I have both a Sega Genesis (square shape) and an NES, both of which give perfect sound, but the pictures are scrambled and some of the words look to be in Russian. We have cleaned the cartriges and took apart the SEGA, but no luck.

The NES, we are using the original A/V coax output cord and the Sega we are using a new component cord (yellow, white, red) that I got off ebay. At first I thought the problem might have been the new Sega cord, but since the Nintendo is doing the same thing, now I have no clue. Would the newer tv's have anything to do with this, do they receive the picture signal differently than older tvs?