Picture tube degaussing
Ron Weston
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?
Phil Allison
"Ron Weston"
>
> 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?
** You sure the internal de-gaussing is still working OK ??
... Phil
AZ Nomad
Any young children?
D Yuniskis
Ron Weston wrote:
> 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 nearby lightning strikes?
PeterD
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.
William Sommerwerck
sitting around", the shadow mask might have gotten deformed.
AZ Nomad
>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.
hr(bob) hofmann@att.net
> On Wed, 21 Apr 2010 23:26:59 -0500, AZ Nomad
>
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> - Show quoted text -
can you hear the degaussing action when you first turn the set on
after it has been off for several minutes?
Robert Macy
> On Thu, 22 Apr 2010 05:23:59 -0700, William Sommerwerck <grizzledgee...@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!
William R. Walsh
> 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
Ron Weston
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.
bz
826d-ea5...@z3g2000yqz.googlegroups.com:
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.
William Sommerwerck
Zenith once made one with a small magnet you spun by hand. It was intended
for small blotches.
AZ Nomad
>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.
With the eraser, turn it on and off at least 5' away from the TV.
Walk slowly to the tv waving it around then back off. Be careful; the
things are very powerful and you might be able to damage the shadow
mask if you get closer than needed.
Arfa Daily
"William R. Walsh" <wm_w...@hotmail.com> wrote in message
news:976ab687-72ed-487d...@z3g2000yqz.googlegroups.com...
Back in't' day, we wuz taught to have the TV switched on, and go around the
four sides of the CRT using circular motions, and to keep those motions
going all the same way. Then to come up to the CRT face, and again use
circular motions, again keeping them in the same direction, and spiraling
slowly away from the face. At a distance of a couple of feet, when the field
from the coil was no longer having any noticeable effect on the picture, the
coil was quickly turned through 90 degrees, and powered off.
As to what caused the problem on this particular TV, could be all sorts of
things. One of the favourites, as I recall, was customers switching off the
vacuum cleaner when near to the TV. You can also get suddenly appearing
purity patches from shadowmask displacement when the spring expansion mounts
move out of place, or spot welds on the shadowmask frame give out. However,
mechanical issues such as these, would not reasonably be expected to cure by
manually degaussing, so I would say that the problem here is magnetic.
Arfa
hr(bob) hofmann@att.net
>
> - Show quoted text -
Just be sure to m,ove at least 10 feet away before shutting it off.
Boris Mohar
Did someone move some leaky speakers nearby?
--
Boris
Ron Weston
coil over the front, sides and top of the TV. There's still a tiny bit
of green in one corner (you have to look closely on a very light
screen to see it) and my friend is satisfied and didn't want me to try
the bulk eraser.
I'm afraid the degaussing circuit in the TV is not working. The green
spots got worse in the week since I first degaussed the set. My friend
is unwilling to give up her TV now so that I can repair it, but when
she goes on vacation this summer I will repair the set.
Thanks again for all the responses and advice. It's greatly
appreciated.
Arfa Daily
"Ron Weston" <Ro...@nosuch.com> wrote in message
news:1ph6t5hdr7o8alpfo...@4ax.com...
>I used my degaussing coil on the TV again today. This time I moved the
> coil over the front, sides and top of the TV. There's still a tiny bit
> of green in one corner (you have to look closely on a very light
> screen to see it) and my friend is satisfied and didn't want me to try
> the bulk eraser.
>
> I'm afraid the degaussing circuit in the TV is not working. The green
> spots got worse in the week since I first degaussed the set. My friend
> is unwilling to give up her TV now so that I can repair it, but when
> she goes on vacation this summer I will repair the set.
>
> Thanks again for all the responses and advice. It's greatly
> appreciated.
>
>
Just another little bit of friendly advice Ron - don't top-post ! It's
greatly frowned upon in newsgroups, and whilst it's reasonably tolerated on
this group, doing it on some others will cause a shed-load of abuse to fall
onto your head ...
Arfa
Phil Allison
"Ron Weston"
> I'm afraid the degaussing circuit in the TV is not working.
** Now he tells us ......
Did he never guess that the failure of the degaussing circuit CAUSED the
green patches to appear ??
..... Phil
stra...@yahoo.com
> On Sun, 25 Apr 2010 12:41:11 +1000, "Phil Allison"
> <phi...@tpg.com.au>wrote:
> determine the internal degauss wasn't working?
I had a TV with a failed degaussing system which caused a serious
color blotch as Phil described. This one failed because of a relay
contact flexing the solder joint on the PCB which eventually failed. I
removed all the old solder and re-soldered it. It went 8 years before
the first failure.
G²