In this video series, I am working on a client’s “Dr. Who” pinball machine that wouldn’t boot up. It was just dead. None of the diagnostic LED blinks would blink on the WPC-89 MPU board, so I go over the process of how to identify and isolate the problem, then I upgrade the board with NVRAM (non-volatile memory) so that it will never need batteries again.
Dignosing and fixing a dead WPC MPU board (with RAM upgrade)