My week old Panasonic 42PC77U had a buzzing problem from day one. It was not very loud but was noticeable 5+ feet away when the room was quiet. I've hunted various buzzing/humming problems in my 2 channel music rig and previous HT setups. With the plasma, it buzzed as soon as it was plugged in without any other cables connected so that eliminated a ground loop however the buzzing was not always present. At times, it was completely gone.
I then tried my balanced power isolator which may have done a little but didn't significantly reduce the buzzing. Today, I considered the halogen lights in the basement. They are on a completely different circuit, a floor apart and the other side of the house. As I suspected, when my wife hit the switch for the basement halogen lights, the buzzing went away. I am pretty certain that the problem comes from EMI caused by the lights or other sources in my house. This set being a budget one may not have a well schielded power supply while other sets have better parts. Also, this does explain the intermittent problem I experience and the fact that a few others reported 2 or more sets buzzing. Hopefully this observation will help others find a solution to their buzzing problems.
I then tried my balanced power isolator which may have done a little but didn't significantly reduce the buzzing. Today, I considered the halogen lights in the basement. They are on a completely different circuit, a floor apart and the other side of the house. As I suspected, when my wife hit the switch for the basement halogen lights, the buzzing went away. I am pretty certain that the problem comes from EMI caused by the lights or other sources in my house. This set being a budget one may not have a well schielded power supply while other sets have better parts. Also, this does explain the intermittent problem I experience and the fact that a few others reported 2 or more sets buzzing. Hopefully this observation will help others find a solution to their buzzing problems.