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. They are always on. That is, the light emitting half of an opto switch is always powered on, as long as the game is powered on. LED's aren't much different than light bulbs; they eventually burn out too.

    Several different optos used in Williams games. The "U" shaped 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 diode shown is a replacement LED transmitter for the stand-up optos, and for opto boards used in ball troughs, etc.

    Optos are used on fliptronics
    flipper switches. Note the plastic
    activator arm that moves between
    the "U" shaped optos. Originally
    Williams made these from metal,
    but switched to plastic to save
    money. The plastic version can
    often warp so they don't clear
    the opto, causing a flipper not
    to work.

    flipper switch optos

      Where Optos are Used.
      Williams uses optos for lots of applications. WPC Fliptronics flipper buttons are opto activated. Many clear ramps have opto ball sensors. Many pre-1990 Williams drop targets use optos (they stopped using them there because the 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 infra-red LED (light emitting diode). The receiver is a light sensitive transistor. The transmitter 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.

      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. The display will indicate if the switch works.

      If an opto switch doesn't work, first check that your +12 volts is working. If you have blown the +12 volt fuse, there will be no power to the optos, and they won't work.

      If there is +12 volts going to the opto, there is a good chance the transmitter has failed. To test the receiver, first put the game into the "switch edge" test. Then block the opto transmitter with a piece of tape. Now shine a penlight flash light into the receiver. The switch should "close". When you remove the light, the switch should "open". If the receiver is working properely, there's a good chance the transmitter has burned out.

      If you have +12 volts in your game (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 almost never dies. That's because it only senses light, and doesn't produce light. The transmitter will be the offending unit 98% of the time. But there is a good way to test the transmitter side of an opto switch.

    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 is so handy.

    testing optos

      Radio Shack sells a $5 credit card sized "infrared sensor". If you put this card right in front of an opto transmitter, you can see if the opto is emitting light. The light will show on the colored band of the sensor card only.

      Optos on Newer WPC games.
      Older WPC games use optos with straight resistive photocells. Newer WPC 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 test card), the opto could still not function properely. Replacing the opto is the only thing that will fix it.

      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 LM339 voltage comparitor on the opto board. If everything else checks out, replace ALL the LM339 chips (and use sockets!) on the opto board (there are usually two of these chips on the opto board).

      WPC Fliptronics Flipper Optos.
      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 your 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), you can swap the left and right flipper opto boards, and see if the problem moves to the opposite flipper. Note: you must have both flipper opto boards plugged in for this test to work! Opto board power is jumped through the left opto board. Both opto boards must be plugged in for the right one to work!

      If indeed one of the flipper optos is bad, and your game only has two flippers, you can 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. Then unsolder both optos, and throw the bad one away. Then re-solder the good opto into the marked position on the flipper opto board.

      Weak Flippers and Bad LM339's on the Fliptronics Board.
      On WPC fliptronics to WPC-S board, chips U4 and U6 (LM339) on fliptronics board can fail. On WPC-95, these LM339 chips are on the CPU board at locations U25 and/or 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.

      Replacement Optos.
      Unfortunately, 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 expensive. The cheapest I've found these optos is from Competitive Products Corp (800-562-7283) for $5 each (long leads too!). For non "U" shaped opto applications, you can get infrared opto LED transmitters cheaply (get a transmitter voltage of 1.0 to 1.4 volts). Note the color of the opto doesn't matter, just as long as it's an infrared emitting LED. Radio Shack sells the infrared LED, part number 276-143C (replaces Williams A-14231). Radio Shack also sells an infrared transistor (receiver), part number 276-145A (replaces Williams A-14232).

      The industry part number for the "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 won't 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.

    3i. When things don't work: Eddy Sensors (electronic ball sensors)
      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 and Theatre of Magic 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 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.

      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.

      Twilight Zone Eddy's.
      Note eddy sensors were used as early as Twlight Zone. The eddy sensor in TZ are different than the later sensors, and does NOT have an adjustment pot (they also are called a different name, like the "Trough Proximity" board). The eddy sensor that causes the most trouble in Twilight Zone is the sensor by the ball trough (switch# 26). Usually the problem is the molex connector. 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. 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 board is available for under $15.

    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.


    3j. When things don't work: Ball Trough Problems (random multi-ball)
      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 ball 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 seven balls (depending on the game).

