1986 to 1990, Part Three
by firstname.lastname@example.org, 04/21/02.
Copyright 1999-2002 all rights reserved.
IMPORTANT: Before Starting!
If you aren't up to repairing your circuit boards yourself, I highly recommend Tom Callahan or John Robertson (in Canada). Note these repair facilities will NOT repair your circuit board after it has been unsuccessfully repaired by you.
Table of Contents
3k. When things don't work: the Switch Matrix
If a switch is not activated in 30 games, or is permanently closed, the switch is assumed to be bad. This will create a test report, which is shown when the game is turned on. If a particular feature of a game is difficult to score, it's associated switch may be (falsely) assumed bad (if not activated in 30 games). To correct the test report, remove the playfield glass, and activate the switch by hand within a game, or within the diagnostics switch edge test.
All switches on a system 11 game (except for the direct switches at connector 1J14, which are only the test button switches) are in the "switch matrix". The switch matrix is controlled by eight switch columns, and eight switch rows. The cross-section of any row and column designates any one of the potential 64 different switches. The switch columns are controlled through CPU board connector 1J8, which connects to 2N3904 transistors Q42-Q49. The output of these goes to a 74LS244 chip on the CPU board at U40. The output of this chip then goes to a 6821 PIA at U38. The switch rows are controlled through CPU board connector 1J10, which connects to 4011 chips at U30 and U39. This then connects to the same 6821 PIA at U38.
Test Button Switches.
Shorting the Switch Matrix to +50 volts.
If after replacing the suspect components, disconnect the switch input plugs from 1J8 and 1J10 at the bottom of the CPU board. Put the game into switch test mode, and none of the switches should be activated! If a whole row of switches is activated, that would mean that something in the row chain is still bad.
Shorting the Flipper EOS switch to the Lane Change
When adjusting or cleaning the flipper EOS switches or lane change switches, make sure the game is turned OFF. This will prevent shorting these two switches together. Also, do not clean the smaller lane change switch with anything other than a business card.
Lane Change on games with Interconnect boards.
in the "down" position (as shown here). If the center
button is "up", you will enter the audits menu instead.
To test switches, use the internal test software. Press the center red button inside the coin door down, then press the black button closest to the coin door. Finally, press the center button again. The button closest to the coin door will take you from test to test. Go to the "switch level" test and activate any switch on the playfield using a pinball (this simulates real game play), and it should show on the game's display.
If a Bad Switch is Found.
If the switch is bad, replace it. If all the switches are bad in a particular switch column or row, start replacing components closest to the switch.
It's a strange problem. You're playing a game, and when the ball goes down the right inlane, the left slingshot fires! Or when you make a ramp shot, the game slam tilts. One switch closes, but a completely unrelated event than occurs.
This is a classic problem of a shorted switch. It confuses the switch matrix into thinking something else has occurred. This can happen from an "air" pinball, that bashes an above playfield switch's contacts together, causing a short. Also a bad switch diode can do this too. In either case, you need to find the shorted switch. Unfortunately, it won't be obvious. The switch matrix is confused, so any diagnostics the game provides will be of limited help.
First, try and find the switch that causes something unrelated ("phantom") to happen. Take the playfield glass off, and start a game. Activate the switches with your hand, and find the switch which activates the phantom (unrelated) switch. Once you have found the switch, go to the game manual and find the switch's number, row number, and column number. Say for example, switch 53 (column 7, row 5) is causing the phantom closure. Now you need to get the other three switches that make up the "square" of this row and column. First get the reverse switch number, switch 39 (column 5, row 7). Then get the other two switches: switch 37 (column 5, row 5), and switch 55 (column 7, row 7). Your switch short will probably be one of these four switches.
If you are having problems figuring out if the short is in the playfield or the CPU board, try this. Remove connectors 1J10 and 1J8 from the CPU board. Then put the game in switch edge test. Using the manual, find which row and column of the switch that is causing the phantom closure. Then cross this row and column directly on the CPU board (with wire and alligator clips, and a diode, as described below in the "testing the switch columns/rows"). The row and column numbers for each pin of connectors 1J10 and 1J8 are listed below. If the phantom switch does not activate, the problem is in the playfield. If the phantom closure still works, you have a CPU board problem.
