Please understand your machine was made in about 1975. The way this machine works the power goes into the common terminal of the switch on motor A, only if the motor is in the home position will the power come out the normally closed terminal and on into the common terminal of the switch on motor B. And on to C, D, E and so on thru all 40 motors.
The problem you have is the silver terminals and points tarnish over time.
Since you start with 28 volts each switch has 2 silver terminals and a set contact points. The power must go thru if you lose .1 volts at each of the 40 switch point and 80 switch terminal you get 120X .1 = 12 volts so motor G5 is only getting 16 volts. At 16 volts often it cannot get started and if it should it may not have the strength to finish its cycle.
If you really want to keep this old machine the motor switches are not that hard to replace and cheap when you buy in quantity.
Walta