[comp.sys.mac.hardware] High Pitched Squeal

alan@metasoft.UUCP (Alan Epstein) (02/12/91)

My (vintage) Mac + just began emitting an ear-folding high pitched
tone, which is giving me a headache. I don't mind the headache so much
(bang, bang!), but I'd like to know what causes the tone, and how I
can fixed it (if I decide I'd rather not have the headache).

Please send replies via e-mail. Avoid net clutter!

Thanks.

-----------------------------
Alan Epstein
Meta Software Corp                   UUCP:  ...bbn!metasoft!alan
150 Cambridgepark Dr        Internet/ARPA:  alan%metasoft@bbn.com
Cambridge, MA 02140  USA
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alan@metasoft.UUCP (Alan Epstein) (02/13/91)

In article <2049@metasoft.UUCP>, I wrote:
> ... my Mac + just began emitting an ear-folding high pitched
> tone... what causes the tone, and how [can] I fix it.


Thanks to Ralph Gonzalez for this insight:
___________________________________________________________________________

Return-Path: <uunet!elbereth.rutgers.edu!rgonzal>
Date: Tue, 12 Feb 91 08:40:04 EST
From: uunet!elbereth.rutgers.edu!rgonzal (Ralph Gonzalez)
To: alan@metasoft.uucp
Subject: Re: High Pitched Squeal
In-Reply-To: USENET article <2049@metasoft.UUCP>

One cause of a very high-pitched squeal is when the glue sealing on
the flyback transformer becomes unsealed.  This often happens when the
transformer goes bad, although supposedly it can sometimes happen on
its own.  If you're lucky, you just need to open up the Mac and pour
some epoxy on the flyback to seal it again.  Else you might have to
replace the transformer, assuming this is what is causing the squeal.

Check our Larry Pina's "Macintosh Repair and Upgrade Secrets" for
troubleshooting info and addresses of parts vendors.

-Ralph