nekonoko

I've only tried the built-in diagnostic so far. I have another IIgs board arriving in the next couple days, once I'm done verifying that one is good to go I'll circle back to the first and see if a diagnostics disk provides a clearer idea.

I went ahead and temporarily removed the mods and bridged the cut trace, but the system stops with "Fatal system error-> 0911". I also socketed the 4464 sound RAM and replaced with some known good chips, but I still get the System Bad: 0C000001 error and screech during diagnostic (with the mods reinstalled of course). As for the revision, the board is marked 607-0173-B (B stamped in ink) on the right side of the board near the slots, and 820-0167-B under the solder mask on the front of the board. Thanks much for your assistance in confirming this is unusual - I may wind up looki

I have a IIgs that's failing diagnostics with System Bad: 0C000001 error. In addition, it often starts up with strange screeches and displays "unclaimed sound interrupt" when this happens. My first thought is to socket and change the 4464 sound RAM, but I noticed a lot of bodges including cut traces on the underside of the board around that area. Is this normal? I can't find any photos of the underside of a ROM0/ROM1 board to confirm if these are factory, meant to address an issue or are causing the issue.

That makes a lot of sense. Just as another data point, I recapped a 1.2A power supply a couple months ago and had a perfectly stable display with Rubycon 16YXJ2200M12.5X20 rated at 1.9A ripple current.

I had the same vertical jump issue on my Lisa 2/5 before I recapped the analog board a couple weeks ago. I too found that the small 16v 10uF capacitors had leaked, in fact one had taken out a ground trace and needed to have a jumper added. I just used some DeoxIT on the potentiometers which restored them to smooth operation.