Quoted from frenchmarky:Strange though since he has an extra ground wire added that's tied right to the aux lamp board, if that is solid then it doesn't seem to be just cooked ground pins on the connector like it usually is on that board.
That's a good point. I've never seen that style ground mod on a Bally game, only on Gottlieb's. I'd certainly verify that the ground pins at J1 have continuity to the ground connection(s) in the backbox--you can check between J1 pin 15 of the aux lamp driver and the ground strap in the backbox for continuity (and verify the ground strap is screwed down in the backbox).
Come to think of it: what exactly is going on here? I presumed this was a ground connection but it seems to be tapping into the +DC voltage for the "DELUXE" lights on the backbox That's definitely not factory, at very least. Not sure if that would be the cause of the problem, and I'm not sure what that small connector at the bottom of the non-aux lamp driver board is either:
Screenshot_20210420_070901_org.mozilla.fennec_fdroid(1).jpg
It looks like J1 must have had a problem at some point, at least. Still worth a look, but the problem could certainly be somewhere else...(possibly something to do with those wiring hacks around the lamp driver boards)