Every 20-odd minutes my SCHT-900 puts out a staticy noise through the right front channel for about 2-3 secs. The picture on my Plasma is unaffected when using Sky. But when I play a DVD, interference will become apparent on the screen as the staticy noise is put out. Any ideas what the problem could be? I've had my system for just over a year so it's typical that something should go wrong with it just after the warranty runs out!