RM-9 Wiring Diagram

Greetings All.  I've got a Music Reference RM-9 amplifier that has some issues.  I've taken it to George Meyer Audio in L.A. who has had it for 6 weeks now, for diagnosis.  Without result.  I called again yesterday and was told the tech has been working to figure out the problem, but is having a hard time since he doesn't have a schematic for the unit.  

 Anyone have an idea where I could get one for that old amp?  It was built in '85 or so, might be a challenge to locate one.  The company ceased operation a year or so after Roger M died I think. 

Thanks for any help.

Jeff