what could be causing it?it didnt buzz at all with the old screen and doesnt buzz as much with a white screen,only with a back or very dark screen does it sound like a bee(it doesnt sound like the normal plasma buzz)power save 2 reduces itI doubt the buzz is caused by loose screws but whatever you do, don't ever power it on with the rear cover removed or you will activate the anti tamper TRAP switch. (also there is a risk of electric shock)
The TRAP switch will disable the TV until someone performs the TRAP reset function.