I was able to eliminate the hum by disconnecting my cable connection (Knology) from the wall. Now the big question is how do I get rid of it permanently because I still want to watch cable TV. Does the local Radio Shack sell these ground isolators? What do they do and where are they installed? Never used one before.

BTW: Somebody suggested I try the component inputs on my TV ... no can do because my 40" Mitso Tube was made before component video inputs were available.