conventional resistor-pot volume control.
to do this,
remove a-12738 sound board jumper w9 to disconnect the
software controlled volume circuit. then
connect a potentiometer (any value 5k to 200k ohms should work) to connector j507:
j507 pin 2: to center pot leg
j507 pin 4: to outside pot leg (analog ground)
general sound repair tips.
the sound on wpc games is very robust; it just doesn't fail
too often. but here are some things that do fail related to sound:
no sound or intermittent sound? check the speaker in the bottom panel of the cabinet.
if one of the leads is off the speaker, or the speaker is broken, sound
won't get to the other speakers (hence silence)! sometimes the bottom
speaker wire connectors are intermittent too. so when a solenoid fires, the
sound can cut off and on.
re-seat all the sound board ribbon cables. surprisingly, this
fixes a large number of wpc sound problems!
check the eprom chips for bent pins and incorrect insertion!
this is very common. the
eproms are about the only socketed chips on the sound board, and often
people will remove/replace/update the chips. and sometimes in their
haste, when the chips are plugged back into the sockets, a pin or two
may bend over (underneath the chip), or bend outside of the socket.
if this happens, just unplug the chip, straighten the bent leg, and
reinsert carefully. a worse problem is if the eprom chips is plugged into the socket
"backwards" (notch on the eprom not matching the notch on the socket).
this will ruin the eprom chip. in either case, bent pin(s) or backwards eprom
chip(s) can cause the sound board to not work at all (no sound),
or to work intermittently.
speakers blown: yes this happens more often than you might think.
if the game was in a noisey arcade, the volume could be up so loud
it blows the speakers. you can test the speakers (with the game
off) using a 9 volt battery. momentarily hook the battery up to the
leads of the speaker. you will hear the speaker cone pull in if
the speaker is good, when you attach the battery to the speaker.
make sure you check the speaker in the bottom of the cabinet too.
often if one speaker is blown, the others will not work.
main amplifier is bad: on pre wpc-dcs games, the sound board uses a lm1875 as the
main amplifier. this device has a large heat sink attached to it.
often, this component has heat failure. the sound works fine until
the game warms up for five minutes or so. then the sound starts cutting
in and out. you can use a logic probe on the leads of the lm1875.
if the probe's beeps correspond to the cut in sound on one of the leads,
the lm1875 is probably bad. the lm1875 is at u1 on the wpc audio board (not used on wpc-dcs or wpc-95).
main amplifiers are bad: on wpc-dcs and wpc-95 games, the tda2030a amps
are pretty fragile too. on wpc-dcs this is at u27 & u28, on wpc-95
at u5 & u6 (not used on pre wpc-dcs games).
check both of the tl084 op-amps too.
depending on the revision of the sound board,
these audio amps can effect a certain type of sound they amplify.
on wpc these are at u7 & u8, on wpc-dcs at u21 & u29, and on wpc-95
at u1 & u2.
bad rectifier diodes on the sound board. often these become
leaky and can cause intermittent problems before they total short.
volume up full and can't turn it down.
the volume control on all wpc games is electronic. on pre wpc-dcs games, this
is controlled by an electronic prom pot. this e-pot is a x9503, at location u5 on the
sound board. if turning the volume up or down has no effect, and the volume
is stuck on full blast, this is the first component that should be checked.
also the capacitor c18 (47 mfd, 25 volts) that connects to the e-pot can fail too, and should
be checked. as described above, the electronic volume control can be disabled by
removing a-12738 sound board jumper w9 to disconnect the
software controlled volume circuit. then
connect a potentiometer (any value 5k to 200k ohms should work) to connector j507:
j507 pin 2: to center pot leg
j507 pin 4: to outside pot leg (analog ground)
static noise and loud whistle.
problem sound boards can produce a large amount of static. the tl084 quad op-amp (u7 & u8 on wpc,
u21 & u29 on wpc-dcs, u1 & u2 on wpc-95) can be the cause of this.
also the tda2030a (wpc dcs and u5 & u6 on wpc-95) amp can also cause this.
finally the large filtering 4700 mfd or (or 10,000 mfd on wpc-95/wpc-dcs)
35 volt capacitors can also be the problem.
aldo check for cracked solder joints on these large filter
caps (solder jumper wires, as done to the bridge rectifiers explained earlier).
another problem i saw on a wpc dcs sound board was a really high pitch
whistle as soon as the game was powered on (in this case jackbot).
the volume control did not the whitle volume, and the game play sound could
be heard behind the whistle. the whistle was so loud and obnoxious
it was difficult to have the game powered on for more than a few
seconds.
first thing done was to isolate the cpu from the amplifier section.
this was done by removing the ribbon cable from the sound board,
and by removing the sound eprom. this way the sound board could not
execute any code, and the cpu was basically detached from the
amplifier. the whistle contined, indicating the problem was not
in the processing of the sound, but in the sound amplification.
looking at the schematics showed that the only things really
not involved in computer processing of sound is the pair of tl084
op-amp chips and the tda2030a ampifiers. in this case it was a
bad tl084 causing the problem.
static/minor hum and the sound board filter caps.
these are often the cause of minor sounds problems such as hum and
static. cracked solder joints at these capacitors is common.
soldering jumper wires from the pcb traces directly to these
capacitors' legs often solves many problems (as described previously
on the power driver board's bridges and capacitors).
wpc-95: c36 and c37, which are 10,000 mfd at 35 volts.
wpc-dcs: c20 and c21, which are 10,000 mfd at 35 volts.
wpc: c24 and c25, which are 4700 mfd at 35 volts.
static & scratchy/tinny sound on early wpc-95 games.
early wpc-95 games (sacred stiff for example) have two capacitors installed at
locations c47 and c51 on the a/v board. these two capacitors are located
between chips u5/u6, and near connectors j505/j504. with later
wpc-95 games, these two capacitors were *removed*. if an early wpc-95 game has
some static noise or just thin tinny scratchy sound,
a good first step is to completely removed these two capacitors.
it doesn't cost anything to remove them, and often provides a solution to the
static.
intermittent sound cuts and shrieks.
after playing a wpc game for a while (5 minutes or longer), the
game sound starts to cut out or in some cases it will emit an extremely loud tone
that can get louder and louder until the speaker (or your eardrum) blows. if you
turn off the game and re-start, the problem will appear again very shortly.
sometimes you can play a while and it never happens. often the heat
sink attachment to the tda amps can be very poor and cause the amp(s) to overheat.
you can feel the amp(s) get red hot. solution is to simply un-bolt the sinks,
re-grease them and re-attach, making sure to use a locking washer or kep nut
to stop it from coming loose.
tda2030a amp chip.
this is a fragile chip used on wpc-dcs and wpc-95 games. it comes in
two flavors; the tda2030 and the tda2030a. you want the tda2030a version,
as the tda2030 does not have a high enough power rating, and can
distort under higher volumes.
loud hum from the speakers.
problem: a loud hum from the speaker which does not change in loudness
as you change increase the game's volume. this is often caused by the
large filter caps on the audio board (as discussed above). for early wpc games, this
is capacitors c24 & c25. on wpc-dcs games, this is capacitors c20 & c21.
and on wpc-95, this is capacitors c36 & c37.
to fix this problem, check for cracked solder joints on the leads
to these capacitors. it is a good idea to solder jumper wires to
the two capacitor's leads to ensure good continuity (like you
did on the driver board's large capacitors).
"popping" sound, hot lm1875, and speakers shorting.
problem: pre-dcs sound board works, but eventually shorts the speakers. first the speakers
start to "pop" (not very loud), every second or so. eventually the speakers short and are ruined.
also the sound board's lm1875 heat sink gets very hot.
dc voltage was measured at the speakers, and found to be 40mv (there should be no dc voltage).
solution: at first the lm1875 was thought to be bad. but the real problem was the capacitors
feeding the lm1875. caps c46-c47 (1 mfd tant), c20 (10 mfd), c22 (22 mfd), c23 (.22 mfd)
were replaced, and the problem was solved. also the lm1875's heat sink now ran cool.
the giveaway here was the dc voltage at the speakers, pointing to the capacitors.
there should be zero dc volts at the speakers. as little as 5mv dc at the speakers
can cause the lm1875's heat sink to run hot.
replacement speakers.
all speakers in a wpc game are 4 ohms. no other speaker value should be
used in these games.
the most common speaker to die on a wpc game is the backbox tweeter (right
speaker, as playing the game). this is a small 3.5" speaker with a capacitor
attached to the negative speaker terminal (the capacitor is the "cross-over",
which filters out all but high frequency sounds).
a quick and dirty replacement tweeter is available from radio shack, part #40-1233, $9.95.
though this is a 3.75" tweeter, the holes can be enlongated slightly to fit the 3.5" bolt
pattern.
the 6" speaker in the bottom of the cabinet can be replaced with a pinballpro subwoofer. see
www.pinballpro.com for
details. they also sell replacement speakers for the backbox.
sound board interface error and sound rom checksum problems.
this is a fairly rare problem. when the game is powered
on, a "sound board interface error" or sound rom checksum message is shown on the display.
often the game will seemingly work otherwise.
first thing to try is reseating all the ribbon cable connectors.
past this, usually the problem is a bad sound rom.
if the error is still present, turn the game off and remove all the
sound roms from the sound board. turn the game on, and instead of the
one power-on "bong", you should hear two "bongs". turn the game off,
and replace the first sound rom (u9, u2, or s2, depending on the
wpc generation). turn the game back on, and three "bongs" should be
heard. keep adding roms one at a time. if there is a problem with
one of the sound roms, a checksum or soundboard interface error message will be displayed
when the problem rom has just been installed. if this happens, replace the rom
in question.
blown sound board fuse.
user states, "on my t2 machine the sound board a-12738-(50013 in this case) kept blowing
fuse f501 on power up. i traced this down to a shorted diode d2. i suspect
that any of the diodes d1-d4 would cause these fuses to blow on any of the
a-12738 sound boards."
i accidentally shorted -125 volts on the av board, and now
my wpc-95 game will not turn on.
this immediately blew fuse f602 (wpc-95, -125/-113 volts), and
burned resistor r30 (wpc-95), which i replaced. if the audio board is plugged into
the game, the game will not start! after checking the +5 volts
at the audio board, i noticed it measured 3.5 volts. if the
audio board is disconnected, the +5 volts measures 5.02 volts,
and the game will boot fine (except for the lack of sound).
in this case, do the easy things first. with the game off, remove all the eproms from
the sound board. then try your game again. the game will complain with a "bong bong",
signifying a sound board rom problem. but if the game turns on fine otherwise,
you know one of the sound eproms is bad.
unbalanced speech and music.
here's a story from phil brown:
i decided to swap the sound boards between my addams family and funhouse to see if the problem
would follow the board or stay with the machine. after i'd done it, i started a game on
addams and noticed that the speech and drum effects were much louder than the music, as if
the balance betwwen them had been changed. i then started a game on funhouse and found
the opposite - it was much harder to hear rudy's speech over the music. this got me
curious and i had a look at the schematics in the funhouse manual for the sound board.
it seemed that there are four sound outputs, cvsd, ch1, ch2 and dac. just before the
point where they are mixed, they travel through four resistors, r22-r25.
in the schematics, r25/r22 are 150k, and r23/r24 are 120k ohms. r23/r24 are on the
outputs of ch1 and ch2, which i presume is the music. the other two are on the outputs of
cvsd and dac, which i presume are the speech and sound effect outputs. i also checked
the schematic in the wpc theory of operation book and found the same thing.
then i had a look at the parts list in the funhouse manual and the taf manual - that's
when my theory was confirmed. this is what i found:
r# schem. funhouse addams
r25 150k 120k 120k
r24 120k 150k 56k
r23 120k 150k 56k
r22 150k 120k 120k
so, at least for these two machines, williams has changed the resistor value to change
the balance between speech/sound effects and music. on funhouse they have biased the
sound toward speech, and on addams towards music.
this means that wpc audio boards are not quite as
interchangable between machines as thought, although they work, both addams and funhouse
sound very different.
