I have no sound/audio from the TV - tried all different sources and inputs but no go.

After the TV has been on for a little bit of time I start to get static on the TV speakers that I can do nothing about (Vol control does not work). So question is has anyone else faced the same problem? Any solutions - pointers?
BTW As a work around - I use an external receiver to route sound to a HT audio and that works fine, but the static from the TV can be failry overpowering! Would like to have the option to use the TV speakers.
Thanks in advance!