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NotTaR of Television Sets : Older TVs with multiple intermittent pro..
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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.
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If the set is say, a GE, with a manufacturing date around 1980, it is possible
you have one of those circuit boards best described as bad solder joints
held together with a little copper. In this case, prodding may get the set
started. The circuit boards in these sets were double sided using what
were called 'rivlets' for vias. The rivlets were relatively massive -
literally little copper rivets - and they were not adequately
heated during assembly so there were bucketloads of cold solder joints
that showed up during middle age. I repaired one of these by literally
resoldering top and bottom of every one of the darn things with a high
wattage iron.
Assuming there are no other symptoms:
If this appears after extended operation - an hour or more - it may
just be a build up of dust, dirt, and grime over the years. After
understanding the safety info, some careful vacuuming inside may help.
Just don't be tempted to turn any screws or adjustments!
Dust is attracted to the high voltage section in particular - even the
front faceplate of the CRT collects a lot and should be wiped with a damp
cloth from time to time.
If the symptoms develop quickly - in a few minutes or less, then there
could still be a dust problem - a power resistor may be heating a wad of
it but other possibilities need to be considered.
If not dust, then probably in the power supply but realize that TVs don't
have a nice metal case labeled 'power supply'. It is just a bunch of stuff
scattered around the main board. Without identifying the part that is
heating, a diagnosis is tough especially if the set really does
work fine otherwise. However, if a series regulator were faulty and putting
out too much voltage, the set could appear to work properly but in fact
have excessive power dissipation in certain components. If cleaning the dust
does not solve the problem, you will probably need a schematic to identify
the correct voltages.
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