I just stumbled upon this thread after going 'round and 'round with Best Buy on this problem. I bought the extended warranty on my TV...and the Geek Squad came out this morning and replaced the power board on my Viera 42", but it still whines/hums. They called Panasonic and Panasonic told them that there was nothing else that could be done and that this is normal for a plasma TV. I've had this TV since 2007 and it just started making this noise 2 months ago!!! Now, Best Buy will not replace my TV (as the warranty states) because Panasonic has told them that this is a normal noise. I told them that if the TV was making that noise when I bought it, I would've returned it within the 30-day return period. Just thought I'd warn you guys, that even though you have a warranty, it doesn't mean they'll fix this problem. I'll think twice about buying another Panasonic product or ANYTHING else from Best Buy.