I'm hoping someone with better skills can help me out, I've been trying to fix this game for a week now. I was playing a game last week when I noticed smoke coming out of the back box, I found C6 15000v cap had burned up. I also noticed F7 had blown, I looked around the board everything else looked ok, so I shotgunned it...I replaced C6 and put a new fuse in. Well, 30 seconds after the turning the game on I noticed C6 was getting cooked again, and almost at the same time F7 tripped too. I turned the game off and started to troubleshoot it properly this time, I also noticed the entire hi volt transistor section Q1-Q16 was super hot. I took the board out and went through it and found Q6 and Q7 were shorted (these are the 2 magnet transistors) I also checked their diodes and they tested kind of flaky. I replaced all 4 components and took out the magnets and checked the resistance in them, the magnets were both reading between 5.5 -5.7 ohms, which I was told is ok.
I figured that should take care of it, I put everything back and kept both magnets disconnected, everything was fine and the hi volt section was cool. I even played a game...all good, but when the wellwalker magnet was connected F7 tripped and the hi volt section got hot again I tested again with the prison magnet connected and the other disconnected...same results. I found out Q6 and Q7 both were shorted again. I don't know what's causing this.....I checked the wiring and took out both magnets to make sure they're not shorting. I'm out of ideas.....
Stern_TWD-.indd (1).pdf