This is a CRT , not flatscreen TV. After it is on for a while, suddenly the picture tube seems to go off. It goes black and there is a tiny bit of light in the center for a split second, like the power is being turned off. At the same time, the audio remains, but diminishes slightly in volume. Then, after a few minutes, the sound come back and the picture returns as well. This problem repeats and repeats. Now that I am watching it very carefully, I notice that in the fact the slight drop in audio volume just barely precedes the blanking of the picture, just by a fraction of a second. Any ideas? Thaks.
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Is it a tube TV or a flatscreen? If it is a tube then it is possible to correct this, however I'm not sure what caused it. Take the back off the TV, and look for the flyback transformer. It is the unit with a red wire coming out of it, going to what looks like a suction cup on the tube. On the unit there should be a small knob labeled focus. Try adjusting this. If it is a flatscreen, sorry, I can't help.
Sony incorporates a video blanking circuit that blanks the picture out when the picture tube begins to get weak. sorry, but short of replacing the tube, there's no lasting solution to this problem. I used to have some success rejuvenating the crt, but I found that it didn't last but a few hours before the blanking circuit starts to activate again.
Sounds like the red picture tube could be shorting internally which would cause the "all red" condition. In which case you'd have to replace the red tube. Are there horizontal (slightly slanted) lines through the picture as well when this is happening and a very very bright screen? If so it's most likely the tube.
sounds like a bad picture tube. Picture and bright settings cranked up for a good pic? Test/rejuv with a crt tester and/or look at the Ik signal on the crt board. A good tube has 3 small pulses during blanking. The crt cathodes are checked with these pulses, pulses too low and the jungle IC will blank the drive. If the picture fades in and out I would check the filament ckt but that doesn't support the "blinks"
These are called retrace lines they occur because of the blanking pulse not turning off the electron guns in the picture tube during the retrace period. Since this is occuring with the red gun there may be a proble with the video circuitry connected to the red electron gun of the picture tube. This would include the red amp and the red driver transistors. You will need a schematic and a multimeter to properly test these items.