3p. when things don't work: general illumination (gi) problems.
note this section does not cover general illumination burnt connectors.
see burnt gi connectors (and wpc-95 gi diodes) for
that information.
the single biggest problem with wpc general illumination.
beside burnt connectors (see burnt gi connectors for
that information), the single biggest problem with wpc gi is broken driver
board traces! yea sure, the gi connector pins got replaced on the driver
board, but were the freshly soldered pins checked, one by one, for continuity
to the fuse holders and to the triacs? i see this problem constantly where the
connectors were replaced, but the plated through holes for the replace
connector pins have cracked. new connectors pins are great, but if they
don't have continuity to the triacs or fuse holders, the gi will not work.
in all the driver boards i have fixed, i have never seen a failed triac.
but i constantly see broken traces at the header pins, preventing the gi
from working.
it is really simple to check. just use a dmm set to "buzz" (low ohms), and
check the continuity from the header pins, to the fuse holder, and to the
triacs. you will need the schematics to verify the pin numbers, fuse numbers
and triacs. but if the gi is not working, it's pretty much a for sure the
problem is a broken circuit board trace (specifically it's usually a broken
plated-thru hole on one of the .156" gi header pins).
cpu control of wpc general illumination.
as a wpc game is powered on, the gi lamps do not come on immediately (unlike
most other solidstate pinball machines). only when the cpu board has
fully booted and initialized the game, does the playfield and backbox
gi lamps turn on. this happens because the general illumination is cpu controlled through
the driver board triacs. the only exception to this is on wpc-95 games.
the gi lamps in the backbox of wpc-95 games are not triac controlled; they come on
immediately as the game is powered on (yet the playfield gi lamps are cpu controlled
through the triacs, and their power is delayed until the game has fully booted).
therefore the backbox gi lamp intensity in wpc-95 games is not cpu controlled,
and is alway "full power".
triacs are used for the general illumination circuit (not needed very
often). the specs for a wpc triac are pretty lose. for example
all these work: bt138-600e, bta12-600, nte5671 (800v 16amp),
nte56010 (800v 15amp), or nte56008 (600v 15amp).
gi string(s) do not dim.
using the wpc general illumination (gi) diagnostic test, the test
can dim the gi strings from very dim to very bright (1=dim, 8=bright).
if this option is not working (that is, the gi lights stay the same
brightness regardless if they are set to 1 or 8), you may have a
problem with the zero-cross detection circuit.
the zero cross circuit serves a couple purposes, one of which
has to do with game resets and dimming the gi lights.
part of the driver board's zero cross circuit are
diodes d3 and d38 (located just below connector j109),
which are both powered from driver board
traces going to bridge rectifier br2. since br2 is often a
replaced part, sometimes the traces going to d3/d38 get broken. this can cause
the general illumination lights to not dim (or the game to randomly reset).
so whenever replacing the bridge rectifier br2, be sure to use a dmm and
"buzz out" the two ac leads of the br2 bridge, making sure they
go to non-banded side of diodes d3 and d38 (solder side top left br2
lead to d38, component side bottom left br2 lead to d3).
this information is thanks to jerry clause.
triacs.
the triacs allow the game software to control the intensity of the gi
circuits. this involves driver board chip u1 (74ls374), which turns on the
triacs, the triacs themselves, and the pnp drivers transistors.
the triacs take 6.5 volts ac from j115,
and when the triac gate is high (in the gi
ilumination test mode with all gi strings at "8" brightness level),
the 74ls374 has a low on the corresponding pins.
with the game turned on using a voltmeter on ac,
connect the ground side of the meter to the ground. now touch the red lead to
the "tab" screw on each of the triac heatsinks. there should
be around 1 volt ac (or a little less) on each of the tabs if all the g.i. lights
are on. this is an indicator the triac is working correctly.
also feel each heat sink and see if it's warm or not. if one feels
somewhat cold, it's probably not "turned on" and is the culprit you
will want to investigate further (but in my experience the traiac
itself is never the problem - it's usually the input connector j115,
the fuse, or a broken board trace).
a triac is like a switch. it has one input pin, one output pin,
and a "gate" that causes the input to be routed to
the output when the gate goes high. when the lights are to be turned
on, u1 (74ls374) supplies a low that turns on the pnp triac driver
transistor, which causes the pnp collector to approach 5 volts.
this 5 volts is connected to the triac "gate", which turns on the triac.
when this gate goes high, the j115 ac voltage (the low side of the
secondary ac) of the triac is routed to the other pin of
the triac, which completes the circuit for the light bulbs to turn on.
the game can turn the triacs on and off many many times per second,
giving them a "duty cycle". this is how a g.i. string can be dimmed
(more "off" time between "on" cycles, and the g.i. string looks dimmer).
component side of a wpc-s and prior driver board. note the broken trace
(yellow circle) from br2 to diode d3, which can be easily seen with br2 removed.
solder side of a wpc-s and prior driver board. note the trace (red circle) which
goes to diode d38, and is easily broken at br2.
if the gi light still do not dim,
replace the driver board's zero cross circuit
lm339 chip at u6 (or u1 on wpc-95).
this will usually fix the problem (assuming there are no broken driver board
traces, as shown above). it could also be the 74ls374 at u1 (or u2 on wpc-95).
note if only one gi string does not dim, the lm339 is probably not the problem
(start with the triac).
gi string refuses to work (and it's not the driver board connector).
if the driver board gi plug is not burnt, and the gi fuses are good,
next check the gi connector coming off the transformer in the bottom of the cabinet. often just
unplugging and plugging this connector several times will clean
it for good contact. also check the traces on the driver board leading
to it's gi connector pins. often these are not making a good connection.
the plug with the yellow wires is the gi connector coming
off the transformer.
testing a gi triac.
the driver board triacs are the devices that allow the gi strings
to be dimmed. i've never had to replace one, but here's how to test
a traic.
first a triac is basically a bipolar (meaning it can be used
for ac voltage) scr (silicon controlled
rectifier). a scr has a cathode (often labeled "k"), anode,
and gate (instead of a base, collector and emitter like a transistor).
a triac also has three connections, but are labeled gate, "main terminal 1" (mt1),
"main terminal 2" (mt2). in this case, the "main terminal 1" is the cathode.
"main terminal 2" is the anode, and the gate is the gate.
the normal "diode test" on your dmm just won't work for
testing a triac (or a scr), because of the device's need to be triggered
first. all you can tell from the dmm's diode test is if the triac is
shorted, but nothing else.
because of this, to test a traic, you will need some sort of power.
the best way to do this is using a 9 volt battery. here's how you
hook up your battery, and a test 555 or #44 light bulb (note this
will probably have to be done with the triac removed from the board).
triac's mt1 (cathode): to battery negative lead.
triac's mt2 (anode): to one lead of the test lamp.
triac's gate: connect to mt1 (cathode) using a 50 ohm resistor.
lamp's last lead: to battery positive lead.
now briefly move the resistor from the gate to mt2 (anode). the
lamp should turn on. move the resistor back to mt1 (cathode), and
the lamp should stay on.
since a triac is bipolor (used for ac applications), reverse
the battery's polarity and repeat the above test. it should work the same.
shorts in the general illumination (blown gi fuses).
if the fuse is blown and blows again when replaced, there is a short
somewhere. first isolate the problem to the power driver board or
the affected gi string. disconnect the gi connector for the string fed by
the blown fuse (j119,j120,j121 or j105,j106 on wpc95),
replace the fuse and power on the machine. using a dmm, check
for about 6.3 volts ac (wpc-s and prior):
gi string 1: j120 pin 1 and j120 pin 7 (fuse f110).
gi string 2: j120 pin 2 and j120 pin 8 (fuse f109).
gi string 3: j120 pin 3 and j120 pin 9 (fuse f108).
gi string 4: j120 pin 5 and j120 pin 10 (fuse f107).
gi string 5: j120 pin 6 and j120 pin 11 (fuse f106).
gi string 5: j119 pin 1 and j119 pin 3 (fuse f106).
if voltage is seen then the driver board
is ok, and there is a short on the playfield or backbox wiring.
common causes of shorted strings include solder drips on or in a lamp sockets,
metal objects in a lamp socket, chaffed wires touching ground, socket terminals
touching another wire or metal, a shorted socket, or even a shorted bulb
(this is why i like to replace gi bulbs one at a time with the power on).
with the game off, use a dmm and test either of the two gi power wires for continuity
to ground (it doesn't matter which wire is tested as there is continuity between
the two gi wires if even one light bulb is installed in the gi string).
if the wire is grounded, examine the wire run for chaffing or a socket terminal
touching metal ground. if neither wire is grounded, remove all the bulbs
from the string and check continuity to ground across each of the two gi wires,
and check for continity between the two gi wires. if there is continuity between
the two gi feed wires, there is either still a bulb installed in the string
or there is a short (probably in one of the lamp sockets). if no
continuity, then reconnect the connector and begin
testing bulbs. a shorted bulb will not blow the fuse or
cause all the gi bulbs to dim noticeably. if the string was indicating a
short with all bulbs removed, then inspect each socket carefully -- inside
and out. another trick is to incrementally disconnect one of the feed wires along the
chain to isolate sections and localize the short to a smaller area. this process will be
tedious but sometimes it's the only means to find the problem.
another neat trick is to take a blown fuses and solder wires from the
ends of the blown fuse to a light socket. then put a good #44 or #47 bulb
in the socket. be sure to solder the wires so that they will
still allow the fuse to go back in the fuse holder. now plug the
blown fuse/socket into the fuse holder which controls the gi string in
question. if all the gi bulbs are removed from this gi string,
the lamp attached to the blown fuse should be off. if the lamp is on
(and all the gi bulbs are removed), you have a short in the gi string
somewhere. you can leave the game on and wiggle wires and exam the
blown fuse/socket to see if the lamp goes off. this will help locate
the short without going through lots of fuses in the process.
