I have a Toshiba V296 DVD/VCR combo player and a Phillips (magnavox) tv. The DVD/VCR came with a a cord with red and white jacks on both endsd, a cord with yellow jacks on both ends, and a black cord. I have it plugged up where it tells me, and the DVD plays fine: sound and picture. On the other hand, when I play the VCR, I can hear it but no picture comes up. I have tried changing the channels and the cords. What am I doing wrong?