Man I'm about at my wit's end with my Kiss machine. Last year it started freaking out off after being on a half hour or so. The GI would dim and a loud buzzing noise would come from the speaker. The I could shut it off and restart it a few minutes later and it would work for a while and then do it again. I couldn't figure it out. I re-pinned all the connectors, checked the grounds, swapped-out boards, nothing worked. Then I tried turning the lights off and saw what was apparently happening. When it would go out there was a spark coming from the transformer windings. It was just by chance that I saw it at all.
So I looked around for another transformer. Kiss is an oddball and uses a 122-125 transformer and they can be hard to find. The only other Bally pins that used it were Future Spa and Space Invaders. Kiss also uses the AS2518-49 rectifier board. I've already replaced the rectifier board with an aftermarket one and nothing changed.
Then all of a sudden the lights started flickering and a real loud hum comes from the speaker. Even if I unplug the speaker wire from the sound board it still hums. The sound board is not bolted to the chassis ground either.
I started disconnecting connectors one at a time to see if I could narrow it down to something. The only thing that did anything was to disconnect the auxiliary lamp driver. I could at least play the game but the hum is still there. It gets worse the longer it is on until eventually the lamps start to flicker. The hum pulses with the playfield lamps.
I rebuilt the sound board and even swapped it out with another one but they both behave exactly the same. As I turn the "sustain" POT even slightly to the right I get a continuous tone. It didn't used to be that way.
Any ideas as to what to look at? I can't find anything wrong and it's driving me nuts.