I’ve worked on many Stern and Bally games. If it don’t boot you count the flashes and that gives you a general idea of where the problem might be. On Williams it basically says to replace the CPU board or replace the driver board. I can’t seem to find any information on booting problems.
I’m working on a Williams Flash (system 4). When I turn it on I get one flash on the LEDs – no displays. When I press the diagnostics button on the CPU I get two flashes. Where do I go from here?