A year and a half ago (two year warranty) I bought a 42 inch LG LED 42LB670V 3D smart Tv. Tonight I observed that my screen was split in three by two vertical black lines, literally parting the screen in 3 equal parts. This is observable only sometimes, probably when the background is mostly one color. Is this something that is caused by the cable provider or is it something to do with my tv? Should I take it to be repaired? Thanks.