NotTaR of Television Sets : Red, green, or blue full on - fog over p..  
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Red, green, or blue full on - fog over picture

This could be a heater-cathode (H-K) short in the CRT, a failure of a component in the chroma circuits or video output (driver board), or bad connections there or elsewhere.

Don't panic - heater-cathode shorts in CRTs can often be worked around.

Note: before proceeding, it is a good idea to make sure that the screen is degaussed - else you could be attempting to track down problems with the wrong color!

Some simple tests can confirm or rule out other possibilities.

Here is the procedure in more detail (example for red full on):

(From: J. K. Emerine (jkemerine@aol.com).)

To identify if the fault is in the CRT or a control problem try this (WITH SET OFF):

On the CRT board, lift the output end of the green cathode final resistor. Do the same with the offending red cathode's resistor. Use short insulated jumpers to 'swap' drive signals - drive the red cathode with the green drive and the green cathode with red drive. (Note that if this problem only occurs after a warmup period, color at turn on will be - well - wierd, but it is just a test.)

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