LED5 (TP7) is out and the flashers don't work.

Driver board LED5 off: flasher 20 V missing (WPC-S and earlier)

Cause: Normal with the coin door open on Twilight Zone and later games. Otherwise fuse F111, bridge BR4 or capacitor C11. Power enters on J102 pins 1,2 and 3,4 and leaves on J107 pins 5,6 (also J106, J108).

Checks

• Close the coin door.
• Check F111, BR4 and C11; measure TP7.

Fix

• Replace the failed part.

Systems

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

Related tips

• Driver board LED5 off (+20 V flashers)
• Bridge rectifiers to use on WPC-S and earlier driver boards
• Bridge positions on WPC-S and earlier driver boards
• Driver board LED1 off: switch matrix 12 V missing (WPC-S and earlier)
• Driver board LED7 off: unregulated 12 V missing (WPC-S and earlier)
• WPC-89/WPC-S driver board LEDs and test points
• Voltages made by the WPC power driver board
• Supplies made on the WPC power driver board

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