Time Machine to The Simpsons swap the L and R banks

On these games the L (A) bank drives flash lamps and the R (B) bank drives coils, the opposite of other Data East/Sega games. Entering diagnostics releases the relay, so on these games a bank-switched coil gets power only when Q29 is grounded.

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

• Only flash lamps work when a game starts (L/R reversed games)
• Flash lamp stuck on and melting plastics on L/R reversed games
• Multiplexed L/R (A/B) banks and wire colours
• Bank select relay and CPU transistor Q29
• All L or all R bank coils/flashers dead: PPB relay K1
• L/R relay burnt or intermittent
• Flash lamp resistors on the PPB drop solenoid voltage for 12 V bulbs
• Solenoid driver layout: 16 multiplexed plus 14 constant

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