3q. when things don't work: test report & the diagnostic dot,
strange game behavior.
wpc's built-in diagnostics are very good. it can determine problems with your
game long before you have even noticed them. when you power a wpc game on,
if diagnostics detects a problem, you'll get a "test report" notification message.
pressing the "begin test" button inside the coin door will display the full test
report. each problem will be shown on the display for a few seconds. if there's
no test report at power-on, the diagnostics thinks the game is working 100%
correct.
most test reports refer to switches that are tagged as defective. often this
is not the case. if a switch hasn't be used in 30 games, it will be listed
as bad. but it could be the switch is working, yet positioned in a place that it
just doesn't get activated much during game play.
if you do get a test report about a possibly defective switch, go to
the "switch edge" test and manually activate the switch. this will
indicate if the switch is working. if it does work, this will reset the 30 game
counter for this switch and the switch will not be reported in the test
report.
prototype rom software and bad switches.
if your game has early prototype u6 cpu eprom software, sometimes
non-existant switches can show up in the test report. this happened
in early versions of twilight zone and judge dredd games. there is no
way to correct this but to upgrade to the lastest u6 cpu eprom software.
a new eprom will need to be "burned" (using an eprom programmer).
the software for this is available at williams' home page at the
http://www.pinball.wms.com/tech/roms.html
website.
the diagnostic credit dot.
if you are checking out a game that is being operated, look for a
period after the number of credits shown on the display during
attact mode. if there is a period (dot) after the number of credits,
this means there is a test report for the game. if there is no period
after the credits, there's no diagnostic test report and the game is
probably functioning correctly.
a getaway with vertical bars on the dmd every
8 bits of data - a ribbon cable wire is broken.
strange game behavior.
wpc games uses ribbon cables extensively for moving address and data
between the cpu, driver board, fliptronics, sound and dot matrix
display controller boards. the ribbon cables are rather fragile devices and
can be damaged easily. they also have gold plating which will require
a re-seating now and then (unlike the .100" and .156" molex connectors
which should not be reseated).
sometimes strange game behaviors can be seen that results from
ribbon cable problems. for example, a series of veritcal lines
in the dot matrix display. or a coil or lights that do not work.
or at power-on more than one beep is heard from the sound board
(signaling a sound board problem).
often just a simple re-seating of the ribbon cables will fix this.
warning: be careful when reseating ribbon cables. they can be
easily damaged where they connect to the plastic connectors.
the ribbon cable damaged the most if the cable with the four connectors
that attaches to the cpu, fliptronics, sound and dot matrix display controller.
an open wire in the ribbon cable can cause a lost data
bit, resulting in wacky sound and dot matrix display data.
this can cause vertical lines in the dot matrix display or
game sounds are wrong. often the problem is the ribbon cable that
links the sound and display controller together fail because they
get old and brittle in the hot backbox.
3r. when things don't work: fixing a dead or non-booting cpu board.
it doesn't happen often on wpc games. you have power
(+5 and +12 volts) getting to the cpu board. the +5 led (lower of the three)
is on, as it should be. but the middle diagnostic led is not flashing constantly (indicating
the cpu is dead). and the blanking led (the top one) is doing nothing (no
flashes when the game is turned on). you have a dead cpu.
cpu flash codes, all revisions.
wpc-s and prior uses a "dx" designation for its cpu leds. wpc-95 uses a "led20x" designation.
d19/led201 (blanking): at power-on should be on for about 3 seconds (1 second on wpc-95),
and then turn off and stay off.
when d19/led201 is on, the blanking circuit is disabled (and will not allow any coils to be energized).
d20/led203 (diagnostic): after d19/led201 turns off, d20/led203 should stay flashing permanently while the game
is turned on. this indicates the cpu is "running".
d21/led202 (+5vdc): this led should always be on. it indicates the cpu has +5 volts dc power.
d21/led202 should *always* be on, as this indicated there is +5 volts
at the cpu board. the board will never run without +5 volts!
problem power-on cpu d20/led203 (diagnostic) flash codes.
if d20/led203 does not flash continually,
here are the flash codes diagnostics:
d20/led203 blinks one time: u6/g11 cpu game rom bad.
d20/led203 blinks two times: u8 cmos ram chip bad.
d20/led203 blinks three times: u9 wpc custom chip bad
(pre wpc-s), or g10 security pic chip bad (wpc-s and later).
d20/led 203 never blinks.
if d20/led203 (diagnostics) never blinks (not even once) and is just off,
check d19/led201 (blanking). is it on and staying on? if so, the first
thing to suspect is a bad game rom at u6 (or g11 on wpc-95).
if the game rom (the read only memory chip that stores the
game's program, which the cpu runs) is bad, the cpu will never
boot (even if everything else is ok on the cpu board.
was this game rom recently upgraded to a new version? was the rom
installed correctly? (no bent pins.)
note the rom chip has a "notch", which should be installed so it
matches the "notch" on its socket.
is the rom the correct size? (if the game's program expects a 4 meg
(27040) eprom yet it was programmed into a 2 or 8 meg eprom, it won't work!)
is the rom chip verified as good? (an eprom programmer is often
needed to verify the chip's checksum, or install the suspect
rom chip into another working game). eprom chips can lose their
memory and go bad (especially if there is no label over the clear
quartz window on the chip). the eprom can also be programmed incorrectly
making it bad.
some basic info on the wpc cpu board.
the wpc cpu board is a pretty tight board. there is a custom asic chip,
which controls most of the board's input/output functions (the asic is
that big square custom chip). frankly it rarely fails (actually its socket is
more of a problem than the chip itself, as the socket is easily ruined
by battery corrosion or somebody trying to remove the square chip without
the proper tool). the next section of the
board is the switch matrix, which comprises most of the components on the
lower 1/3 of the cpu board (and hence generally does not stop a cpu
board from booting). the only other things
on a wpc cpu board are the game eprom itself (fails rarely),
and the u8 (all wpc revisions) 6264 ram chip
(which is very static sensitive, and thus can fail easily).
a bad 6264 ram chip can cause all sorts of strange cpu behavior, and
due to it's static sentitive nature, it should be suspected.
also the ttl chips across the top of the cpu board (u1,u2,u3, all wpc revisions)
can also fail. beyond this, there is not much else on the wpc cpu board!
even the u10 reset chip (34064) and u5 (74ls14) clock chip
does not fail often. broken traces on
the cpu board from previous repairs are very common though.
dead cpu step zero: check the rom jumper setting.
this does not apply to wpc-95 or wpc-s cpu boards.
if the cpu board came from a funhouse, bride of pinbot, or
harley davidson, the game rom jumper w1 may be set for a
1 meg eprom. all other games use a larger 2, 4 or 8 meg eprom
at u6. if a larger u6 eprom is installed but the cpu board is jumpered
for the smaller 1 meg u6 eprom, the cpu board will never work.
before doing any repair work to the board, check this w1 jumper!
see wpc circuit boards section
for more details.
dead cpu step one: remove the ribbon cables.
before you do anything, turn the game off and remove all the ribbon cables
from the cpu. this will issolate the cpu from the driver board, the dot
matrix display board, the sound board, the fliptronic board (if your
game has one), and any other connecting boards. the ribbon cables are
at connectors j201, j202, j211, and j204 (on some games). while you're
at it, you might as well remove the switch connectors at j205 to j209,
and j212. the only connector still attached is j210 (the power connector).
after everything is removed but connector j210, turn the game on. if
the cpu board boots correctly, the lower led (+5 volts) should be
on, the middle led (diagnostics) should be blinking continually, and the top led (blanking)
should be off. if this is the case, turn the game off and replace the
ribbon cables, one at a time, and turn the game back on.
start with replacing the the driver board to cpu board ribbon cable first.
chances are good the cpu board will still boot with this cable connected.
next try the other ribbon cables. if connecting the other ribbon cables
stops the cpu board from booting, chances are good the ttl chips across
the top of the cpu board are the problem (u1,u2,u3 on all wpc revisions).
move to the work bench.
if the above "step one" didn't get you anywhere, don't worry.
now it's time to remove the cpu from the game.
don't try and fix a dead cpu while it's still in the game. you are
much better off fixing it on your workbench. fixing it on the workbench
means you have issolated the bad cpu from the rest of the game (including
it's power supply!).
left: a video game switching power supply. all voltages
and ground are clearly marked on these.
right: a computer power supply. you'll have to check the
power supply lines to get the right voltages on these.
but 99% of the time, red = +5 volts, yellow = +12 volts,
and black = ground. double check them with your dmm.
the best power supply for your cpu is one of those switching video
game power supplies, or an old computer power supply. you need to get
+5 and +12 volts, and ground from the power supply. on computer power
supplies most of time red = +5 volts, yellow = +12 volts,
and black = ground.
the cpu board with an external power supply connected. on connector
j210, the green (or black) aligator clip goes to ground, the red to +5 volts,
and the yellow to +12 volts.
now hook up the power supply to the cpu board using aligator clips.
here's the pinout for the power connector j210 on the cpu board. note
pin 1 starts at the top of connector j210. this applies to all versions
of wpc and wpc-95 cpu boards:
pins 1,3 = ground
pins 2 = key
pins 4,5 = +5 volts dc
pins 6,7 = +12 volts dc
with the cpu on the workbench and issolated from the game, you
can test the board much easier.
re-seat the u9 asic wpc chip.
you would be amazed at how often this works. a dead cpu
can suddenly come to life after removing and reinserting
this large u9 chip. you will need a special tool to remove this
big, square asic chip. you can buy this tool at radio shack,
part number 276-2101, $9.99. do not try to remove this chip
without this tool! note one corner of this chip is "notched",
so you can only re-insert the chip one way. be careful! damage
to the asic chip or socket is very easy, and this chip is
very expensive and hard to get. don't plug the asic chip in
wrong either, as this will likely damage the chip (and of
course the cpu board will never work). there is an angled
notch in the chip that matches the angled notch in the socket.
when you press the chip into place it should "snap" firmly.
but be careful everything is lined up correctly or you may
damage the chip and/or the socket.
using the correct tool to remove the asic chip from the cpu borad.
pic by tx.
boot-up led sequence.
as power is applied to the cpu board on the bench, a working
cpu board will behave the same as in the game:
all three leds briefly flash on, then the top led turns off (while the bottom led stays lit
this whole time), and then the middle led starting pulsing rapidly on and off.
if that's what happens, then the board is "booting" and running.
booting and running means the top led is off, the middle is pulsing quickly,
and the bottom led is on. anything else and there's a problem.
bad socket at u9.
the large u9 wpc square chip can have a bad socket.
it's not much fun to replace this 84 pin socket!
radio shack sells replacement sockets, part number
rsu 11354453, $1.99, but they may not stock it.
use your dmm and check for continuity with the chip
installed before you replace this socket.
good cpu reset and irq.
make sure that the reset pin 37 of the cpu chip u4 (all wpc revisions)
works properly. when the cpu board is first powered on, this pin
should be low (zero volts), and then go high (4.5 volts). the reset
line is held low for an instant so the +5 volts can stablize, and
then goes high, letting the cpu boot. this can
be checked with a dmm. if pin 37 never goes high, the cpu board will
never boot! suspect the u10 (34064) reset chip if this is a problem.
also check the cpu irq signal at u4 pin 3. this should also start low
and then go high.
good clock signal.
using a logic probe, also check for a good clock signal on
pins 34 and 35 of the u4 cpu (6809). if the clock signal
is missing, the cpu board will never boot. the clock signal
comes from the large square u9 chip (pins 81,82), and
from u5 (74ls14). below is a picture of
what the clock signal looks like on an o'scope.
the wpc clock signal on an o'scope.
shotgun approach.
the chips at u1, u2 (74ls244) and u3 (74ls245) and (sometimes u5, 74ls14) are
the ones that affect on a dead cpu the most. the u1 and u2 chips
connect to the address lines. the u3 chip connects
to the data lines. if you are using a shotgun approach, replace
these three chips first.
if replacing these chips yeilds nothing, next try replacing u5 (74ls14),
which is part of the clock signal circuit (if the clock signal
is good, this chip is probably not the problem!)
you can also replace u7 (74ls244) and u12 (74ls240) which
connect to the data lines.
also check resistors r95 and r99 (1 meg ohms) to make sure
these are the correct value. finally u10 (a mc34064
transistor that is part of the reset startup circuit) can be replaced.
address and data lines.
it is not uncommon for an address and data line to become broken
on the cpu board. this can happen from flexing the cpu board,
or scratching (breaking) the traces, or prior "hack" repair
work.
using your dmm set to continuity,
check for continuity of the a0-a12 address
lines between the u4 cpu 6809, the g11 rom, and the u8 ram chips.
also check for continuity betwen the d0-d7 data lines between these
three chips. there should also be continuity between the a13 line
on the g11 rom chip and the u4 cpu 6809. after you have done that,
check for continuity of the a0-a15 address lines and d0-d7
data lines between the u4 cpu 6809 and the u9 wpc chip. if you are
missing continuity between any of these, the cpu will not function!
you may have to use wire wrap to fix any breaks.
the wpc asic chip pinout.
