I too have a Calmec Auto-Pilot, Mark X, Mod 1 that needs work. I also have the original Installation & Operation Manual along with both wiring diagrams and schemetics for all pieces. Actually, I still have the original receipt from 1975 ($516.19).
I have not been able to find the Ameteck or Calmec corporations. They used to be in Pico Rivera, Calif but are no longer.
If you find someone, please let me know.