Well crap. Is it possible for a lamp socket to burn up a transistor?

On my Raven driver board, Q21 caught on fire. It looks like at minimum Q21, Q22, R21, and R22 are destroyed. Q21 controls the light by the front right sniper drop target.

I had two pop bumpers not working, one was just a switch that was misadjusted, but the other was a bad fuse which I replaced. It seemed to work properly with the new fuse, and I didn't notice anything locking on. I know the pops have their own boards, but could the pop bumper have somehow caused this fire anyway?

I also adjusted the flipper EOS, and replaced some burnt out lamps (not the sniper light). These are they only things I have done on this machine. It was running in attract mode when I started to smell an electric fire, I turned the game off as soon as I noticed. But obviously too late. Is this board repairable? How do I clean up the black so I can see the damage?

20160623_233524_(resized).jpg

20160623_233506_(resized).jpg

20160623_233438_(resized).jpg

20160623_233434_(resized).jpg

Thanks guys. I'll get some alcohol on the way home from work today.

It seems strange to me that a lamp out socket could cause this?

I'm just wondering why this happened? Simply age of the parts? The light was lighting up fine when the sniper popped up during play and I haven't touched that socket. I know stuff goes bad, a lot of heat, wear and tear, for 30 year old components, but I want to be sure so when repaired, the same thing doesn't happen again.

Nice.

dead_transistors_(resized).jpg

Cleaned up with a toothbrush and alcohol as suggested. It turned out better than I thought it would.

My board doesn't seem to be a stranger to being worked on. The CPU board has a lot of work on it from what I can tell too.

The red wire in the photo goes to the fluorescent tube, not a ground mod. Some of the ground mods were done, like the grounds in the cabinet.

If I removed Q22 and the two resistors before, could I safely put the board back in the game? I'd like to see if anything seems screwy besides the lights controlled by Q21 and Q22.

20160624_175755_(resized).jpg

20160624_175835_(resized).jpg

20160624_175924_(resized).jpg

20160624_175907_(resized).jpg

I removed the components off the board. I then checked the pin that goes to the socket the with my DMM, one lead on the bolt where the grounds meet, and the other on the pin. I then proceeded to check every pin on that connector and the only pins that read continuity with the ground are grounds on the driver board.

I then plugged the driver board in and the game is back to functioning as it was before the transistor fried. Some things are intermittently working, but when I reseated the CPU to driver cable, things worked again. I'll have to check this cable out next.

Anyway, so far it seems like the damage was limited to those lamp transistors.

I never took a great look at it, it may go to the screw that the tube's tombstone is attached to for a ground. I'll have to check it out.