Williams WPC
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1 Introduction
Put system info here
2 Games
Put list of games that used this system here (including anything that might not have been pinball)
3 Technical Info
4 Problems and Fixes
4.1 Power Driver Issues
This may not apply to some, as MPU might have been part of it.
The WPC System Boardset and History
4.2 MPU Issues
4.3 Power Supply Issues
4.4 Display Driver Board
Possibly doesn't apply to some, can't think of an example.
5 Game Specific Problems and Fixes
5.1 Doctor Who
The time expander in Doctor Who can be very problematic - the opto boards crack and prevent the mushroom targets on the 2nd level of the time expander from working properly. Often the boards can be fixed with jumper wires and resoldering, and there are aftermarket boards available to replace both. Additionally, the plastic carrier the optos are attached too can warp, preventing the warped section from working. Finally, there is a cardboard shield attached to the carrier that prevents stray light leakage from affecting the optos (most notably during the Davros rounds). If it is missing usually you cannot complete the round as the light from the lock lamps prevents the optos from turning off.
5.2 The Shadow
Fast shots to the lower phurba ramp diverted to the right sometimes get stuck because of the switch wireform hanging the ball up. One way to fix this is to get a replacement microswitch with a long wire actuator, and bend it so the activation occurs much later down the wireform ramp, as shown in this photo: Media:shadowswitch.jpg
5.3 Star Trek: TNG
There is a thin wire running from the 8 driver board (right side of backbox) to the single drop target reset coil on the playfield. Make sure this wire is present and secure, as coils will lock on if not. Replace this wire with a thicker variant to help prevent it breaking from vibration and stress.
You might remove the three wires from the lug ( purple wire/green stripe, the thin one looks more lavender) and solder to a single wire and solder the single wire to the coil lug. that way if it ever breaks off from vibration, the three stay together and don't knock out a transistor on the small driver board and lock on a subway coil.
Missing ball or Extra Multi-Ball A common problem is broken wires on the trough optical board(s), especially the large 270 ohm resistors. One way to test is to put the machine in switch edge test mode and bang on the playfield just above the flippers to see if any switch edges register. They should not. Replacement boards are available with shock mounts or you can alter your own boards by drilling out the holes and adding grommets. <<LINK TO CONVERSION INSTRUCTIONS NEEDED.>>
5.4 Indiana Jones
The front right switch on the path of adventure gets hit underneath by ball hits. This shorts the wires/diode/switch lugs. This switch is on the same row or column as the ball jam opto. This is the last opto a ball goes by going up to the shooter lane. So if you are getting extra balls kicked up to the shooter lane, that front right switch is a good place to start. LTG :)
6 Repair Logs
Did you do a repair? Log it here as a possible solution for others.
Medieval Madness
Draw Bridge is acting up
Check the pivot points, they get peened by ball hits and can distort and bind. A bit of work to take apart, they can be flattened or filed to make a smooth pivot point again. LTG :)
White Water
Ball hangs on "lip" of reproduction ramp between Spine Chiller ramp exit and upper playfield
The reproduction ramps from Pinball Inc are excellent. Some Spine Chiller ramps finished manufacture with an almost undetectable "lip" at the exit point of the ramp. Prior to installation, use an Exacto knife or similar to slice that lip off.
Ball sits in "dimple" under "lock-to-upper-playfield" VUK
After thousands of landings from the VUK onto the same upper playfield spot, the playfield becomes dimpled. The ball will sit in that dimple until shaken loose or until another ball emerges from the VUK (as in multi-ball). A "Cliffy" protector will solve this problem quite elegantly. [1]
Ball spins backwards after being launched up the "lock-to-upper-playfield" VUK
Sometimes, the ball will "backspin" after being ejected from the upper VUK, slowing gameplay. Install one (perhaps two) rubber post rings (or rubber grommets) as pictured here: [2]