make sure the dolby fm function is off. If it is the problem is either the preamp or the amp. Use a portable CD player through pre ins to test the amp. If that works the preamp is at fault. I have a service manual for this receiver if needed. As far as the knobs. Unobtanium. They were used only in the 1060 and 1080. They're both rare receivers, parts units are virtually non existant if they even have the knobs. Best bet is to try and find something that fits. I'm fortunate that my 3 1060s and one 1080 have complete sets.