CPU boards are only downward compatible

A version 3 CPU board can be used in a version 1 or 2 game, but a version 2 board will not run a version 3 game because it lacks the CPU-controlled special coil circuit. Fitting a version 3 board to Laser War needs board changes described in Data East service bulletin 6.

Systems

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

Related tips

• Other CPU jumpers and what they set
• Bench-testing a CPU board on +5 V
• CPU board versions 520-5003-01, -02 and -03
• Where the TIP122 drivers are on the CPU board
• CPU board PIA positions and jobs
• CPU jumpers J4 and J5 set the EPROM size at 5C
• Full CPU jumper settings by board version
• Data East CPU diagnostic test EPROM

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