The 192 x 64 display still blanks or resets after the power harness is fixed.

Large display still unstable after the harness fix

Cause: A leaky +5/+12 V bridge DB1 on the power supply, or a shorted backbox bridge BR3 or a failed lug on it or its fuse.

Checks

• Check BR3 and its fuse on the backbox ground plane.
• Check the ground strap to the display controller.

Fix

• Replace DB1. On the solder side, add an 18 gauge wire from DB1 "+" to C4 "+" and another from DB1 "-" to C1 "-" to guard against future cracked joints.
• Replace BR3 or its connectors if faulty.

Systems

• Data East/Sega CPU Version 3b

Games

• Batman Forever
• Baywatch
• Mary Shelley's Frankenstein
• Maverick

Related tips

• Build your own 192 x 64 display power harness
• Large 192 x 64 DMD power supply CN5 pinout
• 192 x 64 display blanks out or the game resets
• Large 192 x 64 display power connectors by display maker
• Large 192 x 64 display blanks or resets (Sega bulletin 106)
• Running the large display on the bench
• Setting up a replacement 192 x 64 display
• The 192 x 64 display makes its own high voltage

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