SE/30 No Video After Recap

[PotatoFi]

I have an opportunity to hand-deliver an SE/30 to a friend on a road trip, and I'm down to about 24 hours to fix this. If you have ideas, I'd love to hear them now!

I'm working on an SE/30 that I picked up about a year ago. It booted and worked when I brought it home, but I knew I wouldn't be able to recap it for awhile, so I pulled the caps and spot-cleaned the board with alcohol. Over the weekend, I pulled it out and installed Tantalum caps. C8 and C9 had damaged pads but I think I was able to get continuity restored.

C1 on the analog board was badly burned due to a cracked solder joint, so I reflowed the joint and inspected the connector.

Now, I get no video from this logic board. Installing it in a known-good SE/30 chassis yields the same results, leading me to believe that there is a video circuity problem on the logic board.

Normally, I'd try a few more things and do some research before posting, but I am short on time and would like to hand-deliver this machine if possible (instead of rolling the dice and shipping it... it's a very nice little SE/30). Thanks in advance!

 

[Paolo B]

I’m more or less going through the same process with my SE/30. After swapping yoke connector, all of a sudden no video. I thought I busted something else, but after carefully reflowing the board (remove old solder and apply fresh one), it got back to life. I honestly suspect thit might have been also somehow related to the male connector pins…
Anyhow, are you sure the logic board is OK? If that is confirmed, then you can focus on the analog board. Else, it will be difficult to follow a logic.

 

[PotatoFi]

Since the problem follows the logic board to a known-good SE/30, the problem seems to be on the logic board.

 

[Paolo B]

Could also be both. You know for sure the logic board is not OK, but doesn’t mean the analog board is OK. I’d move a known good logic board on the faulty Mac for assessing the analog board at first.

 

[pfuentes69]

Since the problem follows the logic board to a known-good SE/30, the problem seems to be on the logic board.

Did you check the UE8/UF8 section? That trends to go bad with the cap goo...

 

[PotatoFi]

Did you check the UE8/UF8 section? That trends to go bad with the cap goo...

I'll do that next. I've ordered a re-supply of Chip Quik so I can pop those IC's off and check everything around them.

 

[PotatoFi]

My Chip Quik showed up, so I popped both UE8 and UD8. Since I had some spare F253 Multiplexers on hand, I replaced UD8. I didn't have a space UE8 on hand. A couple of the pads ripped up with my desoldering - hard to say if that was my fault, the cap juice's fault, or both. Either way, I soldered both chips back down and ran some bodge wires, checked for continuity, and tested...

Video signal, right away! The pre-floppy screen is very garbled for some reason, but but I get a nice clear blinking floppy after a couple of seconds. I figure this could just be the style of RAM, or the stock ROM, or something like that.

Unfortunately, there's another problem to solve: it won't boot from my internal SCSI2SD, nor my external DB25 BlueSCSI. I get a very steady blinking activity light on each. Booting from a floppy works, but I don't see any drives. I'll go search for what might be causing this, and report back if I find a fix.