Fixing a Microwave Oven Turntable

After setting the soup bowl or the left-over chicken breast on the microwave oven’s glass turntable to heat up a quick lunch, you’re dismayed to discover the turntable isn’t turning when you press start. The microwave appears to be functioning otherwise, so why isn’t that glass plate rotating? In this article, we’ll address how the turntable operates, the top reasons for why it’s not working, and how you can fix the problem yourself.

Can you use the microwave without the glass plate?

Is the turntable even necessary to heat up the food? No, it’s not necessary for the microwave to work, but a properly operating turntable will improve performance.

Microwave ovens use a magnetron to emit radio waves which travel through a wave guide (attached to the side of the interior cavity wall) before entering the cooking area. Once inside the cooking area, the radio waves cause water molecules within the food to vibrate intensely, generating heat which cooks the food from the outside in. By rotating the food during this process, the turntable allows the radio waves to cook the food more evenly. Without a properly working turntable, you may find that chicken breast to be pleasantly warm on one end and cold on the other.

Why won’t the microwave turntable turn?

The glass tray will normally have protruding tabs molded on the bottom of the tray that align with the notches in a turntable drive coupling. The rotating coupling is driven by a motor located directly below the cavity floor. A support ring with small rollers props up the tray so it can rotate evenly.

If the turntable won’t turn, these are the five most likely causes:

1. Defective turntable motor – If you suspect the turntable motor may be defective, you can use a multimeter to test the motor for electrical continuity – a continuous electrical path present in the component. If the motor tests negative for continuity, it will need to be replaced.
2. Stripped drive coupling – If the coupling is stripped or broken, it may not be able to engage with the motor shaft or the tabs on the tray. Most couplings are easily removed, allowing you to inspect it for damage.
3. Damaged support ring – The rollers on the support ring may become damaged or jam due to food residue collecting on the cavity floor, preventing the ring from rotating. This part is easy to inspect and replace.
4. Malfunctioning touchpad & control panel – If the turntable is operated by a dedicated on/off button (as opposed to continually rotating every time the appliance is heating), the button could be malfunctioning. In this case, you will probably need to replace the entire touchpad and control panel to solve the problem.
5. Faulty main control board – Although it’s not a common cause, the main control board in the microwave could be faulty. You should first confirm the turntable motor is not receiving power and the other components are intact before considering replacing the control board.

Accessing and replacing a turntable motor or drive coupling

Since a defective motor or drive coupling are the two most likely reasons for a turntable not to turn, let’s take a look at how you can replace these parts with new ones. The good news is that for many mounted microwaves (such as microwave oven/vent hood combos), the turntable motor can be replaced without having to fully uninstall the unit from its mounting plate. While repair procedures will differ from model-to-model, here are some general steps you can follow:

• Unplug the microwave oven’s power cord (for microwaves mounted above a stovetop or range, the cord is normally plugged into an outlet in a cabinet directly above the appliance).
• Lift off the glass tray or plate to access the drive coupling.
• Pull the coupling straight up to detach it from the motor shaft. You can now inspect the coupling for damage to determine if it is stripped or broken.
• To access the motor, unthread the screws securing the microwave’s bottom access panel. Most microwave bottom panels are hinged at the rear; once the screws are removed, the panel will rotate back. You may need to disconnect a light wire connecter to fully release the panel. Be aware: if the microwave oven is built-in, you will need to fully uninstall the appliance to reach the bottom access panel (you should refer to the installation manual for instructions on how to do this).
• Remove the wires from the motor terminals or disconnect the wire connecter. On some models, you may have to detach a terminal cover to reach the wires.
• Unthread the mounting screw or screws securing the motor to remove it. You may need to rotate the motor to fully release it.
• When installing a new turntable motor, you may need to transfer a seal from the old motor shaft to the new one.
• Insert the motor shaft through the hole in the cavity floor and into the coupling, if still in place, then rotate the motor into position, if necessary. Rethread the mounting screw or screws to secure.
• Connect the wire connecter or attach the wires to the motor terminals and close the terminal cover, if applicable.
• Rotate the bottom access panel upwards and reconnect the light wire connecter if required.
• Fully position the panel then replace all of the screws to secure.
• Replace the drive coupling, or install a new coupling, by positioning it on the motor shaft.
• Confirm the support ring is in place, then align the glass tray on the coupling.
• Plug the power cord back in and your microwave oven should be ready for use.

Always put safety first when attempting a microwave repair

Because of the high voltage and high current used by microwave ovens, be aware that repairing this appliance poses a substantial risk for injury or death if precautions are not taken. You should always unplug the microwave before you attempt any disassembly.  Since high voltage capacitors used in microwaves may retain a charge even after the microwave has been unplugged, we recommend that only experienced professionals access and replace internal components.

Repair Clinic stocks the microwave oven parts to fix your problem

Repair Clinic has the appliance parts to keep the turntable turning, including replacement glass trays, turntable motors, drive couplings, support rings, touchpads, and control boards. But you’ll want to make sure you’re selecting the right part that works with your particular microwave, whether you depend on a stand-alone, built-in, oven/vent hood combo, or convection model manufactured by GE, KitchenAid, Frigidaire, Samsung, LG, Kenmore, or Panasonic. Start by entering the full model number of your microwave in the Repair Clinic website search bar to see a complete list of compatible parts. You can narrow that list by using the appropriate part category filter (such as “Glass Tray, Coupler, and Support Roller”) and the part title filter (“Glass Tray Drive Coupling”) to identify the exact part you need.