    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.
      When the opto ball trough was first used on Indiana Jones, 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 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 special rubber gromets where inserted into the holes. Lastly, 1/4" metal tubes 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.

      Ball Trough Upgrade Kit.
      If you want to upgrade your Indiana Jones ball trough to the current design (and solve your random multi-ball problems), you can 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! With some thought and a good hardware store, you can modify your original opto boards to mount like the newer style. It will require enlarging the mounting holes on your existing opto boards. You will also need to find some rubber gromets and small metal tubing (hobby shops often carry this). And if you use the newer metal trough #A-16809-2 (as currently sold by Williams), you will also need to move one of the large blue resistors to the back of the board, and drill a new mounting hole in the opto board. If you want to just be done with it (and spending $50 is not an issue), just order the upgrade kit from Williams, part# A-18244, and get the two new trough opto boards and the mounting hardware.

    This trough isn't too bad, but on the left you can see the start of divots
    being worn in the ball trough. These cause the balls to hang and not roll
    the length of the ball trough.

      Ball Trough Divots.
      Another problem with the new ball trough design is "divots". As the pinballs fall into the ball trough from the playfield, they eventually dig 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.

      To fix this, you can often use a Dremel tool and grind the divots out of the metal. If this doesn't work, you can order a new ball trough, part number A-16809-2. This newer design of the ball trough should last longer and divot less.

      More Random Multiball: the Ball Trough Optic Resistors.
      The ball trough optic boards have several large blue resistors mounted to them. Since these board get a fair amount of shock and vibration from balls, often these resistors can break. If this happens, you'll can get random (and continual) multiball. Check these large blue power resistors for breaks or cracks. Usually the resistor leads break right where they connect to the circuit board.

    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).

    bad DMD

      Dot Matrix Displays.
      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 can'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.

      But the really bad news about DMD's that are failing is how they die. When a DMD starts to get blurry or displays gaps, the power requirements for the display dramatically increases. This stresses the dot matrix controller board. If the display is not replaced, the controller board can fail too. Sometimes the controller board burns beyond repair.

      The moral to this story is to replace a marginally bad DMD with a new display as soon as possible. Don't postpone the inevitable. You can get a new DMD from Competitive Products Corp (800-562-7283) or Pinball Resource (914-473-7114). The whole assembly is about $115.

      Buy an entire DMD display glass and board, or just a new Glass?
      You can just buy a new dot matrix glass only, which will also solve the "outgas" problem. These are available for about $65, which is almost half the price of buying both the display and its attached circuit board. Don't be cheap; just spend the extra $50 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 you have a "pin" style DMD, 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.

      Diagnosing Other 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. On WPC-S and before, these are 3/8 amp fast-blo 1.25" fuses. On WPC-95, these are T0.315 amp 5x20mm fuses.

    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 voltages

      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. Check these voltages at the dot matrix display, or at connector J604 on the controller board. The pin out is:
      • Pin 1: -125 volts
      • Pin 2: -113 volts
      • Pin 3: Key
      • Pin 4: Ground
      • Pin 5: Ground
      • Pin 6: +5 volts
      • Pin 7: +12 volts
      • Pin 8: +62 volts
      If the -125 volts is missing, -113 volts will be missing too. All voltages should be pretty much right at the above specs. If they are not, you need to rebuild the dot matrix controller.

      Display and fuses good, but still missing or low voltages.
      If you have checked the fuses, and you know the display itself is good (tested in another game), you will need to rebuild the Dot matrix controller board. Usually it's either or both of the MJE power transistors (the ones with big heat sinks) at locations Q1 (WPC-95) or Q3 (WPC-S and prior), and Q6. If you want to rebuild the entire power sections, here are the components to replace.

      • MJE15030: Q1 on WPC-95, Q3 on WPC-S and prior. Controls the +62 volts. Connects to F601 to BR1 (and D3 and Q2, Q10 and R4, R3, R12 on WPC-S and prior).
      • MJE15030: Q7 on all WPC versions. Controls the -113 volts (connects to Q6 and D6 and R8, R9 on WPC-S and prior).
      • MJE15031: Q6 on all WPC versions. Controls the -125 volts (and -113 volts). Connects to F602 to BR2 (and D4, D5 and Q4, Q5 and R5, R6, R13 on WPC-S and prior).
      • MPSD02: Q2, Q10 on WPC-S and prior. Q2, Q3 on WPC-95.
      • MPSD52: Q4, Q5 on WPC-S and prior. Q4, Q5 on WPC-95.
      • 2N3904: Q1 on WPC-S and prior only).
      • 1N4759 (62 volts): D3 on WPC-S and prior. D2 on WPC-95.
      • 1N4758 (56 volts): D4, D5 on WPC-S and prior. D1, D18 on WPC-95. Doesn't fail as often as the other above listed components.

