Set an aftermarket "B" display supply for alphanumeric games

Steps

• One common aftermarket replacement supply is sold in A (alphanumeric), B (small DMD) and C (medium DMD) versions; B can be changed to suit alphanumeric games, A and C cannot be converted.
• Remove fuse F7.
• Fit jumpers RS10a and RS30b; remove RS10b and RS30a.
• Cut pin 5 (+12 V) of the board's CN5 connector.

The display power supply carries about 100 V or more; work on it with the game unplugged and let the capacitors discharge.

Systems

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

Related tips

• Alphanumeric games need the 520-5000-00 supply
• Alphanumeric supply: parts for the +100 V side
• Alphanumeric supply: parts for the -100 V side
• Power supply board versions are not interchangeable
• A 520-5047-02 supply can stand in for a 520-5047-01
• Z1 on the power supply is a varistor, not a diac
• Rebuild the alphanumeric ±100 V section
• Power supply board versions and their +5 V filter capacitors

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