Performa 550 won't power on at all after recapping

[nlh101]

Hello all!

I have a Performa 550 that myself and one of my electrical engineering friends recapped a while back. It was in essentially full working order (besides the broken Quantum hard drive) before we recapped it, but I knew it was a ticking time bomb. Since then, we've been struggling to get it to chime at all. All of the new capacitors are correct as far as I can tell.

I've attached some pictures of the analog board. We also recapped the logic board, but that's a significantly easier board to diagnose in terms of capacitors, so we're pretty sure it's working just fine for now. The CRT does make its classic thunk sound when we plug it in from no power, but that's all it will do.

Any immediate ideas? I can provide as many pictures as necessary, but I'm not sure how high-quality or readable they are.

Additionally, if anyone in the Northwest PA area would be interested in looking at it, I would be willing to send it out at my expense.

Thank you!

 

[joshc]

This could be one of those boards that needs low ESR capacitors in certain places - but I wouldn't know which ones need to be low ESR.

 

[Phipli]

This could be one of those boards that needs low ESR capacitors in certain places - but I wouldn't know which ones need to be low ESR.

Generally the output stage of a PSU - the caps near the PSU outputs.

Edit - is the PSU on the analogue board, or separate?

 

[joshc]

It's all in one on these.

 

[nlh101]

If it helps, the analog board is part number "630-1120-" (the dash is silkscreened on the board with nothing after it) and the logic board is part number 820-0368-A.

 

[Amiga of Rochester]

@nlh101 Sent the board in and we were able to correct the issue. Thankfully it was only low esr parts weren't used. We will be finishing the recap as it was incomplete. Photos to come. We also ultrasonic cleaned the logic board, looking spiffy!

 

[nlh101]

Amiga of Rochester did amazing work, and tested the analog and logic boards very thoroughly!

Unfortunately, it's looking like there might be a chassis issue with my Performa 550. This logic board doesn't have a CUDA reset switch, and my ADB keyboard isn't powering it on. I'm going to try the 24 hours plugged-in trick that sometimes works, since every other attempt I've made to fix it doesn't produce any results.