Path: utzoo!utgpu!water!watmath!clyde!att!rutgers!tut.cis.ohio-state.edu!bloom-beacon!mgm.mit.edu!wolfgang
From: wolfgang@mgm.mit.edu (Wolfgang Rupprecht)
Newsgroups: sci.electronics
Subject: Re: need help to reduce a monitor's squeal
Message-ID: <7230@bloom-beacon.MIT.EDU>
Date: 29 Sep 88 03:57:27 GMT
References: <716@pedsga.UUCP>
Sender: daemon@bloom-beacon.MIT.EDU
Reply-To: wolfgang@mgm.mit.edu.UUCP (Wolfgang Rupprecht)
Organization: Freelance Software Consultant, Boston, Ma.
Lines: 23

In article <716@pedsga.UUCP> jeffj@pedsga.UUCP writes:
>I can hear several terminals and televisions 'squeal'.  I understand
>that this is the flyback transformer at the scan frequency.  Is there
>anything I can do to attentuate the squeal?

High frequencies are very easy to absorb.  I have had lots of success
in quieting flyback vibrations using GE's "RTV Silicon Rubber Adhesive
Sealant".

First unplug the power cord, and discharge the flyback's HV section
and keep it shorted to frame ground for the duration of the hacking.
Then disassemble the flyback mounting (and powdered iron core if
possible).  Pack RTV in every crack and mating surface you can find.
Be generous here.  Reassemble everything.  Lastly remove the HV
shorting strap, and plug back in.

Be extremely careful when playing with the flyback.  The HV section
packs enough wallop to kill you, if improperly handled.

-wolfgang
---
Wolfgang Rupprecht	ARPA:  wolfgang@mgm.mit.edu (IP 18.82.0.114)
TEL: (617) 267-4365	UUCP:  mit-eddie!mgm.mit.edu!wolfgang