Having trouble using tv1 coax output to connect my main tv. I keep getting moving white lines regardless of selecting channel 3 or 4. When I select channel 3, I get rolling white lines running from top to bottom of the screen. When I select channel 4, I get rolling white lines running diagonally. I had the installer come back & he called them scan lines due to the tv being several years old. I didn't have this problem with the 508. Tv2 does not have this problem. Anyone have any ideas?