I recently picked up this Rainbow E2 Platinum (Blue) for a pretty sweet price.  It had a foul smell when I fired it up, which made me suspect it was not properly cared for.  The source of the odor was the HEPA filter, which was filthy.  The fan chamber on the motor was filthy too.  Next, I removed the separator and the fan inlet was filthy.  So I made the decision just to replace the motor since it was less then $100. 

Cosmetically, it was in excellent shape.  So after I replaced the motor and cleaned it up, it looks almost brand new. 

There has been some conversation on the forum regarding noise levels in Rainbows.  This model is rather quiet because of the sound insulation surrounding the motor.

Insulation is even provided in the cap.

View of the motor with the computer module removed.  Opening the vacuum and removing the motor is actually a very simple procedure.  There are no longer any screws to contend with!  Just a series of clips.  All that's required to get to the motor is a flat blade screwdriver that's slipped into the right spots to release the clips. 

So now I have a question for those who own a 2 speed.  When I place my hand over the hose end to cut off airflow, the motor shuts down.  But as soon as I remove my hand, then it starts back up again.  Is the motor designed to do that as a fail safe precaution? 

It's pretty clear that the previous owner didn't change the water with much frequency nor remove and clean the separator very often if ever. 

Below the spacer is the location of a bearing.  Dust and moisture can pretty easily get into it when the vacuum is not properly cared for. 

The bottom of the motor housing contains a small circuit board.  This motor has no carbon brushes, so I'm guessing this circuit board has something to do with controlling the electric current so that the armature will spin.  It appears that the circuit board is held in place by a small torx screw.  I don't think I have a torx bit that small, so it will have to stay in place for now. 

It's far simpler than you know.  Getting to the motor requires only a flat blade screw driver to dislodge the locking clips which hold it together.  It's very well designed from the stand point.  Servicing the motor is also very straightforward.  Remove four screws that hold on the lower fan housing and and the nut on the armature shaft and you're in.  You can do it.  All that's needed to service these motors is the replacement of bearings.  There are no carbon brushes to replace and seat.  Plus, the computer controller comes off the top of the motor and snaps back on quite easily and all the wires are installed with harnesses.  No screws.  No soldering.  Very simple to do.