      Also you will need to check resistor values. They should be within 10% of spec:

      • 4.7k ohms, 5 watts: R8 on WPC-S and prior, R43 on WPC-95. Replace if it looks at all damaged, even if it measures OK.
      • 1.8k ohms, 5 watts: R9 on WPC-S and prior, R44 on WPC-95. Replace if it looks at all damaged, even if it measures OK.
      • 120 ohm 1/2 watt resistors at R4, R5 (WPC-S and prior only).
      • 47k ohms 1/2 watt at R3, R6, R12, R13 (WPC-S and prior only).

      Generally either Q1/Q3 or Q6 will go bad. If either of these fail, both should be replaced(make sure you use white heat sink compound when replacing these, and make sure you have them screwed tightly to their heat sinks). The MJE at Q7 comes after Q6, so it usually survives. Also the smaller switching transistors that are connected to Q1/Q3 and Q6 should be replaced (MPSD02 and MPSD52). Finally the zener diodes 1N4759 (62 volts) should also be replaced. The diode 1N4742 (12 volts, D6, D8 on WPC-S and prior and D3, D5 on WPC-95) generally do not go bad. On WPC-S and prior, check the 120 ohm 1/2 watt resistors at R4, R5 and 47k ohms 1/2 watt at R3, R6, R12, R13. Also check the 4.7 ohms 5 watt and 1.8k ohms, 5 watt resistors. Replace any resistors that are out of tolerence or that appear burnt. Always mount the resistors slightly above the board to allow air flow below them.

      Cloudy Dot Matrix Display.
      This is usually caused by heat related problems. Fixing this could be as simple as adding new white heat sink compound to Q1/Q3, Q6, Q7. Also make sure they are tight to their heat sink.

      Wavy Hum-bar in the Dot Matrix Display.
      If you WPC-S or earlier dot matrix display has a "wavy hum-bar", try replacing capacitors C6, C9 and C10 on the dot matrix controller board. These are .1 mfd 500 volt caps that filter the DMD high voltages. If they caps fail, you will get the hum bars.

      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 on the dot matrix controller board.

      Replacing Q2/Q10 and Q4/Q5 on the Dot Matrix Controller board.
      On WPC-S and prior games, the dot matrix controller board uses two MPSD02 and MPSD52 transistors. More common transistors are available for replacement. A 2N5551 can be substituted for the MPSD02, and a 2N5401 can be used for the MPSD42.

    3L. When things don't work: Power-On LED's 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 Flash Codes WPC-S and Prior.
      D19 is labeled "blanking", D20 is labeled "diagnostic" and D21 is labeled "+5vdc".

      • At power-on, D19 and D21 should be ON. D20 should be OFF.
      • During normal operation, D19 should be OFF. D20 should be FLASHING. D21 should be ON.

        Problem Power-On CPU D20 (diagnostic) Flash Codes:

        • blinks ONE time: U6 CPU game ROM bad
        • blinks TWO times: U8 CMOS RAM chip bad
        • blinks THREE times: U9 WPC custom chip bad

      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

      Driver Board Flash Codes WPC-S and Prior.

      • LED1: +12 volts DC switch matrix circuit, normally ON.
      • LED2: high/low line voltage sensor, normally ON.
      • LED3: high/low line voltage sensor, normally OFF.
      • LED4: +5 volts DC digital circuit, normally ON.
      • LED5: +20 volts DC flashlamp circuit, normally ON.
      • LED6: +18 volts DC lamp matrix circuit, normally ON.
      • LED7: +12 volts DC power circuit (motors, relays, etc), normally ON.

      WPC-95 CPU Flash Codes.
      LED201 is labeled "blanking", LED202 is labeled "power" and LED203 is labeled "diagnostics".

      • At power-on, LED201 and LED202 should be ON. LED203 should be OFF.
      • During normal operation, LED201 should be OFF. LED202 should be ON. LED203 should be FLASHING.

