Degaussing a television

as it says in the tin:- I have a middle-aged (about 12 yrs old but generally serviceable!) 20 inch phillips crt TV, and I am getting a patch on the screen, about the size of my hand, where the colour is distorted (Purple/ greens) which I know means the TV needs degaussing, to get rid of it.

There's no "degauss" button on the TV (as there is on some TVs) What can I do to get rid of this problem/ odd colouring?

Thanks in advance.

Pretty shure you would have to get someone in to do it,weigh up the cost against another tv.

you could purchase a degaussing coil but if it works or not is another thing ?

I've seen a Weller soldering gun used to degauss screens with problems you describe.

The gun trigger is depressed to create a magnetic field and the gun is rotated around the screen, from edge to centre, the gun is pulled away from the screen in the centre BEFORE THE TRIGGER is released.

I had a degausser, I lent it to Phileas and he never gave it back. PM him, if he still uses the forum he should still have it.

I thought tellys used to automatically degauss when they were switched on?

Here you go:

Every TV has an auto-degauss feature, which you can invoke by pulling out the mains plug for 30min or so, then plugging the set back in and switching it on. This demagnetising function often causes a brief buzzing sound. Alternatively, place a compass on top of the cabinet, its needle will twitch violently when the degauss circuit is doing its stuff. Never turn the set round while it's running; the Earth's magnetic field will upset beam-landing and purity

http://www.homecinemachoice.com/articles/wvarticles/hardware/200108_tubes.php

The bit about the compass is new to me - use at your own risk

All you have to do is to turn it off with its mains button on the TV, then run your hands across the front to clear the static and turn it on again once it's had chance to cool down.

The easiest thing to do is to turn it off at the mains at bedtime, clear the static and clean the screen with a duster (otherwise you'll end up with static handprints in the dust!) then turn it back on the following day.

It probably needs degaussing and as had been said previously you need either a degaussing coil or a Weller soldering gun.

As other people have said there is a degaussing circuit in every TV that operates for a second or two at switch on, but it doesn't always work if the shadow mask has become magnetised perhaps from a speaker being placed too near the TV or perhaps stood on top of the set? At one time there was a phase among children to run a magnet over the screen and watch the pretty colours, the next day the TV repairman would be getting a call out!

If after using the degaussing coil the problem persists then the positor will have gone and I have replaced hundreds of them in Philips TV's in my time, it was a common fault and generally a new positer cured the problem permanently without the need for a degaussing coil which would only have been a temporary solution anyway if the positor was faulty.

To buy a positor would cost less than a couple of pounds, to pay someone to replace the two legged device would cost around £40.00. I left the trade in 2001 and have never taken the back of a TV since and have no intention of ever doing so again. TV's can be horrible, self-willed, stubborn, complex, and like a flipping minefield a times.

The easiest thing to do is to turn it off at the mains at bedtime, clear the static and clean the screen with a duster (otherwise you'll end up with static handprints in the dust!) then turn it back on the following day.

Random fact - the dust on the front of your TV screen is radioactive. The static preferentially attracts naturally occurring radioactive decay particles.

http://www.hps.org/publicinformation/ate/q157.html

Just a thought, but you haven't recently put something with an electric field such as speakers near your tv have you? That may be the cause.