However, troubleshooting microwave faults must be performed with the greatest care and safety. These ovens probably represent the most lethal appliances in your kitchen today. Handling them without adequate care and safety could have fatal consequences. During periods of operation the microwave utilizes extremely high voltages (5000 V). If you are attempting to remedy any microwave problems, it is essential to realize that this appliance possesses a high voltage capacitor that will stay charged even after the microwave oven has been switched off. Before trying to fix any microwave faults the capacitor must be discharged.
Dismantling the metal cover around the microwave oven can leave you exposed to dangerous electrical connections. Never run the microwave without the cover as there is the potential of irradiation, and you can be exposed to harmful emissions if the waveguide is damaged.
Always take the maximum precautions while working on your microwave. If you are inexperienced in working with such devices, it might be safer to seek the services of a trained service technician.
There are various types of problems that can affect a microwave oven, and analyzing some of these issues can help you troubleshoot these machines
Microwave is dead
If the microwave appears dead, this could indicate a problem with the Line Fuse, which will blow if excess current is being used by the microwave components. While this fuse is easily replaceable, there may be other issues that are causing the appliance to over-draw power. There might also be a problem within the High voltage circuit of the microwave, in particular with components such as the diode, magnetron, high voltage capacitor, or transformer. Other factors that may cause this condition include a blown thermal fuse that should be tested for continuity or Thermoprotector that has tripped. (This is a small component that ensures that the microwave does not overheat.) Certain microwave models may require the system clock to be set before they commence functioning.
Microwave Does Not Heat
Most microwave ovens will include a high voltage diode that is responsible for converting the A/C power output delivered by the transformer to D/C. During this process the voltage reaches its peak capacity of 5000 volts. This generates enough power so that the magnetron is able to provide the cooking energy within the oven. A failure in the diode will result in a lower A/C voltage reaching the magnetron, which may not be sufficient. Diode failure is often accompanied by visible signs of a burn out. If the diode appears to be unaffected, it may be tested with the aid of a volt-Ohm meter that has the capacity for handling diodes.
Most microwave ovens are usually equipped with 3 door switches. A failure with any one of these switches can result in the microwave oven not switching on and consequently no heat is produced. These switches should be checked for continuity with an Ohm meter.
The microwave oven is essentially powered by the Magnetron tube that utilizes a high D/C to generate the waves that are responsible for cooking food. Any damage to the magnetron will prevent the device from heating up. If the microwave oven has been run while empty, this could have burned out the magnetron. This part cannot be repaired and will need to be replaced.
A defective high voltage capacitor may also be responsible for the oven's failure to heat up. Any problem to the HV capacitor will affect the functioning of the complete high voltage circuit. The HV capacitor may be tested only with a specialized VOM meter that has capacitance testing ability. Even when switched off, the HV capacitor may retain a charge of about 3000 volts. Therefore, it is always advisable to leave its testing to an authorized service technician.
There might also be issues with the Thermoprotector, Thermal fuse, or High Voltage Transformer that can lead to this type of problem.
The Microwave Runs Briefly and then Stops
In most cases, this problem is caused by a defective door switch that fails intermittently. These switches should be inspected for any signs of arcing, overheating, or burning. They must also be checked for continuity. Switches that display any visible signs of damage or that display intermittent continuity should be replaced. This type of problem could also be indicative of an intermittent short on the High Voltage Transformer. A tripped thermoprotector or defective thermostat may also result in the microwave running intermittently.
Apart from these issues, this problem might be a sign that certain components within the Touchpad, control Panel, or Main Control Board have been damaged.
The Microwave Light Bulb is not working
The microwave light bulb is usually quite easy to replace. Simply reach in and replace the bulb. If this does not work, it would indicate a problem such as the light bulb socket burning out or some type of wiring defect.
The Microwave Turntable Does Not Turn
In most cases, lack of movement in the turntable is a sign that the turntable motor has been worn out or has burned out. This type of problem can occur fairly often and this part is easily replaced. However, if the motor is still functional this could indicate a defect within the main control board or User Control and Display Board. If the microwave oven has a button on the touchpad responsible for switching the turntable on and off, then this could indicate a problem with the Touchpad and control Panel.
The Microwave Buttons Do Not Seem to Work
In most cases, lack of response from the microwave buttons would indicate that the touchpad or the control panel are defective or have been damaged. (Excessive cleaning of the touchpad can cause this.) Certain microwave models require that the door be shut before the touchpad is activated. Another issue with machines like this is that they tend to go into 'sleep' mode quickly. Simply opening and closing the door once should be enough to re-activate the oven. A 'confused' controller may also be responsible for this type of situation. You can unplug the device for 1-2 minutes to let it reset.
