The Sony Trinitron line of televisions feature cathode ray tube technology, an analogue display technology in which electron beams are projected through vacuum tubes to create an image on the screen. Since CRT televisions are dependent on a magnetic field for operation, any changes or irregularities in their magnetic field can result in a distorted image. Such problems can be fixed by a process called degaussing, whereby the internal magnetic field created within the CRT is reset by the presence of another magnetic field. You can manually degauss your Sony television using a specially made degaussing device.
Turn on your Sony Trinitron television.
Flip the power switch on your degausser.
Manoeuvre the degausser's coil so that it is a few inches away from the face of the screen. Draw the centre of the degausser coil around the entire perimeter of the screen, and then return the degausser to the middle of the screen.
Slowly back away from the Trintron's screen. This serves to decrease the degausser's impact on the CRT's magnetic field to zero. Continue backing away until you are about five feet away from the screen
Flip the power switch on your degausser to turn it off. The CRT's magnetic field should return to its normal state and the picture quality of your Sony Trinitron should improve.
A commercial degausser consists of a coil that contains approximately 100 turns of magnetic wire. An inexpensive degausser costs approximately £6, as of September 2010. If you don't want to buy a degausser, you can try using any magnetic device in your home. The problem with this approach is that a low power magnet may not be powerful enough to fix the problem, whereas a magnet that is too high-powered may ruin your CRT to the point of no repair.
Be sure not to expose the side or back of your Trinitron to the powered degausser, as doing so may cause permanent damage to its CRT.