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NotTaR of Television Sets : Picture fades in and out
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1994-2007, Samuel M. Goldwasser. All Rights Reserved. Reproduction of this document in whole or in part is permitted if both of the following conditions are satisfied: 1. This notice is included in its entirety at the beginning. 2. There is no charge except to cover the costs of copying.
I may be contacted via the Sci.Electronics.Repair FAQ (www.repairfaq.org) Email Links Page.
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If the picture faded away on the order of 10-20 seconds (and if it comes
back, also comes up to full brightness in same time frame - possibly
with the persuasion of some careful whacking) AND with NO other
significant changes such as size, focus, etc., then take a look in the back of
the tube for the filament to be lit - the orange glow near the CRT socket. If
there is none, then you probably have a bad solder connection on the circuit
board on the neck of the CRT. Look for fine cracks around pins on that board.
Try prodding it with an insulating stick to see if the picture comes back.
Resolder if necessary. Dirty or corroded CRT pins/socket contacts can also
do this - remove, inspect, clean, and replace the neck board. It is probably
not a bad CRT as the filaments are usually wired in parallel and all would not
likely go bad at the same time.
However, if only a single color fades in and out, then a bad connection
inside the CRT is a distinct possibility - look for only one of the
filament's glow to be coming and going. This is probably not worth fixing.
If the picture faded away with other symptoms, then there is probably
a fault in the video amplifier/output one of its power supplies -
still probably a loose connection if you are able to get it back by
whacking.