Rock-ola Counter Model selection issue

I have a JR-40 model Rockola counter model. I did a grade one restoration on it nearly 15 years ago. While doing some long-overdue maintanance on it recently, I noticed one of the selector functions isn't working -- when you don't push any button, the selector mech is supposed to drop to the bottom, play record #12, and then automatically push in ALL of the selector buttons. I remember this was done so the juke could be used with non-selective wall boxes of the time -- you put in a nickel and simply got the next tune.

Mine is not pushing in all the buttons -- I'm sure it did when I first overhauled the selector assembly, although I can't say when it stopped. It appears that there is a larger "pin" on the left side that should be pushed in by the cancel lever to select all the buttons. But it seems to be frozen.

Anybody out there familiar with prewar Rockola selectors? It'd be nice to know what it's supposed to be doing exactly before I mess with it. Not only what moves all 12 buttons in -- but does this happend exactly the same way if you select #12 as when you select nothing at all?

I'd pull the selector assembly, but in these counter models, it's almost impossible to do -- you have to remove the entire mech just to get at the bolts.

Thanks! Nick