Gotcha. What sort of test gear do you have available? RF sig gen, VOM/VTVM, scope, or ?? etc You know, so you can shove some RF in one end and try to peak it out the other end. Anything like that would make your task easier with or without a schematic. If you trace the circuits carefully by eye, you can probably determine at least which parts are audio, which are power supply, which are RF, etc.