Red picture. We had dvd hooked up to plasma tv with rbg cables and it was working fine. After

Question

We had dvd hooked up to plasma tv with rbg cables and it was working fine. After adding home theater system we now have a pink and white picture when using the dvd, all connections stayed the same.I just got a KLH DVD home theater system and have the same problem. TV picture is fine, but when i play a dvd the picture is red.