I just bought s smart tv box from a friend and have it hooked up. I can watch movies, but there is no sound at all. How can I hook up this box to the surround sound receiver? I was told to hook up the box directly to the tv with an optical cable, but this doesn't work. I tried hooking it up to the receiver, but am not sure where to put the cable to get sound for a movie. I tried different places on the receiver, but nothing works. The tv is a Sony 50" about five years old and the receiver is also a Sony the same age. This system was bought together from Best Buy. I am very frustrated with this and the man I bought the box from, doesn't know how to help me. I am counting on you.Thanks