How to repair a microwave oven with your own hands: in detail about the diagnosis and troubleshooting

The microwave oven works on the principle of scattering a small amount of microwave radiation in the chamber, which causes the water molecules to vibrate.

And following the law of energy conversion, a large amount of heat is released, which heats up food. That is, it is the liquid contained inside the food that is heated.

But if you violate the rules for operating a microwave oven, sooner or later problems arise with it. The most common are sparking during switching on, as well as a decrease in radiation power.

Is it possible to repair a microwave oven yourself at home? What can you do with your own hands, and when is it better to contact service centers for help

Do-it-yourself microwave repair step by step from A to Z in this article.

It's important to know

The main element of a microwave oven is a magnetron, which is a transformer that converts current into high-frequency voltage. And that is what is extremely dangerous for humans.

Accordingly, when disassembling equipment or performing any work, it is required to carefully observe safety precautions.

Basic requirements:

1. Be sure to de-energize the microwave before repairing.
2. Be sure to use grounding.
3. Do not disassemble the magnetron without proper experience and without the use of dielectric gloves.

A shield is provided inside the microwave housing, which prevents the penetration of microwave radiation to the outside. And it is for this reason that the oven cannot be turned on when the door is open - this is a kind of protective mechanism provided by the manufacturer itself.

But during disassembly, it is possible to close the door lock mechanism. In no case should you turn on an open microwave oven!

Microwave device

Conventionally, the microwave can be divided into the following key nodes:

1. Frame. Acts as a shield to prevent microwave radiation from penetrating outside the microwave oven.
2. Magnetron. A transformer that generates microwave radiation when voltage is applied.
3. Waveguide. A hollow profile of a rectangular cross section that directs the flow of microwave radiation directly into the chamber, where the food is heated.
4. Capacitor. It is used in the power system of the magnetron. Capable of storing electricity. Therefore, even if the microwave is disconnected from electricity, this does not eliminate the likelihood of receiving an electric shock! Disregarding the safety rules is strictly prohibited.
5. Electrical engine. Responsible for turning the plate of the microwave oven during switching on for uniform heating of food.
6. Control block. Regulates the voltage supply, and also allows you to set the microwave operating mode, duration, radiation power.
7. Control Panel. A set of buttons or knobs, with which the user programs the operation of the microwave oven, indicates the required heating mode.

These nodes are among the most technically simple microwave ovens. But the functionality of each model is somewhat different.

In modern microwave ovens, for example, manufacturers often add a heater element to enable the preparation of meat products, as well as a ventilation system that distributes hot air inside the microwave oven.

Power button not working

Possible causes of the malfunction:

1. The microwave oven is not connected to the power supply. It is enough to check whether the power cable is connected to the outlet, and whether there is electric current in it (you can use a multimeter by turning on the measurement of AC voltage).
2. Failure of the control panel button. Its replacement is required.
3. Door not closed. Or the locking mechanism has failed.

Control panel button failure

As a rule, the digital control panel is attached directly to the case with latches, sometimes with 3 screws, and is covered with a silicone heat-protective pad on top.

Quite often, due to inaccurate use of equipment, grease, dirt, moisture get under it. That is, it is enough to remove the panel and wipe the protruding contacts of the buttons with an alcohol wipe (it is not recommended to use detergents).

If a microwave oven is used that does not have a power button, that is, for this you just need to turn the handle and close the door, then most likely the handle itself has failed. To replace it, you will need to remove the control unit.

This is done as follows:

1. Remove the back cover of the microwave oven.
2. Loosen the screws securing the control unit.
3. Remove the protective cover from the front (if present).
4. Remove the plastic handles (in most cases they are held only by latches).
5. Remove the control unit itself through the front part.

After that, it will be possible to unscrew the fasteners of the handles and install new ones in their place.

The door is not closed or the locking mechanism is broken

First of all, you need to check whether the door closes tightly, whether there are any dirt, stains along its frame on the inside, and if necessary, clean it.

You can use either alcohol or a special microwave cleaner.

If the problem is in the lock, then you will need to remove the door. The lock itself is located near the control unit.

Removing the door is quite simple, as most manufacturers mount them on external protruding hinges. That is, it is enough to unscrew just one screw (on top), after which - pull the door up.

But to remove and replace the lock, you will have to disassemble the microwave and remove its front part.

To do this, you must first remove the rear protective cover, unscrew the screws securing the front panel, then unfasten it from the latches.

When you turn on the microwave oven, the switchboard switches off.

If, when the microwave oven is turned on, the machine works, that is, it “knocks out” electricity in the house, then this indicates that there is a short circuit in the power supply circuit of the device. Most often - in the power cable itself or in the transformer.

First of all, you need to visually inspect whether there are traces of burnout near the lead-in wire, as well as on the plug itself (which is inserted into the socket).