If your phantom switch problem is on the CPU board, don't forget to look at the 1k ohm resistor pack SR10 on the CPU board. When this resistor pack goes bad, it can cause intermittent phantom switch closures. Use your ohm meter, and test the resistor pack. If in doubt, just replace it.
Bad Switch Diode.
Fail-Safe Diode Test.
Testing a switch diode on a microswitch without removing
You can test the diode on a microswitch without unsoldering a diode lead from the switch. This technique assumes the switch is wired in the standard configuration: green (ground) wire to the center lug, the banded end of the diode to the far switch lug, and the non-banded diode lead and the switch wire(s) to the close switch lug (as shown in the pictures above).
Testing a Blade/Leaf Switch's Diode.
Testing a switch diode on a blade/leaf switch, without
You can replace the diode with a 1N4004 (or 1N4002 or 1N4001) diode. Make sure you install the new diode with its band in the same orientation as the old diode (assuming it's correct!). If you're unsure, compare the diode's band orientation to a working switch and diode. Most (but not all!) switches have the green (ground) leads connected to the center (normally open) lead of the switch. Then the row (white) wire is connected to the switch lead closest to the center lead (the normally closed lead). The banded end of the diode is connected solo to the far (common) switch leg, and the non-banded end is connected to the same leg as the row (white) wire. There are some exceptions to this mounting. Your game manual will specify any non-standard switch installations.
On a micro-switch, the ground (green) wire usually goes to the center
lug, the "live" wire and the non-banded side of the diode to the lug
closest to the center. The band on the diode goes to the solo,
far third switch lug. The leaf switch uses the same connection method
(ground to center, banded end of diode solo). Note there are some
exceptions to this mounting.
If you are getting an error message that you have a switch matrix row or column problem, you need to determine if this is a CPU board problem or a playfield problem. The easiest way to do this is to unplug the switch matrix row and column plugs at 1J10 and 1J8. Now enter the game's diagnostics (coin door center red button down, press the black button closest to the coin door), and go to the switch edge test. If the row or column problem is gone (no switch reports), you have a problem in the playfield wiring. If the problem is still there, you have a problem on the CPU board. Note most shorted switch matrix problems are caused by a bad switch matrix column 2N3904 transistor at Q42-Q49 (which affects the entire column).
Switch Matrix Plug and Pin Numbers.
1J8 Switch Column Pin Numbers
1J10 Switch Row Pin Numbers
the test lead is attached to pin 9 of 1J10, and is stationary. The
other clip holds the non-banded side of the diode. Then the banded
side of the diode is touched to each pin of connector 1J8. The
"switch levels" test should indicate switches 1, 9, 17, 25, 33, 41, 49, 57
when moved from pin 1 to 9, respectively.
To test the switch columns, do the following:
If a particular column number does not display as closed, or is closed without any test lead connection, there is a problem on the CPU board. Usually this is a bad switch matrix column 2N3904 transistor at Q42-Q49.
Testing the switch matrix rows: Using a diode and a test
To test the switch rows, do the following:
If a particular row does not display as closed, or is closed without any test lead connection, there is a problem with the CPU board.
Testing the Switch Matrix Columns and Rows with a Logic
Resistor Network Testing/Explaination used in the Switch
If a resistor network is "560 x 8" and has 9 pins, that means it's BUSSED; all the resistors are tied to one common pin (this pin is labeled with a white square around it on the circuit board). Simply put, if a resistor network has an odd number of pins, it is probably bussed.
If a resistor network is "1K x 4" and has 8 pins, this is an ISOLATED resistor network; a bunch of resistors in the same small package, so it uses two pins per resistor. Simply put, if a resistor network has an even number of pins, it is probably isolated.
