I have a JVC tv bought less than a year ago so I will go and have it fixed under warranty - but with it being so close to Xmas I just wanted to try and make sure my tv won't die on me during the holidays.... Anyway any advice as to what is happening with my tv would be greatfully received.... Basically in the bottom corners of the screen there seems to be a colour distortion - like a creeping colour varying from greens to purples....does this mean the tube is going? pls help
More likely it means you've got something magnetic, like a set of stereo speakers too close to the TV. Otherwise the degaussing coil needs to be fixed assuming the TV hasn't been dropped.
thanks James - nearest speakers are about 5 feet away - that's okay isn't it? - the only things near are my VCR, digital box, radiator and champagne bottle - but tv is 28" and hasn't been moved in 11 months although the speakers were brought in at the weekend...could it be that? - thanks so much
More than likely when the speakers were carried by, they got too close to the tv set and magnetized it.
Probably a simple matter to have the tv properly degaussed without even opening it up will fix the issue. You may also need to have the radiator demagnetized if it is close to the tv as it is probably magnetized a bit from the close proximity to the speakers as well when they were carried in.
Just schedule to have the technician come out and look at it to confirm the magnetization and degauss the set if that really is the issue.
It's worth trying to degauss it, there may have been a nearby lightning strike or some other magnetic source at some point. If you have a bulk tape eraser or one of those big Weller soldering guns you can use either one as a degaussing wand, or just buy the real thing, I found mine for $10 on ebay a while back.
Almost certainly your TV needs 'degaussing'. What has happened is the 'shadow mask', a metal mesh screen just behind the glass inside the tube, has become magnetised and the electron beam gets disturbed by the magnetism. This can be caused by having speakers or other sources of magnetism too close to the screen, or by a faulty degaussing circuit in the TV itself. It can also be caused by a nearby thunderstorm believe it or not!
Either way, the problem is usually neither difficult nor expensive to remedy, unless the problem was caused by dropping the TV, which can permanently damage the shadow mask. If it's caused by a magnet nearby, the TV repair man will wave a special device called a 'degaussing wand' near the screen which will remove the magnetism from the screen. If there is a fault in the TV's degaussing circuit, the most common failure here would likely be a device called a 'degaussing thermistor', which is a relatively cheap and easy to replace component.
Once the source of the problem is addressed, it is not likely to return soon provided you ensure no sources of magnetism are too close to the screen.
To answer your last question, no, it is very unlikely there's any permanent damage to the tube, unless you have dropped the TV.
This may work or more likely will not help if it was due to the speakers being carried close to the tv set.
Modern tv set degauss circuits are no where near as strong as they were years ago. They are designed to demagnetized anything caused by the earth's magnetic field, not magnetism from large speakers that were carried to close to the tv set. I have yet to see a tv set made in the last 10 years that has a degauss circuit that will take care of a strong magnetization problem from something other than the earth's magnetic field.
If the tv had simply been turned on its axis and the problem showed up from that in one and maybe the opposite corner, then the internal degauss would be expected to take care of it after several cold turn on starts.
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