Newsgroups: sci.electronics
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From: alung@megatest.com (Aaron Lung)
Subject: Re: how to get rid of flyback whine?
Message-ID: <C63onB.BM6@megatest.com>
Organization: Megatest Corporation
References: <1993Apr26.012517.23391@Princeton.EDU>
Date: Mon, 26 Apr 1993 17:07:35 GMT
Lines: 36

In article <1993Apr26.012517.23391@Princeton.EDU> jsm@shade.Princeton.EDU (John Scott McCauley Jr.) writes:
>I recently took apart my color Sony TV to clean the volume pushbuttons and
>when I put the beast back together, the flyback whine got much louder.
>
>Is this easy to fix? Which part is resonating? I have heard rumors of a
>spray that will fix the noise.  Is this a simple thing for a TV repairman
>to fix?
>
>	Thanks,
>
>		Scott

Ah-ha!  I'm not alone at last!  Which Sony do you have??  I have a
27"SXR (pre-XBR series, circa 1987).  That damn thing used to
make noise like a mad-man.  I had/have 2 separate problems...one being the
flyback, the other was the assembly where the windings of the yoke
came together. 

First:  I found by poking around the windings on that assembly,
the thing would make noise.  I guess that there was enough of a potential
in that assembly to leak, so I sprayed it with a dielectric insulation
spray--I think it was urethane or acyrilic.  That fixed it.

Second:  Flyback...for the life of me, I can't isolate this one.  If I
leave the cover off, the TV will be quiet.  If I put the cover back on,
and let it heat up, it'll start to whine--kinda hard to solve with the
cover on!! :-(

A friend of mine who used to fix TV's says there might be a pin-hole
leak somewhere on the flyback.  Usually it's surrounded by a bunch of
black dust/dirt.

I hope this is a start...if you find something out, let me know!

aaron