When testing a BUSSED resistor network, first find pin 1. This pin will have a white square around it, to isolated it from the rest of the pins. Use a DMM set to ohms, and put one lead on pin 1. Put the other lead on each pin 2 to 9. The same reading should be seen for each pin 2 to 9.
When testing an ISOLATED resistor network, put the DMM leads on the two adjacent pins furthest to the right or left, and note the reading. Then move both DMM leads down one pin. The same value should be seen. Continue down the resistor, moving both DMM leads one pin at a time, until all adjacent pins are tested.
Bad Switch Column: How to Fix it.
Bad Switch Row: How to Fix it.
Further Diagnosing of the Switch Matrix.
What is that loud "Popping" when I turn my Game On?
What the game is trying to tell you is that switch #35 has not been actuated (ie: closed) in about 30 games or so. That's usually sufficient reason to suspect that the switch as bad. The game will do its best to compensate for the bad switch (by using other switches around it), but it is trying to say that the switch needs to be looked at.
Inside the coin door there should be three operator diagnostic test switches. Make sure the middle one is in the "Down" position, and then press the one marked "Advance" or "Enter". This puts the game in Test mode. Keep pressing Advance until you see the "Switch Edges" test (remember at this point the playfield is "live", so watch those pop-bumpers, slingshots and flippers). Now verify that the bad switch really doesn't work by activating it. Test it using the ball if possible and not just your hand.
Now turn the game off and remove the balls and lift the playfield. Locate the switch under the playfield. There should be a bunch of "blade" (or possibly micro) switches. The one that doesn't work may have a broken wire, or some other sort of mechanical failure. If it is a leaf switch, it may simply be dirty. Find a business card and gently press the switch leafs closed, and pass the card between the two contacts. These switch contacts should be gold flashed, so don't use anything abrasive (the business card is all that is needed).
The leaf switch could also be out of adjustment. There is one moving blade, and one stationary blade. To adjust the switch, bend the *stationary* blade only to move the switch contacts closer. Test the switch with a ball to make sure it is working correctly.
If the game has microswitches, a simple adjustment to the activator arm may be in order, or the switch itself has failed.
Test the switch again in switch test, and see if this solves the problem. If it doesn't, check for a problem with a broken wire on a nearby switch. The switch wires "daisy chain" from switch to switch in the same row/column. So a non-working switch could be a broken wire "upstream".
3L. When thing don't work: Infrared Optic Switches (Drop Target switches)
Williams also used optic light emitting diodes (LED's) for some switches, even on the older System 11 games. Mostly Williams used "U" shaped optics for detecting the position of drop targets. The problem with this is vibration. Often the optics will actually break off the circuit board because the drop targets take so much abuse.
Optos have two sides to them: a transmitter, and a receiver. The transmitter is the part that fails 95% of the time. Essentially the transmitter is a light bulb, and all light bulbs burn out eventually. And the optics are always "on", even when the game is in attract mode (another good reason to turn your game off when not in use).
A nice tool to have in your tool box is the Radio Shack infrared detector card. This $5 credit card sized card will show if the optic transmitter is producing light. Without this card, you can not see this wave length of light. So this handy little card is quite good to have. Remember you must have the card positioned in front of the transmitter to see the light on the orange colored band (having it in front of the receiver won't show anything!). The "red" side of the "U" shaped opto is the transmitter side of the optic.
System 11b and Later Optic boards.
New Style Optics on Optic boards with LM339 Chips.
Replacing the Optics.
3m. When thing don't work: Score Display Problems
One of the most frequent system 11 problems relates to non-working or weak score displays. Fortunately, often there is a very easy fix for this problem.
The simplest thing to check when the score displays do not work is the +100 and -100 volt DC power section of the power supply. If either of these voltages are bad, your displays will not work. And quite often, this power supply section does go bad.
The 39k ohm Power Supply Resistors.
Here is the same score display after the 39k resistors were
changed on the power supply board. This cheap 50 cent fix shows that the
score display glasses themselves were good!
Check the +100/-100 volts at the Power Supply board.
Power Supply D-8345-xxx (where xxx is the game number). Used from High Speed to Swords of Fury ??.
