ThinkClassic

Nick ThaPizzaBox

Member

Registered: 2014-05-28

Posts: 8

Macintosh IIsi Power supply

Hello there. Hope everyone's well. I seem to be having an issue with my Macintosh IIsi Power Supply Unit. It has now been fully re-capped and it just still refuses to allow the machine to boot up. All I hear is a faint click from the relay, the fan twitches, led flashes and speaker makes a noise...Then nothing until I un-plug it, and then it happens all over again.

The caps did not seem bad but most had goo coming out of them. Figured doing all would be safe. The machine itself powers up as I got it to work a couple of times and it stayed up the entire time until I went to shutdown. Speaking of shutting down, I noticed that each time, instead of the machine turning itself off, it gave me the "it is now safe to turn off your Macintosh". I would then have to un-plug the machine. The IIsi has also been fully re-capped.

Anyone have any info on this? I have found some stuff regarding this like diodes being the issue but never really found any information on it. Anything I could be missing?

Thank you for your time.

Nick.

uniserver

Member

From: Sf, Mi

Registered: 2014-05-15

Posts: 956

Website

Re: Macintosh IIsi Power supply

i would like to see a picture of the PSU board... maybe see if we can have a look at the Polarity stripe on the electrolytics...

I think you got a cap backwards in there... I have seen a backwards cap do pretty much what you are talking about right now.

http://www.maccaps.com/MacCaps/Capacito … upply.html

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Nick ThaPizzaBox

Member

Registered: 2014-05-28

Posts: 8

Re: Macintosh IIsi Power supply

Well I took some pictures to post but am not sure how to do so. I looked through the FAQ but didn't really see anything and the icon of the tree, which says insert image,  just gives a script prompt. But I did take it apart and look it over just to make sure. I have them in the correct way but I had to use radials as that's what I was able to get in town. The pictures were great to look back at.  Still same results but, what is that little dial on that circuit board for?