So I bought this Samsung 5.1 system. 1000 watts at SAMs. I have Direct TV and a sharp flat screen TV. I set up the surround and put a blu ray disc on. The sound was great. All speakers worked. Switch to TV and only the right front speaker works with a little subwoofer sound. If I press the 3d button, the back two speakers turn on. No sound from the center or front right. I read in the instructions that I needed a digital optic cable do I used it with no luck. What am I doing wrong?