Power Supply D-11883 and D-12246. Used from Taxi ?? to Doctor Dude.
WPC AlphaNumeric Display Board. Used on Funhouse, Harley Davidson, the Machine.
Power Supply Diodes Leak.
Blown high voltage score display Fuse(s) in the
Also a blown UDN7180 chip on the master display board can cause the high voltage fuse(s) to blow on the power supply board. These chips can short the +/- 100 volts directly ground, and blow the fuse.
Increasing Score Display Life.
The original diodes used at ZR2, ZR4 are 1N4764A. These are 100 volt, 1 watt zener diodes. If you replace these with 1N4763A diodes, which are 91 volt, 1 watt zener diodes, only 91 volts (instead of 100 volts) will power the displays. This will make your displays slightly less bright, but it will also DRAMATICALLY increase their life span! Since glass score display tubes are becoming so expensive, this is highly recommended. Note on the newer WPC alphanumeric games, diodes D5 and D6 were changed to 1N4763 diodes from the start.
If any of the high voltage fuses are blowing, you probably need to rebuild the 100 volt power supply section. You will need to replace the following parts on the power supply board.
Positive System 11 100 volt section parts to replace:
Negative SYstem 11 100 volt section parts to replace
power supply. The leads on the MJE15030 and
MJE15031 must be "twisted" to replace the
older SDS201 and SDS202 transistors. This should
ONLY be done on power supplies that originally
used the older SDS201 and SDS202 transistors.
When installing the newly fixed board, measure the output voltages BEFORE you plug in the connectors going to the score displays! Output voltage should be between 95 and 105 volts.
Score Display Ribbon Cable Problems.
Slow Display Strobing Problems.
This is usually caused by weak high voltage going to the score displays. Instead of plus or negative 100 vdc, the voltage can be as low as 50 volts. This low voltage can be caused by resistors R1 and/or R4 (39k ohms) on the power supply board, or a bad high voltage capacitor C1/C3 (100 mfd 250 volt), or C2/C4 (0.1 mfd 250 volt metal polyester cap) on the power supply board.
Partial Segment Failures on Score Displays.
This can be caused by one of the hex input buffers at U10, U11, U15-U18 (14050 or 4050) on the Alphanumeric master display board, which are CMOS chips and static sensitive. You can check these with your ohm meter. Connect one lead to ground, and the other lead to each input/output pin of the 4050 chips. Any pin that doesn't read the same as the others probably means the chip is bad. Sometimes you'll have to test these chips with an analog ohm meter, and watch the needle "bounce". A pin that doesn't "bounce" like the others again probably means that chip is bad.
More Segment Problems: the UDN7180 chip.
Both these chips are easy to test: both have an input and output side. If the input side is pulsing (check this with your logic probe), then a good signal is probably getting to the chip. Next check the output side. It should be pulsing too. To test these, put the game in it's diagnostic display test. Then single stepped to the next digit test (all zeros, 1's, 2's, etc) and check the input and output pins at each step. If the input side is pulsing, and the output side is not, then the chip is probably at fault.
The UDN6118 and UDN7180 both have the same pinout: pins 1 to 8 are the input side of the chips, and pins 11 to 18 are the output side. Check the schematics to see exactly which chip controls which display when diagnosing these. Here's an example:
Problem: segment 'b' (top right) always on for players 1 and 2, and ball-in-play score display (but not credit display!).
Answer: looking at the display board schematic found that U13, U14 (UDN7180) are common components to these displays. Chip U13 drives segments "h,j,k,m,n,p,r" and the period, while U14 drives "a" to "g" and the comma. Since UDN7180's are becoming rare and are expensive, the input and output signals were double checked by comparing them with a logic probe (or an oscilloscope). Putting the game in display test so it could be single stepped to the next digit test (all zeros, 1's, 2's, etc). On chip U14, the input pins 1-8 showed activity and changed when I advanced to the next digit test. Next tested the U14 output pins 11-18. The output pin 18 (for the "b" segment) was constant and did not change when the test was advanced. The conclusion was to removed and replace the UDN7180 at U14 (after installing a socket), which fixed the problem.
