One lamp does not light.
A single controlled lamp out
Cause: A dead bulb, a wire off the socket lug, the lamp diode broken off, or a corroded socket (common on games imported from abroad).
Checks
- Check the bulb for continuity with the meter.
- Check the wires and diode at the socket.
Fix
- Replace the bulb, resolder the wire or diode, reseat the bulb, or bend #555 socket tabs for better contact.
Systems
Related tips
- All CPU-controlled lamps out
- Single lamp out, dim or flickering
- Lamp lights twice or two lamps act as one
- Part of a lamp row or column stays off
- Flash lamp dead on an early System 11 game
- Single matrix lamp out with good bulb and wiring
- Lamps in two columns light together in single lamp test: failed lamp column transistor
- System 11 lamp matrix
Source: Repairing Williams System 11 Pinball 1986 to 1990, Part Two, Clay Harrell (pinrepair.com)