Fuses F104 and F112 on the power driver board blow when the game starts or the coin door is closed, even with some solenoid connectors unplugged. The fault comes and goes depending on whether the playfield is down, raised, or resting on its support.

F104 and F112 blow at start-up: auto-plunger coil wire touching its bracket

Cause: The fine lead wire from the auto-plunger coil to its lug had moved and was touching the coil's metal bracket. The bracket is only grounded through the playfield support arm in some positions, which is why the fault changed with the playfield position.

Checks

• Unplug solenoid connectors one at a time (or pull F104) to narrow down which circuit blows the fuse.
• Disconnect suspect devices (here the glove magnet connector seemed to be the cause) and then inspect every coil on that supply for a lead or lug touching metal.
• Test with the playfield both down and raised.

Fix

• Move the coil's lead wire away from the bracket, insulate it, and resolder it to its lug.

Systems

• WPC-Security (WPC-S)

Games

• Johnny Mnemonic

Related tips

• Which fault blows which driver board fuse (WPC-89/WPC-S)
• Finding whether a blowing fuse is a board or wiring fault
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• WPC: fuse holder snaps off the power driver board: replace the clips properly
• WPC power driver board fuses and what they feed
• WPC-89/WPC-S driver board fuse ratings
• Fuse F116 keeps blowing

Source: Pinball Repair help group!! (Facebook group)