        Problem Power-On CPU LED203 (diagnostic) Flash Codes:

        • blinks ONE time: G11 CPU game ROM bad
        • blinks TWO times: U8 CMOS RAM chip bad
        • blinks THREE times: G10 Security PIC chip bad or for different game

      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

      WPC-95 Driver Board LED's.

      • LED100: +12 volts DC regulated, normally ON.
      • LED101: +5 volts DC digital, normally ON.
      • LED102: +18 volts DC lamps, normally OFF.
      • LED103: +12 volts DC un-regulated, normally ON.
      • LED104: +20 volts DC flashlamps, normally ON.
      • LED105: +50 volts DC coils, normally ON.

    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.

      The Battery Holder: a Weak Link.
      If after replacing the batteries, you still get a "Factory Setting Restored" 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.

    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.

      Is power getting to the U8 RAM chip?
      With your game off and 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, this 1N4148 diode is bad.

      Next test for voltage at the CPU U8 RAM chip. 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.

      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 Restored" or "Set Time and Date" errors, you may have a bad CPU U8 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 U8 RAM chip is a 6264-L or 2064 RAM chip.

      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.

      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?).
      • Remove the old batteries and discard.
      • Check the battery holder's terminals for any corrosion. 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.

    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 lives here

    The MOV is the green disc soldered across the
    lugs of the radio frequency interference filter.

    the MOV


      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 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:

      • Re-seat all the sound board ribbon cables. Surprisingly, this fixes a large number of WPC sound problems!
      • Bad rectifier diodes on the sound board. Often these become leaky and can cause intermittent problems before they total short.
      • 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: 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.
      • If the LM1875 isn't at fault, check both of the op-amps too. Depending on the revision of the sound board (DCS or pre-DCS), these audio amps can effect a certain type of sound they amplify.
      • On DCS games, the DAC for the DSP chip dies, and the TDA2030 amps are pretty fragile too.

      Volume up FULL and Can't turn it Down.
      The volume control on all WPC games is electronic. On pre-WPC95 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.

      Lots of Static.
      Problem sound boards can produce a large amount of static. The TL084 quad Op-Amp (U21 on WPC-S and prior) can be the cause of this. Also the TDA2030 amp can also cause this. Finally the large filtering 1000 mfd 35 volt capacitors can also be the problem. Finally check for cracked solder joints on these 1000 mfd caps (solder jumper wires, as done to the bridge rectifiers explained earlier).

    3p. When things don't work: Test Report & The Diagnostic Dot.
      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.

    3q. 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.

      WPC-S and Prior CPU Flash Codes .
      D19 is labeled "blanking", D20 is labeled "diagnostic" and D21 is labeled "+5vdc".

      • At power-on, D19 and D21 should be ON. D20 should be OFF.
      • After the CPU board "boots" (during normal operation), D19 should be OFF. D20 should be FLASHING. D21 should be ON.

        Problem Power-On CPU D20 (diagnostic) Flash Codes:
        If D20 blinks at power-on, and then stops blinking, here is what the blinks translate to:

        • blinks ONE time: U6 CPU game ROM bad
        • blinks TWO times: U8 CMOS RAM chip bad
        • blinks THREE times: U9 WPC custom chip bad

      WPC-95 CPU Flash Codes.
      LED201 is labeled "blanking", LED202 is labeled "power" and LED203 is labeled "diagnostics".

      • At power-on, LED201 and LED202 should be ON. LED203 should be OFF.
      • During normal operation, LED201 should be OFF. LED202 should be ON. LED203 should be FLASHING.

        Problem Power-On CPU LED203 (diagnostic) Flash Codes:
        If LED203 blinks at power-on, and then stops blinking, here is what the blinks translate to:

          • blinks ONE time: G11 CPU game ROM bad
          • blinks TWO times: U8 CMOS RAM chip bad
          • blinks THREE times: G10 Security PIC chip bad or for different game

      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. When the CPU doesn't boot, you have found the connector (and hence the board) that is dragging the CPU down.

      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 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:
      • Pins 1,2,3 = ground
      • 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 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 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.

      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.

      Shotgun Approach.
      The chips are U1, U2 (74LS244) and U3 (74LS245) are the ones that affect on a dead CPU the most. If replacing those yeilds nothing, then try replacing U5 (74LS14). 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 startup circuit) can be replaced. Using a logic probe, also check for a good clock signal on pins 34 and 35 of U4 (6809).

    3r. When things don't work: Miscellaneous Oddities.

