I have a Sony Bravia TV and a digital cable box.
My kids (23 and 25 yrs old) visited this weekend. They left and I came home from work and turned on the TV. It had no sound, I turned the volume up to max, nothing, I checked all the cables, still nothing. I called my son, no answer, I called my daughter, no answer. A couple minutes later my daughter called back, I ask if she did anything to the TV, it has no sound. "Did you turn up the volume on the TV?" So I grabbed the TV remote (that we never use) and turned the volume up. Yes it works. A few minutes later my son returned my call, I told him I didn't have any sound on the TV, but your sister fixed it. he said, "did you turn the sound up on the TV" As I said I never use the TV remote but the kids, ignored the Cable Box remote and turned down the sound on the TV. I later texted them and told them to quit laughing at your dad!
Mikek