I would have opted for 1800SAMSUNG and their techs for the appraisal. The symptom sounds like heat and if you are an electronics repair type you know what to do next and the safety issues involved that can result in death so this is as far as I can write here.
I'd ponder the call to Samsung and if you do, get that transaction number along with the longer samsung part number to post here.
I have a 50" Series 850 Plasma purchased 10/2009 at Best Buy. The TV is turning off by itself, and while it is off it sits and clicks and will not turn back on. Also, the TV goes black for periods of 5-10 seconds. As the unit is out of warranty and I did not purchase protection plan at time of purchase, I decided to have Geek Squad come and fix it (for-fee service). Geek Squad came, charged a $150 trip charge, and told me parts alone to fix would be $700+. They advised that I can buy same TV now for $1000, so paying for that repair probably does not make sense. So I paid them $150 and sent them on their way. TV continues to have the same problems, and a phone call to Samsung said they cannot help. Geek Squad installed software update, but it did not help the problem. Am I really stuck with this broken TV? I know (from forums like this) that thousands of Samsung/BestBuy customers have experienced these same issues, and Samsung claims no knowledge of the problems.