Product review (1 stars): Unrepairable.  Just throw it away.
I cannot recommend this unit at all, having bought one in 2009 and then finding that once it stopped working, the factory authorized service technician simply said that "it is not worth repairing.  It is so difficult to take apart and replace parts that it is cheaper to just replace it. "  Of course, the warranty had expired six months earlier.  KitchenAid, when called, said "too bad about it not being able to be repaired but the warranty is over."
So, we are expected to throw away a $2000 appliance made out of expensive stainless steel and glass because it is so poorly designed that it cannot be economically repaired.  I won't be looking at a KitchenAid when I replace this one.