SE/30 with no video after recapping

[jbreams]

I recently got an SE/30 that booted up to a grey screen with a mouse pointer and did nothing else. The screen was bright and clear though. I took it apart, cleaned the logic board and let it dry completely and then recapped it - there's some minor corrosion from leaking capacitors, but the board is clean and it didn't look like any traces or critical ICs were damaged.



After that, it played the startup chime got as far as the disk with a question mark. Success! So, I turned it off and reconnected the floppy drive to test booting it up, and now it turns on, I hear the startup chime, the fan spins, and you can hear the floppy drive spinning and reading, but the display never turns on. After reading the dead mac scrolls and other troubleshooting docs, I thought it might be R22 on the analog board, but that resistor looks fine both visually and with a multimeter. In fact the analog board looks pretty good overall, no leaking or bulging capacitors, and it was working fine just a few days ago!

Hopefully someone has seen this before and has some advice. Thanks in advance!

 

[Bolle]

Can you get a close up picture of the UE8 area?

One of the traces right next to C7 looks sketchy, but that might as well be just flux residue, can’t really tell.

It is also possible UE8 did just die. There is corrosion on its legs, if you can swap it out for a new 74LS166 and see if it brings back your screen.

Did you try reseating all those socketed PALs yet?

 

[tanaquil]

Sorry to ask the obvious, but are you quite sure that the analog to logic board cable is firmly plugged in? I have had this symptom more than once when I reassembled a compact Mac and thought I had cables plugged in properly when they weren’t. 

Check the yoke board too (the thing that sits on the crt neck), it is easy to jostle it out of position. 

 

[DistantStar001]

I had a similar problem with my Macintosh SE, and I have to say, I felt really stupid when I realized that a gentle push was all I needed to fix it.

 

[jbreams]

I think all the connections are firmly plugged in. I went through and unplugged/replugged them all. The yoke seems sturdily on the CRT neck as well. I replaced UE8 with no luck. Below is a picture of the video section of the board as it is now.



The logic board is definitely POSTing though, it reads a floppy for a while and then ejects it.