LED7 is out; optos, motors, relays and some displays lose power.

Driver board LED7 off (+12 V unregulated)

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

Checks

• Check F116.
• Measure TP1.

Fix

• Replace the failed part, and find the 12 V short if the fuse blows again.

Systems

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

Related tips

• Driver board LED7 off: unregulated 12 V missing (WPC-S and earlier)
• Voltages made by the WPC power driver board
• Supplies made on the WPC power driver board
• WPC power driver bridge rectifiers and +5 V regulator
• Driver board LED4 off and the game won't boot (WPC-S and earlier)
• Driver board LED1 off: switch matrix 12 V missing (WPC-S and earlier)
• Shorted or open bridge rectifiers
• Where the CPU board gets its power

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