Apple and Mac 68k Forum

MacOS · Last edited by MacOS on Sun Jun 17, 2007 12:16 am; edited 3 times in total

Hi there,

I have bought a nice Classic Mac

Classic II, but after switching it on it starts
to squeak for a few seconds, the hard drive is running and the system is
booting. If the Classic II is running it squeaks in a sequence of c. all 60 seconds for about 5/8 seconds.

The Classic is in good condition, seems good handled over the years.
The shipping was ... ok - maybe the Mac had a hard tour.

I have opened the Classic II
to localize the source of the squeaking sound.
It is based at the analog (video) board left side of the Mac Classic II.

It seems not to come out of the speaker!
I disconnected the speaker and the squeaking remained.

Here is a video:
http://www.youtube.com/watch?v=c-Idzb5kL5E
As I shot the video I thought it came out of the speaker.

Does someone ever heard of that problem?
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MacOS aka Oliver

applefreak · Joined: 11 Oct 2006 Posts: 59 Location: belgium

more info about classic II
http://developer.apple.com/documentation/Hardware/Developer_Notes/Macintosh_CPUs-68K_Desktop/Mac_Classic_II.pdf
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my apple computers

Bolle · Joined: 08 Jun 2007 Posts: 8 Location: Strausberg b. Berlin

sqeaking speakers are most times caused by bad capacitors. you should inspect your mobo for leaking caps and clean it if there are some. if the problem still exists after cleaning you should replace the old caps.

MacOS · Posted: Mon Jun 11, 2007 10:08 pm Post subject:

Hi Bolle - thank you for the info.
It seems not to be caused by the speaker itself
if I disconnect the speaker cable the squeaking remains...
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MacOS aka Oliver

MacOS · Posted: Sun Jun 17, 2007 12:11 am Post subject:

Some more details about my squeaking Mac Classic II:

The Motherboard squeaks! The capacitors look like they have lost some liquid that is now attached to the logic board.

I added the logic board to another Classic II an it starts to squeak emidiatly.
So it seems not to be the analog board - on both machines the display is sharp.

The squeaking is coming out of the analog board but it is based on a partial defected logic board.

I think I replace the capacitors and have a look if the squeaking remains.
Let you know.
_________________
MacOS aka Oliver

Bolle · Joined: 08 Jun 2007 Posts: 8 Location: Strausberg b. Berlin

dont forget to get the conductive goo that leaked from the caps off from the board. maybe you want to try to wash it before you replace the caps? use some isopropyl or wash it with water+soap - after that rinse with clear water to get ALL the soap off. let it dry for a day or two and should be OK again.

edit: really works: http://www.flickr.com/photos/21088395@N00/647796643/ Very Happy

MacOS · Posted: Wed Jul 04, 2007 10:22 pm Post subject: Thanks

Thank you for the details, I will use a Mac Classic II for a RetroChallenge Project - the ClassicÂ¥s Motherboard will be replaced (it produces a striped screen) with a Performa (68040).
So I have a good test board to learn some solder skills Smile

Thanks for the photo - SE Geeks out there - have a look what User

Bolle did to repair his SE :

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MacOS aka Oliver