In the past couple of weeks I've noticed this faint high pitch frequency coming from inside the TV. It didn't bother me at first, but lately it's been getting louder. Still pretty faint to most ears, but it's driving me crazy. Does anyone know what could be causing this? If I put my ear to the rear of the set, near the vents, that's where the sound is coming from. I'm starting to think I might need a tech to come out. Sigh...more money to spend..