Breaking my SE/30 out of JAIL!

[Garrett]

Apologies for the click bait title... I couldn't resist! Needless to say I'm working on a troublesome SE/30 which appears to be in "jail". When I first received this board it did boot to a cursor and flashing disk, which makes this all the more frustrating. Thinking it would be simple, I did the recap and ultrasonically cleaned the board. Now, I have no chime and no real signs of life.

Here's where I am at now:
I have tried known good combinations of RAM and ROM SIMMS - board behaves the same with or without ROM/RAM installed.
Reset button does work - screen goes dark and comes back on again.
No sound or death chimes with speaker connected.
Broke out the schematics and verified UE8 continuity to UC6 and UC7.

My first thoughts are that there was a weak trace or connection somewhere, and it broke during ultrasonic cleaning. Unfortunately, this board looks even cleaner than my other SE/30 board which actually works (ugh). I know Bruce and JDW have had boards with this similar pattern showing after a recap, but I am unsure what steps were needed there for resolution. I am going to keep troubleshooting, but if anyone has seen this pattern, please chime in!

 

[Garrett]

Exciting update to share tonight - found the culprit. One of the address lines from the ROM was not connected to the ASC. I didn't want to remove the entire chip, so I ran a bodge on the bottom side of the board from the ROM SIMM pin to the via connected to the right pin on the ASC. When I had the board working, I was able to bring the jailbars back by removing the video ROM chip. Might be useful for others in their troubleshooting.

I hope this is a help to others! These little gremlins are tough to find sometimes.

 

[caver01]

Nice!

Here’s a photo I took underneath my ASC when I was troubleshooting similar issues. It might help you if you want to pickup the broken trace with your bodge somewhere closer, or maybe the via was the problem. In any case, maybe the photo helps.

I had a lot of gunk under my ASC so I am glad I took it off. No broken traces for me, but plenty of opportunity for shorts or breaks at common failure spots.