68kMLA Classic Interface

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Mac IIci No Power
Posted by: superseth on 2022-07-30 10:11:52 Hello! I recently dug some decade old projects out of storage and the first one I wanted to tackle was an IICI machine. It had obviously leaking caps on the board so I took it out and replaced all the surface mount ones. There was some trace/pad damage but I think I got everything hooked back up. Just to confirm things were working I stuck the basics back together and tried to power on, got nothing from either the rear power switch or a keyboard. I don't have a PRAM battery installed right now. I have heard the power supplies can go bad pretty easily in these machines as well. I ordered the caps to rebuild it but after cracking it open I suspect that repair job is going to be over my head. Anything I should try with this machine? I am leaving it plugged in for a while as I heard that sometimes is needed if there isn't a battery. Is there anyone that does power supply rebuilds for Mac II. I will admit I had a LC during their reign so I don't have a lot of experience with this line of machines.
Posted by: Papichulo on 2022-08-01 04:39:44 I would get a different power supply And recap the board
Posted by: KennyPowers on 2022-08-11 03:43:40 I recapped my IIci power supply and it was a pain...using a modern replacement might be wise. Also, check the condition of UB13, UD13, and UE13. These ICs are part of the soft power-on circuit, and they're commonly damaged by leaking capacitors. Two of them flaked right off my IIci board and had to be replaced. I also had to replace UH1 for similar reasons. Basically, thoroughly look for any components or traces that have been damaged by leaking caps, recap the logic board, and get a working PSU in there. You said there was some pad damage/corrosion when you recapped the board. If the pads aren't clean and shiny, then you might not have a good connection for the new cap. Got to clean all of that corrosion off. I did this with tedious scalpel scraping under magnification. A fiberglass brush might work too.
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