I have 1972 King Kool pinball machine. When I plug in the machine, the switch position motor starts running and will not shut off to allow the game to start playing. I have no pinball repair experience, but I do have the electric schematic to the machine to refer to. When the motor is running the contacts appear to be opening and closing properly. Any ideas on what the problem may be will be appreciated

 

What contacts are opening and closing?

Trace all the electrical paths to the motor with a multimeter. One of them is not opening properly.

 

hello there
most likely that one of the relay points on the game over relay,hold relay or tilt relay is not making proper contact or misaligned. also make sure that the coin switch(es) on the coin door are not stuck or closed . they must be open for the motor to stop being triggered.the same goes for the start button switch.after that it might be one of the reels (score counters) not being reset to zero that keeps the motor turning.
good luck