I recently bought Yamaha psr s500 for my choir but the usb button is not functioning. The worst of all is that when I load styles, they look like they are playing yet I don't hear any sound. How shall I do it so that sound will be heard. Let me know the procedures from the first to the last. I can successfully load it but it fails to play. I have so many styles with me. I am waiting for your answers please.