I’ve only had this TV for about two years, and it’s a Sony WEGA 27". A few months ago, it started making a very irritating sort of droning/chirping/squealing sound from the rear - almost like a cricket. If I give it a good thump (go ahead, Caveman), it goes away for a while, but comes back after a few days. Also, if I “push” on the connectors on the back, it cuts out.
What the hell is this, and why’s it doing this? How can I permanently fix it?
It is possibly the coils in the tube. They operate at 15KHz and some people can pick up that frequency or subharmonics of them. there is so much voltage acroos them that they actually vibrate slightly in operation, sometime quite audibly. No idea if they can be fixed by a repairman short of replacing the tube.
here are some possible ideas to fix it. Disclaimer - it is very dangerous to poke around in the back of TVs
http://repairfaq.ece.drexel.edu/REPAIR/F_tvfaqa.html#TVFAQA_010
Have you tried one of those ressitance filters that plug into the co-axial cable? I did on mine and it didn't fn work. I moved.