3s. when things don't work: game specific & miscellaneous repair tips.
problem: the game clock won't keep time.
the internal time clock appears to be running very slow, only about 25% of real time speed.
numerous spot checks show that it advances about 6 hours per day. the batteries, which when weak can
cause the clock to lose time, but these are brand new.
answer:
first check the batteries again! make sure they are installed correctly.
if the middle battery is installed the wrong way, this will cause a low
memory protect voltage. although game statistics will be saved, the clock
will stop every time the game is switched off. all batteries should be
pointing the same direction.
the clock function is handled by u9 (the asic chip) and u21 (a cmos 4584), and the 32.768khz crystal.
i have seen where both legs of crystal x1 were soldered to the same trace, and looks like it came from the
factory that way. after removing the crystal and putting both legs in the correct locations,
the time tracks correctly.
the 32.768 khz crystal is very common and used in everything from wrist watches to computers
to anything that keeps time. the reason for that particular frequency is 2 to the 15th power
equals 32,768. the frequency is very easy to divide by two, fifteen times, using flip-flops
or some other form of divider network. this nets a one second time increment. since the
crystal was shorted, the oscillator was free running at a rc-determined frequency
that undoubtedly drifted with temperature and miniscule voltage changes, hence the
accumulated errors.
problem: i can't enter my high score initials on funhouse.
the game works fine, but won't let player advance through the initials
by pressing the flipper buttons when a high score is achieved.
the start button works correctly as "enter",
and the flippers work fine in game play.
answer: there are two optocouplers on the power driver board at u7 and u8
that are numbered 4n25. if these go bad, they will prevent the flippers
from moving through the high score initials. since this game does not
have fliptronic flippers, these optocouplers don't effect the flippers
themselves. when the advent of the fliptronics board, these (no longer used)
optocouplers were eventually removed from the driver board.
problem: my twilight zone's dot matrix display shows random vertical
lines. at first it was just occassionally during game play, but now they appear from
the moment i power on the game. the problem has gotten worse, and
now every time i turn on the machine, all four flippers
energize.
answer: the problem was a bad ribbon cable. there is a single ribbon
cable that goes from the cpu board to the fliptronics board to the
sound board to the dot matrix controller. if the ribbon cable was
mis-installed by one pin, or the cable has torn at its connector,
this problem can happen. the ribbon cable houses the address and
data lines to the fliptronics, sound and dot matrix controller.
often the ribbon cable's connectors can just be dirty, so reseating the
connectors sometimes fixes this problem. if the ribbon cable is
damaged, mis-installed or the connectors are dirty,
strange things like this can happen.
another potential cause could be the lack of 12 volts getting to
the dot matrix display controller board.
problem: the flippers and dot matrix display died while playing a game.
the flippers on my indy jones died. the dot matrix display only has one vertical line
which is always lit. the gi lamps are fine, as are the controlled lamps.
i turned the game off and back on, the game continually launched balls
from the ball trough.
answer: the +12 volts has died, probably from a bad fuse at f116, or maybe
a bad br5 bridge. some dot matrix power is derived from the +12 volts,
and the +12 volts also powers the optos (hence the auto ball launching
problem and no flippers). if the +12 volts is good, unplug the fliptronics
and sound board ribbon cable, leaving just the dot matrix display plugged
in to the ribbon cable. now see if the display clears up and you can see the error report.
problem: strange error message when i turn my creature from the black lagoon on.
i get the error message "check switch #f6 u.r. flipper". but this game doesn't have an
upper right flipper.
answer: every flipper opto board has two optos. one is wired to the lower and
the other to the upper flipper switch inputs. this is true even on games with
just lower flippers. if the flipper opto board has a dirty opto, you can get
this error, even if your game doesn't have the flipper reported in the error
message. clean your flipper opto board optos with a qtip. replace the opto
if the problem doesn't resolve.
problem: the backbox beacon light on my getaway is constantly running after
i put it in test mode.
capacitor c11 (15,000 mfd 25 volts) on the driver board gets really hot and starts
smoking.
answer: install a 1n4004 diode on the bottom end of the large ceramic resistor right above
the test point for +20 volts dc on the driver board. install the diode with the banded end
going towards the driver board. the non-banded side goes to the bottom side of the ceramic
resistor. this diode prevents feedback voltage from going back to the driver board, and
damaging the c11 capacitor.
problem: star trek next generation diverter coil stuck on!
star trek next generation (stng) uses more coils than there are transistors
on the power driver board. williams solution was to add a small auxiliary driver board,
mounted above and to the right of the main driver board in the backbox. this small auxiliary
driver board holds more tip102 driver transistors for the additional coils needed in stng.
this board needs +50 volts for a "tieback diode" voltage for the circuit. the power is
connected by a thin violet/yellow wire which connects to the playfield's single
drop target coil (at the back of the playfield). if this wire breaks, or if some
other power wire in this coil power daisy chain breaks, it can cause the two
diverter coils to lock on (after they are first
activated in game play!) if the problem is not found quickly, the diverter coils and their
driving tip102 transistors (usually q15) can fail.
transistors on the auxiliary driver board will fail
in one or even a couple of activations if the tieback voltage is not
present on the board.
answer: if the two diverter coils lock on after a game is started, check the
violet/yellow tie-back wire which connects to the playfield's single drop target coil.
this wire than daisy chains to the other coils controlled by the auxiliary driver board.
it's not a bad idea to add a second back-up wire from the single drop target coil
(or another adjacent coil) to the circuit board, just in case one wire breaks.
additionally, add two 1n4004 diodes to each of the under-the-playfield
diverter coils (banded side of the
diode to the power lug with the thick wire).
also make sure the diverter coils are the correct
type and resistance. the correct coil type is very important (ae-25-1000, but
always confirm with the manual).
remove one wire going to each coil, and measure the
resistance with a dmm. it should be around 12 ohms and no less. another
common problem is when moving the game and the backbox is laid down,
the ribbon cables get pulled, and it wasn't plugged in fully on the board.
so if a wire in the ribbon cable is faulty, a diverter coil can lock on and burn
and ruin its associated driver transistor on the auxiliary board in the process.
the stng tie back wire on the drop target coil.
picture by jelle nelemans.
problem: star trek next generation cannons work intermittently,
or upon power on, the cannon(s) continue to rotate and won't stop
(this applies to many other games with similar cannons, such as terminator2, or other
similar moving devices like the trolls on medieval madness).
answer: the constant back and forth
movement of the wires leading to the moving device cause an intermittant break
in the wires. usually this break can not be seen, since it is inside the
insulation covering the wire strands. usually the break is at a wire tie
or some major angle. checking the wires using the a dmm continuity setting
is helpful, but does not alway work. on star trek next gen, just replace the
cannon wiring loom! (believe me, they need replaced, it is a high wear part.)
they are available from
pinballheaven.com/cannon.htm.
after replacing the star trek cannon wiring loom, check the optics for each
cannon in the switch test (the optics tell the game when a ball is loaded in
a cannon). if an optic is dead, this can can confuse the game too.
finally, sometimes the cannon plunger becomes magnetic, and will
stick in the fired position (and this in turn will block the cannon opto, confusing
the game). replace the plunger to fix this.
problem: my stng (star trek next generation) has random multiball problems, and i have
done all the ball trough upgrades, as described earlier in this document.
answer: this was a combination of
problems including dirty optos below the playfield in the diverter tunnels,
and a not properly working drop target below the borg ship.
problem: on stng (star trek next generation), when i turn the game on, it
constantly tries to load balls in the under ball runways.
it starts with all 6 balls in the ball through. now it starts the initialization and shoots one ball
via the catapult into the left side tunnels below the playfield. it ends in the upper
tunnel, then it kicks out a second ball via the catapult which is again going
into the upper tunnel. now the strange thing happens. it ejects one of the balls from the
upper tunnel and lets it drain. as soon as the ball drains, a new ball gets kicked out via the
catapult (and going into the upper tunnel again).
this is an endless loop as the ball drain and re-catapulting steps are repeated. why?
answer: the game is trying to load the two guns endlessly (the machine loads a ball under each
gun at initialization). it should put one ball in the upper tunnel and one ball under the left
gun, and one under the right gun. then three balls should stay in the trough.
be aware if fuse 103 on the power driver board is blown
(3a slow blow), the game will not start and will constantly throw
out balls. fuse 103
powers the solenoid which controls the upper diverter on the
under-the-playfield diverter. without a working diverter, the game can't
load the balls where it wants, and the game will attempt to
load and reload balls continually.
as a test, try this: go into the feature adjustments and
set both guns to "broken=yes". this will disable the guns. if the machine
then starts up ok, you have a problem with a gun assembly optos, or the
under-playfield diverters. enable each gun individually to see which one
causes the failure. also a dirty/broken opto in the upper tunnel can
cause this problem.
problem: the frogs are missing on my scared stiff. where can i get
replacements?
answer: the frogs used in scared stiff are standard toys, with a slight
modification. the bottom of the frog is drilled and tapped for a threaded
rod. often the frogs and their associated rods are missing. replacements can be
purchased from
pinballheaven.co.uk.
problem: how do i prevent playfield wear around upkickers?
answer: cliffy (www.passionforpinball.com) and
mantis amusements (mantisamusements.com) sells metal protectors that can
be attached to the bottom of the playfield, preventing this wear.
they are also available in europe from
pinballheaven.co.uk.
problem: shadow battlefield optical sensors work intermittently.
the battlefield would sense a ball on the sides of the battlefield,
but not when the ball was in the center of the battlefield! interestingly, the problem
went away when the playfield glass was removed.
answer: the ball is "seen" by optics on the battlefield. the beam of
light provided by the optic transmitter is too wide/conical. so wide, the light
was reflecting off the playfield glass and back to the optic receiver
(that's why removing the playfield glass solved the problem). the solution
to this is to put a piece of 3/8" long black heat-shrink tubing (without shrinking it)
over the optic transmitter (and maybe the receiver too, if needed)
to sheild the light beam into a tighter pattern.
problem: none of my whitewater's coin door buttons do not work!
the volume buttons do not work, nor do the diagnostic menu buttons.
there is a shared ground wire that "daisy chains" (goes between) all four coin door
buttons. check that this wire hasn't broken. also all the coin door buttons are
electronic buttons. if the game is missing its +12 volts digital power, these
buttons will not work. check fuses f114 and f115. the red 12 volts led on the
power driver board should be lit also.
problem: on my indiana jones, the path of adventure mini-playfield "stutters",
when it moves in one direction during game play (but not in diagnostic mode). why?
answer: the poa (path of adventure) uses the flipper buttons during game play
to move left or right. if the flipper opto board's "u" optics
are dirty/failing, this can cause the poa to "stutter", as it moves.
also the game uses two "u" optos on the poa switch board (mounted against
the back inside panel of the playfield), and these
too could be failing.
use a q-tip and some windex, and clean the flipper board optics and
the poa switch board optos.
now go to the poa test in the diagnostics. does the poa stutter
in diagnostic mode? if so, the poa switch board optics are failing
and need to be replaced. now retest in diagnostic mode. if the poa
works fine in diagnostic mode, but the poa still stutters in game
mode, replace the flipper "u" optos (if the poa stutters to the left,
it's the left flipper opto board). another
way to test if the flipper optos are the problem is to swap
the right and left flipper opto boards, and
see if the problem moves to the other side.
