The game is dead and LED4 on the driver board is out.

Driver board LED4 off (+5 V missing, game will not boot)

Cause: No +5 V: fuse F113, bridge BR2 or capacitor C5; less often the LM323 regulator at Q1. The supply runs from J101 pins 1-2 through F113, BR2, C5 and Q1 to J114 pins 3-4.

Checks

• Check F113.
• Measure TP2 to TP5 for 5 V.
• Test BR2 and C5.

Fix

• Replace the failed fuse, bridge, capacitor or regulator.

Systems

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

Related tips

• Driver board LED4 off and the game won't boot (WPC-S and earlier)
• 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)
• Driver board LED6 off: lamp matrix 18 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
• Driver board filter capacitors wear out
• Voltages made by the WPC power driver board

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