Fixed...see details in later posts.
Just wrapping up an all day session cleaning up my GnR for a little party tomorrow. Replaced a couple broken targets, converted all bulbs to LEDs outside of the ones that are stapled in (what a stupid thing). Vacuumed out the game, vacuuming the wire harnesses on the floor of the game as well.
With the machine on, I drop a nut driver and it hits the ball launch Wireform near the top rollover lanes. I'd just finished replacing the bulbs here. This doesn't strike me as something that would trigger what happens next...unless this is the mother of all shorts.
All of a sudden the game starts wigging out...starts repeating, over and over, the "you're in the jungle baby" part of the song, but stuttering, not finishing the phrase except for every once in awhile...and then starting over with the stuttering. The GI blinks on and off, with a clicking in the back box. The insert lighting cycles on and off. The dot matrix flashes "free play". The "guitar feature" kick out hole fires over and over, every three seconds or so.
Hitting the coin door voltage cut does nothing. I can't get the game to go into diagnostics. I've looked under the game for loose wires, something pressed together that shouldn't be...I've reseated random connectors in the area of the guitar kick out. Done same in back box...nothing makes it stop except turning the game off. Upon turning the game on, same thing. Although, strangely, it always thinks balls (all six, four, that I've seen) are missing, although all 6 balls are in the trough.
Anyone have any ideas here? I hate the idea that GnR will be down for tomorrow nights party.
Thanks in advance for your help!