The first thing to do is try hooking up the external speaker that might work. Go into menu and make sure you audio is set to stereo.
The hum or buzz is usally caused by failing capacitors. If you take the back panel off, it will be on the board where the coaxel is, or cable connection is. (RCA cable hook up) Check this for swelled caps, if so then you will have to replace this board.
flyatyou66, April 2014