note in the diagnostic mode, the coin door buttons
are used instead of the flipper optos to move the poa. this is why a flipper opto
problem does not show any problems in diagnostic mode, but only in game mode!
problem: on bride of pinbot, the game does not show the correct "face"
during game play.
answer: under the playfield, there is a small circuit board with a relay
on it. this relay controls the direction of the motor, which
controls which face is shown. usually the solder joints on this
relay crack, causing the relay to not always engage, and showing the wrong face during game play.
resolder the relay's solder joints to fix this.
problem: on tales of the arabian nights (totan), after six "tiger loops" are made for the extra
ball, the game shuts down!
answer: this seems to be a software problem in all versions of the cpu rom code.
the problem is caused by switch 45 (inner right loop) not working. after the extra
ball light comes on, the software compensates for the non-working switch 45 by
resetting the game! to fix the problem, make sure switch 45 is working correctly.
problem: on roadshow, the bulldozer blade refuses to go up.
the eddy switches in front of the dozer blade and in front of ted's head work perfect.
also the dozer blade works fine in test mode.
answer: check the two "u" shaped optos on the dozer opto board, which determine the position of the
dozer blade. if either one of these "u" optos has failed or are dirty, the dozer
blade will not work properly. sometimes these optos will seem to work correctly
while in the diagnostic switch test. but if they are starting to fail, instead
of giving a solid 0 volt or 5 volt signal, they give something in between (like 0.4 volts).
to fix this, first try and clean the optos with a q-tip
and some windex. if still a problem, replace the "u" optos.
problem: on getaway, the rotating beacon on the top of the backbox is missing.
answer: happ controls
makes a great replacement for this 12 volt beacon and
lamp. call happ at 888-289-4277 (buy-happ) and order part number 95-0115-10uc.
price is right around $40. this is a red beacon light assembly with a chrome
ring and outer mounting plate. the happ motor is dc,
and the game's driver board supplies ac voltage. to convert the voltage to dc,
use a 35 amp 200 volt bridge rectifier (as used on the driver board). connect the
two wires coming off the small beacon board to the ac leads of the bridge.
connect the two wires coming off the beacon to the "+" and "-" leads of the bridge.
problem: on indy500, the lighted targets have broken off the plastic opto activators
(the part that passes between the "u" opto.
answer: use some duct tape or electrical tape and tape both sides of the plastic stub
that is left on the target, so the tape is sticking to the stub and itself.
then trim the tape with a razor blade. note the reason the plastic tab breaks is
because the two foam pads on either side of the clear
target that prevent the plastic flag from hitting the back of the opto are missing.
these can be easily replaced with new 3/16" weatherfoam on the sides of the target
to prevent non-broken target tabs from breaking in the future.
problem: on johnny mnenomic, the glove does not work.
answer: first, remember the glove motor works off the 20 volt flash lamp
circuit. so if the coin door is open, the glove motor will not work. therefore
if the coin door is open when the game is turned on, the power-on glove test
will fail, making the glove not work (until the game is reset). on the last
johnny i owned, i wired the coin door interlock switch so the 20 volt flash
lamp circuit didn't turn off when the coin door was open (the 50 volt solenoid
circuit was still disabled with the coin door open). i found this to be much
less confusing and more convenient when i was working on the game (i typically
leave the coin door open to turn off the 50 volt solenoid power).
the glove on jm uses four "u" shaped optos (for x/y direction),
two microswitches to locate the center and left most position of the glove,
and a switch inside the hand's magnet.
test these switches by going into the wpc diagnostic switch test t.1.
one microswitch finds the "mid" position
of the hand (forward and back). the other microswitch finds the left most
position of the hand. make sure both of these micro switches are working
in the switch test t.1 by activating them manually. then
make sure when the glove moves these switches actually close.
next check the four "u" shaped opto switches for the glove. these four
optos tell the computer the x and y position of the glove. they
are mounted on two small pc boards, positioned behind the back panel of the
playfield (pull the playfield all the way forward to see these). the
glove moves much like a genie garage door, on threaded rods (one rod for
x movement, one for y movement). each rod has a metal interuptor,
which rotates between two "u" shaped optos.
the threaded rods can be spun by hand. in switch test t.1,
make sure both optos ("a" and "b") work
for each rod (these "u" optos are the five leg variety).
if just *one* of these four optos does not work, the entire glove assembly
will not work, and an error report will be generated when the game is
turned on (or when entering diagnostics). the error relating to these
optos is "no x movement detected" or "no y movement detected". this
signifies a problem with any one of these four "u" optos.
if one of these "u" optos does not work, or works intermittently,
just replace it (see here for info on replacements).
another problem can be the small .100" molex connectors on the glove's two opto
boards. often just reseating these connectors will fix a glove opto problem.
if reseating does fix the problem, it is suggested the connectors be replaced.
also check the header pins for cracked solder joints on these two opto boards.
also check the glove direction motor board mounted under the playfield.
often there are cracked solder joints around the header pins on this board.
resolder the header pins to fix this.
finally check the "ball in hand" switch. this switch is located inside the
magnet, under the moving glove. use a *pinball* to check if this switch (labeled "f5"
in the switch matrix, right most column) is working. it is important to test
this switch with an actual pinball (opposed to just using a finger).
after all switches are confirmed as working, go into the solenoid test and
make sure the glove's magnet is working.
last, make sure the latest cpu rom software is installed in the game.
the latest is version 1.2. a new u6 cpu rom would need to be "burned"
if a game has a revision other than this (the cpu revision number is
shown upon game boot up, and when entering diagnostics).
problem: my scared stiff crate leds are broken. where can i get replacements?
answer: the crate leds are standard red t-1 sized leds. any t1 led should work,
but here are some that mimic the originals, from
mouser.com,
part# 604-l934srcd, kingbright super bright led lamps t-1 red water clear, $0.34.
or part# 351-3230, led lamps t-1 red water clear, $0.25 as a second choice.
problem: my cirqus voltaire neon lamp is not working.
answer: first check that 12 volts is present going *into* the neon
lamp's transformer (is the fuse blown?) the easiest way is to check for 12 volts at the molex
connector going to the transformer (under the playfield), or at the power driver board.
past that, if the neon tube itself is
not damaged, the transformer itself is probably bad.
the neon transformer takes 12 volts dc and converts it to a very high voltage
(about 1500 volts, at low current). because of this, to get the ul rating,
williams was required to rivit close a plastic case around the transformer! to access
the transformer, the rivits will need to be drilled out with a 1/8" drill bit
or grind off the heads of the rivets (on swe1, do not try and remove the decorative
plastic "light saber handle" from half of the plastic transformer case; they
uses silicon to attach it, and it does not come off without destroying the
decorative plastic!)
once the rivits are removed, the transformer can be removed and checked.
is there any high voltage (1500 volts dc) being output? if your dmm
does not go this high, just replace the transformer. the cheapest
way is to buy a car neon license plate transformer.
if needed, wire the automobile neon transformer under the pf
(if it doesn't fit in the ramp housing), and run
the high voltage wire up to the ramp and bulb. note if you do this to be
sure to use wire rated for at least 2000 volts (it'll have thick insulation; look
at the wire already on the bulb if you need some reference).
specs for the original neon transformer are
here. but basically these are the specs:
model vt 1510-12
input voltage: 12 vdc (+/-10%)
output voltage: 1500v
input current: 650 ma (max)
driving distance: neon 1-5 ft in length, based on a 12mm tube
output current: 10 ma
operating temp: 0° to 104°f
length: 1.5 in.
width: 1.0 in.
height: 2.25 in.
mounting: 1.15 in.
weight: 3.0 oz.
the original williams star war episode 1 transformer (part number 04-10947)
may also still be available.
the original transformer for cirqus voltaire (and swe1) was a ventex model vt12d5,
but they seem to have changed their model numbers so now it's
vt1510-12. a replacement is ventex model nps-12d5 and it fits and works fine.
key specs are input 12 volts dc at 0.6a, and output 1500v 5ma.
you can find it at
www.ventextech.com/lowv.htm.
note the output connector will need to be changed to a molex connector.
another transformer source is
www.sunsupply.com/transformers/winind.html.
after getting the new transformer test it using some aligator test leads, and hook it up
to the game's 12 volts and to the neon tube. make sure everything is safe and insulated
and turn the game on (remember 1500 volts output!) after you're sure the new transformer
is working properly, reassembly the ramp. you can use small screws instead of rivets
if you don't have the proper rivets and rivet tools.
testing the neon tube itself, without using the high voltage transformer, and not
that easy. there is no to test a neon tube with a dmm - basically
the gas inside the tube conducts electricity. so a dmm can't generate a big enough
voltage to test it. they make little inductive testers - the tube will glow when this
thing is held near the neon tube, if the gas is still in there. also try taking
the neon under some high voltage power lines at night to see if it glows
(and to scare yourself about how much energy is leaking out of them!)
problem: in my getaway high speed2 the
the ball does not accelerate well around the
super charger, and was blowing fuse f103 after a few revolutions.
also all three magnets seemed to pulse no matter which supercharger
opto was activated.
answer: clive suggested the problem may be one or both of the cmos chips on the
accelerator board, or the lm339's on that board. by checking the accelerator optos in
switch test mode, verified the optos all work fine and there were no
multiple openings for each opto. if this tests good, the lm339 chips are
probably fine. this leaves the cmos chips u2 (4011) and u3 (4071) as
suspect, so replace those.
problem: where can i get a replacement strobe light tube for
my attack from mars?
answer: though replacement strobe lights can be gotten at
local discount stores and pep boys, they are really not the correct
replacement for your afm game. the proper strobe rate for afm is
6.25 lights per second. the inexpensive replacements will only
allow maybe 2 or 3 lights per second. what is needed is a "low-pressure"
horseshoe type of strobe light. the low-pressure is key, because it
allows the strobe capacitor enough time to charge and discharge,
lighting the strobe 6.25 times per second. the proper strobe light is
available from
http://www.pinbits.com (go to the
afm parts section). when installing don't touch the bulb.
and before assuming the bulb is bad check the power supply board
mounted under the metal box in the back. make sure the game is unplugged
before taking it off. you need to take it off anyway to take the strobe
assembly off. i had two leads broken off on the small blue box on the
board on a recent repair job.
problem: on medieval madness the ball hits the trolls, but doesn't always register
a hit.
answer: there are two main reasons why the troll would only register hits intermittently,
or not at all. the first is that a one of the soldered wire connections on the switch
attached to the troll head has broken. the second is that the contact rivets have
become loose on the switch blades on the troll head switch, allowing only
an intermittent connection at best. to fix the problem of
loose contact rivets remove the switch assembly from the troll head assembly and
then peen (flatten with a small hammer) the switch stack rivets so this removes
any play in the switch stack, allowing for good contact with the switch blade.
problem: monster bash sometimes slam tilts when the ball goes down
the right outlane.
answer: check the switch behind frank, airballs will short the
switch causing the problem (only when the frank targets are raised).
problem: how do i link two nba fastbreak games together?
answer: (from louis koziarz) the nba fastbreak link option is done through the a/v board's
serial port. installing a serial port on wpc-95 games is easy, and you can save the
money by doing it yourself instead of buying the kit.
the wpc-95 a/v board comes with those two serial port chips missing by
default, so these chips will need to be purchased and insert them into
positions u22 and u24 on the wpc-95 a/v board.
