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