hocuslocus

Was it a faulty opto in the end or something else? I have the exact same problem, my daughter registered 400+ warps, and I had to shut down the machine as it was triggering like crazy

Thanks

Thanks, I'll try that. Although that one opto is a pain to reach, and relatively far away from any other electronics (since it's behind the backboard).

I noticed that it most often triggers when there is heavy rumble (shaker, bumpers), at least when the failure does appear. This make me believe this is more a mechanical issue (opto alignment, connector getting loose) than electrical, but I'll check nonetheless.

I checked yesterday all wires and connectors. It turns out that the main connector from the optoboard to the CPU board was slightly (very very slightly) unseated. The opto cables were fine.

Since I reseated this connector, everything has been running fine, about 30 games so far. No need to dismount the opto and change them, lucky me.