Being inside the entertainment center could be restricting the natural air flow and affecting the dissipation of heat from around the unit causing it to run hot. Check the owners manual regarding placing the unit inside an entertainment center and ensuring proper heat dissipation. If the buzz continues, I'd get it checked by a service tech before the warranty expires.
Good luck....!
I bought this TV about 6 months ago. I LOVE the excellent picture. It is awesome. But I noticed that after it has been on 3-4 hours in HD programming (I watch a lot of sports in HD) it develops a loud, annoying buzzing sound. It's loud enough to ruin the game. From my non-technical perspective the TV seems to me to run "hot" and I have to turn it off and let it "cool down". I called customer service and they told me to turn down the brightness and to increase the space between the TV and the wall. *The TV is wall mounted in an entertainment center about 6" from the wall.* I toned down the brightness a little (below 50%) and pulled it out another 1"-2". It does not help. If I turn the brightness down more the picture is not nearly as brilliant. Unfortunately I have NO extended warranty. Any experienced/knowledgeable feedback will be VERY appreciated.

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