Onkyo anti-skate not staying in position

[CZ4A]

The anti-skate mechanism of my Onkyo CP-1015A isn't staying in the place where I set it. As you can see from the pictures it is a slider mechanism. The slider pulls on a spring that in turn pulls on the tonearm. The spring pulls the slider almost to the "off" position once the stylus hits the run-off groove unless something is wedged in place (in this case a twist tie). It won't do this if the slider is past 3, but I don't have any cartridges that have a VTF greater than 2 g so it never gets set there. The factory service manual doesn't show how the tonearm is put together. Has anyone used this type of TT/tonearm before? Is the anti-skate supposed to slide back to off near the end of a record anyways?

 

[Blue Shadow]

Is it supposed to rezero after each record? Only if it resets to the previous setting when you return the arm to the rest, otherwise, it need something to jam it up and keep it in place. I'm sure a quick look at the mechanism will let you figure out a bit more elegant prop than a green disintegrating twist tie.

 

[CZ4A]

Maybe it needs to rezero? I've noticed that when the slider is jammed in place, the tonearm tends to pull back towards the last track once the stylus reaches the run-out groove. Unfortunately, the owner's manual for this model of TT is lost to the ages and the FSM says nothing about the anti-skate.
I'll try to take a picture of the mechanism without taking apart the tonearm. This is a minor issue, really, but slightly annoying. The Onkyo works fine otherwise.

EDIT: Here are two more pictures of the anti-skate mechanism, including one with the spring visible.

The second picture almost makes it look like there is supposed to be a another spring to counter the pulling force of the anti-skate spring, but I see no evidence another spring was ever there. What few pictures of the CP-1015A are available confirm this.