Sony 36" TV with impure lower-right corner

Borrow a degausser and give it a try.

No offense, but why should a degausser work, when a bulk tape eraser with the power to handle metal-particle tape doesn't? You have to stand about 8' from the set before the bulk eraser's effect is no longer visible.

William:

The inductive kick when the eraser was shut off is quite large. If you bring the bulk eraser to the same location as before, can you see any effect on the picture? If you can, try turning it on and move it slowly away to several feet before shutting off.

I would take a very strong magnet, such as from an old magnetron, bring it near to the tv, in the same place as the eraser was when you shut it off, and then rotate the magnet rapidly wile slowly moving it away from the tv. It effectively reverses the magnetism back and forth while slowly reducing the strength. That will clear many problems in my experience. I have a dozen old magnets from scrapped uwave ovens, they are about the strongest I can find except for magnets from very large loudspeakers and are so strong you don't want your finger between two of them.

H. R. (Bob) Hofmann

Are you kidding? The bulk eraser has a huge effect.

My approach has been to follow the standard procedure -- bring the demagnetizer near the set, then slowly back away to let the flux gradually decline, until there is no visible effect on the image. This does _not_ remove the splotch.

How is this approach different from slowly moving a degaussing away from the CRT? Is the magnetron magnet significantly stronger than a degaussing coil? (The implication of what you wrote is that it is.)

Zenith used to make a bar magnet on the end of stick. You started the magnet spinning (by hand), then pulled it away from the CRT. The idea was to clear small splotches of magnetism.

Somebody suggested that I had damaged the aperture grille. Is this possible? Does anyone know?

Back in 2006, a friend helped me disassemble one of my Apogee speakers (which has lots of magnets). The speaker came rather close to the set, and for a few minutes the splotch was gone. (And, no, the speaker is not the cause of the splotch.)

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OK - what I would try next is turning the bulk eraser on and off in the same position that it was when you caused the problem, to see what happens. If it was the bulk eraser that casued the problem, something should change. If nothing changes, then maybe there is something else magnetized somewhere else in the set. Is it possible something got magnetized and then moved so that it is no longer affected by the bulk eraser? Have you pulled the back to see if anything seems out of place?

Bob Hofmann

I'm guessing--and it's only a guess--that you did, indeed, damage the aperture screen...deformed would be more accurate. The fact that a permanent magnet in proximity to the crt temporarily 'fixed' it is both a clue and a path to a fix of sorts.

I'm thinking that the field from the magnet pulled the grill back into shape--and that the effect should be repeatable. Although it's not really a cure, leaving a magnet in proximity to your TV is preferable to watching a splotch....

jak

What you're suggesting is to repeat the same thing which he (and I) suspect damaged the tube in the first place--abruptly and possibly permanently flexing the shadow mask. The possibility exists that he could make it even worse. Unless concentrated degaussing of the area makes some improvement, internal damage is about the only possibility.

jak

On Feb 8, 11:03=A0pm, jakdedert wrote: > hr(bob) snipped-for-privacy@att.net wrote: > > On Feb 8, 4:16 pm, "William Sommerwerck"

Trinitron aperture grills are stretched top to bottom on a cast iron frame inside the CRT. How do you 'deform' it?

GG

Trinitron aperture grills are stretched top to bottom on a cast iron frame inside the CRT. How do you 'deform' it?

Twisting it?

There is no question that turning off the bulk eraser caused the problem. None whatsoever. (Remember, I did this deliberately to magentize the aperture grille.)

I've thought of this, but the set is very close to the wall, and almost impossible to move.

Agreed. I've put up with it for a few years, so there's no need to fix it immediately. I'll start looking for a magnetron magnet.

And I might just call Sony and ask their opinion. (Hah!) In fact, as the set came from Magnolia, I just might stop by (when I get a car!) and ask.

I hadn't thought of that. The bulk eraser runs about a minute before it cuts out, possibly longer if I leave it in the freezer overnight. Perhaps a hair of the dog that bit the set might work...

I'm not a TV tech...don't even play one on the internet; but I do know that bulk erasers put out a pretty hefty field. I'd go for something with a little less flux that you could keep on longer...and keep it moving. The Weller soldering gun somebody mentioned is what I've used for 'spot' degaussing.

jak

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If the bulk eraser will stay on for even 20 secondds, that is enough to turn it on, move it around the area of the tv where it was before, and then back away slowly.

H. R. Hofmann

I've done that many times, and it doesn't fix the problem.

Another source of magnets that are very strong and easy to obtain is the motor drive from the old 5 1/4 floppy drives from computers. They are usually discarded everywhere. Justy.

Does that blulk eraser cause the colors in the corner to swirl around?

Maybe just glue some magnetic rubber to the inside of the cabinet near the corner in question if you can fix the color in the corner that way.

I'm out of any other ideas.

Of course! It's rat purty.

I might experiment with magnetic business cards.

Damn. I was expecting omniscience.

I'm damn good, but not God.