Resets and low power to the driver board.

Burnt spade connectors in the power box

Cause: The single spade terminals on the power switch and RF line filter loosen and burn.

Checks

• With the game unplugged, inspect the power switch and RF filter terminals for heat damage.

Fix

• Solder the wires straight to the switch and filter lugs instead of fitting new spade connectors.

Unplug the game: the power box carries line voltage.

Systems

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

Related tips

• Repair a burnt GI connector on the driver board
• GI string dead with a scorched connector
• GI connectors on the driver board
• Burnt J115 connector on the power driver board: GI current, re-crimp
• Backbox GI out while flashers work: burnt connectors at J120 and J121
• Resets from worn power connectors between transformer, driver and CPU boards
• Check the AC power input connectors too
• Lamp matrix connectors on the driver board

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