My sound drops intermittently when on a music station, sometimes it is for an instant then sometimes it's for 20 minutes or longer. Sound will eventually return but I found the immediate solution is to hit pause, then play and the sound returns.
I also lose sound when fast-forwarding through commercial breaks on recorded programs. Occasionally sound goes out of sync with the picture. Again, the immediate solution is to hit pause then play and the sound corrects or returns. It's an annoyance and I'd love to find the long term solution.