      The Clock won't keep Time.
      Problem: The internal time clock appears to be running very slow, only about 25% of realtime 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, are brand new. The clock function is handled by U9 (the ASIC chip) and U21 (a CMOS 4584), and the 32.768KHz crystal.

      Answer: Both legs of crystal X1 were soldered to the same spot! It looks like it came from the factory that way. After removing the crystal and putting both legs in the correct locations, the time is tracking 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 your 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.

      I can't enter my high score initials on Funhouse.
      Problem: 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. If this was a fliptronics game, the flippers wouldn't have worked either.

      The flippers and dot matrix display died while playing a game.
      Problem: 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.

      Strange Error Message.
      Problem: 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.

      Dot Matrix Display Got Blurry.
      Problem: 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 ribbon cables in their sockets.

    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.

    non-fliptronics flipper  fliptronics flipper
    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.

      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. Here are the relative flipper coil strengths, from weakest to strongest:

      • FL-11753: used for small flippers, like the "Thing" flipper on Addam's Family.
      • FL-11722: used for weak flippers, like Twilight Zone's upper right flipper.
      • FL-11630: "standard" flipper strength, as used on older games like Earthshaker, Whirlwind, etc.
      • FL-15411 : strong flipper, as used for main flippers on Addam's Family, Twilight Zone, etc.
      • FL-11629: strongest Williams flipper. Used on most of the newest WPC games.

      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.

    coil stop removed  mushroomed and fixed coil stops

    Measuring the coil stop with a dial caliper.
    The thickness of a new coil stop is .440 inches.
    After re-working, if yours is .425 inches or less,
    replace it.

    measuring a coil stop

      Removing 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 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, 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.

    pawl removed

      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 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?
      If the game was played so much that the coil sleeve wore out (thanks in part to a worn plunger link), 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.

      Replace the Flipper Bushing?
      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.

      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.

    flipper pawl assembly  mushroomed plunger

      Rebuilding 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 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 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.

    new and old style links

      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 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.)

      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.

    new heat shrink tubing

      Replacing the Pawl Heat Shrink Tubing.
      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 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.

    pawl spacer tool in place

      Flipper Coil Types.
      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 Coil.
      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.

      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).

      Tightening the Flipper Pawl Assembly.
      Now you are ready to tighten the flipper pawl assembly to the flipper shaft. 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.

    Using a toothpick as a flipper alignment tool.
    toothpick alignment tool

      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 on the flipper). With the flipper positioned correctly, lift the playfield and tighten down (very tight!) the flipper pawl assembly's allen bolt. Remove the flipper spacing tool and the toothpick. 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 your playfield!

    Both flippers in the "up" position. Notice how they look symmetrical.
    flippers in 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.

      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 small 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, make sure the EOS switch doesn't hang on the flipper pawl when the flipper is fully extended. 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.

      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 (or A-15847 which has a slightly meatier link). Use this plunger/link for the older spring set up where the cone-shaped flipper return spring is over the plunger.
      • Nylon Flipper Link only: #03-8050 (or 03-8753 which is the meatier link).
      • EOS Switch: non-Fliptronics version #03-7811. Fliptronics version #SW-1A-193.
      • Coil Stop: #A-12390 (uses two allen head 10-32 x 3/8" bolts)
      • 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, the Pinball Resource (914-473-7114), or Competitive Products Corp (800-562-7283).

    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

    protected slignshot plastic

      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.


      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.

      There are a number of products available for cleaning the playfield. Millwax comes to mind. (Personally, I would avoid this product. Millwax isn't even really a wax. It's a cleaner with extremly small amounts of wax and lots of solvents to keep the cleaner/wax in an easy-to-apply liquid form. It's false protection; you're not waxing your playfield, you're only cleaning it with Millwax. Also Millwax contains petroleum distillates, which are probably harmful). Stay away from Wildcat products. They react with plastic and can crack mylar and yellow plastic ramps.

      Personally I like Novus#2 plastic polish for cleaning playfields. It works great, and leaves a great shine. It contains no harmful solvents. It's very gentle, yet cleans fast and well. I buy it at my local grocery store, but you can also get it through most pinball retailers. It is also the product recommended by Williams for your playfield!

    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 Johnson's Paste Wax 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, unless it was designed for it. 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. But in reality, black rubber creates black dust, so you have to clean the playfield and parts more often. 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 and Attack from Mars were two 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. Johnson's Paste Wax, Meguires Carnauba Wax, 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. 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.