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Macintosh Classic Making weird static sound

T

thegenerallee86

Experienced Member
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Feb 1, 2021
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My Macintosh Classic was fine and then after a shutdown and startup started making a static sound through the speaker which would change when I moved the mouse and at first would only happen when I moved the mouse. I also took the mac apart and reseated the cables and that seem to make a difference, but now it does it once on boot up for a second or so and then stops but software sounds and os sounds are normal?
 
Probably some electrolytic capacitor used for decoupling failing. Has it been re-capped already?
 
Timo W. said:
Probably some electrolytic capacitor used for decoupling failing. Has it been re-capped already?
Click to expand...
Yes it has and it is a recapped with Tantalum capacitors not the electrolytic ones but only on the Logic board not the analog board though.
 
Here are some pictures of it
 

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I would highly recommend recapping the analog board as well. It may or may not fix the problem, but it's important anyway, as most caps there leak as well.
 
It seems to be only doing it on bootup now and only when it has sat for while not being turned on.
 
I would just replace them all. It's preventative maintenance and you are going to have to go back there again anyways for when the video circuit and the power supply start giving you trouble, so why not do it all at once and not risk breaking the plastics on the second or third entrance?

Full cap list is here: https://recapamac.com.au/macintosh-cc-analog/

Edited: I'm an idiot and just realized NOW that you meant the classic and not the color classic. Sorry.

recapamac.com.au

Macintosh Classic I + II Analog Board (220V - 240V version) - Recap-a-Mac

The Macintosh Classic and Classic II share the same analog board, and they share the same little cluster of leaky capacitors. There are...
recapamac.com.au recapamac.com.au
 
Last edited:
NeXT said:
I would just replace them all. It's preventative maintenance and you are going to have to go back there again anyways for when the video circuit and the power supply start giving you trouble, so why not do it all at once and not risk breaking the plastics on the second or third entrance?

Full cap list is here: https://recapamac.com.au/macintosh-cc-analog/

Edited: I'm an idiot and just realized NOW that you meant the classic and not the color classic. Sorry.

recapamac.com.au

Macintosh Classic I + II Analog Board (220V - 240V version) - Recap-a-Mac

The Macintosh Classic and Classic II share the same analog board, and they share the same little cluster of leaky capacitors. There are...
recapamac.com.au recapamac.com.au
Click to expand...
Thank You and I will definitely look into fixing it myself I've got the soldering iron and Multimeters, and Oscilloscope as well and also will look for an analog board that has already been recapped as well.
 
When it was recapped, did you thoroughly wash the board as well? I'm leaning more towards there being some crossed signals on the logic board
 
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