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From: hr(bob) hofmann on 22 Apr 2010 11:24
On Apr 22, 6:49 am, PeterD <pet...(a)hipson.net> wrote:
> On Wed, 21 Apr 2010 23:26:59 -0500, AZ Nomad
>
>
>
>
>
> <aznoma...(a)PremoveOBthisOX.COM> wrote:
> >On Thu, 22 Apr 2010 00:01:33 -0400, Ron Weston <R...(a)nosuch.com> wrote:
> >>My friend has an inexpensive 9-inch TV, about 6 to 10 years old. It
> >>suddenly developed two green spots on the screen, one in the upper
> >>right corner and one in the lower right corner.
>
> >>I have a "GC Electronics Professional Degaussing Coil" and I made two
> >>attempts to degauss the TV picture tube. After the second try the
> >>lower green spot was just about gone, and the upper spot is much
> >>smaller but can still be seen.
>
> >>I'm going to try again next week and I would like some advice. In my
> >>attempts so far I moved the degaussing coil around only the front of
> >>the TV. Should I try degaussing the sides, top or back of the TV, or
> >>might this make things worse?
>
> >>Nothing unusual happened to cause the green spots. The TV hasn't been
> >>moved in years and no magnets were placed near the TV. Any theories
> >>about what happened?
>
> >Any young children?
>
> Absolutely, highly magentized small/young children mess up TV sets all
> the time! <g>
>
> But in addition to young children (with their magnetized toys) any
> nearby lightning strikes?
>
> And as Phil says, you should check the built-in degaussing coil.
>
> And yes, do the sides of the set near the face of the CRT.- Hide quoted text -
>
> - Show quoted text -

can you hear the degaussing action when you first turn the set on
after it has been off for several minutes?
From: Robert Macy on 22 Apr 2010 11:53
On Apr 22, 6:20 am, AZ Nomad <aznoma...(a)PremoveOBthisOX.COM> wrote:
> On Thu, 22 Apr 2010 05:23:59 -0700, William Sommerwerck <grizzledgee...(a)comcast.net> wrote:
> >I'm wondering if a bit of banging might help. But it's not clear how, "just
> >sitting around", the shadow mask might have gotten deformed.
>
> The "tool" I used to use for massive degausing was a bulk tape eraser.

and in a pinch, use a cheap electric pencil sharpener.

Those motors produce a lot of field

But always, always be careful of deforming the internal screen!
From: William R. Walsh on 22 Apr 2010 12:56
Hi!

> Have your friend hide the magnets from the kids. The internal
> degauss should take care of the remaining spots provided it
> works.

Sometimes it isn't stout enough to do the job. Some years back, my
younger brothers managed to put a faint "blob" on a MAG Innovision 17"
CRT. No amount of degaussing with the monitor's built in coil would do
the job. Even though the coil came on at every power up, it just
didn't seem to have the oomph. Operating it manually through the
monitor's menu did not help.

Being busy at the time, I took a quick look and decided that they'd
damaged the monitor's picture tube. And then, after a while, I managed
to acquire a large electric bulk eraser, which I eventually decided to
try using as a degaussing wand for this monitor.

It worked brilliantly. I started from several feet away by turning it
on and moved very slowly toward the CRT itself. Then I ran it slowly
around the CRT face, maintaining several inches worth of distance.
When I was satisfied, I moved away the same several feet and shut the
coil off.

William
From: Ron Weston on 22 Apr 2010 14:47
Thanks for the replies so far. My friend is a senior citizen and lives
alone, so no children have been near the TV. There have been lightning
storms so that may be what caused her TV problem.

I have a bulk tape eraser. When I visit again first I'll try my
degaussing coil on the side of the TV as well as the front, and if
that doesn't work I'll try the eraser.

I'll report back what happens.


Ron Weston <RonW(a)nosuch.com> wrote:

>My friend has an inexpensive 9-inch TV, about 6 to 10 years old. It
>suddenly developed two green spots on the screen, one in the upper
>right corner and one in the lower right corner.
>
>I have a "GC Electronics Professional Degaussing Coil" and I made two
>attempts to degauss the TV picture tube. After the second try the
>lower green spot was just about gone, and the upper spot is much
>smaller but can still be seen.
>
>I'm going to try again next week and I would like some advice. In my
>attempts so far I moved the degaussing coil around only the front of
>the TV. Should I try degaussing the sides, top or back of the TV, or
>might this make things worse?
>
>Nothing unusual happened to cause the green spots. The TV hasn't been
>moved in years and no magnets were placed near the TV. Any theories
>about what happened?

From: bz on 22 Apr 2010 14:01
"William R. Walsh" <wm_walsh(a)hotmail.com> wrote in news:976ab687-72ed-487d-
826d-ea5359e01050(a)z3g2000yqz.googlegroups.com:

> Hi!
>
>> Have your friend hide the magnets from the kids. The internal
>> degauss should take care of the remaining spots provided it
>> works.
>
> Sometimes it isn't stout enough to do the job. Some years back, my
> younger brothers managed to put a faint "blob" on a MAG Innovision 17"
> CRT. No amount of degaussing with the monitor's built in coil would do
> the job. Even though the coil came on at every power up, it just
> didn't seem to have the oomph. Operating it manually through the
> monitor's menu did not help.
>
> Being busy at the time, I took a quick look and decided that they'd
> damaged the monitor's picture tube. And then, after a while, I managed
> to acquire a large electric bulk eraser, which I eventually decided to
> try using as a degaussing wand for this monitor.
>
> It worked brilliantly. I started from several feet away by turning it
> on and moved very slowly toward the CRT itself. Then I ran it slowly
> around the CRT face, maintaining several inches worth of distance.
> When I was satisfied, I moved away the same several feet and shut the
> coil off.
>
> William

I have successfully degaussed CRT monitors using an old magnetron magnet
suspended from a stout rubber band fastened to a bent wire in the a hole in
the center of the magnet.

I would wind up the magnet/rubber band combo and let it spin rapidly
Holding it near the monitor and slowly moving it away as it spun.

Any strong and rapidly spinning magnet that is aligned so that the magnetic
field alternates directions should work.

Some 'bulk erasers' spin a magnet using an electric motor.




--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.
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