No Power To The Buttons?

I have a 1950 AMI C, which is having selection problems(the buttons do nothing). The first time i tried it, it tripped a selection, and then that was it ,the contacts where the coin would hit, don't trip and it does'nt seem like their is any power going to the buttons. I have just got a-hold of an entire button essembly that I installed (do to the fact that the other one was missing some buttons), and still the buttons do nothing. I was thinking it may have something to do with a small unit that plugs into the coin mech. It will play if tripped manually.
Any ideas ?

Usually there is a lockout circuit that causes the coin checkers to reject all coins to the coin return and keeps the buttons from being pressed while the selection or credit units are busy doing something else. The purpose of this is to keep the customer from losing his money by activating the device at the wrong time.