JVC TH-C30 Issues

My JVC Surround Sound will only play sound out of the Center and Subwoofer feeds, nothing from the right or left channels. All speakers are in working order as I switched them to the center and they work fine there. Also getting no sound at all from the AM Radio. I get speaker feedback if I place the tip of my finger on the end of the "C" transistors for the right/left channels inside the case next to where the input S-Cable conects from the receiver. Any ideas? Thanks