u22 is a max239 rs-232 driver chip, and u24 is a 16c450 uart.
digi-key (www.digikey.com) is currently selling the max239 for $7.55
and the 16c450 for $5.60 (using a buffered 16c550 as an
equivalent part).
the pinouts for the a/v board are on page 9 of the schematics, but
here's a summary:
j607-1 - ground
j607-2 - tx output
j607-3 - rx input
j607-4 - cts
j607-5 - rts
j607-6 - dtr
j607-7 - dsr
j607-8 - key (no connection)
j607-9 - ri
j607-10 - dcd
for basic rs-232 operation, all that is needed are the first three signal
lines, and you should be able to talk to the board. if not
familiar with rs-232 interfacing,
obtain a copy of the wpc-95 schematics, as these go a long way in helping
understand how the system works.
if the chips are installed properly the operating system should detect
the board automatically and start sending audits out the port. it
may need to enable printouts in the adjustments menu, i don't remember
if that option trips automatically.
that's all there is to it. nba fastbreak also used this port in a
null-modem configuration for the head-to-head gameplay (swap tx and rx
lines between games).
linked game play works like this: the first player presses start, and their display shows
"waiting for 2nd player." you can play a stand-alone
game by pressing both flipper buttons, or press start on the second machine for a linked game.
linked games are broken down into four quarters, with a halftime. the
quarter length can be modified in the menus.
the gameplay is constant, there is not limit to the number of balls
(because it's a timed game). if a player drains the ball,
a new ball is served with no penalty (other than the time this takes). the
head-to-head players select their teams and play begins. the players
work together to complete modes. for example, player 1 might complete
the two left "in the paint" shots, and player 2 may complete the two
right "in the paint" shots, which allows that mode's multiball to
start. if both players complete all modes and reach the final (wizard)
mode, they compete for the championship ring(s). if there is a tie the
game goes into an extra overtime period.
problem: what motor is used in my wpc game?
answer: see the web page gearbox.htm
for details.
problem: the auto adjust eddy sensor board in my monster bash or circus voltaire has
the led continually flashing (instead of coming on when a ball
approaches the pf sensor, and off with no ball near the sensor).
answer: the auto adjust eddy led will flash if
1) you don't have the coil plugged into the auto eddy sensor board,
2) you have the wrong (resistance) coil plugged into the eddy board,
3) you have the wrong value capacitors for c1 and c2 installed in the eddy board.
how can the caps be the wrong value? if the eddy board was transplanted from
circus voltaire to monster bash (or vice versa), this can happen. check
yor game manual for the correct cap values.
problem: on my twilight zone, i get the error,
"clock is broken". how do i fix this?
answer:
on my tz clocks, this problem occurs because of
high heat inside the clock from the #86 general illumination
lamps. to fix the problem, all the "u" slot optos should
probably be replaced (along with the feeding 470 ohm 1/2 watt
resistors r1-r8, and the .100 interboard connector),
and the heat some how decreased inside the twilight zone clock.
there are two trends on decreasing the heat inside a tz
clock: using diodes on the clock's #86 gi lamps, or installing
bright leds instead of the #86 lamps.
if the clock's heat issue is not address, the internal heat will
cook the "u" slot optos and other parts, giving a "clock is broken"
error message.
rottendog amusements and
pin lizard
sells replacement tz clock boards with bright leds already installed.
using their boardset, the internal heat can be
reduced from about 160 degrees in an unmodified clock, to about 100 degrees.
but if using the original boards, they can be modified for leds to
reduce the internal clock heat to about 125 degress.
this will decrease the power consumed
by the clock from about 8 watts to 1 watt (as documented by pbliz), thus reducing heat.
the existing tz clock boards can also be modified for leds. to do this,
first get four t1-3/4 size (5mm diameter) water clear white leds (pbliz suggests digi-key,
part# cmd333uwc-nd). the brighter the led, the better for this application.
also get four 100 ohm (or 133 ohm) 1/2 watt resistor,
and install them in locations d1-d4.
bend the led leads as shown in this photo
here.
this spreads light more evenly over the clock face (click
here and
here).
note that the leds can be installed in either direction; there is no need
to pay attention to how the led's "flat spot" is installed (since the supply
current is ac volts). but since the supply voltage is ac, it is ideal
if the leds can be mounted so two are "on" and two are "off" during
any half of the ac cycle (see the picture above for this mounting configuration).
please remember, just putting in leds does
not fix previously damaged boards. often original clock boards will have
burnt traces, bad "u" optos, bad opto resistors r1-r8, a damaged .100"
inter-board connector going between the two clock boards, or cold solder
joints on the interboard connectors.
also the look of clock leds is quite different than the #86 bulbs; it is a more
blue colored light. some people don't like this look, as it is not "stock".
there is another clock modification which retains the original look of the clock
(some people do not like the look of leds).
four 1n4004 diodes can be installed at
locations d1-d4 on the clock board (williams actually has zero ohm resistors installed
there), and the original #86 bulbs can still be used (the diodes will
decrease the current to the #86 bulbs, lowering the internal temperature).
also install the d2,d3 diode bands in the reverse of the silkscreening on the
original clock board. this will cause lamps one and four to light
on one half of the ac cycle and lamps two and three to light on the opposite half of the ac
cycle. this mod will decrease the consumed clock power from 8 watts to about 6 watts,
lowering the heat yet still retaining the original look of the clock. with this
modification it is recommended the plastic clock housing be drilled on the top
with two 1/4" holes to vent the heat, directly above the top two #86 lamps
(no bottom holes are needed since
there are already bottom holes for the connectors).
problem: how do i prevent my addams family magnets from burning
my playfield?
answer: the three under-the-playfield mounted magnets are energized by
a small board with three tip36 transistors (mounted under the playfield).
if one of these tip36 transistors shorts on, the magnet will stay on,
and could get hot enough to burn the playfield.
to prevent this, it's a good idea to install three 2amp slow-blow fuses (one for each
magnet) under the playfield. this way if a magnet locks on, the fuse
for that magnet will blow before the magnet gets hot enough to burn
the playfield.
installing three fuses under the playfield for the addams family magnets.
4a. finishing up: rebuilding flippers
regardless of your playing skill, the one thing everyone notices
about a pinball game is the flippers. novices and pros alike can tell
you if your game has good, powerful flippers, or whimpy, limp, dead
ones. flippers are the interface between the game and the
person playing. if you don't maintain anything else on your game,
at least maintain the flippers. games with good flippers are
fun. games with bad flippers aren't fun (regardless of what the game
title is).
flippers get weak because they have moving parts that get substantial
use. when they wear, the mechanisms get play (slop) in these moving
parts. instead of the flipper coil transmitting all
its energy in propelling the ball, some energy is absorbed by the sloppy
mechanisms. rebuilding the flippers removes this slop, and will
dramatically increase the strength and feel of your flippers.
how flippers work.
flipper coils are actually two coils in one package.
the "high power" side is a few turns of thick gauge
wire. this provides low resistance, and therefore
high power. the "low power", high resistance side is many turns of much
thinner wire. this side of the coil is important if
the player holds the cabinet switch in, keeping the
flipper coil energized. the high power low resistance side of the
coil is only active when the flipper is at rest.
to simplify how the two sides of a flipper
coil work, it's best to examine the non-fliptronics
version. in this case, when the flipper is
energized and at full extension, the normally closed eos
switch opens. this removes the high powered side of the
coil from the circuit. the low powered side of the flipper
coil is always in the circuit, but is essentially ignored
when the high powered side is in the circuit. this happens
because the current takes the easiest path to ground
(the low resistance, high power side of the coil).
the low power high resistance side of the
flipper coil won't get hot if the player holds the
flipper button in.
a simplified drawing of the flipper circuit in non-fliptronic
games.
eos switches: normally closed or normally open?
pre-fliptronics games have a high voltage, normally closed end-of-stroke
(eos) switch. but fliptronics flippers are basically an electronic (instead of
mechanical) version of the above explained non-fliptronics flippers. the main difference is
fliptronics flippers have
eos switches that are low voltage, normally open switches
(instead of high voltage, normally closed as used on non-fliptronics flippers).
left: non-fliptronics wpc flipper. note the capacitor to minimize eos
switch arc, and the style of return spring used. the eos switch is a high
voltage, tungsten contact, normally closed switch. this flipper coil
is installed incorrectly; can you see why?
right: a freshly rebuilt fliptronics wpc flipper. there is no capacitor,
and a different return spring. the eos switch is a low voltage, gold contact,
normally open switch. this flipper coil is installed correctly.
answer to the above trivia question ("what's wrong with the left
picture's flipper coil?"): the problem shown on the left is the flipper
coil is installed upside down!. the wire terminals that the flipper
coil wires connect should be as far away from the coil stop as possible.
the coil stop is where most flipper vibration originates. the coil plunger
slams into the coil stop, causing vibration. this vibration will eventually
break the coil wires off of the coil wire lugs. to minimize this, the coil
is mounted so the wire lugs are further away from the coil stop. the coil
picture on the right is mounted correctly. note many pre-fliptronics wpc
games had the flipper coils mounted incorrectly from the factory!
non-fliptronics wpc flippers.
when the player presses the flipper button, the high-powered side of the
flipper coil is activated and fully extends the flipper. then the end-of-stroke (eos) switch
is opened, and removes the high-powered side of the coil
from the circuit.
as the flipper reaches it's end-of-stoke, the flipper pawl opens
the high voltage, normally closed switch.
the electricity now only passes through the low powered side
of the flipper coil.
the use of the low powered, high resistance side of the flipper coil
consumes less power. this allows
the player to hold in the flipper button without burning the flipper
coil. if the high-powered side of the coil was activated alone for more than a few
seconds by itself, the coil would get hot, smoke, smell, and burn.
non-fliptronic eos switches use a 2.2 mfd 250 volt capacitor
(part number 5045-12095-00). this minimizes the high
voltage electrical arc between the contacts of the eos switch.
the eos switches on these games do need
periodic maintainence. since they are high voltage switches, there is
some electrical arcing. this will cause the switch contacts to pit
and burn, and cause some resistance. as the resistance increases,
more arcing occurs (which causes even more resistance). eventually,
bad eos switches will make the flippers very weak. they must be filed
clean with a small point file periodically. the switch contacts are
made of tungsten.
fliptronics wpc game flippers.
the fliptronics board allows computer control of the flippers. when the
eos switch is damaged or broken, the fliptronics board can turn off the high powered side
of the flipper coil. this provides a better level of reliability.
the eos switch is now a low voltage, normally open switch.
as the flipper pawl reaches its end of stroke, it now closes the eos switch.
when the player presses the flipper button, the cpu turns on the
high powered side of the flipper coil.
when the eos switch is sensed closed, the high powered hold side of the coil
is turned off. if for some reason the eos never closes, the cpu turns off the high
powered side of the coil after a short period of time (a few milliseconds).
the low-powered hold side of the coil is
powered for as long as the player holds the flipper button.
computer control of the flipper coil via the fliptronics board
provides an extra level of reliability to the game.
the computer now controls this. the eos switch is monitored,
and if the computer sees a problem, the operator is notified
via a diagnostic message. but if the operator chooses to ignore
this, the game will still function as designed. also, since
the eos switch is now a low-voltage, gold plated contact device,
it requires no big maintanence schedule.
flipper coil numbers and strength.
when you get a new game and are rebuilding the flippers, check
the game manual and make sure the proper flipper coils are installed.
often operators will replace flipper coils with the wrong coil.
use what the manual suggests for proper game play.
resistance is included below so a questionable flipper coil may be tested.
