Greetings sci.electronics.repair community,

I have a GE TV that has a really weird audio problem. The TV information
is as follows:

Model #: 27GT720
Service #: 27GT720TX2
Chassis #: CTC203AX1

While watching the set, the audio will randomly disappear (from all
channels, this particular set is a low-end model with no baseband inputs, so
the only audio I can verify this with is from the internal tuner). When the
tuner sound goes away, you are left with a barely audible hiss which does
vary in intensity with the volume control, so I believe the final stage of
the output amplifier is fine.

The weird part is that once the sound goes away, it will stay away for as
long as the set is powered off, as long as it is plugged into the wall. If
I unplug the power and plug it back in, the sound will return and function
normally for a random amount of time (typically not less than 20min and not
more than 1hr). I first suspected thermal problems when observing this, but
if I unplug the set immediately after the audio goes away, it will still
return right away and may stay on for over an hour before failing again. If
the sound would disappear entirely and never come back, or at least not
return until the set cooled down, this problem would make more sense to me.

I have not fixed a television set in particular before, but I am used to
the safety issues and precautions for working around high voltage supplies
and have experience working around CRTs in devices other than televisions.
I do have respectible soldering skills and access to hot air tools for
surface mount rework if required to make a repair.

Can anyone give me a pointer as to what may be going wrong here?

Thank you!

Scott