Here's one that has me stumped. My JP was on location for over a year, no problems, tons of play. I moved it home, it sat in the garage for about 3 weeks, moved it into the basement a couple days ago. On the first game after setting it back up on ball 3 all coils go dead, CPU controlled lamps go dead.

Power off, game will boot, no CPU controlled lamps. Go into diagnostics, switch test works. I can start a game but T-Rex won't move, no coils, no CPU controlled lamps.

I check all the usual suspects. Fuses all good. All voltages good. Voltage present at all coils.

Then I notice that when booting the blanking LED never comes on. The PIA LED flashes, 5v LED comes on and stays on, the blanking LED never comes on.

Swap in a different JP game EPROM. No change.

Swap in good RAM. No change.

Take out the CPU board. Put it on the bench with Leon's test ROM, get out the logic probe. PIAs test good. Everything looks good. Put the game ROM back in and boot it on the bench. Boots fine, blanking LED is on.

Put the CPU board back in the game. Boots fine, blanking LED comes on and stays on. Start a game, plays fine. This is with the same game ROM, same RAM, same everything. Only thing I did was take out the game EPROM, run it with Leon's test ROM, then put the game EPROM back. Any ideas? Pinball gremlins? Magic?