I purchased a Samsung 5052 TV in Nov '06, so it is a little over 1 year old.
This is a fantastic Plasma TV..the HD channels come in incredibly clear.
A Direct TV H20 HD receiver is connected to the TV with a HDMI cable.

I have only had one issue that I am concerned about. Not every time, but at times, a loud buzzing sound is heard when I change stations. There are usually 2 buzzing noises heard: one when the screen exits one station and another when the new station appears.

I have checked all connections and even had a Direct TV technician look at the receiver/TV hook-ups. Nothing evident can be found.
Has anyone experienced this before?

Thanks in advance

It sounds like it's your Direct TV Box.