On 07/29/04 09:49, Ernie Bornn-Gilman said...
I am not sure
just what part of the tube gets demagnetized...
It's the shadow mask, which is just behind the CRT face, and is what makes sure the electrons hit individual phosphor "dots", sort of like a spray-paint stencil.
By being magnetized, the shadow mask can alter the path of the electrons (improper deflection), and results in the typical color variations as the wrong dots are illuminated.
It's made of steel, which is ferrous. It's even possible to overheat a shadow mask to the point of glowing red-hot and/or warping, and obviously can ruin a CRT.
This problem is a bit unusual in a 27" TV, though,
unless there is a speaker or something else nearby,
where its magnetic field influences the picture
tube.
Another possibility is any nearby electronics with a transformer and/or motor, both of which produce quite strong magnetic fields. Try moving the TV while other components are unplugged, not just switched off.
Larry
www.fineelectricco.com
