Hi Robert

A while back I restored my first jukebox, A Rock-Ola 474 machine.

I too had problems with both of these motors.

I was really lucky and managed to find two brand new old stock armatures for them. And after a complete rebuild and regrease, they now run brilliantly.

They are 28V DC Motors. I tested mine by connecting them to a Bench Variable Power Supply unit, and wound up the voltage slowly while monitoring the current. Mine were both taking in excess of 2A which is the limit of my PSU. By the time I got to 20V DC

I found that after the rebuild the motors would run off load and consume in the area of 500mA, while at the full 28V.

I didn't have a problem with shorted turns on mine. The problem I had was that the commutators (sections where the brushes connect the armature) had a deep groove worn in them, plus the grease in the gearboxes had congealed, and needed to be cleaned out completely, then fully regreased.

Also with the armatures and brushes removed, you may like to check the suppression capacitors (tubular devices connected across the motors) for a short circuit.

These capacitors are installed to reduce motor noise. Strangely the motors in my machine did not have these fitted.

Hope this info helps

Pete