A game that ran fine stops working or loses features after being moved and set up.

Game worked before the move but not after

Cause: A pin has slid out of a head-to-cabinet plug housing, or a wire has broken right at its crimp.

Checks

• Inspect every plug between the head and cabinet, pulling gently on each wire.

Fix

• Reseat loose pins and re-crimp broken wires with new pins.

Systems

• Williams System 3
• Williams System 4
• Williams System 6 / 6A
• Williams System 7

Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part One, Clay Harrell (pinrepair.com)