***Solved: No sound on just one channel!***
I had to call the TV repair guy because I was stumped. All the sound problems I've read about were regarding no sound at all on all channels. I had a unique problem where I wasn't receiving sound from just channel 2. The repair guy was stumped as well at first, so through process of component elimination he solved the problem. He said, lets eliminate the STB and plug the cable (antenna), directly into the TV and do an initial setup to automatically search for all channels. That worked!! I was now receiving sound on all my channels including channel 2. He said that there must be something wrong with the STB that wasn't allowing the sound from channel 2. He said all you have to do is re-channel your cable through the wall like you have the other cables to tidy everything up.
So, after thinking about what we did, I thought, how about if I plug the cable back into the STB and do the initial setup to automatically search for all channels again. I needed this STB box to record TV shows. I really didn't want to loose this capability. Well to my surprise, It worked!! Go figure! For some strange reason the STB decided to drop the audio on just one channel. So glad to have my Sony Bravia working again.