10 Most Common Microwave Problems (and Noises) and How to Fix Them

Microwaves are essential kitchen appliances—but when they stop heating or start making odd noises, it can disrupt your routine. Whether your microwave won't start or it's making a strange humming or clicking sound, many problems have simple fixes.

Here are 10 of the most common microwave problems and noises, what causes them, and how to fix them with the right parts from Reliable Parts.

1. Microwave Not Heating

Common Causes:

• Faulty magnetron
• Broken high-voltage diode
• Burnt capacitor

DIY Fix: Test the magnetron, diode, and capacitor—these are high-voltage parts, so only attempt repair if you’re experienced. Otherwise, consult a technician.

2. Microwave Won’t Turn On

Common Problems:

• Blown internal fuse
• Door switchfailure
• Faulty control board

DIY Fix: Check the main fuse inside the unit and test the door switches with a multimeter. Replace any that show no continuity. Inspect the control board for burn marks or damage.

3. Microwave Making Loud Humming or Buzzing

Possible Issues:

• Magnetron failure
• High-voltage parts vibrating
• Turntable motor failing

DIY Fix: If the humming is louder than normal, the magnetron may be going bad. Check for loose mounting parts and test the turntable motor if it hums while not spinning.

4. Microwave Turntable Not Spinning

Likely Causes:

• Broken Turntable motor
• Worn-out coupler or roller guide
• Faulty control board signal

DIY Fix: Remove the glass tray and test the turntable motor. Inspect the coupler and roller ring for cracks or wear. Replace any broken parts.

5. Microwave Sparks Inside (Arcing)

Common Reasons:

• Metal inside microwave
• Damaged waveguide cover
• Burnt stirrer or rack support

DIY Fix: Never use foil or metal containers. Inspect the waveguide cover and replace it if damaged. Look for signs of burn marks on internal parts like the stirrer.

6. Microwave Display Not Working

Top Causes:

• Faulty control board
• Blown display panel
• Loose ribbon cable

DIY Fix: Open the control panel and inspect the display cable. If connections are secure, the issue is likely with the control board or display module, which can be replaced.

7. Microwave Buttons Not Responding

Likely Problems:

• Faulty membrane switch
• Damaged control board
• Moisture in the control panel

DIY Fix: Dry out the panel if it was exposed to steam. If buttons still don’t work, replace the membrane switch or control panel.

8. Microwave Door Won’t Latch or Open

Possible Causes:

• Broken door latch or spring
• Misaligned door hooks
• Faulty door release mechanism

DIY Fix: Inspect the door latch assembly and hooks. If the door won’t open, access the latch from inside the housing and replace any broken plastic parts.

9. Microwave Shuts Off Mid-Cycle

Common Issues:

• Overheating due to blocked vents
• Faulty door switch
• Failed thermostat or thermal fuse

DIY Fix: Clean vents and test the thermal fuse and thermostat. If overheating is the issue, allow the microwave to cool down before restarting.

10. Burning Smell or Smoke

Typical Causes:

• Food residue causing sparks
• Shorted components
• Internal arcing

DIY Fix: Unplug the microwave and inspect for food spills or damage. Clean thoroughly. If the smell persists, a burnt magnetron or electrical short may require part replacement or professional service.

Many microwave problems are easy to diagnose—and with the right replacement parts, you can fix them yourself. From turntable motors to door switches and control boards, find everything you need at Reliable Parts.