Degaussing a TV...possible?

[old_tv_nut]

If the distortion is not right where the magnet was against the face, you are probably lucky and the mask is not deformed - however, this tube was subject to strong fields and a built-in degausser may take a large number of cycles (approaching infinite) to clear it up completely - you really should try manual degaussing, and you will know in a minute if it's recoverable or not. - Good luck!

[wa2ise]

It sounds like the amount of magnetic field the kid applied will need external degaussing to remove. The soldering gun trick should help. Or a tape eraser. Maybe the thermister that the internal degausser uses went bad. It's a variable resistance that has low resistance when cold, and high resistance when hot. It's usually in series with the degaussing coil across the powerline on the load side of the power switch. The thermistor heats up to hot in a second or two. You might be able to salvage one from an old computer monitor. It looks a little like a disc ceramic.

[AgentWinchester]

i saw a soldering gun at the pawn shop the other day-i'll check it out. I'm not about to fork over $40 for a soldering gun. My mother has a aquaintence who runs a tv repir shop, did a vertical circuit rebuild on our big toshiba, i'll see what he charges compared to the price of a coil/gun....Maybe a soldering gun might be a good investment anyhow...

[Whirled One]

[Sorry 'bout the late reply; I'm just catching up on posts after having been away from the forum for a bit...]

While I can't find or remember the book I saw this in, a few months ago I was flipping through an old TV repair book and it described a simple method for constructing your own color CRT degaussing coil. Unless I'm hallucinating, the instructions were basically:

- Get some ordinary 18 gauge insulated wire (single conductor, type and gauge not critical)
- Coil it up into a ring about 12 inches in diameter (I don't remember the number of turns you were supposed to make, probably something like 20 or so)
- Wrap electrical tape tightly around the loop of wire you just made to keep the coil turns held tightly together
- Strip both ends of the wire and connect them directly to an AC line cord.

...and that's it!
At first, this idea seemed a bit too simple (and perhaps unsafe) -- would a simple coil like that generate enough inductive resistance to prevent it from looking like a short circuit? ...but come to think of it, that's probably pretty much how a commercially-produced degaussing coil is made anyway. Any thoughts? Am I forgetting something important here? Would this be a practical servicing tool or a death trap? [...Then again, I think this might have been something I saw in a TAB book... ]

[old_tv_nut]

The construction is generally as you describe, but you should not guess at the gauge of the wire or the total length - it is mainly the resistance thar limits the current, not the inductance. It WILL get warm and eventually hot after only a little while. Commercial units usually have a "hold to operate" switch. We had one with a shorted switch once, and it's a good thing it was lying on a fireproof bench. Of course, if there's no switch, you would turn it off by unplugging, which you are unlikely to forget (I hope!). So, if you find the article and follow the numbers, it should work fine.

[bgadow]

I tried salvaging the coil out of a later model rectangular set once, just hooked it to AC. It took about 5-10 seconds to start smoking. I guess the commerical coils are wound on a form, maybe a steel ring? From holding it, it seems so.

[dewickt]

Made one many years ago when I worked for Phillips, memory is that it was 400 turns of #22, it could rattle the shadow mask and got warm after 30 seconds, could demag any tube !!

[kc8adu]

hit the yard sales and flea markets.
i just got a weller 100/140 gun in good shape for a buck at olive road flea.

[outlawmws]

OK enoght messing with half measures and guesses. here are 2 sites on hoew to build a de-gauser. I like the first one, but whatever floats your boat.

Site 1


site 2

[glen65]

I pulled this from an old 25 inch console 20 years ago.
I dont have a light bulb in series with it. It
seems to stay cool long enough for me
to get the job done and the strongest of any
I have ever used.