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From: wmartin@brl-smoke.UUCP
Newsgroups: net.video
Subject: Re: Magnetic fields and Color TV Warning/Questions
Message-ID: <673@brl-smoke.ARPA>
Date: Mon, 3-Feb-86 14:09:11 EST
Article-I.D.: brl-smok.673
Posted: Mon Feb  3 14:09:11 1986
Date-Received: Thu, 6-Feb-86 21:21:53 EST
References: <499@oliven.UUCP> <2baaf68e.39c@apollo.uucp>
Organization: USAMC ALMSA, St. Louis, MO
Lines: 21

I've got a Zenith System 3 that has a color splotch in the lower right
quadrant that comes and goes, sometimes being more noticeable than other
times, and which is probably due to a degaussing problem. I've tried
degaussing the set with a reel-to-reel tape bulk eraser, which produces
a similar sort of rapidly fluctuating magnetic field to a regular
degaussing coil, but, if it cleans it up, the effect is temporary.

What I can't figure out is why such a magnetized area would would fade
away and then return over a timespan of some months; I could understand
it appearing and never going away (due to either a permanent damage to
the shadow mask or to the failure of the set's degaussing circuits), or
appearing once in various random locations and then going away when the
set's internal degausser wiped it out, but why would it persist in the same
region of the screen, fading slowly and strengthening slowly, over months
and years? (One clue: it is in the area of the screen nearest to the set's
own internal speaker -- could there just be a design defect allowing the
magnet in that speaker to affect the picture tube internally? If so, it's
another nail in the coffin on Zenith System 3 sets. Don't ever buy one
of those dogs!)

Will