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Macintosh IIsi Magic chime sound. What does it mean?

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Got a Macintosh IIsi computer.

 

1) Got computer.

2) After plugging it in, it auto turned on? This doesn't seem right, PSU maybe?

3) The screen would show gray, then go off and make an error chime.

4) So I replaced the caps as I thought that might be the root issue (sound was super low as well).

5) Now I have the same issue (but load sound). So computer auto turns on when power plugged in and screen goes on then off and makes a error chime sound.

6) I replaced the ram with "confirmed working" 4 256kb dimms for a total of 1mb but have the same issue.

 

Any ideas? My only idea is PSU but idk. I also washed motherboard as caps probably leaked but maybe I need to wash more?

 

Video of issue: https://photos.app.goo.gl/TNdpiKy4Tk6m1b8f8

First beep is my bird so ignore that lol. Any ideas are welcome!

20180805_225426.jpg

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Also is there another PSU that can be used on these computers for testing?

I'm reading these can go bad in IIci computers so guess its the same with IIsi?

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I *think* a IIcx/ci PSU is electrically compatible?

 

The IIsi is quite unique, so most parts form other machines (aside from disk drives, cables, and other such things) won't work without some effort.

 

c

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11 hours ago, bibilit said:

On the back of the IIsi, the power button can be turned 90° to switch on when plugged to the wall.

The switch is not in the server position. I tried both to make sure.

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Maybe have a try with another PSU, did you recap the PSU ?

 

Those can be tricky to repair, but depending of the supplier, a lot of capacitors to replace.

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9 hours ago, bibilit said:

Maybe have a try with another PSU, did you recap the PSU ?

 

Those can be tricky to repair, but depending of the supplier, a lot of capacitors to replace.

I only replaced the caps on the motherboard (47uf - 16v to 47uf - 50v).

I might just use the MacCaps service to get the PSU done.

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So opened up the PSU and thats got to be the issue (should have taken a picture).

The caps that look like they're on the board that control the on/off switch look messed up and super leaky.

 

Man this PSU was the dumbest design. To fix the caps on this are just way more work then it should be, its wonky as **** in there.

Apple really did the wackiest job on these computers I have ever seen. The speaker, power led and back fan are all just surface contacts... the PSU is a joke of a design.

 

I sent it into MacCaps to get repaired. Cost 75$ because of how crazy these are.

 

The computer is in really good shape all things considered so I have high hopes.

Will report back once I get the PSU back (fingers crossed)...

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Why did you install to 50v 47uf caps?
There is also axial caps on the board as well - they may need replacing to.

100% for sure the PSU does need recap - It has known it gets shorten to start it up on its own.

Yes IIci/Quadra 700 PSU does fit on IIsi board - I've done that to eliminate the power on test/shutdown test etc.

FYI - Maccaps is not 100% accurate some caps may be different as per spec so double check what you're replacing to same value.

Cheers

AP

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I recapped my IIsi, with exception of the axial caps, which I now have.  The originals were supper clean.  The caps in my IIsi were not leaky at all but I replaced them all the same.  

 

About the PSU, how do you open it up?  Mine seems to have no screws but perhaps rivets?  Not sure.  Mine seems to be made by Magnetek (www.magnetek.com)  Made in Italy, it appear.  Sticker on the supply says 26th week of 1992.  My IIsi must be a later model.  

Edited by Zippy Zapp

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Thanks for the info.  I had read about the bad caps with the Sony ones too but never really read anything about the Magnetek PSUs.

 

When I get some time I will have to have another look at it.

 

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