Picture tube degaussing

"Ron Weston"

... Phil

Any young children?

Any nearby lightning strikes?

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

Absolutely, highly magentized small/young children mess up TV sets all the time!

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.

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.

ext -

can you hear the degaussing action when you first turn the set on after it has been off for several minutes?

ust

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!

Hi!

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

"William R. Walsh" wrote in news:976ab687-72ed-487d- snipped-for-privacy@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.

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.

R>My friend has an inexpensive 9-inch TV, about 6 to 10 years old. It

Do you know how to use a degauss coil?

Zenith once made one with a small magnet you spun by hand. It was intended for small blotches.

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.

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

Just be sure to m,ove at least 10 feet away before shutting it off.

Did someone move some leaky speakers nearby?

-- Boris

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.

R>Thanks for the replies so far. My friend is a senior citizen and lives