Recently my television started making a high pitch noise, it might be ok for hours on end but then starts making the sound. It seems to vary slightly between channels but remains until turned off and then shows up again later on other times seems to be alright.

But, it makes no noise when turned on any HD channel. While making the noise on any and every standard definition channel it's turned too.

I figured I'd check to see if this could be an issue with something other than the TV at this point, since it hasn't conked out on me yet, or at least try and single out something specific it might be.

Thanks!

Strange it only happens on certain channels??? Need to determine where the noise is coming from... the speakers or from the back of the Tv, etc?