Lowering GI voltage with a bridge rectifier

Steps

• Turn the game off and unplug it.
• Break one side of the GI circuit (feed or return, the yellow/white transformer wires) and connect the two ends to the bridge's + and one AC lug.
• Jumper the + lug to the - lug.
• Jumper the two AC lugs together.
• Screw the bridge down to a heat sink, as it gets warm. No extra fuse is needed; if the bridge shorts the GI just returns to full voltage.
• Power up and confirm the GI voltage has dropped by about 0.5 V AC.

Unplug the game before working on the transformer, line wiring or power supply board.

Systems

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

Related tips

• Replacement bridge rectifiers
• Choosing replacement bridge rectifiers
• Transistors, diodes and chips to keep for CPU and driver repairs
• No or low +5 V from the power supply

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