After a teardown and reassembly, one trough opto (ball 4) never registers and the game reports a missing ball. Swapping the opto, the trough boards, the CPU and the driver board changes nothing.
Trough opto dead after reassembly: flasher plug on a switch connector
Cause: During reassembly a ramp flasher plug had been pushed onto a switch connector, which upset the switch matrix.
Checks
- Before swapping boards, walk every connector you unplugged and match it to the wiring diagram or your photos.
- Look for plugs with the same pin count that fit more than one header.
Fix
- Move the misplaced plugs back to their correct headers. Here nothing was damaged and the opto worked again.
Systems
Games
Related tips
- Trough keeps ejecting balls: loose ground pin starving the opto boards
- One switch does not work
- A switch does not register in the switch test
- Narrowing a switch matrix fault to the CPU board, wiring or opto boards
- Several switches in one row or column dead: a broken daisy-chain wire
- One switch also triggers another: corroded switch connector on the CPU board
- "Check Switch ##" message
- Switch matrix chips on the CPU board
Source: Pinball Repair help group!! (Facebook group)