the upper measured ohms should be within 10% of the values below, and the
smaller measured ohms should be within 3%. to measure flipper coil resistance,
used a dmm with one lead on the center coil lug, and the other
dmm lead on either outside coil lug.
the flipper coils are listed below from weakest to strongest.
fl-11753: used for small flippers, like the "thing" flipper on
addam's family. 9.8 ohms/165 ohms. usually a yellow coil wrapper.
fl-11722: used for weak flippers, like twilight zone's upper
right flipper. 6.2 ohms/160 ohms. usually a green coil wrapper.
fl-11630: "standard" flipper strength, as used on older games
like earthshaker, whirlwind, etc. 4.7 ohms/160 ohms. usually a red coil wrapper.
fl-15411 : strong flipper, as used for main flippers on addam's family,
twilight zone, etc. 4.2 ohms/145 ohms. usually an orange coil wrapper.
fl-11629: strongest williams flipper. used on most of the newest wpc
games. 4.0 ohms/132 ohms. usually a blue coil wrapper.
flipper rebuild kits.
williams sells a flipper rebuild kit that contain all the parts
you would need to rebuild two flippers. it includes parts like
the entire right and left flipper pawl and plunger/link assemblies, coil sleeves,
coil stops, eos switches, eos switch capacitors (for the non-fliptronics kits),
and other parts. at $20 a kit (to repair two flippers), it's a pretty decent
deal because it's all the parts you'll need in one kit. but you can
save some money if you just replace the parts that are worn
(the plunger/link, link bushing, coil sleeves and usually the coil
stops). for fliptronics flippers, the kit's part number is a-13524-8. for
non-fliptronics flippers, it's part number a-13524-1. the genuine williams
kits come in a cute plastic claimshell container.
rebuilding fliptronics and non-fliptronics flippers.
regardless whether you have fliptronic or non-fliptronic flipper,
the rebuilding process is the same (except for the cleaning and adjustment
of the eos switch). these two styles of flipper
assemblies even share the same parts (except for different
eos switches and return springs).
left: flipper assembly with the coil stop (and coil) removed.
right: the coil stop. notice the mushroomed head on the top example.
below that is a re-worked coil stop (using a file). it is recommended
replacing the coil stop rather than re-working it.
step1: remove the coil stop.
first, use your allen wrench and remove the two 10-32 x 3/8"
bolts that hold the coil stop in place. this will release the
coil from the assembly. move the coil to the side for now.
examine the coil stop. often, the coil stop will have a "mushroomed" head.
this happens from the coil plunger slamming into the coil stop. if
this is the case, replace the coil stop. in a pinch, you can
re-work the coil stop and file the mushroomed head flat and
bevel the edge. the problem with this is plunger travel length increases.
if excessive, the plunger link could now slam
into the top coil bracket, destroying it. also the increase
in plunger travel can cause the flipper pawl to hang on the eos
switch (leaving the flipper in the up position).
new coil stops are cheap, so i suggest just replacing them.
for wpc-dcs and wpc-95 games, use coil stop #a-12390.
for pre-wpc-dcs (addams gold being the last wpc-dcs game)
and wpc games (and system 11 games), use coil stop #a-12111. if the newer #a-12390
coil stop is used on an older wpc game, the flipper bat will have less travel.
two allen head tempered black 10-32 x 3/8" bolts are used to hold the coil stop.
if the used coil stop is worn, there can be
problems with the flipper pawl hanging on the eos switch,
especially on fliptronics flippers.
the flipper assembly with the pawl
assembly removed. the flipper shaft can
be seen extending thru the playfield,
and thru the nylon flipper bushing.
step 2: removing the flipper pawl assembly.
on fliptronics flippers, remove the one side of the return spring from the
flipper pawl. then using your allen wrench and an open 3/8" wrench (needed
for most pawls, though newer style pawls may not need the 3/8" wrench),
loosen (but don't remove) the bolt
that clamps the pawl assembly to the flipper shaft. from the playfield
side, turn and pull the flipper while holding the pawl assembly until
the flipper can be pulled from the playfield. the pawl assembly can
then be removed from under the playfield.
step 3: check for worn coil bracket.
if the game was played so much that the coil sleeve wore out
(thanks in part to a worn plunger link) and the coil stop mushroomed, the plunger could
then come in contact with the coil bracket. this
would elongate the bracket's hole. also, if the
coil stop was filed (to removed a mushroomed head) and
plunger travel increased, this could ruin the coil bracket too.
in either case, the coil bracket will need to be replaced.
step 4: check the rubber flipper plunger stop.
a trivial flipper part that is often overlooked is
the black rubber plunger link stop. this little black piece of
rubber softens the flipper's return to home. if the rubber
piece get chewed up, it can cause problems.
first, the flipper plunger will have too much travel. next
the plunger and link will wear quicker (due to the increase
shock to the plunger's link). and last, the flippers will not align properly
when fully extended.
if in doubt, replace this trivial part.
shown is "flipper drag" playfield wear (see the wear in the
word "twlight"?). this is caused by worn or broken nylon
flipper bushings. this allows the bottom of the flipper bat
to drag on the playfield, causing this wear.
step 5: replace the nylon playfield bushing.
the nylong playfield bushing is a nylon part that the flipper shaft
passes through. it is very common for this part to crack,
or wear excessively.
this can cause the flipper bat to drag on the playfield finish.
if this happens, ugly playfield wear marks can result (see picture above).
it's pretty easy to tell if the bushings need to be replaced. with the
flipper pawl removed from the flipper shaft, wiggle the flipper on the
playfields, side to side. there should be some play, but not excessive
play. the bushing should also stick up above the playfield about 1/8".
if the bushing is too low to the top of the playfield, this will allow
the flipper bat to drag on the top of the playfield. to play it safe,
always replace both nylon flipper bushings. flipper drag marks on the
playfield are not worth the risk!
left: williams nylon flipper bushing, top and
side view.
right: the top right picture shows how the
flipper bushing should protrude above the
playfield 1/8". the bottom right picture shows
a playfield bushing that is much too low,
allowing the flipper bat to drag on the
playfield.
when replacing the flipper bushing, remove the
entire flipper bracket from under the playfield.
this allows access to the three 6-32 x 3/8" bolts and nuts that hold the bushing
to the bracket. these bolts have nuts on the bottom side of the flipper
bracket, which can't be accessed with the bracket in place.
left: note the flipper link's hole has enlongated. also, the black
heat shrink tubing on the pawl is very worn from activating the eos switch.
although it doesn't look it, the flipper link spacer bushing (lower left) is
also worn.
right: note the plunger tip has mushroomed, and there is considerable
plunger pitting.
step 6: replace or rebuild the pawl.
the flipper pawl assembly can now be rebuilt (if you buy
a whole new flipper pawl assembly with a new plunger/link
for about $10, skip this section). remove the allen
bolt that holds the plunger/link to the pawl. the
plunger/link can now be removed (you may need to use a screwdriver
to spread the pawl assembly slightly to release the plunger/link).
before proceeding, check the hole in the pawl which bolts the plunger/link
to the pawl. this hole can enlongate (egg-shape), making the pawl
useless. even if a new plunger/link is installed, the eggshaped hole
will create "play" in the pawl assembly. if the pawl holes are enlarged
or eggshape, the pawl must be replaced (or just buy a completely new
pawl/plunger/link assembly). also check the bolt that goes through the
pawl and link (and link bushing). often its center section wears again causing play.
the only solution to this is a new bolt.
top: new style, fatter and more substantial flipper link.
middle: old style, thinner flipper link; the preferred version
for the newer style return spring set up. since it's not as thick, it
doesn't hang up inside the flipper pawl assembly as easily. it's also
a more versatile link, and can be used in most williams (and dataeast!)
games from the mid-1980's and forward.
bottom: old style, chewed up link from a flipper plunger
return spring. this is why williams went to the newer style
(top) plunger link. the plunger return spring just hacks away
at the link.
inspect the flipper link spacer bushing, which should be inside the
flipper link's hole. brand new bushings have an outside diameter
of .310 inches, and an inside diameter of .090 inches.
if you have a dial caliper, measure yours.
if even .003" less than these values, replace this bushing.
if in doubt, just replace it.
replace the flipper plunger and link. a new plunger/link can
be bought cheap (rebuilding the plunger is
hardly worth it. spend the $1.50 and get a new plunger/link. if
rebuilding the plunger/link is your only option,
here's what to do: grind
and bevel the plunger tip to
remove the mushroom. using a 1/8" metal punch, remove
the roll pin that holds the link in place. install a new link, and
hammer the roll pin back in place. make sure the new link moves
freely.)
install the plunger/link and a flipper link spacer bushing.
remember the allen bolt that holds this is place goes through
the pawl assembly with the nut on the same side as the pawl
(see pictures).
a new plunger/link and new spacer bushing. note the
freshly installed (white) pawl heat shrink tubing and allen bolt.
step 7: check or replace the pawl heat shrink tubing.
skip this if a new pawl was installed.
one of the flipper pawl's job is to activate the eos switch at the flipper's
end of stroke. this metal pawl tab is factory coated with heat shrink tubing
to prevent wear to the eos switch. when the coating is worn, metal-to-metal
contact (pawl to eos switch) occurs. this will shred the eos switch blade.
when the eos switch blade frays, it will hang-up on the flipper pawl.
this will cause the flipper to stick in the up position (regardless of
the condition of the return spring).
the heat shrink tubing also provides insulation between the metal flipper
pawl and the eos switch. this is especially important on non-fliptronics
games (as the eos switch is a high voltage switch). worn or
missing heat shrink tubing on these games can cause all sorts of strange
game behavior.
new pawl heat shrink tubing should always be installed
when rebuilding the flippers. cut the old tubing off using a razor
blade. cut a 1/2" length of new 1/4" heat shrink tubing. push it
over the pawl, and use a heat gun or hair drier to shrink the tubing
in place. trim with a razor blade as needed.
installing the flipper pawl and flipper
coil. note the use of the white plastic
flipper "tool" to get the spacing correct.
step 8: check the flipper coil type.
often, operators will replace a flipper coil with the wrong
type. this happens quite often. you should verify in the manual
that your particular game has the correct flipper coil installed.
step 9: re-install the flipper pawl assembly and flipper coil/coil sleeve.
after the flipper pawl assembly is rebuilt (or replaced),
reinstall it. put the plunger through the coil bracket.
make sure the pawl is down (toward the playfield). push
the flipper shaft through the flipper bushing and into
the pawl assembly. do not tighten yet.
put a new coil sleeve in the flipper coil. if you can't
get the old coil sleeve out of the coil, replace the entire
coil (it has been heat damaged otherwise the coil sleeve would
easliy slide out). the coil sleeve should be installed
from the non-terminal end of the coil, and extend through the
coil at the terminal end about 1/8".
put the flipper coil in place, the coil end with the wire terminals goes
closest to the flipper pawl. note the nylon "tab" that is
molded into the the nylon terminal portion of the coil. this tab will
fit into a notch in the coil bracket. the extended part of
the coil sleeve will go through this coil bracket too.
install the coil stop and its two allen bolts.
step 9b: changing to the new style flipper return spring on older flippers.
williams changed flipper return spring styles in 1992. before, there
was a cone-shaped flipper return spring that went over the flipper
plunger. the problem with this set up was it chewed up the flipper
link, and often the spring just got weak and broke from the constant
contact with the flipper link.
to combat this problem, williams made two changes when they
went to fliptronics flippers. first they changed the
style of flipper link to be thicker, and have a more rounded
contact point. second they stopped using a plunger style
return spring. the return spring was moved outside of the plunger,
where it takes less abuse and doesn't chew up the flipper link.
