I'm having a problem with my Medieval Madness pinball, all original, never had an issue with it since new.

Game does one of three things, randomly:

CPU LED201 and LED202 turn on and stay on, LED203 does not flicker, indicating a bad CPU boot. In this case the A/V board bongs once and the LED flashes on and off. The display doesn't work and has vertical lines. The playfield lights are all off.

CPU LED201 turns on and then turns off, LED202 turns on and stays on, LED203 flickers, indicating a normal CPU boot. The A/V board doesn't bong and the LED is off. Case 1: playfield lights are active, and the game can be played, but no sound and the display has vertical lines. Case 2: playfield lights are not active, the game won't start or play, and no sound and the display has vertical lines.

I have reseated all of the chips on the CPU board that are socketed, reseated all of the ribbon cables on the CPU board and A/V board, and reseated all of the power connectors.

With the CPU isolated, no ribbon cables, the CPU will boot with the normal LED pattern, or with the defective pattern (LED201 and LED202 solid on).

I will go through and swap boards, cables, chips, etc. back and forth, but I'm posting this on the off chance that this peculiar behavior is narrow enough to indicate a particular problem.

Thanks for any help provided!

-- Paul