How to repair a microwave oven, not heating

How to repair a microwave oven, not heating

In many people’s daily lives, the microwave is one of the most important household appliances. This appliance is used to avoid wasting too much time at home. That’s why when a microwave gets damaged and doesn’t work, it’s a problem.

Here you will have two main options. One of them is to call a professional and spend money on the repair. The other possibility is to know what is necessary to repair yourself. That is why we will help you perform this procedure here.

Also, when you know how to repair a microwave oven not heating you can save some money and avoid calling the professional. It is even a set of three components that you can check to continue using your microwave. So, grab a multimeter and get to work.

Common microwave problems

Below, we can list some very simple steps that everyone can do. Three main components often fail in this type of appliance. So, if you want to try something before calling an expert, you should follow these steps. If you are lucky, then you will have the opportunity to save some money.

  1. Check the high voltage diode

A microwave oven as well as any other household appliance has some important parts inside. So, depending on the components that have failed, then you might notice certain problems in this unit. Generally, one of the most common problems is that the microwave does not heat but does turn on.

Therefore, the magnetron needs a high voltage diode to obtain the necessary energy supply. So, you should check this component in your microwave to see what the real problem is. This way, you will know if you need to replace this part or if the problem is elsewhere.

To begin with, you should have a digital multimeter, since it is necessary if you want to check the high voltage diode. So, it is advisable to use a digital multimeter as they are usually much simpler to use.

  • You can start by turning off the microwave and of course unplugging it from the outlet. Here it is necessary to consider that the great majority of accidents in the home are produced because of some distractions. So, if you start repairing your microwave with electricity, then the result will not be good for you.
  • Secondly, you must locate exactly where the high-voltage diode is located. Today you can use the web to search for images of exactly what a high-voltage diode looks like. Once you can find it, then you must remove it. Here the objective is to check the continuity using the multimeter. So, to access this piece, you must remove the entire cabinet.
  • Third, you must set up your multimeter exactly so that you can check the continuity of the high-voltage diode. Here you need to place your tool in Rx1. Next to that, you use the waves to touch each of the terminals.

Also, invert the probes of the multimeter to check the continuity oppositely. So, this is done to check that there is no continuity in one direction and if there is in another direction.

  • Fourthly, you must check that there is continuity in one of the directions in which you have used the probes. Here you will need to replace the high-voltage diode if you find continuity in both directions.

The same situation is if you do not find continuity in either direction. For the component to work properly the continuity must be in one direction and not present in the other direction.

  1. Check the door switch

Another very common problem when your microwave not heating but it does turn on may be due to a problem in the door switch. Most commonly that component is damaged and fails to function normally. This switch has the important task of informing the entire microwave whether the door is closed or open.

So, when the signal means that the door is open, then the microwave should not be turned on. The opposite situation occurs exactly when the switch gives the signal that the door is closed. Therefore, when the switch does not work then the signal cannot be sent. Therefore, the operation does not receive the signal that enables power and heating.

You may even notice that both the agitator and the fan motors are running. Of course, this does not mean that the microwave is providing the temperature in normal operation. So here you should take your digital multimeter if you want to check the proper operation of the door switch.

  • Again, you should start by disconnecting your microwave from the power source. While this is the easiest step of all, many people forget to perform this step. So here it is important to avoid all kinds of accidents due to distractions.
  • Secondly, it is important to mechanically check that the door hooks are working properly. To do this, these components should be activating the door switch as usual. If these hooks are functioning properly then the cabinet should be removed from the unit. This is necessary to test the continuity of the door switch. 
  • Here you need to configure your digital multimeter to measure the continuity of these components. So, your tool needs to be set to Rx1. Use the probes on the multimeter to locate them on the switch terminals.

While you do this, you must hold down the microwave button. If there is continuity then the reading on your multimeter should be 0.

  • Finally, if you find that your readings are out of sync, as with the high voltage diode test, you will need to replace this component. Otherwise, the microwave will not be able to receive the signal to start the microwave heating.

You may also like: How to fix a microwave with no power

  1. Check the magnetron

Finally, it is necessary to check the magnetron, as it may be the cause of a malfunctioning microwave. In fact, by checking this component you can avoid hiring home service for microwave ovens. To do so, it is necessary to perform the following steps.

  • As we have mentioned before, you should start by disconnecting the microwave from the electrical source. Along with this, you must also take your multimeter to check that the magnetron is working correctly.
  • As a second step, you must remove the microwave cabinet to access the magnetron. Along with this, the high voltage capacitor must be completely discharged.

Also, the mounting bolts must be properly tightened and the high-voltage diode must function properly. So, if these components are correct you must remove the magnetron to test it.

  • Again, if you want to test the magnetron, then you need to set your multimeter to Rx1. You will notice that the multimeter reads two or three ohms of resistance level when you touch the probes to the terminals.

This should not result in a continuity reading. Also, remember to touch the metal housing of this component when you move the probe.

  • To conclude here, the results should match the tests on the rest of the microwave components. In case you do not have the expected results then you should purchase and replace the magnetron.
Common microwave problems


Why is my microwave not heating?

There are several reasons why a microwave may not work. As we have discussed here, this could be caused by the failure of the high-voltage diode, the door switch, or the magnetron.

Therefore, if this happens, you will need to open your microwave cabinet and check these components with a multimeter. If necessary, you will need to replace some of the parts to use your microwave again.

What material will not heat up in the microwave?

Some materials will not heat up in a microwave. Some of them are bowls, paper plates, paper parchment, paper wax, and of course paper towels.

So, it is a set of materials that are safe to use inside the microwave. Along with this, it is not recommended to introduce newsprint or brown paper bags since they are unsafe at all times.

Why does ceramic heat up in the microwave?

As with some materials, dry ceramic can absorb much of the temperature of the microwave. However, here it is necessary to take into account that ceramics can also absorb water because it has a porous structure.

Final Words

After you learn How to repair microwave oven not heating, you will have the ability to fix various problems with your microwave. It is one of the essential appliances to avoid wasting time during any day of the week.

In turn, it’s always a good opportunity to extend the life of the microwave without spending money on a technician. So you will undoubtedly get excellent advantages here.

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