left: here the flipper plunger spring has gone soft, and won't
return the flipper back. note how the spring is biting into the flipper
link (new style flipper links help prevent this).
right: a conversion to the new style return spring. this involved
using fliptronic flipper pawl parts, and drilling a 1/16" hole in the
metal bracket holding the flipper capacitor.
to change to the new style return spring on older flippers, just order the fliptronics
style flipper pawl. then drill a 1/16" hole in the bracket that
holds the flipper capacitor. this hole will anchor the new style
return spring. entire flipper pawl, with plunger and link is part number #a-15848-l (left),
or -r (for right). the flipper pawl only is part number #a-17050-l (left), or -r ( for right).
step 10: check for flipper bat up and down movement.
williams provides a white plastic spacing "tool"
(that comes with every game) which
fits between the flipper bushing and the flipper pawl (see above
picture). this spacer is .030" thick (1/32"), or about the thickness of
three business cards. it is designed to provide a bit of up and down
movement of the flipper bat inside the nylon playfield bushing so
the bat doesn't bind (and the flipper doesn't "stick"). i personally
don't use this tool - just make sure there's a bit of up and down
movement (as you pull the flipper bat from the top of the playfield)
so the bat does not bind.
using a toothpick as a flipper alignment tool.
step 11: aligning the flipper bat.
on the top of the playfield, note the roll pin inserted
through the playfield, just behind the flippers. this pin
is used for alignment purposes at the factory when the
playfield was first assembled. put a toothpick into
the roll pin, and move the flipper against it (with the
rubber installed or not installed, it varies from game to game).
this will give you a general idea of where the bat should
be aligned. i wouldn't suggest trying to push the
roll pins back through the playfield for flipper alignment; just
use toothpicks. no need to possibly damage the playfield.
now take a straight edge and use the lane guides to give
the flipper bats a final position adjustment. i like the
ball to roll off the guides and to the flipper bat in a
straight line.
step 12: tighten the flipper pawl.
now you are ready to tighten the flipper pawl assembly to the
flipper shaft. with the flipper positioned correctly,
lift the playfield and tighten down (very tight) the
flipper pawl assembly's allen bolt.
use an allen wrench and a 3/8" open wrench (if needed).
if the flipper spacing tool is still in place remove it
and the toothpick.
both flippers in the "up" position. notice how they look
symmetrical.
step 13: check flipper alignment in the up position.
when you are finished, extend both flippers to the up position.
they should look "equal", both extending the same amount.
if not, you will need to re-align one or both of the flippers.
if you didn't replace the flipper coil stops (and instead filed
them down to remove a mushroomed head), the flippers may not
line up when extended. this happens because the plunger travel
has increased from filing the coil stop.
also worn rubber flipper plunger stops can cause the flippers
to not align with fully extended.
step 14: check/adjust flipper travel.
from the flipper's rest to full extension should be 2 1/4" of flipper
travel, measured at the center tip of the flipper bat. if there is
less than this, the game will not play right. this is often due from
using the wrong plunger/link or wrong coil stop (if there is too
much travel, that is usually caused by worn flipper parts). but fear not,
too little flipper travel can be easily adjusted.
measuring flipper travel from rest to full extension should be 2 1/4 inches.
to fix too little flipper travel, use a set of channel-locks and
bend the *rest* flipper link bracket. just bend it a bit, then
re-check the flipper for 2.25" of flipper travel. note the resting
flipper position will need to be adjusted after bending the rest flipper
stop. you will have to re-position the flipper pawl on the flipper bat,
so repeat above step#11 and step#12.
bending the rest link stop for added flipper bat travel (2 1/4 inches).
step 15: cleaning and adjusting the eos switch.
cleaning and adjusting the eos (end of stroke) switch is the last step in rebuilding flippers.
this is very important, especially on non-fliptronics games.
on non-fliptronics games, the eos switch
is what diverts power away from the high-powered side of
the flipper coil. if not adjusted correctly and the eos switch
stays closed, the flipper coil can burn. if the eos switch is
dirty and doesn't make good contact, the flipper will be extremely
weak. therefore it's critical that the eos switch be adjusted and
cleaned on non-fliptronics flippers. on fliptronics games
the eos switch is less critical, but should still be inspected.
on non-fliptronics games, clean the eos switch contacts with a
file. there should be no pitting in the contacts when done.
the eos switch is a normally closed switch. so adjust the non-fliptronics
eos switch so it opens about 1/8" at the end of the flipper's stroke.
on fliptronics games, clean the eos switch contacts with a rag
and some alcohol. or clean the eos switch
by running a business card through the closed contacts once or twice.
the eos switch is a normally open switch. so adjust the fliptronics eos switch so
the contacts close when the flipper is at its end of stroke. adjust
the eos switch to close at near the end of the flipper bat travel
make sure the eos switch doesn't hang on the
flipper pawl when the flipper is fully extended.
last, turn the game on and put it into diagnostic test mode.
close the coin door (to turn power on to the flippers).
now press the cabinet flipper buttons and again check the
eos switch spacing and adjusted as needed.
parts reference.
flipper rebuild kits (for two flippers). includes all the following
parts, plus some others. part number a-13524-8 for
fliptronic flippers, #a-13524-1 for non-fliptronic flippers.
entire flipper pawl, with plunger/link: #a-15848-l (left), or -r (right).
flipper pawl only: #a-17050-l (left), or -r (right).
plunger/link: #a-10656 old style with a less meaty link and a
tapered link shape and a shorter plunger, giving the entire plunger/link
assembly slightly less length. the newer a-15847 which has a
more robust link with a boxier shape, but the overall length of the plunger/link
is longer (the newer style a-15847 plunger/link may not allow as much
flipper travel if installed on pre-fliptronics games).
because these two plunger/link assemblies have different lengths,
they must be used with the correct coil stop. otherwise the flipper may have
less travel than the game intended (making it play strange).
nylon flipper link only: #03-8050 (or 03-8753 which is the
meatier link).
coil stop: for wpc-95 games, use coil stop #a-12390.
for wpc-s and wpc games (and system 11 games), use coil stop #a-12111.
if the newer coil stop #a-12390 is
used on an older wpc game, the flipper bat will have less travel.
two allen head tempered black 10-32 x 3/8" bolts are used to hold the coil stop.
eos switch: non-fliptronics version #03-7811. fliptronics version #sw-1a-193.
coil sleeve: #03-7066-5, 2 3/16" long.
flipper link spacing bushing: #02-4676
flipper bushing: #03-7568 (uses three 6-32 x 3/8" bolts and nuts)
all of these parts are available from your local williams distributor
or one of the suppliers on the
parts and repair sources web page.
4b. finishing up: new coil sleeves
replacing the coil sleeves on all major coils has a big impact
on snappy game play. if you didn't rebuild your flippers,
definately replace the flipper sleeves at a minimum.
it makes an amazing difference in flipper power. replace the coil
sleeves on the pop bumpers and slingshots. your game will have much
more snap. just replace the flipper, pop bumper and slingshot coil sleeves
(and any other ball action coil sleeves).
4c. finishing up: protecting slingshot plastics
corners of slingshot (kicking rubber) plastics often break. this
happens because the ball comes off the flippers with so much force,
it breaks the overhanging plastic. to protect this plastic from breakage,
put a 3/16" by 1" round fender washer underneath the plastic. you
can get these washers at any decent hardware store. this
way the ball will hit the metal washer instead of the plastic when
coming off the flipper.
a fender washer underneath
the slingshot plastic.
note you install the washer between the metal post and the plastic
post. that is, you remove the slingshot plastic. then you remove
the lower metal post that holds the plastic star post in place.
then put the metal post through the washer, and through the plastic
star post. re-installed the metal post/washer/plastic star post
to the playfield, and re-install the slingshot plastic.
4d. finishing up: cleaning and waxing the playfield
keeping the playfield clean is of major importance
in game performance. dirt on the playfield slows the ball down,
and increases playfield wear.
williams recommends using
novus 2
plastic polish for cleaning playfields. it works
great, and leaves a great shine.
it's very gentle, yet cleans fast and well. it can be used on
both the playfield and on plastic ramps. i buy it at my local grocery store,
but you can also get it through most pinball retailers.
there are a number of products available for cleaning the playfield that
should not be used.
millwax and wildcat 125 come to mind. avoid these
products. millwax and wildcat aren't even really waxes. they are cleaners with extremly
small amounts of wax and lots of solvents to keep the cleaner/wax in
an easy-to-apply liquid form.
also millwax and wildcat contains high levels of petroleum distillates.
williams recommends not using these products on their games.
please see this service bulletin dated
october 1989.
a diamondplated funhouse playfield.
if your playfield is diamondplated, using a wax after cleaning is
optional. all williams playfields were diamondplated starting with
terminator2. prior to that, the playfield will say
"protected by diamondplate" in one of the outlanes if it is
indeed diamondplated. diamondplate is basically a polyurathane
top coating originally used to protect hardwood floors.
a good hard wax such as treewax or
meguires carnauba wax works great, even
on diamondplated playfields. ball speed will improve, and
playfield wear will decrease. both of these
waxes are just that; wax! they have little or no detergents or
cleaners in them. notice how difficult they are to remove and polish after
they haze (as applied per the instructions)? this is good! it means your pinball
will have a hard time getting them off too. i like to quickly re-wax my
playfield every 100 games with these waxes.
also a scratched ball can slow and
damage the playfield. replace the ball if it's not shiney like
a mirror. they are only about $1.25 each. throw the old balls away.
4e. finishing up: playfield rubber
clean white playfield rubber will keep your game in tip-top shape.
many suppliers sell rubber ring kits; just specify the name of your
game, and they'll send you the exact rings for it. don't forget
to get flipper rubber and a new shooter tip, if not included in the rubber kit.
i would recommend not using black rubber on your games.
it looks bad, is much harder, and hence
has different (less!) bounce. black rubber is now pretty much standard
equipment on most williams games after about 1995. for an operator,
black rubber gives a distinct advantage: it doesn't show
dirt! this creates an illusion.
for the hobbiest, i would recommend using white rubber instead.
it gives a brighter look to your game. and
on newer games that don't have much rubber, white
rubber can give more ball bounce.
some games were designed, and looked better, with black rubber.
scared stiff is one such games. later new games
(like circus voiltaire, 1997) were going to be designated for
white rubber by the designer, but got black rubber installed at the factory.
clean rubber has amazing bounce properties. dirty rubber has seriously
reduced bounce. the more bounce, the more fun your game will be.
if you want to try and clean your old (only slightly dirty) rubber,
you can use wax. meguires carnauba wax, trewax or even
novus#2 plastic cleaner works great on lightly soiled rubber.
just remove the rubber and wax it
with a clean rag, and wipe off the excess. wax will keep your rubber
supple and uv protected. you don't even have to remove the rubber
if it's not too dirty. for dirtier rubber,
try alcohol, westley's bleche white tire cleaner,
or goof-off (but be careful with goof-off, as it damages
plastic). use a clean rag and wipe the rubber
down. if flipper rubbers are wearing out quickly, reverse it
(turn it inside out), and re-use it.
end of wpc repair document part three.
* go to wpc repair document part one at http://marvin3m.com/~cfh/wpc/index1.htm
* go to wpc repair document part two at http://marvin3m.com/~cfh/wpc/index2.htm
* go to the pin fix-it
index at http://marvin3m.com/fix.htm
* go to marvin's marvelous
mechanical museum at http://marvin3m.com
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