Polaroid TV Purple screen on "TV" Mode?

I havent really ever used the tv except to watch my anime on adult swim ever saturday night, It was connected via an ancient SHARP Vcr's cable thingie then it went into the TV's coax. I just turned it on now to see what was on and the screen was purple, with no audio. So I decided to pull the cable from the VCR and attach the cable from the Wall directly to the TV, as its ALWAYS been before i added te VCR into the combo. I got sound, no picture. so... I Tried switching the TV to S-Video mode we're all my consoles are hooked up using a radioshack switch and they all worked fine. Picture, audio everything.