I HAVE A WIDE VERTICAL LINE DOWN THE MIDDLE OF THE SCREEN. BEEN TOLD TO LOOK INSIDE THE BACK OF TV FOR WHITE RIBBON WITH VERTICAL MARKINGS AND CAREFULLY CLEAN WITH ERASER TIP AND THEN CLEAN WITH A DRY TOOTHBRUSH TO WIPE AWAY ANY RESIDUE. WILL THIS REALLY WORK? THANKS

Televison & Video - LG - 55LV4400 55 Class LED HDTV - 1080p, 1920 x 1080, 16:9,...