The Microwave Display does not function
Usually this type of problem is related to the functioning of the microwave Display Board. A complete failure in the display would indicate a problem with the main board or display board. However, if part of the display is available, there is clearly a malfunction in the display board. You might also be dealing with a display panel that is physically broken and will need to be replaced. Sometimes, this type of problem may be resolved by resetting the microwave. (Switching off for 1-2 minutes)
The Microwave Starts by itself
This type of problem usually indicates a faulty triac or relay, or could point to a problem with the controller. You can try resetting the machine to see if the situation corrects itself. If this does not work, it could indicate problems with the power supply or defects in the touchpad.
The Microwave is Arcing (Sparking)
If sparks are produced in the microwave oven at the time of operation, this could indicate that the Waveguide Cover is defective or has shorted out. You may remove this cover to check if this solves the problem. Sparking can cause damage to the microwave cavity and any damaged areas should be repaired. The waveguide cover will have to be replaced if any of the underlying connectors are burnt out or have melted.
If there is sparking along the side walls of the microwave oven, this could indicate that the paint along the side walls has been chipped. This type of problem can be fixed by covering up any exposed metal spots in the oven with a microwave safe paint. This type of sparking may also be seen near rack supports, where the paint has worn away leaving exposed bare metal within the oven.
In general, any exposed metallic edges or carbonized food residue within the oven cavity can cause arcing.
The Microwave Door does not open
If the oven door is stuck and does not open, there is every possibility that the Open Lever has broken, and will need to be replaced. There might also be an issue with the Door Spring located within the door. This spring is responsible for exerting a downward force to the door hook.
This type of problem might also indicate the presence of a broken door latch. This latch is mounted on the inside surface of the oven, and engages with the door hook to ensure the oven door remains closed when it is switched on. A broken door latch or actuator will prevent the door from being opened.
In addition, problems with the Door Hook, Button, Button Spring or the Handle Actuator might stop the door from opening.
FAQs
Try unplugging the microwave or turning off the circuit breaker for two minutes, then attempt to turn it back on. This will reset the computer inside the microwave and may correct the problem.
Can I fix my microwave myself? ›
That's because a microwave can hold an electrical charge of thousands of volts in its capacitors for hours or even days after it has been unplugged. The Consumer Product Safety Commission reports that people have been electrocuted trying to repair their microwaves. So don't try it.
How do you fix a microwave fuse? ›
Once you have located the fuse, remove any necessary wires and fasteners to free it from the microwave. To replace the fuse, connect any necessary wires to the new part, and secure it with any clips or fasteners if necessary. Replace the panels or covers and secure them with the screws.
How many years should a microwave last? ›
The average microwave oven lasts about seven years with normal use, and even less with heavy use and poor maintenance. A large family may find themselves replacing their appliance every four to five years as they become more reliant on its use to heat up snacks and leftovers, or to defrost meals.
What causes a microwave to suddenly stop working? ›
The most common cause of a microwave not working is that the main fuse has blown. The fuse will often blow because of a power fluctuation or a defective door switch. It can also blow because another part, like the magnetron or capacitor, is defective.
Is it worth fixing a microwave? ›
Consider a replacement if you have a basic model that can cost as low as $60. On the other hand, an expensive model with special features or a mounted microwave might be worth repairing. High-end microwave models can run from $500 to $1,000, so repairing these devices is often cheaper than replacing them.
What is the most common cause of microwave failure? ›
The most common cause of microwave failure is its magnetron. The magnetron is what produces the microwaves that cook your food, and it's also the part that is most likely to burn out. Symptoms of a faulty or burned-out magnetron include a microwave that doesn't heat food properly or doesn't work.
What blows a microwave fuse? ›
To prevent microwaves from leaking out, door fuses will blow if the door is not closed properly. Thermal fuses will blow to prevent the microwave from overheating and potentially causing a fire. A fuse will also blow if there is a surge in electricity, which can cause a short circuit.
Where is the fuse in a microwave? ›
Microwave ovens use one or more thermal cut-outs, sometimes called thermal fuses, to protect the oven from overheating. They are located inside of the cabinet, often near the oven cavity or the magnetron.
Is there a reset button on a microwave? ›
Microwaves can stop responding due to software glitches or unintended microwave settings. Press the cancel/reset button to do a soft reset on your microwave. If necessary, perform a hard reset by unplugging your microwave for 30 minutes, then plug it back in.
A broken magnetron is the most common reason that your microwave is running but not heating your food. The magnetron is an essential part of a microwave which is responsible for creating the microwaves needed to heat your food.
How many fuses does a microwave have? ›
Your microwave may have two types of fuse. The line fuses are usually familiar ceramic tubes, about 1¼ inches (3 cm) long. The thermal cutoff fuses are typically squat black cylinders with two prongs on the same side. Their exact location depends on your model, but check behind the control panel.
Can I bypass a microwave fuse? ›
A thermostat fuse is designed to protect your microwave from overheating. If your thermal fuse has been activated by your microwave overheating, your microwave will stop working. Never bypass your microwave oven's fuse! There is a very good chance that you could set your microwave oven on fire.
