I have an LG Plasma Model 42PX4D. Since I've had the unit, I've notived a slight buzzing sound that ocurrs when the TV is turned on and stops once the TV is turned off. For the longest time, I thought it was the Furman Line Conditioner that is mounted behind the Plasma, but after some advice, I'm pretty certain that the sound is coming from the TV. Has anyone experienced this? What can I do about it? Thank you in advance for your help.