hum lines or what?

hi just installed my samsung le40a656 but it seems to have hum lines on the cable channels.dvd is fine though. i heard that i can get a filter to maybe stop the possible interference, or maybe that my scarts are just not man enough although they were ok on my old widescreen.please help someone!!!!!!

Maybe the cable box isn't set to RGB mode and is in composite, or you have it plugged into a scart socket that doesn't support RGB. On most sets one socket is RGB compatible and one isn't.