Suggestion #1
The Fix-It shop charged you $150 to fix the machine. The first time
you attempt to use the machine, it does not work. Question as to
whether the machine was actually fixed at all. I believe a refund of
your $150 may be in order.
Suggestion #2
The delicate nylon gear ..... intendedto break under high stress in
order to protect the motor .... Check out this page and maybe you
have a simple repair: <http://www.neilcrockett.com/mixer.htm>
Suggestion #3
Contact Kitchenaid to locate an authorized repair center.
If you are fairly good at following the repair videos, you have
little to lose by trying. But I would certainly ask for a refund if
the machine did not perform when you picked it up from repair.
Good luck,
Deb