Segment Still doesn't work: Check the Resistors before replacing
Check these resistors with your multi-meter to make sure they are at the correct value. Using the schematics, find the segment letter identifier you are missing. Then follow that segment through the UDN7180 and its corresponding resistor. Make sure that resistor is within 10% of the schematics specified value. Or if you don't have a schematic, just check ALL the resistors on the Master display board with your multi-meter. The slightly larger 1/2 watt resistors tend to be the more troublesome resistors.
"Outgassed" Score Displays.
Two Versions of the Alpha-Numeric Display Boards.
Taxi and Police Force have an alpha-numeric display at the top, and an alpha-numeric display which is only used for numerics on the bottom in the backbox. The reason for this is that when they installed the extra display they needed a way to run it. The bottom 16 digit display on these games only uses 8 segments (the middle segment of the display is used to make the number zero into an eight, which is two segments). This leaves six segments and the "comma" left unused. The unused segments are then used to drive the extra display. This is the reason there's a second place to hook up a ribbon cable on the Taxi/Police Force display boards.
The Taxi/Police Force style display board can be converted to work in the other 16 digit alpha-numeric system 11 games, with a small modification. Simply install the missing seven resistors into locations R62 to R68 on the Taxi/Police Force display board.
3n. When thing don't work: "Factory Setting" or "Adjustment Error" (Battery Problems)
Often when you buy a used system 11 game, upon power up, you'll get an error message stating, "Adjustment Error" (if the coin door is closed) or "Factory Setting" (if the coin door is open). This message indicates that the CPU RAM chip at location U25 on the CPU board has forgotten the game's bookkeeping and options settings.
"adjustment error" message.
If the coin is open, and the batteries are dead, you'll get a
Why Do I Get These Error Messages?
If after replacing the batteries, you still get a "Factory Setting" error, 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). Put the red lead on each of the CPU board's POSITIVE battery terminal SOLDER POINTS. Test each of the three batteries' positive leads individually. You should get about 1.5, 3.0, or 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.
The best battery holder to buy 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 original system 11 design, and will fit perfectly on a system 11 CPU board.
Testing for Battery Voltage.
Next check for voltage at the U25 RAM chip. With the game off, you should get about 4.3 volts DC at pin 24 of chip U25 (ground is pin 20 by the way). If you don't, the battery voltage is not getting to the U25 RAM chip. This will cause the game will boot up with the "Factory Setting" or "Adjustment error". Note pin 24 of the 24 pin RAM 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. This chip is a 2k by 8 CMOS static 24 pin RAM chip. The part number will be 2016 or 6116-L or NTE2128. Early system 11 games specify this chip as a 5177, but this chip can be replaced with a 6116 instead.
You can still have problems even if you installed new batteries and all the voltages check out. If your game is still giving "Factory Setting" or "Adjustment error", you may have a bad CPU U25 RAM chip. But make sure you 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 three AA batteries are connected to the U25 RAM chip via a "blocking" diode. This 1N4148 switching diode at D2 is connected in series between the battery and the U25 RAM chip. It's job is to prevent +5 volts from going back to the batteries (it only allows power from the batteries, not to them). Sometimes this diode shorts out or goes open. If this diode shorts, the CPU board will try and charge the three AA batteries! This will cause the batteries to leak, and could damage your CPU board. If the diode goes open, the batteries will never power the U25 RAM chip, and the game will boot up with the "Factory Setting" or "Adjustment error". Check this diode with the game off and your DMM set to the "diode" setting. You should get between .4 and .6 volts in one direction, and a null reading in the other direction. You can also test the diode (with the game off) by setting your DMM to DC volts. Put the black lead on ground, and you should get 4.2 to 4.8 volts on either side of diode D2 (the banded side will be about .5 volts higher). If you only get voltage on one side, the diode is open and needs to be replaced.
If you install new batteries with the game turned on, the machine will not forget the old option settings or bookkeeping totals.
