Several unrelated playfield switches stop registering: none of the 10-point rebound switches score, a rollover is dead, the outhole works only now and then, and one switch on each drop target bank stops reading so the banks never reset.
Rebound, rollover, outhole and drop target switches dead: corroded J6/J7 switch plugs
Cause: Corroded, crusty contacts in the playfield switch connectors J6 and J7 at the MPU board, which sits in the area most affected by battery and age corrosion on System 1 games.
Checks
- Unplug J6 and J7 at the MPU board and look at the pins and housings for green or black corrosion and loose contacts.
- Remember that the 10-point rebound switches are wired in parallel, so one switch stuck closed stops all of them; check none are touching before blaming the connector.
- Test any suspect switch-matrix diodes on the diode boards while you are there.
Fix
- Replace the J6 and J7 connector housings and crimp pins with new ones (repin rather than cleaning badly corroded contacts).
- Replace any bad diodes found on the diode boards.
Systems
Games
Related tips
- Game over relay won't hold in: poor 5 V pin from the CPU to the driver board
- Target bank, outhole kicker and some lamps dead after board swap: miswired new cable
- Kickout hole fires nonstop once a game starts: blown 7405 in the switch circuit
Source: Pinball Repair help group!! (Facebook group)