Had the below start happening to my Whirlwind. Figured a video would be best to show exactly what is happening. As you can see, I can get some semblance of digits during the display test. Swapped out ribbon cable; no change. Re-seated all cables between display boards and the boards in the backbox; no change. Checked voltages and both are correct and strong at 100 and -100 where they should be. PIA at U41 is brand new. Could this be something relative to the display boards themselves?

It actually is booting. You just don't hear the "bong" because I'm having a separate issue with my sound board and sound overlay board which I *think* I have licked. I can still get into the tests and have sound but no music. 5v and blanking are behaving showing normal and the diagnostic led is blinking as it should; not showing any codes (or at least I don't think so).

Yup that's definitely on the list. Was wondering if there is an IC on the display boards that could possibly be the issue or maybe something on the MPU. Repinning wouldn't hurt though.

So the board luckily never had any battery leakage so that ruled that out. I got a nearby collector to loan me his display and swapped it into my game. Worked fine. Swapped my original display back in and same problem. So, looks like it was a bad display. Bought a blue Rottendog one and Whirlwind is back in business.

No sound was due to a bad ribbon cable. Also found a shorted logic chip (U1) that was causing some solenoid issues on the solenoid/sound overlay board.

Fixed up those issues and we are now good to go.