Looking to purchase an 82 Bally Rapid Fire that the owner admits has a shooting problem. Is there any part(s) that might be needed to fix that are not available to purchase? I am assuming what I need to repair can be bought. Thanks in advance

I actually have an excellent reason why.. My grandson is 3 and cannot yet grasp what a flipper does or when to hit the button but he could hold the fire button in on a rapid fire and enjoy the noise and action.

If you were me, besides the boards what portion of the firing mechanism would you look at? The actual firing pin to see if is still functioning or the ball loading mechanism? Thanks in advance