Is it worth repairing a microwave magnetron? ›
No matter how new your microwave or if there's only one problem, if the magnetron is out then you might as well replace the entire appliance. The magnetron is the heart of a microwave that actually makes the micro-waves. Replacing it is about equal to the cost of buying a whole new microwave, sometimes even greater.
How do you test a microwave signal? ›
Currently, microwave power can be detected using a device called bolometer. A bolometer usually consists of three materials: Electromagnetic absorption material, a material that converts electromagnetic waves into heat, and a material that converts the generated heat into electrical resistance.
What causes a magnetron to fail? ›
If the lower polepiece is not seated properly against the transition, causing a gap, it will allow microwave leakage between the joints which causes arcing. This arcing can then melt the plastic sleeve which causes the tube to run hot. This in turn can then melt the plastic sleeve which will overheat the tube.
How can you tell which fuse is blown? ›
Open the fuse box and look at the glass containers that hold the fuses. If you can see that the fuse is visibly broken, or there is metallic residue on the glass from the fuse blowing, you will need to replace that particular fuse. Always turn your power off before replacing a fuse.
How can you tell if an electrical fuse is blown? ›
Go to your home's electric service panel - usually, a gray metal box on an interior wall of your basem*nt or garage, near your outside electric meter. Open the door of the service panel and see if a circuit breaker is tripped (or a fuse is blown). If so, reset the breaker (or replace the fuse).
Why is my microwave not working but has power? ›
The first and main cause of microwave not working but has power is an issue with the line fuse. If more than required current flows through the microwave circuitry then the line fuse will blow.
What is the best time of year to buy a microwave? ›
When to Buy New Appliances. The beginning of fall is the best time to buy a washer and dryer. It's also the best time to buy kitchen appliances such as ranges, ovens, built-in microwaves, and dishwashers.
Not cleaning it regularly
If you don't clean your microwave regularly, you're shortening its lifespan. Food particles and grease can build up on the interior of the unit and cause damage. Even if you only use it for heating up food, food particles can build up and cause problems.
What is the average life of a microwave? ›
The average microwave oven lasts about seven years with normal use, and even less with heavy use and poor maintenance. A large family may find themselves replacing their appliance every four to five years as they become more reliant on its use to heat up snacks and leftovers, or to defrost meals.
What are the signs that a microwave is going bad? ›
6 Signs It's Time to Replace Your Microwave
- Smoke, sparks, and burning smells.
- Food isn't cooking properly.
- It makes horrible sounds as it cooks.
- The door doesn't seal properly.
- The keypad doesn't function.
- It's over 10 years old.
To prevent microwaves from leaking out, door fuses will blow if the door is not closed properly. Thermal fuses will blow to prevent the microwave from overheating and potentially causing a fire. A fuse will also blow if there is a surge in electricity, which can cause a short circuit.
Is it worth replacing a magnetron in a microwave? ›
No matter how new your microwave or if there's only one problem, if the magnetron is out then you might as well replace the entire appliance. The magnetron is the heart of a microwave that actually makes the micro-waves. Replacing it is about equal to the cost of buying a whole new microwave, sometimes even greater.
How do you test for a bad magnetron? ›
Set the meter to its highest resistance scale and check from the terminals of the magnetron to the metal magnetron housing. Now by doing so the meter should read infinite, regardless of the polarity of the meter. Even a little bit of reading will be a signal that the magnetron is defective.
How much does it cost to replace a magnetron in a microwave? ›
Magnetron Replacement
Replacing a microwave magnetron costs between $100 and $200 on average. Labor for replacing the magnetron makes up half of the cost, so if you want to save money, consider installing this replacement part yourself.
Can you use 20 year old microwave? ›
Should I replace my 20-year-old microwave? If your microwave works, keep using it and keep it clean. Three things could go wrong, but they are all rare – especially for a 20-year-old microwave. The door or seal on the door could break and microwaves would leak into your kitchen.
How long does a magnetron last in a microwave? ›
Magnetron tubes have a lifetime of only a few thousand hours—from 2,000 hours up to 8,000 hours depending on the tube.
What does a bad microwave fuse look like? ›
It's easy to tell if a glass fuse is blown; it will show scorch marks, and the filament will be melted. To check a ceramic fuse, use an ohmmeter or continuity tester. With an ohmmeter or multimeter, you should see a reading close to zero ohms if the fuse is intact, or infinite if it's blown.
Bad microwave magnetrons can make various noises, and the noise is often very loud. Usually, faulty magnetrons make a high-pitched screaming or screeching sound. A magnetron may also make a loud buzzing or humming noise, depending on the issue.
What does a bad microwave diode look like? ›
Defective diodes will usually emit an electrical burning smell, signifying its defectiveness. Also, it may have split in two, or it may exhibit a burned crack, or possibly even a blistered spot.
