This indicates an Automatic Gain Control (AGC) problem often caused by
a dried up capacitor. You will probably need a schematic to go much
further. This could be a problem in the tuner, IF, or video amplifiers.
|NotTaR of Television Sets : Picture is overloaded, washed out, or no..
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The following assumes you are sure the signal source is strong - try a VCR or
other local one (channel 3/4, not the RCA jacks).
(From: Glenn Watkins (email@example.com).)
Substitute a variable voltage source for the tuner's AGC voltage. Most of the
time the range of AGC is from 1 to 7 volts. If you can get a decent snow
free picture with an external AGC source, then the tuner is probably OK.