Hi all! I need a little help troubleshooting a WPC Indiana Jones.
Symptoms are a coil firing repeatedly in the multiball subway. Intended behaviour is that when the middle subway opto is blocked by a ball, it triggers a coil, opening the subway gate. The problem is, the coil continues to fire every 20-ish seconds afterwards, as if the opto is still blocked even though it's now clear. This continues throughout the game and in the subsequent attract mode. If you enter the operator menu it stops, and doesn't start again until the next time the opto is blocked in game/attract.
The opto is working completely normally in switch test, nothing unusual. The coil is also working fine in test. I've cleaned then replaced the opto transmitter and receiver with a known working pair, no difference. I've also tried swapping over the whole power driver board just to rule it out, no changes.
Now I'm a bit clueless on where to look next. My next guess would be something on the CPU board, but I don't have a compatible donor board to test that, and I didn't want to start poking it until I knew where to look. Anyone have any ideas, or seen something similar?
Thanks for your thoughts!