Voltages a small or medium dot matrix display needs

Alphanumeric displays use -100 V, +100 V and +5 V. The 128 x 16 and 128 x 32 dot matrix displays need -98 V, -110 V, +68 V and +5 V, and some also need +12 V. All should be within 10 percent of nominal.

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 3
• Data East/Sega CPU Version 3b

Related tips

• Checklist for a dead small or medium dot matrix display
• The dot matrix display has its own computer
• Dot matrix controller CPUs by display size
• Small display shows vertical lines
• The three Data East dot matrix display sizes
• Display not working: check +5 V at the controller first
• Dot matrix controller boards
• Dot matrix display goes blank after a few minutes

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