Need Help. Hello! I bought a Panasonic Home Theater System yesterday. On the receipt it says

Question

Hello! I bought a Panasonic Home Theater System yesterday. On the receipt it says SC-PT760. We hooked it up and everything worked. We went to watch a movie and 30 minutes into the movie the main unit to the surround shut off. The TV said Check Signal Cable. A little bit later it came back on and we started watching the movie again and it did the same thing about 30 minutes later.