Repairing Guides

how to repair microwave oven not heating

by Keara Lebsack Published 3 years ago Updated 2 years ago
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How to Repair Microwave Oven Not Heating

  1. Defective Door Switch Most microwave ovens have 3-4 door switches that only allow the microwave to operate if the...
  2. Blown Fuse A microwave contains several fuses, such as a thermal fuse, a cavity fuse, and a thermoprotector. The...
  3. Defective Diode The microwave’s diode converts alternating current (AC) to direct current...

Part of a video titled Top Reasons Microwave Is Not Heating - YouTube
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Since the part is not repairable a burned-out magnetron will need to be replaced with a new one. TheMoreSince the part is not repairable a burned-out magnetron will need to be replaced with a new one. The high voltage capacitor.

Full Answer

How to fix an oven that will not heat up?

The Oven Won’t Heat

  • Use a screwdriver to remove the old igniter or heating element. ...
  • To get to your igniter, remove the broiler or storage drawer.
  • Make sure to turn off the power to your oven before servicing it.
  • If your heating element is of the hidden variety, you may need to call a repairman to replace it for you.

Is it worth the money to repair your microwave oven?

When your microwave problem involves a single component, it’s often worth making the repairs to fix that one thing. A broken microwave door handle, the glass plate or roller guide, for example, are common aspects that break and can quite easily be replaced.

How to repair a microwave that does not heat?

  • The high-voltage diode will be attached to the high-voltage capacitor, which you have just discharged. ...
  • Next, unscrew the other end of the diode from the support bracket.
  • The diode may be visibly damaged, in which case it should be replaced. ...
  • The diode should only allow current to run one direction. ...

More items...

Why is my microwave oven not shutting off?

We had operated the oven as we do every time which includes:

  • Setting it to 400 degrees
  • Set the timer on for 20 minutes
  • Pressing the “Off”/Cancel button on the oven. This would normally shut it off and the oven would cool off by half-hour.

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Why is my microwave running but not heating?

If the microwave is running but not heating your food, another possibility is the diode has burnt out. A diode allows the electrical current to flow in only one direction. If the diode fails, it could mean there is a short, which will allow the current to flow in both directions, or only part way in one direction.

Is it worth replacing a magnetron in a microwave?

Smaller components like a fuse or door interlock switch are usually worth replacing, however. The cost of replacing a magnetron is usually as much or even more than the cost of buying a new microwave, which makes it an impractical option instead of replacing the whole oven, most of the time.

How much is a new magnetron?

Replacing a microwave magnetron costs $100 to $200. This includes a part price of $50 to $100 and $50 to $100 for labor. A magnetron is the primary component that produces heat for the appliance. This part creates microwave energy.

Is it cheaper to repair a microwave or buy a new one?

The cost to install a new microwave ranges from $110 to $190, plus $100 to $700 for the appliance. Consider a replacement if you have a basic model that can cost as little as $60. High-end microwave models can run from $500 to $1,000, so repairing these devices is often cheaper than replacing them.

Safety Warning

Repairing a microwave is more dangerous than repairing most other household appliances. 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. Before repairing internal microwave oven components, the capacitor should be discharged.

1. Defective Door Switch

Most microwave ovens have 3-4 door switches that only allow the microwave to operate if the door is closed. This is a safety feature to stop harmful microwaves from escaping the microwave when it is in use. If a door switch is defective, it can prevent the microwave from heating, even if the door is closed.

2. Blown Fuse

A microwave contains several fuses, such as a thermal fuse, a cavity fuse, and a thermoprotector. The fuses are all designed to keep you safe by cutting power to the microwave if it becomes too hot or there is a power surge. If a fuse is blown, it cannot be reset, so it will need to be replaced.

3. Defective Diode

The microwave’s diode converts alternating current (AC) to direct current (DC), which doubles the voltage and powers the magnetron that heats the food. If the diode is defective, the magnetron will not receive enough voltage, and the microwave will not be able to heat the food.

4. Defective Magnetron

The magnetron is responsible for creating the microwave frequencies that heat the food. If the magnetron is failing or defective, the microwave will not heat properly. Other symptoms of a defective magnetron include food not cooking properly and an increase in the typical hum a microwave makes when cooking.

5. Defective High-Voltage Capacitor

The high-voltage capacitor works with the diode to convert the alternating current to direct current and double the voltage. If the capacitor is defective, the microwave will not be able to get the voltage it needs to heat and cook food.

6. Failed High-Voltage Transformer

Another reason the microwave may not be heating is that the high-voltage transformer has failed. A defective transformer will often arc (a rapid release of energy) and produce a burning smell. The transformer has three windings, which can be tested with a multimeter to determine if the transformer needs to be replaced.

Why does my microwave not heat up?

Your microwave may turn on but not heat up. This could be caused by a problem with the high voltage diode, which helps to power the magnetron.

What does it mean when a microwave doesn't heat up?

Need Help Finding Your Model Number? When your microwave turns on but does not heat up, it may mean the door switch is broken. The door switch signals other microwave components to supply power when closed, and to stop heating when open. The door switch can also be called an interlock switch.

How to test magnetron in microwave?

How to test microwave magnetron with a multimeter: Before beginning this inspection, verify that you have disconnected the appliance from the power source. In order to access the magnetron, you will need to remove the appliance’s cabinet. Next, discharge the high voltage capacitor, then verify that the high voltage diode is working and ...

How to test continuity of microwave?

If they do, remove your microwave’s cabinet, locate your door switch, and remove it in order to test it for continuity. Using a multimeter set to Rx1, while depressing the actuator button, touch the probes to the switch’s terminals. This test should produce a reading of 0, which indicates there is continuity.

What to do if your diode does not show continuity?

If your diode does not show continuity, or shows continuity in both directions, you will need a replacement high voltage diode.

Why is my microwave not heating?

If your microwave isn’t heating, a number of parts can be responsible for the issue, from door switches to magnetrons. With the help of a multimeter, you can troubleshoot the three most common problems on your own; just be sure to unplug the microwave before inspecting the inner workings! However, if you’re unsure of how to approach the problem, ...

How to check if a microwave magnetron is working?

You can check to see if the magnetron is working by unplugging the unit, removing the cabinet housing, safely discharging the high-voltage capacitor, and removing the magnetron. With your multimeter, you can check the charge from the terminals. They should read 2 to 3 ohms of resistance if the magnetron is still working. Then, use one probe to touch the metal housing that encloses the magnetron; if it reads zero, there’s a problem. This step should only be completed once the capacitor has been discharged properly using a rubber-handled screwdriver or other safety tool.

Where is the diode on a microwave?

The diode is the piece of equipment that helps channel and provide the electricity in one direction to the magnetron, and it’s usually located behind the microwave front panel near the controls. If it’s burned out, then the microwave won’t generate power to spin the magnetron and heat the food.

Can you heat up food in microwave?

Microwaves are handy for reheating leftovers, warming water, and much more, but believe it or not, they are not able to heat up certain foods. Though the instances of making this error are uncommon, it’s a good idea to check that you’re not heating up very dry or fat-free foods.

Is it safe to use a microwave with the door open?

It’s a good safety mechanism, as a microwave would be operating unsafely with the door open. A good indicator that the door switch is the problem is if the light stays on when the door is shut and the microwave isn’t running.

Can you microwave meat?

Remember that there are certain foods and materials that should never be heated in the microwave for safety reasons. Heating metals can cause significant damage to your appliance (and even your home), and defrosting meat in the microwave can be unsafe due to bacteria growth.

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