The score displays are dark or barely lit, with the high-voltage fuse intact.

Alphanumeric displays dim or dead

Cause: The two 39k 1 W resistors R8 and R9 in the ±100 V section have drifted high or opened.

Checks

• Measure ±100 V at CN5 (see the voltage check).
• Measure R8 and R9 with the power off.

Fix

• Replace R8 and R9 with 39k, 1 or 2 W flameproof resistors, mounted slightly above the board for airflow, before blaming the glass.

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

• Run alphanumeric displays at 91 V for longer life
• Alphanumeric displays show only a few digits at a time
• Displays weak with low 100 V even unplugged
• High-voltage display fuse F3 keeps blowing
• Rebuild the alphanumeric ±100 V section
• Alphanumeric supply: parts for the +100 V side
• Alphanumeric supply: parts for the -100 V side
• Score display boards by game range

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