The turntable in your microwave is not just to show off your food as it cooks; it has a very important function. If the turntable does not spin, your food is not cooked unevenly. You may have experienced this in the past with a plate, takeout box, or piece of pizza that was just too large for your microwave and refused to spin on the plate. Microwaves cook from the inside out and that spin ensures that the orb of heat expands from the center evenly. Without it, you get the notorious old microwave hot and cold spots.
So if those hot and cold spots have been showing up recently because your microwave plate has stopped spinning entirely then it’s time to take a closer look at your microwave plate array and explore your repair options.
The Microwave Plate Array
The spinning microwave plate is made up of four parts, and if any of them fail the entire system can cause your plate to stop spinning.
- The Microwave Plate with Bottom Grooves
- The Roller Guides
- The Plate-Motor Coupler
- The Microwave Drive Motor
Dirty or Broken Microwave Plate Grooves
We’ll start from the top down to make your inspection and repair work easier. Start by removing the microwave plate and checking the underside. It is possible that previous spills and aerated-condensed foods could have gotten into the grooves of the plate that fit onto the coupler, or that your microwave plate has become so uniquely dirty that it is catching on the roller guides or the edges of the microwave.
Scrape out anything that may have gotten into the grooves underneath, then set the plate to soak and be scrubbed for good measure. It takes a very dirty plate to cause this problem, but then, some microwaves get more hard use than others.
Cracked Roller Guide
Next, take a look at your roller guide. Technically, this is the most delicate part of the array as they are usually made of thin plastic with little plastic wheels. The purpose of the roller guide is to hold up the outer edge of the heavy glass plate and help it spin based on the turning of the drive motor and coupler. If your roller guide breaks, then the plate may no longer be able to spin smoothly and can create enough ‘drag’ on the motor to prevent spinning entirely.
You may have also noticed that the microwave spins haltingly without food inside but fails to spin with food in the plate, which is often an indication that the roller guide is to blame.
Check your roller guide for grime, in case food particles have crusted in the little wheels keeping it from rolling smoothly. If it is dirty, soak and clean it. Then check the roller guide for signs of cracks in the plastic from some previous impact or hard microwave use.
You can pick up a replacement roller guide for very low cost by looking up and ordering the correct part for the make and model of your microwave.
Dirty or Broken Plate-Motor Coupler
The next part to check is the coupler. The coupler is a three-ridged device that fits into the bottom of your microwave plate and fits on top of the post for the drive motor, When the drive motor spins, the coupler spins the plate which then rolls on the roller guide and spins your food.
The coupler usually slides right off the top of the drive motor so that it, too, can be washed if food buildup has simply made the ridges too crusty or greasy to be used. Once clean, take a close look at the plastic piece itself. If the plastic is cracked or damaged, the coupler may not have enough integral strength left to turn the heavy plate or the plate laden with warming food.
A crack in the post-cap of the coupler, the part that connects to the drive motor, is even worse news because this means it cannot grip to the drive motor well enough to turn itself or the plate. Once again, you can order a new coupler based on your microwave make and model and simply pop it into place to complete a replacement repair.
Broken or Burnt-Out Drive Motor
Inspecting the drive motor is a bit more complicated. For this repair, you will want to unplug your microwave for safety and grab a multimeter on the “test” setting along with a screwdriver. Use your screwdriver to remove the bottom plate of your microwave and reveal the drive motor. Then attach each probe of the multimeter to the incoming and outgoing wires of the drive motor to detect if it can run a current. If your multimeter indicates that there is no available current or high resistance (depending on your meter) then the drive motor is burnt out. If you do get a positive signal but it doesn’t turn, then the motor is just broken. It will need to be replaced either way.
Order a replacement motor and when you’re ready to do the repair, make sure your microwave is unplugged.
Remove the old motor by unscrewing the fastening screws and losing any latches. Disconnect the wires or wire clips (each model can be different) and throw away the old motor. Attach the wires or wire clips to the new motor exactly as you just removed them and set the new motor into the space the old motor just occupied so the shaft is pointing straight up into the center as the old one was.
Re-secure any clasps and screws that hold the motor in place and then return and resecure the bottom plate of the microwave. With the coupler, roller guide, and plate stacked in order and the microwave plugged back in, everything should be back in working order.
Test Your Success
Once you have replaced whichever part or parts were broken in the assembly, your microwave should be back in ship-shape and ready to go. Plug it in and punch in 30 seconds so you can watch that plate turn. If it’s hard to see through your microwave door window, pop something visible in and see if it turns. If the repair was a success, pat yourself on the back. You just fixed the microwave.
Contact us for more home repair guides or the assistance of a trained appliance technician.