Success!
I got my package from Germany today that had my replacement pinball display board (that runs on LEDs instead of Neon). Once I could see what the pinball machine was saying to me, I could put it in test mode to determine that a Slam Tilt switch was stuck closed, preventing it from doing much. Likely, it (quite correctly) got jostled during transport. It still doesn’t have batteries (meaning that it can’t keep high scores or Free Play settings through a reboot), about 20 lights don’t work, some switches don’t work, and launching the ball onto the playfield via the plunger (you know, the normal way of launching a ball onto a pinball playfield) gets the ball stuck at the top somewhere. But we can play games, and it mostly works.