The fact that the clapper pulls over when connected means that you are getting very close. We now know that the ringer coil is good and it appears that the capacitor is either bad or not wired into the circuit. Check to see that the slate and slate/red wires from the ringer coil are connected to terminals A and K on the network respectively.
Without the capacitor to provide DC isolation, your ringer coil is basically placing a short across the line.
