Greetings all. I have a South Park that was working without issue until Saturday. The right flipper locked on and blew the fuse. Found the diode on the coil broken. Replaced it and it locked on immediately again. Turned power off and found the controlling transistor on the driver board shorted. Replaced it and the flipper is back to flipping again. Unfortunately, something else inexplicable occurred as a result of the flipper locking on. I've lost power to half of the coils. 2 of the 3 pop bumpers, the Cartman VUK, the auto launcher, and Kenny's left movement coil do not fire. All of the switches test good. As a coincidence, all these coils share the same ground. What's even more odd is that all 3 pop bumpers have the same ground but only 1 of them fire. I rang all the wires from the coils to the driver board for continuity with the connectors disconnected from the driver board. All good. I tested every transistor, every fuse, every testable component on the driver board. No joy. I even swapped the driver board with the one from my Austin Powers since they are the same. The problem did NOT follow over to Austin Powers, and the exact same issue(s) remain with Austin Powers' driver board installed in South Park.
So it's not a wiring issue, not a driver board issue...I'm stumped. I scoured over all the wiring looking for anything that could cause this. I found nothing. This machine was 100% before the right flipper locked on. I'm very certain the current issues are related to that occurrence and nothing I did in the repair of it. The only anomaly I found was the wire that goes from the left slingshot coil to the driver board has a constant 54vdc even when the coil wasn't firing. If I remove the wire from the connector, the voltage goes away. If I remove the wire from the coil, the voltage goes away. The coil fires normally when the switches are activated so I don't know what's up with that but thinking it may be part of the problem, I removed the wire at both ends and it made no difference at all.
That's where I'm at. Not sure if it's a CPU issue or not. I've ruled out the driver board itself, the wiring (the wiring from the coils to the driver board), the coils, and the diodes on the coils as the cause of the issue. I'm not sure where else to go at this point. Any help would be appreciated. Got a tournament coming up this weekend and I'd like to get this going. Thank you.