The turntable in our microwave stopped moving. It was clear that the plastic pin on the motor that turns it broke. But since the case used safety torx to hold the cover on, there was no good way to get inside, until I got the security bit set.
First thing was to open it up to see whether the pin on the motor could be fixed or the whole motor had to be replaced. That decision took about an hour, including time to figure out how to take the microwave apart and put it back together. Sears has online parts diagrams for all their appliances, which made it easy to identify the motor and order it. Once that arrived, it was about 15 minutes to swap it out. It would have been less if I hadn't taken pictures. Works great now!
The trickiest part was seeing how to rotate the bottom panel to expose the motor without disconnecting the internal wires to the transformer and other parts. Since the transformer is the heaviest part of the microwave, and is attached to the bottom panel, this configuration was a bit unstable. I also had to pay attention to how covers came off so I could get them back on.