Finding whether a blowing fuse is a board or wiring fault

Steps

• Game off. Unplug driver board connectors J114, J116, J117 and J118.
• Fit a new fuse and turn the game on.
• If the fuse blows, its bridge rectifier is most likely shorted; replace it.
• If it holds, the boards are fine and a shorted wire in the game must be traced by hand.

Systems

• WPC Alpha-Numeric
• WPC Dot Matrix
• WPC Fliptronics
• WPC DCS
• WPC-Security (WPC-S)

Related tips

• Which fault blows which driver board fuse (WPC-89/WPC-S)
• Fuse F116 keeps blowing
• F111, F112 or the line fuse keeps blowing
• F104 and F112 blow at start-up: auto-plunger coil wire touching its bracket
• Switch matrix fuse F115 (F101 on WPC-95) blows as soon as it is replaced
• WPC: fuse holder snaps off the power driver board: replace the clips properly
• WPC-89/WPC-S driver board fuse ratings
• WPC power driver board fuses and what they feed

Source: Repairing Williams/Bally WPC Pinball Games from 1990 to 1999, Part Two, Clay Harrell (pinrepair.com)