What would cause a microwave to stop working?

Microwaves have become an essential appliance in most homes and offices for quickly heating up or cooking food. However, like any electronic device, microwaves can malfunction or stop working unexpectedly. Troubleshooting and determining the cause of a microwave not working properly is important to decide whether you can repair it yourself or will need professional service.

Quick Overview on How Microwaves Work

First, it helps to understand the basic components and functioning of a microwave oven. A microwave oven uses microwave radiation to heat food. It contains a magnetron that generates electromagnetic waves. These waves are concentrated into the oven’s interior through a waveguide and distributed via a rotating turntable. The microwaves agitate water molecules in the food, generating friction and heat which cooks the food.

Microwaves have timing and power controls to set the intensity and duration of operation. Built-in sensors monitor humidity and temperature to prevent overheating. A door switch interrupts cooking when the door is opened. A microwave oven is powered by household electricity through an internal transformer that converts high voltage electricity from the outlet into lower operating voltages.

Possible Causes of Microwave Failure

Based on the working mechanism, here are some common reasons a microwave can fail:

Power Problems

• No power – If the microwave display is blank and does not respond at all, it likely lacks power. Check that the power cord is firmly plugged into a functional outlet.
• Tripped circuit breaker – The circuit breaker for the microwave’s outlet could have tripped, interrupting power supply. Reset the tripped breaker switch.
• Faulty outlet – Try plugging something else into the microwave’s outlet to test if the outlet itself has an issue.
• Blown fuse – Microwaves have an internal fuse that could have blown. The fuse needs to be replaced by a technician if blown.
• Damaged power cord – Inspect the power cord for damage or loose connections which can prevent power from reaching the microwave.

Door Problems

• Faulty door – If the door does not close properly, this can trigger the safety door switches to disable the microwave.
• Broken door hinges – Check that the hinges are intact and door can still pivot easily.
• Obstructed door sensors – Grease or debris built up around the safety door switches could prevent the microwave from sensing door closure.

Internal Failures

• Burnt out magnetron – The magnetron tube converts electricity into microwave radiation. They degrade over time and will eventually need replacement.
• Waveguide damage – Faults in the internal waveguide that directs microwaves into the cooking chamber can lead to poor heating.
• Motor trouble – If the turntable motor malfunctions, the microwave may not distribute heat evenly within.
• Bad control board – Defective relays or blown diodes on the control boards can lead to key microwave functions not working.

Common Signs of Problems

Here are some visible or audible signs that often accompany a non-functional microwave:

• No heating – Food does not get hot at all when microwave runs.
• Uneven cooking – Some parts of food heat more than others indicating poor wave distribution.
• Sparking inside oven – Arcing or sparking inside when operating means something is shorting.
• Dim or flickering interior light – Usually signals an underlying electrical issue.
• Turntable not rotating – Points to a failed turntable motor.
• Burning smells – Could indicate an overheated component or short circuit.
• Unusual humming or noise – Abnormal sounds from the magnetron can mean it needs replacement.
• Display not working – If display is dead, likely a control board or fuse issue.

Steps to Diagnose the Exact Problem

With some basic troubleshooting, you can narrow down the source of the malfunction:

1. Check power supply – Verify the microwave is getting power and outlet is working.
2. Inspect door – Test to see if door is closing and switches are engaging properly.
3. Test components – Check if interior light, turntable and display are functional.
4. Try heating water – This can determine if the magnetron is still able to generate microwaves.
5. Listen for noise – Unusual sounds made during operating can indicate faulty components.
6. Get professional help – If you cannot find the cause through basic testing, you likely need a technician’s diagnostic expertise.

Common Do-It-Yourself Repairs

Many microwave problems can be fixed by the owner with proper precautions. Here are some common DIY repairs:

Replace Fuse

Using a multimeter to check for continuity, you can test if the internal fuse has blown and needs to be replaced. Unplug the microwave first and remove the outer case to access the fuse.

Replace Door Switch

Faulty door switches just need to be properly aligned or cleaned of debris to get working again. You can also replace damaged switches, which simply involves unplugging connectors and installing a new switch.

Replace Turntable Motor

Remove the turntable, outer casing, and bracket to access the motor. Unscrew the motor, disconnect the wiring plug, and install a new turntable motor of the same specs.

Repair Door

You can replace broken door hinges or realign the door if it is not closing properly. Take care not to damage any of the door switches while doing repairs.

Clean Ventilation Ports

Blocked air intake or exhaust vents can lead to overheating. Clean the openings with a vacuum hose and use a vent brush to remove built up debris.

Professional Microwave Repair

For many microwave problems, it is best to call an experienced technician. Professionals have specialized tools and expertise to properly diagnose issues and make repairs. Reasons to get professional microwave repair include:

• Microwave has no power at all – Indicates an internal electrical issue a technician can troubleshoot and fix.
• Microwave starts arcing or smoking – Signals a severe problem that is hazardous for DIY repair.
• The oven still doesn’t heat up – If you cannot get the magnetron working, then replacement is needed.
• Keypad buttons are unresponsive – Likely need replacement of control board which is intricate work.
• Do not want to risk electrical shocks – Professionals know how to safely work on microwave internals.

Technicians can determine whether the magnetron needs to be replaced and do intricate control board or waveguide repairs. They have specialized tools like dielectric leak detectors to accurately diagnose faults. Proper disposal regulations are followed when replacing defective components containing hazardous materials.

Cost of Professional Microwave Repair

The cost of repairing a microwave professionally can range from $200 to $400 on average based on the following factors:

Repair Type	Typical Cost
Replace magnetron	$200 – $300
Replace control board	$150 – $250
Replace door switch	$10 – $30
Replace turntable motor	$80 – $120
Professional diagnostic fee	$50 – 100

When to Replace Instead of Repairing

Replacing your microwave altogether might make more sense than repair in certain situations:

• Microwave is very old – Over 10 years old, repair costs likely exceed a new unit cost.
• Prior major repairs – If magnetron or board needed replacing before, further issues signal end of life.
• Diagnosis reveals multiple problems – Several faulty parts means ongoing issues likely.
• Rust or exposed wires inside – Cannot safely repair due to extent of damage.
• Repair costs over $300 – More than half the price of a new microwave, better to replace.
• Newer model has desired features – May make sense to replace with convection or sensor cooking model.

Tips to Extend Microwave Lifespan

You can minimize the chances of microwave failures by following proper usage and maintenance guidelines:

• Keep it clean – Wipe down interior regularly to avoid grease buildup damaging components.
• Use open containers – Closed containers prevent ventilation and lead to overheating.
• Don’t run it empty – Always have either food or a microwave-safe container with water when operating.
• Follow wattage recommendations – Don’t exceed wattage labeled on food packaging.
• Give it space – Don’t cram the microwave in tight spots that block ventilation.
• Listen for problems – Unusual sounds are the first sign of potential faults.
• Get annual maintenance checks – Technicians can spot minor issues before they become major.

Conclusion

Microwaves make cooking and reheating food incredibly convenient. But they are still electrical appliances subject to wear and tear. The most common causes of microwave failure include magnetron burnout, faulty door switches, power supply issues, and problems with waveguides or motors. Many problems can be addressed with do-it-yourself troubleshooting and repairs. However, it is best to get professional service for any malfunction involving the high voltage components or microwave radiation system of your oven. With early intervention for minor issues and proper maintenance, you can maximize the lifespan of your microwave.