Mine has recently cooked the brush motor too.
The brushes were accidently stopped for a few seconds, and apparently this can have knock-on effects. A family member who knows a bit about motors and electronics has provided some advice which fits the symptoms.
If you stop an induction motor it can quickly overheat, and cook. It will also blow fuses in the circuit. That is also true, as the fuse soldered into the circuit board (in the handle) has blown.
I hope to fix it by replacing to brush motor and the circuit board. If I can find a replacement fuse, I will try just soldering a new one in.
I saw a motor advertised for $129 and a board for about $50.
If that doesn't do the job then it is back to the drawing board.
MG, February 2012