Clearing a "Factory Setting" or "Adjustment Error"
Once you have the "factory setting" message, press the black button closest to the coin door twice. Then move the center red button to the up position. Then press the black button closest to the coin door again (twice if you had an "adjustment error" message). The game should now go into attract mode.
New CPU Batteries Die very Quickly.
If either diode D1 or D2 is bad, it can let the batteries attempt to power all the +5 volts logic for the whole CPU board when the game is powered off. Or it can let the +5 volts from the power supply attempt to charge the batteries when the game is powered on. In either case, this will cause the batteries to die quickly.
If you have batteries that are dying very quickly, replace both diodes D1 (1N5817) and D2 (1N4148) on the CPU board.
3o. When thing don't work: Miscellaneous Oddities
Problem: In attract mode, the pop bumper coil on my F-14 behaves normally (did not fire or energize). Once a game was started or test mode entered, the coil would fire and stay energized. In attract mode, the coil could be fired by hitting the pop bumper skirt switch (this is NOT normal behaviour, and the others pop bumpers did not work this way)! Grounding the metal tab of the Q69 TIP122 transistor while the game was in attract mode energized the coil and released it (properly).
Answer: A close look at the 7402 chip at U50 (which is the controlling TTL for this coil) revealed that pins 5 and 6 where shorted together. This was caused by a solder splash from a previous repair. Removing this short fixed the problem!
I turn my system 11 game on, and the score displays will only
show 0's and X's in the middle of them.
Answer: there is a slam switch inside the coin door, just above the coin door lock. This switch should be normally open. If this switch is shorted or bent closed, you will have this problem. Often people will accidentally bend this switch when putting credits on the game (a good reason to have the game set on free play!). If the switch is not shorted closed, the switch matrix could also be damaged, as the slam switch is part of the switch matrix. See the Switch Matrix section of this guide for info on fixing that.
A system 11 game coil is always energized.
Answer: some 50 volt coils are driven by a TIP36 transistor on the Auxiliary power driver board. If the TIP36 is shorted, the coil will stay energized (regardless of what you replaced further up the electronic river).
"When I turn my Fire! game on, the score displays would flash
quickly at a high brightness, and the speakers would be noisy, but the
game does nothing more."
Answer: there were two failed components, a 555 timer chip at U43 and a bad 2N4403 transistor at Q50.
To test the blanking circuit for proper operation, check U20 pin 2 or U43 pin 3 at power-on, using a logic probe. You should get an initial LO for a few seconds, followed by a continuous HI after the game has booted.
All score displays are out, game will start but flippers and ball eject do not work. While the game was being played (when it worked) the displays began acting strangely then the game died. Any further attempts to start a game resulted in above problems.
Answer: Examining the display board discovered a glob of flux on U11 (4050 hex buffer) shorting pins 14 and 15 together. Using the schematics and wiring diagrams was able to trace those pins back to the CPU board. The short killed U51 (PIA 6821) on the CPU board. Removed U51 (6821), added machine pin socket, and replaced it with a new 6821 PIA.
"No Sound on my Pinbot."
Answer: No -12 volts DC, which is used for the sound. In this case it ended up being the bridge rectifier that converted the 12 volts AC to DC voltage that had failed.
When the flipper button is pressed, the game resets. When the
ball hits the slingshot, the game tilts.
Answer: First I would suggest looking for a bad, missing or mis-wired switch diode. But in reality this was not the problem. A switch matrix column transistor (2N3904) was bad, as was the switch matrix column resistor network SR15.
The CPU software for Road Kings on the Williams web site does
not seem to work.
Answer: Indeed the EPROM software for Road Kings on the Williams web site is bad. For working software, click here for working EPROM files.
On My F-14, I need a new rubber belt to drive the rotating
beacon lights. Where can I get this?
Answer: This rubber drive belt is available from any local John Deere tractor store! Just ask for part number H85996, cost is about $2.00.
4a. Finishing Up: Rebuilding Flippers
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 Flipper Coils Work.
