GI is out or weak and the driver board GI headers are not burnt.

GI dead but the driver board connectors look fine

Cause: The round-pin Molex plug that joins the transformer's yellow GI wires to the harness in the cabinet bottom has overheated.

Checks

• Power off and inspect the plug carrying the yellow and yellow-white wires near the transformer.

Fix

• Replace it with new .093 inch pins: female 02-09-1119, male 02-09-2118.

Line voltage is present in the power box and at the transformer whenever the game is plugged in; unplug it before working there.

Systems

• WPC Alpha-Numeric
• WPC Dot Matrix
• WPC Fliptronics
• WPC DCS
• WPC-Security (WPC-S)
• WPC-95

Related tips

• GI still out with good board connectors: check the transformer plug
• Driving the Haunted House up-kicker from a pop bumper driver board
• Parts for converting an export Data East or Sega game to 120 V
• One GI string dead with good fuses and connector
• WPC transformers look alike but are not interchangeable
• One GI string dead though the board and fuse test fine: burnt connector in the cabinet
• GI string still dead after replacing J115: broken through-hole, add a jumper
• Two GI strings still dead after fixing a burnt J120: broken pads and traces

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