I recently moved and when I set up my 50" Pioneer Plasma in my new place, I noticed a buzzing.
If the tv is on, but is just displaying a blank screen, it will be completely silent (how I remember it from my old place). However, if it displays anything at all, including the alert for auto power off after 5 min and even a mouse cursor from my computer, it starts up with this horrendous buzzing again. I keep trying to tell myself that maybe it has been there the whole time, but I don't think there's any way I wouldn't have heard this humming for 3 years.
Could it be the power lines in my new apt? Did something go wrong in the move? How can I figure this out?