OK, so resurrecting this thread since I actually made it out there today.
Machine indeed powered on and was stuck on tilt. I was pretty proud of myself when I popped open the PF and the tilt relay switches were stuck closed. Adjusted them, and the game coined up. Played a game, just about everything worked.
Then I noticed that after a drain, I'd have to coin up and hit start again. The ball in play never got off of #1. So the machine would play a single ball per game.
I thought possibly the outhole switch might be bad, but even jumping it didn't cause the machine to advance to ball 2. But on the ball #1, game played, scored, pops worked, etc.
Checked the boards, they were untouched originals. Data Sentry battery. At first glance, very very mild damage. I pulled the board to inspect it, put it back, and the game refused to even coin up.
I took it home with me since I didn't have the time on site today, but I'm going to pull it off and see the damage.
I'm thinking new CPU, new interconnect cable, ground mods, and re-capping the power supply?