Some or all of the general illumination is out and the playfield looks dark.

GI lamps out, game dark: burnt power supply connector 3J8 (pre-Banzai Run)

Cause: The GI output connector 3J8 at the lower right of the power supply board overheats; its pins, solder joints and housing burn, adding resistance until the circuit opens or the GI fuse fails.

Checks

• Check the GI fuses.
• Unplug 3J8 and look for brown or black pins, a charred housing or cracked solder joints on the header.
• The yellow transformer GI wires arrive on a pigtail connector beside it, which rarely burns.

Fix

• Replace the header pins on the board as well as the housing and female pins (see the burnt connector repair).

Systems

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

Related tips

• Whole game flickers off and on, then dies: burnt ground pin at the power supply board
• Repairing a burnt GI connector properly
• Right-side playfield GI out: a wire not seated in a new power board connector
• Random resets, days or minutes apart: burnt power supply AC input connector
• What the System 11 power supply board feeds
• Power supply board fuses (typical game)
• Game resets when the flippers are used: recap supply and renew MPU power connector
• Rebuilding the +100 V section of the power supply

Source: Repairing Williams System 11 Pinball 1986 to 1990, Deel 1, Clay Harrell (pinrepair.com)