Hi David,
I had my auto control III completely gone through and tuned up at Century in Mineral Wells about six months ago. They did excellent work while I waited then we did some air work for final verification. They had parts in stock and if not their shop is capable of rebuilding the components right there while you wait. I thought it worked ok before but now is excellent.
It was very interesting to hear the stories from the staff there about how they had teamed up with Roy Piper to install all the autopilots in the piper aircraft back in the day and rename the century autopilots piper autocontrols.
Regards,
Dan