On starting a game the flash lamps work but no coils fire, so the game cannot be played.

Only flash lamps work when a game starts (L/R reversed games)

Cause: On these seven games the PPB L/R relay K1 is wired the other way round: with K1 off, the L bank powers the flashers. A K1 with cracked solder joints never switches to the coils.

Checks

• Inspect K1 on the PPB for cracked or ringed solder joints.
• Confirm CPU transistor Q29 switches the relay.

Fix

• Reflow all eight K1 solder joints; replace the relay if its contacts are burnt.

Systems

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

Games

• Back to the Future
• Monday Night Football
• Phantom of the Opera
• Playboy 35th Anniversary
• Robocop
• The Simpsons
• Time Machine

Related tips

• All L or all R bank coils/flashers dead: PPB relay K1
• Balls keep launching as soon as a game starts
• Random coils firing and dead flashers on Tales from the Crypt
• Time Machine to The Simpsons swap the L and R banks
• A coil or flasher comes on and stays on at power-up
• Several bank-switched coils or flashers dead, or firing the wrong device
• Flash lamp resistors on the PPB drop solenoid voltage for 12 V bulbs
• No voltage at either lug of a coil

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