Some channels on TV have no volume

What model TV? What is your source? Cable? Satellite? Antenna? How is it connected? HDMI? Component (red, green, blue)? Composite (yellow)? etc. Are these channels always without sound or only just sometimes? What channels are these (specifically what networks, not channel numbers)?

If you have cable or satellite, have you attempted calling your service provider?

We need more details in order to answer your question.

TV is a Samsung 32" lcd , the provider is Time Warner Cable it is hooked up to a regular coax cable, there are also 3 other TV's in the home that are all working fine. The affected channels always have no sound.