Many GI lamps are dark at once.

A group of general illumination lamps is out

Cause: A blown GI fuse, or burnt pins in a GI connector at the power supply board or the interconnect board.

Checks

• Check the fuse for that GI string.
• Look for darkened or burnt pins in the GI connectors.

Fix

• Replace the fuse; repin or replace any burnt connector and header.

Systems

• Data East CPU Version 1/2
• Data East CPU Version 3
• Data East/Sega CPU Version 3b

Related tips

• General illumination dead or dim
• Bulb spares: #44 for CPU lamps, #47 for general illumination
• Every CPU-controlled lamp is out
• Group of lamps out
• Lamps on a plug-in lamp board do not light
• All controlled lamps out, GI fine: blown lamp supply fuse by the big filter cap
• One controlled lamp never lights, bulb is good
• Test each lamp column driver with a test lamp

Source: Repairing DataEast 1987 (Laser War) to Sega 1995 (Batman Forever), Part Three, Clay Harrell (pinrepair.com)