h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Does anyone know if a TV that has been ruined by a magnet being put on it, can be fixed. We're getting used to it now, but the bottom fifth or so is a black fuzzy mess. It's terrible for watching Who Wants to be a Millionaire.

Magnets and TVs don't mix?

It *should* hopefully sort itself out eventually, but it could take anything from a few hours to weeks depending on how strong the magnet is and how long it was left there.

Turn it off and leave it off for a while. The field should dissapate after a bit. What sort of magnet was it and for how long?

Liam.

We had a permanent funny circle in the middle of our tv when we were growing up. The magnet wasn't strong enough to muck up the picture but it made a small circle look distorted.

There were four magnets in total - attached to the limbs of a furry monkey. I didn't see it happen, but it was about a year ago!

"attached to the limbs of a furry monkey"

There is a special tool for fixing that called a demagnetizer. You should be able to find one at a electronics supply store.

Not a real monkey! I think the idea was that the monkey could wrap around things and it's arms and legs could "hold on" to each other. The warnings not to wrap the monkey around TVs were obviously not clear enough.

I don't know why anyone would want to wrap a monkey around a TV in the first place.

Bunch of savages in this town.

Just done a bit of digging, and apparently fouling up your TV with magnets is very similar to the aroura borealis.

http://www.geocities.com/llgagnonmobile/aurora.htm

Look up TV repairs in your local telephone directory. They will come along with a device that will sort all that out in minutes. We had a really bad electrical storm a couple of years ago and the TV went "funny" - purple and green blobs all over the bottom of the screen. Mr TV man came along and 5 minutes and £20 later all was perfect.

Give it a go - what have you got to lose? (and the first person that says £20 gets a )

"fouling up your TV with magnets is very similar to the aroura borealis"

But not nearly as nice!

I didn't expect such a great response. I'm starting to think it may be more serious than just magent damage. From what I know about cathode tubes and the like, and from what it said on the Aurora site, I think magent damage should cause a more localised and colourful effect, whereas my TV looks more like a video with bad tracking. I think it would be worth calling a repair man because it's a lovely telly.

Have you seen the Northern Lights Stephen? That is one of my '10 things to do before I die' I did sort of see it when I was flying back from the US a couple of years ago. We were on a night flight and were crossing Greenland, I can never sleep on planes so decided to lift the shutter next to me and look out the window. I don't know what I was epecting to see! Stars I guess - but instead saw all these shimmery white "curtains". I would love to see the coloured lights though.

If it's a color TV then, yes, the effect should be a very pretty warping of colors... maybe a slight warping of the picture... but anything more serious than that is probably something else

You can damage the TV by doing that, but it's not the CRT that you damage it's the shadow mask - the very fine mesh that the electrons pass through. If the shadow mask become warped then electrons can end up lighting up the wrong phosphor dots - hence funny colours.

You can degauss your TV by passing it through a large coil of wire with an AC current flowing through it - this technique was used by the navy to prevent limpet mines from taking to ship hulls - you can imagine the size of the coil


Liam.

Hmmm, yes I thought about de-Gaussing. Do any tellys have a button like some PC monitors? I had a look at the TV this lunch time and there is nothing wrong with the colours, just a distinct lack of any picture about 5 inches across the bottom, and about an inch across the top (perfectly horizantal) - it is now a wide-screen TV!

I may try the old AC wire trick. A lamp flex would work wouldn't it.

Yes some lamp flex might work, but it needs to be a long one. You'll need a couple of thousand turns of it.

It sounds like you have a partial horizontal field collapse. It's a bit more serious, you've affected the coils that control the electron scanning. I would call out a TV repair man if the TV is fairly new - if not you may need to look at getting a new one.

Most modern TVs will degauss on startup - but not like the cool effect you get on a monitor *presses degauss and grins*

Liam.

A partial horizontal field collapse. Just what I had feared! I might try and find my longest lamp cord, or I may give up. The TV came with the house that my girlfriend lives is, and no-one is really bothered about it. It's a old Bang and Olufson so I thought if it could be fixed, it would be worth it. Whenever anyone visits they always comment, but we're all used to it now.

Cheers for the help. I wish my monitor had a degauss button!