Waltham Regulator Wall Clock

This clock keeps perfect time but something is going on with the chime. It chimes when hands are moved, but when you go to wind up the chime, you can hear the spring slip, so it basically will only chime if you wind it a little and not to the point of the spring slipping. The door has been sloppily repaired by someone where the joints meet, easy fix even for people not familiar with carpentry. The pendulum is present, but no key.