Samsung Microwave Noise? Here’s What to Do

Samsung microwave owners will be familiar with the typical sound their microwave makes. But what should you do when that familiar hum becomes louder or your microwave starts making rattling or thumping sounds? There are some easy fixes to this problem, while others require a little more investigation.

Where is the noise coming from? Is it at the base of the microwave, or is it a grinding sound coming from the back? Is the microwave still heating your food? Does the noise stop and start, or is it continuous? Follow this guide to diagnose and fix the problem.

This guide applies to the following models:

MR5471G

MR6471G

MU4270W

MW1010

MW3252T

MW4271G

SMH7174BCXAA

SMH7174CC/XAA

SMH7174WCXAA

SMH7174WEXAA

SMH7175BCXAA

SMH7175CCXAA

SMH7175WCXAA

SMH7178STDXAA

SMH7178STEXAA

SMH7185STGXAA

SMH9187BXAA

SMH9187STXAA

SMH9187WXAA

SMV9165BCXAA

SMV9165SCXAA

Important: Repairing a microwave can be extremely dangerous.

The high voltage capacitor inside the microwave can store a lethal amount of electricity, even after the microwave has been disconnected from the power for several months. To safely access electrical components in the microwave, the capacitor must be discharged.

Due to the risk of electrocution, it is recommended that the more complex issues be repaired by a trained microwave professional.

Turntable

The first place to check is the turntable. Open the microwave door and check that the microwave plate is sitting securely on the turntable support. If that appears in place, take out the turntable support and examine it. If debris is caught in a roller or a roller is defective, this can cause a rattling or thumping sound.

Check that the turntable plate and roller support are installed correctly.
Check the rollers for wear and tear and debris.
Make sure you are not overloading the turntable plate.

If the turntable support or turntable plate is damaged, replace it with a new one.

Turntable Motor Coupler

While examining the turntable, also check the turntable motor coupler. This part attaches to the turntable motor to ensure the plate turns smoothly. A broken or dislodged motor coupler will cause your microwave to make a thumping or rattling sound.

The coupler can be accessed from inside the microwave oven, beneath the turntable plate. On some models, you may need to access the turntable coupler from the turntable motor cover underneath the microwave.

Check the condition of the motor coupler.
Replace the coupler if damaged.

Magnetron

If the typical hum your microwave makes has become louder and the microwave is no longer heating your food, the likely cause is the magnetron. The magnetron produces the microwave energy that cooks the food. If you run the microwave on a low setting and the noise gets quieter, this also indicates the magnetron is at fault. Another symptom of a faulty magnetron is if the noise issue comes and goes, as this indicates the magnetron is engaging and then disengaging.

A faulty magnetron can be replaced; however, you should exercise caution. The microwave must be turned off, and the high voltage capacitor must be discharged. You will also need to remove the top panel of the microwave to gain access. It is recommended that you wear gloves to avoid cuts from the sharp metal edges.

Disconnect the microwave from the power.
Remove the top microwave cover to access the magnetron.
Discharge the capacitor.
Test the magnetron for continuity.
If defective, remove and replace the magnetron.

Diode

A faulty diode will cause the same symptoms as a faulty magnetron. So before replacing the magnetron, it pays to check the diode. The diode is located near the magnetron, so the same care should be taken when examining it.

Make sure the microwave is disconnected from the power.
Make sure the capacitor has been discharged.
Test the diode for continuity. The diode should only show continuity in one direction.
If the diode is defective, replace it.

Turntable Motor

If you are experiencing a grinding noise coming from underneath the microwave, you most likely have a defective turntable motor. The turntable motor is responsible for rotating the turntable plate. A noisy microwave that is still heating also indicates a problem with the turntable motor (also the stirrer motor).

The turntable motor is easily accessed on most models by removing the cover panel underneath the microwave. You will need to turn the microwave on its side to access the cover panel. Be careful not to lose any screws inside the cabinet as you take the panel off. If you cannot access it from underneath, you will need to remove the microwave casing.

Disconnect the microwave from the power.
Remove the turntable plate, tray, and support roller from inside the microwave.
Turn the microwave on its side to access the turntable motor cover panel.
Remove the panel to access the turntable motor.
Inspect the turntable motor for damage.
Test the turntable motor for continuity.
If defective, replace the turntable motor.

Stirrer Motor

A grinding noise not coming from underneath the microwave points to a faulty stirrer motor. The stirrer motor powers a metal blade that is responsible for deflecting microwave energy randomly throughout the microwave. A noisy microwave that is still heating food is a good indication that the stirrer motor (or turntable motor) is causing the issue.

Disconnect the microwave from the power.
Access the stirrer motor from inside the microwave cavity, above the turntable plate.
Remove the stirrer motor cover.
Inspect the stirrer motor. If the blade has become loose or is damaged, it will need to be replaced.
The stirrer motor can also be tested for proper voltage with a multimeter.
Replace the stirrer motor cover when done.

Cooling Fan

Rattling or clicking sounds coming from the rear of the microwave suggest the cooling fan may be obstructed. Sometimes debris can get into the cooling fan, or it can become dislodged. To check the cooling fan, you will need to remove the microwave top panel. Remember to exercise caution when accessing the cooling fan. If you need to remove other parts to access the fan, make sure the capacitor is discharged and the power is off. Taking photos to remember how to reassemble the microwave is also advised.