Thanks for the help Bill, Danny and Olivier.  Exactly what I needed to know.   And yes Olivier, this was once Ann Harsh’s boat.

Our steering system was replaced half way through Harmonie’s second circumnavigation, so it is much newer than the boat herself.

My original autopilot installation was a Autohelm 6000 and an Autohelm 7000.  I quickly learned to love the 6000, but not so much the 7000. Nothing wrong with it, it was just primitive compared to what I am used to.

As part of our overall electronics upgrade, we swapped out the AH7000 for a new, more sophisticated, B&G autopilot which I love even more.  

Frequently, while sailing near to close hauled, I will just tell the  B&G pilot to just hold a constant rudder angle, and let the boat steer herself with the sails.  In this case, the AP computer commands a rudder angle of (for example) 2º port.  Once there, it should stay without further motor activity.  And it does--if I use the lineardrive motor connected to the quadrant.  

If I use the chain drive, it struggles as the rudder flops a tiny bit back and forth with the slack in the cables changing the reported angle.  It keeps trying to adjust, to hold that 2º angle when it should just be locked in place.

Like I said, it’s a tiny movement, but enough to be annoying and uselessly wearing on things.