Neato Robotics - Oh don't give me none more of that Old Janx Spirit...

If you are like me you love gadgets. You may even be reading this on a small gadget just because you can.  It won't be easier than reading it on a proper computer or even a laptop but you do it to justify your little gadget to the world, and yourself. Fine. But be warned; I use small words and large pictures.

I love my gadgets too. I love my robotic vacuum. It's got lasers!  What's not to love...
Maneuvering perfectly around my home with a proper plan to clean the place.  That's more than I ever had.

But today it sits there sulking!  "My left wheel is stuck..."
Running to the aid of my robotic pet I find it is pulling a fast one on me.  It is sitting there and lying to my face. Claiming disability will get it nowhere unless it can prove it with a note from the doctor I say.
There was nothing jamming the wheel, and the gearbox seemed fine.  But turning it carefully by hand lead me to think it was running tougher than the other wheel. The doctor decided to operate.

Quick work of the case showed the culprit to be the motor. That is the drivemotor with the tiny hall-sensor on it that Neato robots use to scuttle around your home in a very precise manner. Somehow it seemed the motor had burned out or was just drawing too much power. Measuring it while carefully turning told me it was definately shorted somehow...

Luckily I had the right tools for the job so I quickly disassembled the motor. What caught my eye was all the dust in the can.  It seemed to be from the brushes.

Closer view of the can and brushes revealed the brushes to not even be fully worn in yet.  Way too soon for a motor to fail.

Looking closer at the commutator made the whole thing sadly obvious. The brush-dust had settled in the grooves between the commutator-plates leading to half-or full short between stages in commutation. This half-shorting lead to the stalling and overcurrent causing the Neato to reject the motor.

A quick pick with a scraper between the plates made light work of the collected dust and I reassembled the motor.

To my great relief it runs fine now and current seems to be back to the low levels of a good motor.
Looking over what I did and narrowing down what I had to do to get this motor running again I would say dislodging the dust in the grooves must be done somehow.  Since they are not accessible from the outside and the hall-sensor board blocks the access you need to the release-grooves for the brushes I'd say you need to at least remove the hall-sensor magnet-disc and sensor-board. This will give you access to the two curved slots on the back of the motor to lift up the brushes from the commutator. This is important to avoid bending or otherwise damaging them when you pull the back cap off the motor.
Before this can be done, you will need to pry open the bent tabs that lock the back onto the motor.

It is not necessary to remove the pinion.
Happy repairs!