I had a working MacSE Astec power supply which I recapped. Before I put it back together I tested the voltage on the orange wire and got a steady 5.02v. I buttoned it up and put in a known good machine and nothing, not even the fan spins. Pulled it back out and now the 5V line has nothing. Opened it up again and I can get voltage readings on the primary side but nothing on the secondary. Any hints or tips or suggestions on what to check would be very much appreciated. Thanks.
Help troubleshooting a Mac SE Astec power supply
- Thread starter spacerog
- Start date
either something's shorted or the transformer blew open, do you hear any clicking or high pitched noises? If your ears aren't sensitive to high pitched noises, there are apps you can get for iPhone and Android that are spectrum analyzers
you can test it with a multimeter in resistance mode or an LCR meter in inductance. if it shows as open circuit on either the primary or secondary, the transformer's done for. Has the power supply been recapped?
there is a new board that uses switch mode supplies to generate the voltages needed
I have seen those options, was just really hoping to fix this original one. Just expended so much effort already I hate to give up.
Yes, it was recapped. In fact it was working fine before recapping. After recapping it tested good, I got 5.2V on the orange wire. So I closed it up and installed it. But I got nothing. Took it back out and tested the orange wire again but got nothing. Now when I test inside the supply I can only get voltage readings on the primary side of the supply Nothing on the secondary. Just hate to give up on it after I put in so much work.
Perhaps something got damaged during the process of putting the pcb back into the enclosure. I’d check the underside of the printed circuit board for scratches across the traces. As mentioned by Nixonthenight, I’d also check the transformers. If one of the transformers is shot, I’m sure there are several of us with Astek supplies used for parts who could help you obtain a replacement transformer.
Is there any chance you damaged an adjacent component or connection when peeling away the hot-melt glue to remove caps?
Some of those caps are pretty tight in there, but I have double and triple checked and i can't see anything visually wrong.