Working on a dead System 80b, and I would love some advice/help. I've had a few 80b's over the years, but never one quite this dead.

Current status, GI only.

- Unplugged everything on the outgoing side of the power supply board and tested it. 5.23 VDC. Powered off, hooked up the MPU, powered back on and tested at the Capacitor. Found 5.00 VDC there, so it seems good up to that point.

- Unplugged the 'reset' board, since I know that's not needed.

- Slam Tilt mod complete via jumper (C30 and resistor R20)

Not sure where to go next. Normally I get some life given the above, but so far nothing. Thanks in advance for any help!

Thanks for the reply! Does all of that apply to the 80B games? Asking because it only specifies "System 80". I've often read that in order to show some signs of life, usually the 5V and Slam Tilt are the primary things that need to be addressed. Would that list be accurate for completely dead situations on an 80B?

Yeah, I tested for 5V at the capacitor C1 up near the top of the MPU board, as well as over on the chip in the top right corner Z7. Had 5.00VDC exactly on both. (It was 4.69V because the pot on the power supply was a little low initially, but I adjusted it as needed to get it to the correct voltage)

I did the old "press on the daughter board" thing, but no change.