Drive Motor
If the glass tray in your microwave doesn’t turn, it may be due to a broken drive motor. Most units have a round glass turntable which has a motor driven coupler and roller guide turning the tray.
How to test a microwave drive motor with a multimeter:
- Disconnect your appliance from the power source.
- The drive motor will be found on the bottom of the microwave, and likely will be held in place by wires and a retaining screw. You will need to remove the cabinet in order to access it. Once you have located it, remove it in order to test it.
- Using a multimeter set to the highest setting, test for continuity by touching the probes to the terminals, you should receive a reading of zero if your motor is functioning properly.
- If your test results differ from the above, or if your microwave makes grinding noises, then you may need a replacement drive motor.
Coupler
If the glass tray in your microwave won’t rotate, the issue may be with the drive coupler.
How to inspect a microwave drive coupler:
- Similar to other inspections, disconnect your appliance from the power source before starting.
- Locate your drive coupler in order to inspect it. In some models, you will need to remove the motor from the floor of the microwave to access the coupler. However, in most models, you will only need to remove the glass tray and roller guide.
- Take the drive coupler off the motor shaft and looking for any signs of cracking, discoloration, or wear, visually inspect your drive coupler.
- If you identify any issues during your inspection, you will need a replacement drive coupler.
Roller Guide
If the glass turntable in your microwave won’t rotate, the issue may be with the roller guide, which lies under the glass tray and helps it to stay on track while rotating. The roller guide works with the coupler to rotate the turntable.
How to inspect a microwave roller guide:
- This inspection is very simple; you will not need any tools to complete it.
- To access the roller guide, open the door to your microwave and take out the glass tray.
- Remove the roller guide from the microwave and inspect the wheels on the guide to ensure they turn freely with no resistance. Next, visually inspect the guide for any signs of wear, cracking, discoloration, or damage.
- If you find any issues during your inspection, you will need a replacement roller guide.