Time Warner Cable TV/Voice → No sound on TV

I am not at grandma's house to physically troubleshoot the TV and Grandma is not that technologically inclined but her TV has a picture but no sound. She has a Time Warner DVR. The TV is a flat panel Samsung HDTV. She checked the volume on the TV.

What is more likely, the TV or the DVR. I think the DVR is a tan colored Scientific Atlanta 8300HD. I'll be going there in a few weeks but I don't want grandma to suffer without TV for the next few weeks. I offered to call and setup a truck roll but she is apprehensive about visitors because she has a dog that wrecked her house (enough said) but I'm actually glad she has the dog because it makes her get out of bed and remain active.

What kind of cable is connected between the TV and box?

If it's coax or yellow/red/white composite, then maybe the volume on the box was turned down or the red/white stereo cable was unplugged.

If it's HDMI, then maybe the audio output on the box was turned off or switched to a non compatible format (PCM or Dolby Digital).

Either way, it's possible the TV speakers were turned off or SAP may have been turned on (and there isn't an SAP channel).

Most of this is accessed through a series of menus on the TV or box... other than the box volume which might be accessed through the front box controls or remote if it's in the right mode and the volume controls are unlocked.

Then again, none of this may have happened and the box or TV went out.