I have a Toshiba CX32D70 that when I turn it on, sounds fine. But after several minutes the sound fades so that it's only audible if I turn up the volume as high as it goes. When we use the XBox or any other device coming in on video 3, everything is normal. The picture is unaffected no matter what, so the set seems worth keeping. What could this be and how can I fix it? Thanks!
So the first thing, we know the audio amp of the TV set is good because it works normally you said on input 3. This would steer me to the audio processor, I.F. section, or the audio Quad coil and the circuits around them. What is sounds like to me is a regulator that ia built into an IC to process the audio could be going bad after the set is turned on, or sounds like maybe a bad coupling capacitor. This is going to need a signal tracer or injector to trace where your losing the audio. I would suggest you call your local repair shop as this is not a repair you can do without the proper equipment. Good Luck, and let us know how you made out.