Why does my Wurlitzer Omni 3000 Organ have no sound?

I recieved a Wurlitzer Omni 3000 Organ today from a friend. When I got home, I plugged it in and tried to play it. It was then that I realized, everything had lighten up, and all of the ons were working right, but there was absoulutely no sound. My friend had said that he had it in his garage for a long time and was sorry but did not know what had happened and had suggested to ask a repair man to come, but I'd rather ration my decisions so I came to Yahoo Answers first. Any suggestions on how to fix this problem would be greatly appreciated. Thank-You so much(: