You know, for other’s following: it’s the horizontal wheel at the top of the arm.

I am guessing, by the precise feel of the rotation and tiny sensation of clicks, that it’s a very delicate spring (the other immobile end of the spring, due to the increased tension caused by anti-clockwise coiling, pushes out to a speck or a speck more, and, at any degree of tension, maintains that outward push, and is
not effected by rotation or lift of the arm on it's bearings.
however I don’t know that, and I am definitely not taking that mechanism apart.
Anybody know what’s in there, how it works?

