One question, are we trying to locate a fault here in the set,have you bought the set for watching the break in slides. Play the media you want to watch, the HD stuff, TV, dvd rips, whatever and check the set out. If there are issues then make noise and push samsung.
I feel at times we go overboard in locating a fault in the set, rather than enjoying the pleasure of buying a new porduct. The other day there were few members who were putting the tv on mute and trying to hear the buzzing sound. Which was surprising to me.As you are searching for something which is not an issue and is common with most plasmas and the efforts being made to listen to the buzz.
So my 2 cents, watch what you bought the set to watch, incase of any issues complain, check if there is a firmware update for the same.
If it does not impact what you want to watch just be happy with it. ...