An old TFM-C720 from 1972 getting a replacement gear. The motors, made by Copal Denki in Japan, were very robust and simple. Nevertheless, we sometimes see them chew up a gear. It is most commonly the first gear coming from the brass spindle gear on the other end of the stator wheel. The stator wheel is spun by a rotating field coil. The motors were never meant to be serviced...just replaced. They are riveted together with a torque-multiplying gearbox to drive the clock movement.