I heard that you might need to check to see if your Cable connection Outside your house is properly grounded.
Hum when cablevision is plugged in to tv
I am trying to watch & listen to DVD's through stereo but get hum out of speakers when the cable tv is hooked up to back of tv. When I disconnect it the hum goes away. Never had this problem before until I moved to this apartment in big house. Any advice would greatly be appreciated.