The second part of the flipper coil is the low powered side. This acts much like a hold relay; lots of turns of thin wire with high resistance. This part of the flipper coil is intentionally shorted out and turned off by a normally closed end-of-stroke (EOS) switch.
Answer to the above trivia question ("what's wrong with the above 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. Unfortunately, Williams didn't identify this problem on system 11 games, so usually the wires are too short to install the coil correctly!
Flipper worked different on games High Speed to Millionaire. These games used a series wound FL23/600-30/2600 flipper coil. The common lug (where both the low and high powered coil wires were connected together) on these flipper coils was the middle of the three lugs. Also these coils used ONE diode across the two outside lugs. The EOS switch on these games, when opened, enabled BOTH the high power and low powered coils together. This style of flipper coil did NOT use a 2.2 mfd anti-spark EOS capacitor. The problem with this series wound coil was the "back spike" of current that occured when the EOS switch was opened. This cause the EOS switch to excessively wear and pit.
The EOS switch Capacitor.
Flipper Coil Numbers and Strength.
Convert to the Newer "Parallel Wound" Flipper
Left: A parallel wound FL11630 flipper coil. Note the lug on
the far right is the common lug, with both the thin and thick coil winding
wires attached. The center and the left lugs connect to the EOS switch
(the wires going up). The two outside lugs are the power and return wires,
with the gray power wire going to the right lug (the lug with the diode
If you get the two outside lug power wires reversed, a 50 volt solenoid fuse will blow, and the flipper buttons will not control the flipper coils! Instead they will do something weird like turn the flash bulbs on. Just reverse the wires and install a new fuse, and you're all set to go.
The CPU Board Flipper Relay K1.
EOS Switch Maitainence.
Adjusting the EOS switch.
Shorting the Flipper EOS switch to the Lane Change
When adjusting or cleaning the flipper EOS switches or lane change switches, make sure the game is turned OFF. This will prevent shorting these two switches together. Also, do not clean the smaller lane change switch with anything other than a business card.
Lane Change on games with Interconnect boards.
Flipper Rebuild Kits.
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.
Measuring the coil stop with a dial caliper.
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 will 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). A new coil stop is .440 inches thick. If your coil stop, after filing, is less than .425 inches thick, you should replace it. Less than .425, and you'll have problems with the flipper pawl hanging on the EOS switch. Coil stops are less than $1 each. If in doubt, just replace it!
assembly removed. The flipper shaft can
be seen extending through the playfield,
and through the nylon flipper bushing.
Use your allen wrench and an open 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.
Worn Coil Bracket?
The flipper bushing is a nylon part that the flipper shaft passes through. Unless it is cracked, or the flipper was very weak, or the game has more than 30,000 plays, it may not be necessary to replace this part. It's pretty easy to tell if it needs replacing. 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.
Right: Note the plunger tip has mushroomed, and there is considerable plunger pitting.
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 flipper 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).
Top: New style, fatter and more substantial flipper
Replace the flipper plunger and link. A new plunger/link can be bought for $1.50. (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.)
freshly installed (white) pawl heat shrink tubing and allen bolt.
The flipper pawl's job is to activate the EOS switch at the flippers' 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 can 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 because 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.
coil. Note the use of the white plastic
flipper "tool" to get the spacing correct.
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.
Re-installing the Flipper Pawl Assembly and Flipper
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 easily 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".
Williams changed flipper return spring styles in 1992. So on system 11 games, there's a cone-shaped flipper return spring that goes 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. First they changed the style of flipper link to be thicker, and have a more rounded contact point. Second they stopped using a cone 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).
Tightening the Flipper Pawl Assembly.
Cleaning and Adjusting the EOS Switch.
Clean the EOS switch contacts with a small metal 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. If the switch is in really bad condition, replace it.
End of System 11 Repair document Part Three.
* Go to System 11 Repair document Part One
* Go to System 11 Repair document Part Two
* Go to the Pin Fix-It Index at http://marvin3m.com/fix.htm
* Go to Marvin's Marvelous Mechanical Museum at http://marvin3m.com