My 3 year old LCD HDTV all of a sudden no longer has any audio. It has been about a month now. Basic set up, Just using a coaxial cable from cable jack to the TV. Have a VCR(yellow, white, red hookup) and DVD(HDMI) also attched to TV and when watching a movie from them, I have no sound. I bought a new cable and even a new TV. The sound worked on the new TV when I first hooked it up but only worked for one day. TV works downstairs and this new TV and my old TV work if I take them downstairs. I actually just switched from cable to satelite(not because of this, just cause I wanted to) and they used the existing wiring when installing. Still no audio on upstairs TV. So to me it has ruled out everything except the wiring to the cable jack. Any idea how I can fix or what could be wrong. Should I investigate or get an electrician or someone to look at it. The jack is a little loose from the wall. Wondering if some wiring is loose inside. Could that cause no audio but still good picture. Thanks.

Try unplugging TV for a minute and plug back in.

Since your TV works downstairs, it is possible that it is the wiring upstairs. I assume since you moved the TV downstairs that you unplugged your TV to do so unplugging and plugging back in your TV has already been tested.

You can take the plate off the wall and it is just a coupler (sometimes called a barrel connector). So there should be a coax wire with the end on it screwed snuggly into the back of the plate. Make sure that there is a good end on the wire too. It will be a compression fitting instead of a crimped end. The end on the left of this picture:

http://forums.klipsch.com/forums/storage/5/1371797/HOWTO-Compression-Connectors.jpg

Is an example of a compression fitting.

If you are not comfortable with terminating wires like this, there are plenty of how-to guides online and on YouTube. Otherwise your cable company should fix this for you.

If you get no sound from your TV when you play a dvd movie, then the problem has nothing to do with the coax cable coming from the wall.