have just set up my plasma via sky and vcr using auto tune feature. good picture on channels but no sound only buzzing noise. sound increases with volume control. bypassed sky and vcr and connected aerial direct, still same problem. connected up as original setup and tuned in sky via manual tune. picture good but sound louder, but still buzzing and distorted. re-connected back to old t.v, picture and sound perfect. any advice would be appreciated.