A couple of things to look at. First the video adjustments on cable channels vs s-vid input can be actually different and the set has memory for each input. Adjust picture settings to be the same on each input (S-vid and rf). Second just because you have monster cable dont assume its working properly substitute a cheap one to try or a composite cable. Third make sure your s-vid cable isnt coiled up are running next to power (ac) wires.