None of the controlled (matrix) lamps light; GI still works.

All CPU-controlled lamps out

Cause: The fuse feeding the large 30,000 mfd lamp matrix capacitor in the backbox has blown, or there is a broken lug on that capacitor or the bridge beside it.

Checks

• Check that fuse.
• Inspect the capacitor and bridge lugs and wires.

Fix

• Replace the fuse and repair any broken lug or wire.

Systems

• Williams System 11
• Williams System 11A
• Williams System 11B
• Williams System 11C

Related tips

• A single controlled lamp out
• System 11 lamp matrix
• Testing lamp matrix columns with a test socket
• Testing lamp matrix rows with a test socket
• Lamp matrix still wrong after replacing transistors: upstream parts
• Part of a lamp row or column stays off
• Flash lamp dead on an early System 11 game
• A column of controlled lamps out: failed lamp column transistor Q60

Source: Repairing Williams System 11 Pinball 1986 to 1990, Part Two, Clay Harrell (pinrepair.com)