Starting a game sends ball after ball into the shooter lane and onto the playfield, as if multiball began (common on 1992 Star Wars).

Balls keep launching as soon as a game starts

Cause: Cracked solder joints on the PPB L/R relay K1. The relay stays in the coil position, so when the game tries to light the flasher paired with the ball popper it fires the popper instead, and the auto-launch sends the ball in.

Checks

• Inspect the K1 relay solder joints on the PPB.

Fix

• Reflow the relay joints, or replace the relay if its contacts are burnt.

Systems

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

Related tips

• Only flash lamps work when a game starts (L/R reversed games)
• All L or all R bank coils/flashers dead: PPB relay K1
• Random coils firing and dead flashers on Tales from the Crypt
• Under-playfield relay boards and the PPB board
• A coil or flasher comes on and stays on at power-up
• Flash lamp resistors on the PPB drop solenoid voltage for 12 V bulbs
• Solenoid driver layout: 16 multiplexed plus 14 constant
• Multiplexed L/R (A/B) banks and wire colours

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