Testing the legacy special-solenoid circuit at CN18

Steps

• Remove the backglass, switch on and start a game, leaving the ball in the shooter lane.
• If CPU connector CN18 has a plug in it, unplug it.
• Clip a jumper to the backbox ground strap and touch the other end to CN18 pins 1 to 6 in turn.
• Each pin should fire its special solenoid; a pin may do nothing if the game does not use that output.

Systems

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

Related tips

• Special solenoids: switch-fired on CPU Rev 1/2, CPU-fired on Rev 3
• Special coil locks on only when a game starts or diagnostics begin (pre-Rev 3)
• The solenoid L/R select relay and transistor Q29
• Solenoid driver layout: 16 multiplexed plus 14 constant
• Version 3 CPU fires special coils once per switch closure
• Special coil stays on even after replacing its driver chain (Rev 3)
• Multiplexed L/R (A/B) banks and wire colours
• Bank select relay and CPU transistor Q29

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