I picked this one up last year with a generic E1 error code for $50.  Reseating all connectors and performing a master reset (reset key in and turned, internal power switch cycled, reset key removed) brought it right up.  Been working fine for a little over a year then the hopper quit working.  Display would show “HE” when it tried to spit out tokens.

Removed hopper and inspected it – nothing jammed up, and all switches/optos in the bottom were functioning correctly.  When the hopper is started (using the switch within the cabinet), it moves just a slight amount.  Removing the motor shows that the motor spins about 1/3-1/4 rotation and then stops, with no resistance on the gear/spindle when I turn it manually.  If I leave the motor powered, I can start to smell that electrical smell that tells me something is bad within the motor.

I only know a little about DC motors, so I figured this one would be good to take apart and have a look at.  On the inside, one brush was almost completely worn down and the interior winding of the motor, the stator, and the commutator were also covered in carbon dust.  I noticed that carbon dust was in between the conductors on the commutator (dunno what they are called – the parts on the commutator that connect to the motor winding?), making me think that maybe the dust was causing problems by shorting things out?

Not knowing what else to do, I sprayed the whole thing out with electrical cleaner and cleaned out a bunch of the carbon dust with it (and there was a LOT).  After it dried, I used a small piece of paper folded in half and carefully cleaned between the conductors on the commutator as well.

I also learned what the additional holes in the cover of the motor (which held the brushes) maybe were for.  You can stick an object through them to hold back the brushes as you replace the cover otherwise you will not be able to get them back onto the commutator.

After that, I tried it briefly with the test switch and the motor was spinning happily!  I let it run for a little bit to make sure nothing was burning or gonna catch fire and mounted it back on the hopper.  Replaced and reloaded the hopper and tested it and coins came flying out!  Success!

Did a few test plays and the unit is working correctly.  My first DC motor repair!  Sweet!