I still do not know, how exactly the control shaft and hydraulic power are interacting on T/R servo of AW169
Hoistop - if the bottom diagram in my last but one post doesn't explain it then I have run out of ideas to show you.
The input lever from the yaw controls moves the pilot/spool valve which allows hyd pressure to one side or other of the piston - that piston is part of the control rod.
The feedback link stops the spool valve directing fluid once the piston has moved in the appropriate direction.
It is that feedback link that came undone on the 189 meaning that the follow up action was removed and the piston did what the spool valve asked it to do - and it kept motoring until it reached full travel.