LED7 (TP1) is out; motors, relays and optos fed from the unregulated 12 V don't work.

Driver board LED7 off: unregulated 12 V missing (WPC-S and earlier)

Cause: Fuse F116, bridge BR5 or capacitor C30. Power enters on J112 pins 1,2 and 3,5 and leaves on pin 2 of J116, J117 and J118.

Checks

• Check F116, BR5 and C30; measure TP1.

Fix

• Replace the failed part.

Systems

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

Related tips

• Driver board LED7 off (+12 V unregulated)
• Driver board LED5 off: flasher 20 V missing (WPC-S and earlier)
• Driver board LED1 off: switch matrix 12 V missing (WPC-S and earlier)
• Bridge rectifiers to use on WPC-S and earlier driver boards
• Bridge positions on WPC-S and earlier driver boards
• Driver board LED4 off and the game won't boot (WPC-S and earlier)
• WPC-89/WPC-S driver board LEDs and test points
• Voltages made by the WPC power driver board

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