If I manually feed a quarter into the cradle, the coin does get accepted (i.e. falls though onto the switch). The cradle fits the quarter snugly, so I don't think the cradle has been replaced/modified to accept another denomination or token, (this theory is further supported by the coin door's reject buttons which display .25 cents). The cradle does move freely and easily.
I inspected the plastic hinge; it appears to be in good working order. No sagging or cracking found.
The root of the problem seems to be that the quarters are getting rejected even before the cradle has a chance to evaluate them. Adjusting the "kicker" (is this the manual coin reject?) was mentioned. How is this accomplished? Aside from the aforementioned brass and nylon screws, I don't see any other obvious place to place to make adjustments of any type.
Thanks for your help.