I get picture but no sound coming from my TV. If I turn it to dvd mode it will play the dvd with sound but once I put it back to cable there is no sound. It is not on mute. It will not play any live TV sounds or dvr sounds from previously recorded shows. How do I fix this?

Double check the connections going from the cable box to the TV. If they are secure on both ends, then try a different input on the TV.