Replaced both the motor and the rotating ring assembly (both were causes). The wall-mounted microwave is just a kit for a countertop model. Although it takes several screws to remove the microwave from the wall, the process is very easy.
Some mentioned a small access door for the motor, however this model did not have that. The bottom cover of the microwave is a single piece and can be loosened enough to access the motor.
The repair itself is extremely easy.