If nothing of the kind is found, then you will need to disassemble the microwave, remove the transformer and check it for a winding short circuit. Naturally, this must be done only if you have the proper experience and observing the safety rules.

The transformer and magnetron are located at the rear. That is, you need to remove the protective cover, the retaining plates (also fastened with screws), and then, in the "dialing" mode with a multimeter, check if the transformer windings are closed.

Sparks during microwave operation

If, when you turn on the microwave, sparks and sometimes electric arcs are noticeable inside the heating chamber, then the reason for this may be:

1. Getting on the walls of fat, water.
2. Metallic (incompatible) utensils are used.
3. Damage to the magnetron screen (mica).
4. Enamel damage.

Grease, water on the walls of the microwave oven

The inner walls of the microwave are coated with a dielectric coating. Most often it is enamel or ceramics (the same enamel, but with the addition of ceramic chips), as well as acrylic (in "budget" microwave ovens).

And if fat gets on them, it can burn, thereby damaging the dielectric layer. That is, after that, microwave radiation hits the metal part of the case, the microwave begins to spark and crack.

To fix the problem, the screen will need to be replaced.

Used metal utensils

For heating or cooking food in microwave ovens, you can only use food-grade plastic dishes (the package must have a label indicating that it can be used to heat food in microwave ovens), as well as glass or ceramics.

Metal - it is impossible, since it acts as a radiation accumulator, which causes sparking (current discharges).

Magnetron screen damage

In each microwave oven, the magnetron waveguide must be covered with a mica screen. If fat gets on it, then there is a possibility of burnout.

This is not difficult to check, just look at the plate (usually located on the inside on the right). If it has signs of burnout, it will need to be replaced.

enamel damage

If the microwave has sparkled, then you should carefully consider the inner surface of the case. Even small scratches on the enamel will cause sparks, as microwave radiation will hit the metal part of the screen. It will need to be replaced.

Reducing the power of the microwave oven

This happens in two situations:

1. Waveguide burnout.
2. Malfunctions in the power circuit of the magnetron or control unit.

Waveguide burnout

The waveguide directs the flow of microwave radiation to the heated food.

But it works properly only if there is no fat or other contaminants on its walls.

Accordingly, if the power of the microwave oven has dropped sharply, then it is necessary to check its condition. If necessary, replace (located directly next to the magnetron, that is, you will need to remove the back wall).

Malfunctions in the power circuit

In most cases, it is associated with the failure of the capacitor.

Its replacement is required, since the supplied current to the transformer is underestimated, therefore, a smaller amount of microwave radiation is generated than necessary.

Timer doesn't work

The error occurs in the following situations:

1. Faulty digital control unit. Actual for microwave ovens, in which the operating mode is set using the buttons or the touch panel.
2. The handle of the timer and power selection is faulty.

Faulty control unit

It will need to be diagnosed and replaced.

It is recommended to contact the service center, since in most cases the breakdown is associated with the failure of the quartz element on the board. Repair in this case will be inexpensive.

Timer handle defective

It is necessary to remove the control box and replace the damaged handles.

Microwave magnetron repair

A failed magnetron, as a rule, is not repaired, but replaced with a new compatible one.

How to fix mechanical damage to the door

The door itself must be removed from the hinges. If the protective glass was broken, it can be replaced. It is held, as a rule, only on latches (dismantling should be carried out from the inside).

To replace the hinge (as a rule, there is only one, located at the top of the door), it is enough to unscrew it (it is held on by 2 - 3 bolts) and install a new one.

By the way, spare doors for microwave ovens in most cases are sold already assembled with hinges.

How to replace mica in the microwave

Mica is recommended to be replaced after about 3 years of regular use of the microwave oven, or when traces of burnout appear on it.

It is held in most cases with 1 - 2 screws, as well as latches. That is, first you need to unscrew the plate, then pry it with some sharp plastic object.

Mica should not be thrown away, as it can be cut into a new blank for installation in a microwave oven. Or purchase a new one directly from the manufacturer.

In total, the general principle of operation of a microwave oven is quite simple. Most often, it is the magnetron with the transformer that fails (replace), the control unit (models with mechanical control are more reliable), as well as the door hinges.

And to significantly reduce the risk of any breakdowns with a microwave oven, it is recommended to clean it regularly. And use special detergents for microwave ovens for this (they do not contain components that can harm enamel, acrylic or ceramics).

In total, most microwave malfunctions can really be fixed on your own at home. Even if it is a serious breakdown, by the type of failure of the control unit.

Purchasing spare parts even for old models of microwave ovens should not be a problem, manufacturers do not experience interruptions in their supply.

Useful video

How to independently repair a microwave oven if it starts to spark is described in detail in the video clip: