Is it possible to fix the microwave. DIY microwave repair: what could be easier? Cooking chamber and waveguide

We are 100% sure: it is enough to understand what is inside to repair the microwave. Let's start with the simplest model, inside which there is a grill and a turntable, then it is not difficult to generalize the case to inverter models. We speak in simple language, because we discovered that on the Internet, when discussing a topic, they say either a useless nonsense, or broadcast in a too highly specialized language that is difficult to understand.

The device of the simplest microwave oven

In a microwave oven, electrical components are connected in series. Let's start with the power supply circuit of the magnetron. Open the lid, you will see a huge transformer, next to it is a large (really large) capacitor, next to which a diode and a fuse are huddled in a ceramic case (insulator). These are the things that grab a beginner's attention in the first place. This is a circuit for generating a high voltage (3-5 kV) power supply of the magnetron. Don't put your hands in there, a screwdriver. We believe that the capacitor will slowly discharge, and if the plug is pulled out of the socket, an electric shock is unlikely. The principle of operation is as follows:

A voltage of 230 V is supplied to the primary winding of the transformer. The coil is located at the bottom, wound with a copper core, at times seemingly bare. The metal is covered with transparent varnish insulation. The coil is located under the secondary windings.
There are two secondary windings. One literally represents several turns of copper wire, carelessly wound next to the primary: heating the cathode. Provides 6.3 VAC to help electrons leave the surface. Above, in good, good insulation, there is a high-voltage winding. Provides 2 kV output power for the magnetron.
At the output there is a capacitor shunted by a diode. It turns out that the negative half-wave passes to the cathode, the positive one charges the capacitance. In the next half-cycle, the electrode will already be under double voltage: removed from the transformer and the discharge of the capacitor. The result is about 4 kV. Enough to start generating.

Please note: the output windings are paralleled on the magnetron, the cathode has two inputs. The anode is grounded separately.

It turns out the electrical layout:

A current of 6.3 V flows through the heating coil.
A potential of 4 kV is applied to the cathode, which is balanced by the ground at the anode.

The heating coil and the cathode are electrically connected. The power of the magnetron is controlled by a timer, and a start relay is added to the circuit to prevent sparks from occurring. Let's move on to the front panel!

Front Panel

On the front panel of the microwave oven there is a mechanical programmer that sets the modes. Under the round handle is a shaft equipped (in our case) with two cam discs. The first is responsible for the power supply of the transformer that forms the power supply of the magnetron, the second is for quartz lamps grill. Cam mechanisms control the buttons of two relays:

a key transistor that blocks the power supply of the magnetron;
quartz grill lamps.

If the cam is low, the button is released, the relay is in the normal position. With a high protrusion height, the relay button is pressed. It is easy to see that in this way we will ensure a constant supply of voltage, but it is necessary to regulate the power. Let's talk below, but first let's get back to the starting relay. The gizmo, which initially removes the current load, is connected in parallel with the input winding of the transformer. Power contacts are connected in series. In parallel, the relay is a capacitor and a zener diode.

When there is a front that forms a spark, the capacitance represents zero resistance to the drop, the inductance of the transformer is separated by open contacts. Large current does not flow! The capacitance begins to charge to the voltage limited by the Zener diode. A diode connected in the right direction interferes with discharging. When the threshold is exceeded, the relay picks up and a large current flows from the transformer and magnetron supply. Thanks to the clever operation, the timers of microwave ovens with a protective relay are almost not lit. Now the programmer!

Equipped with a gear, gear transmission that regulates the clock. Depending on this, the intervals of operation and downtime of the magnetron change. The longer the rest, the less power is released. On the magnetron, let's add: the introduction of inverter control shifts the control of the cycles from the timer to the sensor circuit for measuring the temperature. The sensor evaluates the radiation spectrum of the food and decides how to operate the microwave. It is not the idle time (operation) of the cycle that changes, but the duty cycle of the pulse repetition. Packages come more often, more power. As a result, it becomes possible to flexibly adjust to the current situation.

Protective relays

Before talking about the grill, the magnetron cooling fan, the working compartment illumination lamp and the table motor, I would like to mention the protective relays. Contactors provide complete shutdown of mechanisms when the door is opened. Two break the power circuit (ground and phase), one necessarily controls the performance of the other:

The door is open, the relay buttons are pushed out, the contacts, initially normally closed, are connected.
In this case, the power circuit must break twice.
But in the second relay, the ground is closed to phase.
The first relay has worked - nothing terrible happens, the circuit has already been broken.
The first relay is stuck, the fuse will knock out, since the ground is shorted to phase.

Abort the program by opening the doors. Perform the required operations. Close the compartment. The program will continue executing. Electromagnetic radiation instantly disappears, as soon as the protection relay breaks the contacts.

Not a power fuse housed in a housing and hanging under a magnetron, but located on an electronic board. Consider the curious features of protective relays. One (third) feeds the phase to the starting relay. Without this, the supply of voltage to the magnetron is, in principle, impossible. The power fuse evaluates the power consumption of the magnetron. If an abnormal situation arises, the protective element burns out, protecting the generator from damage. This will happen if you turn on an empty microwave oven, or put a fork, spoon, or a metal object inside. The single edging golden ring of the cymbal is capable of provoking an abnormal situation.

Service mechanisms

Usually a swarm of units is connected in series in a microwave oven. Now we are discussing the secondary mechanisms: fan motors, table motors, quartz grill lamps, a backlight lamp. This is done to reduce the number of wires. Constructive changes simplify microwave repair to the maximum. Result: the burnout of one element blocks the operation of the furnace. The magnetron threshes, as does the starting relay. The noted effect is a characteristic feature of the cause, which is hidden in the auxiliary mechanism. Equivalent result in case of breakdown of the third relay, breaking the power circuit in the normal state (the door is open and the button is released). but if a relay is powered from it (as mentioned above), microwave oscillations will not be generated.

The above diagram is typical for microwave ovens, we believe there will be other designs. Just take note of the constructors' inventions. The elements inside the microwave are powered by 220 volts. There are no other, special sources inside. Models stuffed with electronics are dramatically out of the ordinary. The inverter requires a number of voltages to operate.

I would like to note that in microwave ovens with hybrid modes, you will test almost 100% of the component parts of the product separately. Examine the construction of the programmer. It is convenient to shine the light on the grill while the magnetron is off. Beginners wonder how the grill power is regulated. We assume that the fraction of this component of the microwave oven costs the energy not consumed by the magnetron. The microwave works longer, less remains for other components electrical circuit.

Now let's say a few words about the occurrence of a fire inside the microwave oven: thunder-lightning strikes. At the output of the waveguide that transmits microwave energy to the compartment, there is a mica filter. Visually dense fabric, reminiscent of building insulation. The surface must be clean and dry. Otherwise, thunder and lightning will arise without difficulty. Fat promotes insulation breakdown, as a result of which a discharge will occur inside. Be foolish to put a plug in the compartment - the lightning will easily pierce the enamel coating. A black speck will remain, at worst the wall will burn through and through.

The main types of malfunctions are listed, the design is told - we hope that the readers will play the serve.

Please note that microwave radiation is harmful to health. Therefore, repairing microwave ovens on a regular basis better work you will not name.

Typical breakdowns

In microwave ovens, a weak point is the inability of the owners to properly operate the product. Buyers are sure: plates with a gold rim cannot be put inside, the dishes will break (peeling off the metal border), not the microwave. Everyday thinking is wrong. If you put a steel spoon inside, there is a huge possibility of an electric arc, if the jet of ionized air does not burn out the magnetron (high-voltage fuse), it will leave indelible marks on the walls of the working compartment.

Mica gasket

Let's start with a typical breakdown: a breakdown of the case at the mica gasket. The magnetron, through a pin, supplies energy to the waveguide, which is sensitive to the presence of impurities inside. Greasy stains burn, spark, and interfere with the normal operation of the device. Therefore, the output of the waveguide is covered with a mica cloth. A relatively inexpensive, soft flexible material sold in large cuts, use scissors to scissor into a suitable shape. The principle of operation is based on the ability of mica to pass the 2.45 GHz frequency of heating the microwave oven. Otherwise, the fabric gets very hot and burns out after a short time. Mica prevents the conductive walls from getting wet - it is important if the soup is heated inside: flying splashes cause irreparable damage to the cleanliness of the compartment. It has long been noticed: water just absorbs 2.45 GHz radiation, which promises trouble. If the liquid gets inside the waveguide, an emergency situation will immediately arise: evaporation of molecules, which changes the dielectric properties of the air, instant breakdown, burnout of a high-voltage fuse, in the worst case, a magnetron and other electronic filling.

Why the protective mica pad becomes unusable. The hostess prepares food, often among the ingredients of the recipe are fat, oil, and other substances. Substances do not boil, they shoot dirty drops. Fat gets on the mica tissue, a conduction bridge is formed. Separately, the natural mineral is a dielectric, it reliably isolates the waveguide from the housing, a single drop of oil that has soaked the gasket is capable of blowing up this wall. An arc is formed instantly:

between the walls of the waveguide and mica tissue;
between the mica cloth and the body.

Thunder and lightning are the first signs of an impending microwave breakdown.

Correct grounding

If the instrument is not grounded, the state of affairs is extremely dangerous. Stop grabbing the kitchen faucet with your right hand (substitute your palm with a stream of water), with your left hand accidentally touching the microwave oven to die. It is pertinent to remind: devices connected near water sources work in tandem with a differential circuit breaker. Proper grounding is required. It is often not enough to neutralize the corresponding terminal. Here are two pitfalls:

Ground resistance is negligible. Units, fractions of an ohm. 10 is already considered an invalid value. Therefore, in the circuit, not wires are often used, but tires (tapes) of steel or other metal (alloy) of a large section. It is clear that for home network such conditions cannot be provided.
The differential circuit breaker works by fixing the leakage current. The output, input values are measured, the difference is found. If the leakage current goes to ground by zeroing, the magnitude of the difference is zero, even when the fuses are blown out by the overload, plus the magnetron.

Differential protectors are often equipped with fuse slots, but should not be confused with safety features. The black humor of TV repairmen reads:

The fuse is the last to blow when everything that could break has already broken.

This means that the differential protection device cannot save human lives. It is required to properly ground the microwave oven. The devices belong to electrical safety class I. The terminal is located on the plug. Install euro sockets correctly connected. And this is first grounding, why - has already been explained. We add that a regular outlet or fuses from an accident may not protect you. In the case of a microwave oven, the chance of a favorable outcome of an accident is great.

High voltage fuse

Regarding this, many have a question mark in their head the size of a mountain, what is a high-voltage fuse. Explaining! The microwave oven device includes two fuses (minimum):

An ordinary small transparent (glass), white (porcelain) cylinder on an electronic board. Ensures the safety of hinged, integrated elements. Low voltage fuse, belongs to the power supply circuit of the electronic board. It will burn if the capacitor breaks through, it will close the resistor located on the printed circuit board.
The magnetron has its own power supply circuit formed by a step-up transformer, diode, capacitor. The source supplies a potential of several kilovolts to the cathode. Items are easy to find. The capacitor looks monstrous: a can of one hundred grams of steel, to which a diode is attached by the end, the second leg is soldered (screwed) to the case. Nearby, you will notice a box of ceramic or other dielectric (often brown). There is a high voltage fuse inside the Egyptian sarcophagus. Protects the magnetron against overheating. If the cathode current becomes too high (breaks through the mica gasket, or someone puts a spoon in the working compartment), the high-voltage fuse will burn out first. By the way, repairmen for microwave ovens rarely complain about a power element. Therefore, it regularly performs its duties (or, conversely, serves as the reason for the failure of the magnetron).

You cannot remove the high-voltage fuse from the electrical circuit, try to make an accessory with your own hands. It is simply dangerous for the device and people around it. There will be a fire, someone will be electrocuted.

Magnetron voltage generation circuit

Of course, you have heard about inverter microwave ovens. Firstly, they do not differ much in design from standard microwave ovens, and secondly, not everyone likes the flexible heating control mode, it is imperfect. The constructors provide the option to disable, cook and enjoy. To understand how a scientifically sounding inverter microwave oven works, consider the magnetron voltage generation circuit:

The microwave oven starts with a power transformer. The input winding is lower than the secondary winding, assembled with a copper wire with transparent varnish insulation (heat transfer to the outside by infrared radiation) for better cooling. Above is a pair of sloppy turns, forming a voltage of 6.3 volts of the cathode filament. Finally, the step-up winding is located on top, from where a potential of 2 kV (amplitude) is fed to the rectifier.

The anode of the magnetron is seated on the neutral wire (not the case). The cathode is additionally heated to make it easier for electrons to leave the surface of the emitter. Negative voltage is used for power supply. The capacitor is positively charged. The next half of the period the cathode is under double voltage. The potential difference is formed by the difference between the secondary winding of the transformer and the capacitor. A forced measure to reduce the requirements for the power section of the electrical circuit.
The primary winding of the transformer is supplied with a mains voltage of 230 V. In the case of inverter control, the duty cycle of the pulse train is modulated. As a result, the result is determined by the effective value. The farther the pulses are from each other, the lower the level, the less power the magnetron gives to food.

Please note: the magnetron has two terminals, three wires are wound up. A single one feeds the heat, with a double one - it supplies energy to the cathode, closes the 6.3 V circuit. The anode is connected separately, at the back of an ingenious design. The electronic circuit contains a relay to supply voltage to the transformer. The measure protects the programmer (contacts controlled by a timer) from arcing. In parallel, the relay is connected to a zener diode, a capacitor that takes the shock of the front of the connected voltage. Then the armature is triggered, power is supplied to the transformer. When the microwave oven is operating, clicks are periodically heard - the relay in question. The use of a structural part significantly increases the service life of the timer.

Timer (programmer)

The programmer is often formed by mechanical relays. The stem shaft contains a ring of different heights. Turning the knob, we select the combination of the states of the relay group. Depending on this, the microwave oven goes into desired mode... It is clear that there is nothing to break here (and if it breaks, then it is difficult to restore). We will check any relay if necessary, it is not required more often than such steps. The grill contact has failed - the lamps will go out. Let's say the same about the magnetron circuit.

The timer is more complicated. The shaft is riddled with gears, each closes (opens) a contact. In a microwave oven, devoid of inverter control, the timer sets the frequency of turning on (off) the magnetron. The relay mentioned above blocks the arcing of the timer contacts. With inverter control, there is an infrared radiation sensor in the compartment, according to the sensor readings, the pulse duty cycle (frequency) is controlled.

What can break. Imitation of the clockwork inside the timer is a spring. When you see a breakdown, you should replace the steel with a new one. The mechanism is durable, contacts rarely break. We have described the main types of malfunctions, of course, you need to start with the cord. A trivial breakdown, to blame in 20% of cases. Now readers are pretty much aware of how to fix a microwave oven.

Microwave oven breakdowns

Many people are interested in how to check whether the oven produces the required characteristics. In the literature it is written: the measurement method is in NVN 100 GOST 19308 - 80; provides a drawing and useful information to guide the assessment process. The beginning of this paragraph is taken from a 2003 book on repairing microwave ovens. It is alarming that GOST is difficult to find in practice. The authors googled and found GOST R IEC 60705-2011. And the document is called “Household microwave ovens. Methods for measuring functional characteristics ". It is from him that it is proposed to dance further. The book is a little out of date. The text cites less and less used microwave oven designs: radiation enters the working chamber from above. An outlandish modern design move was supposed to create a uniform field in volume. Today the waves come in from the right, the repairs are done differently.

Already hundreds of pages are covered with capacitor breakdown, diode burnout, fuses. Schoolchildren seem to know what's breaking. It is proposed to discuss the non-blurred aspect - the microwave field, power, distribution of the intensity vector, features and danger. When carrying out repairs, we often forget that the device is designed to help the family, and not to destroy humanity. A Whirlpool can easily wipe out the gene pool without proper security measures.

American scientists have long established that 2.4 GHz devices cannot be placed on your lap (look at today's teenagers). The action negatively affects the reproductive function. Cell phones and other gadgets work on a wave of 1-2 GHz (approximately).

Microwave field distribution inside the microwave oven

In expensive microwave ovens, the tray is stationary; the design of the chamber creates conditions for the constancy and uniformity of the field pattern. Readers already have a question mark in their heads the size of a house! If the light is on, it is dark behind the cabinet, light under the chandelier. It is not difficult to understand the sequence of light and shadow. Ilyich's lamp emits a non-fixed frequency - a band! As a result, the interference pattern escapes the eye. Coherent waves can be added and subtracted better. Identical in frequency. Let physicists avoid blaspheming the review for too loose interpretation of the concept of coherence, an overlooked aspect of the phase of the electromagnetic oscillation.

The wave enters the working compartment, begins to be reflected by the walls in an incredible way. As a result, at an arbitrary point in space, two oscillations can meet in phase or antiphase. The picture is just the opposite (light, shadow).

In the first case, we observe double the power, in the second - zero! Notice the human eye at the 2.45 GHz frequency, the working chamber of a microwave oven would appear to the individual as speckled, streaked with light and shadow. It is important not to allow food to be in the zero field.

After repair, if work was carried out with a magnetron and a waveguide, the picture will turn out to be unpredictable. Knowing Russian craftsmen, we are sure that a dozen microwave ovens with a radar magnetron will be found in the country. Indeed, what's the difference, on the microwave runway and in the microwave kitchen. In this case, it is recommended to check the parameters in the ways indicated below, to assess the safety of people using the device. For sure, there is no special equipment at home, therefore, it is proposed to simply substitute glasses of water on this side of the door and wait to see if it is warming up. Now the measurement technique is in accordance with GOST R IEC 60705-2011.

Parameter check

The process begins with general measurements and settings:

The room temperature should be 20 ± 5 ºС.
The temperature of the transformer, magnetron should not be more than 5 ºС higher than the environment. Alternatively, wait 360 minutes after microwave operation. In the room, of course, where the measurements take place.
To measure power, water is taken from the tap.
The dimensions of the microwave oven are determined according to the figure below. The usable radius is the distance from the center of the worktable's axis of rotation (or the center of the working chamber) to the nearest wall or door, and the usable height is measured from the surface of the turntable to the closest top limit point. The useful volume is expressed in liters, equal to the product of the useful height, depth, width.
If there are several mains voltage ranges, the generally accepted in the given country is taken.

The measurements are carried out in a cylindrical bowl made of borosilicate glass, 90 millimeters high, with an outer diameter of 190 millimeters and a wall thickness of 3 millimeters. The material of the container has a low coefficient of thermal expansion, which means that the water will retain its original shape. If anyone thinks that it is impossible to get borosilicate glass, then this is a mistake. Microwave glassware is made from the specified material. We tend to think that the cook will find what is needed at home to take measurements.

The water temperature at the beginning is 10 ºС. Then an electronic scale is taken, a bowl is placed on top, the readings are reset to zero. A liter of water weighs exactly a kilogram. The error in the mass of the liquid taken for the experiment does not exceed 5 grams. If there is no electronic scale, then come up with another way to collect exactly 1 liter of water. Take a syringe and measure out 5 milliliters.

The microwave oven is switched on (in the mode for which the power is measured), the microwave radiation works while the liquid is heated to 20 ± 2 ºС. Wait 1 minute with the chamber closed and record the final value of the water temperature in the bowl. Please note that the liquid is stirred before measurement. A subtle point. You cannot do a technological operation with an iron spoon. For example, a plastic scoop from a multicooker will do. So that the liquid does not lose some of the heat. Steel has a high thermal conductivity, which is why the room seems colder than plastic items. Although the temperature difference is zero. The power of the microwave oven in the selected mode is found according to the formula:

m w, m c - masses of water, container; That, T1, T2 - temperatures of the environment, water at the beginning and end of measurements, respectively; t is the time during which the required temperature is reached. The resulting value is rounded to 50 W according to the general rules of mathematics. Measure the wattage of a microwave oven, a big surprise awaits hardworking readers. We have already said that it would be nice to put a bowl near the door outside, and another inside. Using a similar technique, evaluate the quality of the protective net. Violate, whirlwinds of microwave energy will burst into the kitchen and fry whatever comes in your way. For those who do not know, we inform you that working with antennas, as well as transmitting and receiving devices, is considered a harmful factor. Therefore, those who get a job at a specific job undergo additional examinations, they pay extra for harm from above. Has the chef's family already passed the medical examination?

Take the trouble to assess the microwave leakage from the chamber. The reason for the poor quality of insulation lies in the lack of grounding. Most microwave ovens are classified as electrical safety I. The plug is equipped with a grounding lug. Contact hanging in the air interferes with the normal operation of the microwave oven. Try grounding as recommended by the standards and re-evaluate leaks.

Ideally, if you put a cell phone in a switched off microwave oven (the plug of which is in a grounded outlet) and call it, then the call should not go through. This means that the metal mesh on the door really does its job 100%. For the hokhmachi, we add that outside the microwave oven, the signal should confidently pass, responding with a vigorous call to the request for communication towers.

When starting to repair your microwave oven, remember about safety precautions. Usually there are women and children in the kitchen. Why is there a harmful factor? It would also be nice to have a thorough knowledge of the microwave oven. According to our recollections, if the screen is not grounded, then it extinguishes (reflects) only half of the radiation. The rest passes. Therefore, you can safely catch half of the measured power in the kitchen if the microwave oven is installed incorrectly. In conclusion, we wanted to give a couple of pictures from the standard. Everyone at their leisure can watch, read a text, measure values. In this case, we will talk more about the distribution of the field (we wrote about this at the beginning). Well, for example, if you need to heat a beer, it will become clear where to put it! And in no case do not heat milk in baby bottles in microwave ovens. The dangers of such an approach have already been scattered (as corrupt officials would say) a review. Don't forget to watch the video instructions in our article!

Simple DIY microwave repair: 5 solutions to basic problems

Rarely can a kitchen be imagined without a microwave. Recently, she is pr If you have no experience in microwave repair, then it is better to seek professional help. she took her own positions in the everyday life of housewives. So when it breaks down it's like a small disaster. Someone immediately takes it to the service center, and someone tries to fix it with their own hands. It is quite possible to do this if you have basic knowledge of electronics and device design.

DIY microwave oven repair: the main elements of the device

If a microwave oven breaks down, you can immediately take it to a service center, or you can try to repair it yourself, while saving money.

But before you start repairing a microwave oven, you should understand that a person who has at least some knowledge in electronics and electrical engineering can qualitatively repair a microwave oven.

Before you start repairing a microwave oven, you should study its components.

Also, when working, you must comply with all safety rules.

To repair microwaves, you need to know the following basic elements:

Energy converting transformer;
Magnetron;
Rectifier;
Fuse;
Fan;
Capacitor;
Control block.

It is quite easy to understand where and what is located. Right in the middle of the chamber is a magnetron and a transformer underneath. The fuse, capacitor and rectifier should be located to the right of it. As for the control unit, it is often located near the input panel.

Before starting repairs, be sure to disconnect the device from the mains!

If the breakdown consists in the failure of one of the main elements, then it will be easiest to replace it. The fact is that many parts of the stove cannot be repaired, but only new ones can be bought. This is especially true for capacitors, fuses and diodes.

If the replacement is real, then the following actions should be performed:

Disconnect the oven from the mains;
Discharge the transformer (this will take about 5 minutes);
Disconnect the desired part from the terminals and remove;
Replace the work piece.

When replacing, you need to pay attention to the correspondence of the circuit and the new part. If the new element and the circuit turn out to be incompatible, then this can lead to new breakdowns.

In the event of a failure of the electronics, it is still better to seek help from professionals who will conduct quality repair microwave oven.

Frequent breakdowns of the microwave: DIY repair, in detail

The fact that the stove is broken or does not work, as a rule, are signaled by some signs. According to them, the cause of the breakdown is determined.

Very often microwaves break down due to unstable voltage

So, what can it be, in more detail:

The microwave does not turn on - in this case, the power cord may be damaged, the door is not fully closed, or the fuse has blown. If the problem is in the cord or the outlet is overloaded, then the problem is solved simply by replacing the elements. An open door may prevent the microwave from starting, as it is dangerous, so it is worth checking the latch and door operation. If the fuse (which prevents the device from breaking due to power surges) or thermal relay has blown, then they are also easy to change.
The stove works without turning off the relay responsible for supplying electricity to the device - this can happen due to sticking contacts. The relay needs to be removed and its operation checked with an ohmmeter, and if it does not work, replace it.
The microwave works, but turns off after a few seconds - the problem is in the thermal fuse. Unfortunately, it will not be possible to repair it - you will have to buy a new one.
The plate with food does not spin - in this case, you need to check the connection of the plate itself and the engine. It is necessary to remove the pallet and look at the integrity of the wire, if it is disconnected or clogged, then you need to clean it and connect it again.
The stove hums a lot - most likely the problem is in the fan or transformer. The latter is unlikely to be repaired - it is easier to replace it. A fan problem can occur due to recycling if the device has been actively used for a long time. In this case, the blades of the cooling element must be cleaned.

This is how the most common malfunctions look like that you can do yourself. When working with electricity and checking the elements of the furnace, one should not forget about the observance of safety measures.

Do-it-yourself microwave touch panel repair

The microwave oven may have a touch control panel or a conventional control panel, which may not work due to exposure to high temperatures.

As a rule, problems with this part occur after 3-4 years of intensive use, and are expressed in the refusal of the buttons to "obey the command". At the same time, an error may appear on the scoreboard. The stove can turn itself off or off. The main reason for such phenomena is the closure of the panel contacts.

Materials for repairing the microwave touch panel are sold in a hardware store

Self-repair of the touch panel of the device consists of the following steps:

First, you need to disconnect the microwave oven from the mains and disassemble the panel - the latter consists of a film with buttons painted on it and two membrane gaskets with contacts.
Next, you need to pry off the sensor film with a thin sharp knife, while trying not to damage the membrane. It is best to start at the bottom or top left corner.
After removing the membrane, you need to check the operation of the panel by closing the contacts. You can put a container with water inside the oven. If everything works, you can start repairing the panel.
Again, you need to disconnect from the network and wipe all contacts with alcohol. To increase the gaps between them and eliminate the possibility of short circuits, you need to glue these places with pieces of electrical tape or tape.
Next, the upper membrane is put in place, after which the operation of the microwave is checked. If again something does not work or reacts with difficulty to pressing, turn off the stove again, peel off the membrane film and remove the electrical tape or add it somewhere (whichever does not work). This should be done until the buttons work as expected.

A touch panel repaired in this way can work for about six months, but it may continue to bend further, after which it will have to be "straightened" again or bought a new one.

Do-it-yourself microwave magnetron functions and repairs

If the microwave oven sparks, stopped heating food, or began to do it for too long, the problem is most likely in the magnetron, which is the main heating element of the microwave device.

By the way, it is unprofitable from the economic point of view to change the magnetron in the microwave, which has been serving for more than 5 years.

Before proceeding with the repair of the microwave magnetron, you need to watch the training video and familiarize yourself with the recommendations of specialists

As a rule, this device is "set" on terminals and screws that fix it to the base of the stove. However, replacement of the magnetron is rarely required. Basically, problems in its operation begin when the protective cap of the element burns out.

In this case, there are several options for solving the problem:

The cap is manually cleaned from scale and rotated 180 degrees;
A new cap is made from a suitably sized capacitor body;
It will also not be superfluous to replace the mica plate that is exposed to harmful rays.

Actually, there is nothing difficult in repairing a magnetron, but if the problem is not in the burnt cap, but a little more serious, then it is better to entrust such repairs to specialists.

DIY microwave repair (video)

You can repair a microwave oven yourself if you have some knowledge of the operation of electrical appliances. However, there is nothing complicated in such a procedure. The main thing is to remember about safety measures and proceed with caution. Knowing the basic elements of the device, you can calculate the cause of the breakdown yourself and eliminate it.

"A-Iceberg" - 25 years with you. 5 million repairs completed.

We will repair the microwave oven at home today. We will install original spare parts and provide a guarantee. We leave for any area of Moscow and the Moscow region.

Modern microwave ovens produced by leading world companies are durable and high quality assembly. But even such reliable units fail over time due to improper operation of the device or wear of its structural elements. If the device does not turn on, works without stopping, sparks, makes a lot of noise, does not heat food, does not respond to pressing buttons, then the best solution would be to repair microwave ovens by professionals.

Microwave oven repair at home

Service Center "A-Iceberg" offers high-quality repair of microwave ovens at home. Experienced specialists fix the most difficult breakdowns of microwave ovens of all types and brands in one visit. They have the best equipment, professional tools and high quality consumables at their disposal. Repairs are made at home in accordance with the technical requirements of the manufacturer. We use original spare parts and provide a guarantee for the entire list of work performed and replaced components.

Typical Microwave Oven Malfunctions

Malfunction
Doesn't start	Defects in the network cable, malfunction of the electronic control unit, temperature sensor or mains fuse, through which the circuits of all units of the device are supplied with voltage. Perhaps the control module does not receive a signal to close the door (the door lock microswitch fails) or there is no voltage on the windings of the transformer designed to convert 220V to 2000V for normal operation of the magnetron. The transformer itself could fail if its primary winding was broken or the thermal fuse burned out
Does not turn off automatically (works continuously)	The control unit is faulty or the relay supplying the transformer winding with supply voltage is faulty (the relay contacts may be stuck); open circuit of the power supply circuit of the starting relay or printed circuit board
Emits extraneous noises	The blower fan or the high-voltage diode is faulty, the through-feed capacitors of the magnetron filter are broken, the winding of the high-voltage transformer has shorted (if a burning smell comes from the furnace and translucent smoke is visible)
Heats food for an unusually long time	The voltage in the network is less than 200V or the emission indicator (electron emission density) of the magnetron cathode has decreased significantly. Poor emission indicates a breakdown of the magnetron - the main unit of the microwave
Does not respond to control panel buttons	Sticking of button contacts or breakage of their conductive tracks, abrasion of the membrane (if the panel is touch-sensitive), violation of insulation between the conductors of the touch "keyboard", defects in the power supply circuit of the programmer
Food remains cold (no heating function at all)	Malfunction of the magnetron, inverter (for inverter models) or the intermediate relay of the control board (the main relay did not cope with the available power); failures in the operation of microswitches that interrupt the supply of voltage to the units of the device at the moment the door is opened. A high-voltage fuse has blown for one of the following reasons: the metal of the fuse has worn out, one of the capacitors has opened, a magnetron short circuit or an interturn short circuit in the transformer windings has occurred
Sparks visible inside the chamber	Breakdown of the mica plate, provoked by the long-term operation of the magnetron in the mode of large overloads (loading dishes with metal inserts or heating small amounts of food). Probably, long-term operation of the device with a punctured plate led to burnout of the magnetron antenna cap. Other reasons: grease and liquid have accumulated on the mica, the inner lining of the loading chamber is damaged
The rotating mechanism of the cymbal does not work	Breakage of the elements of the supply circuit of the electric motor of the rotation mechanism. It is possible that grease and liquid accumulated on the engine have caused the coil winding to burn out.

What brands do we repair

We equally professionally repair microwave ovens of any type: mechanically controlled, solo ovens (monofunctional), models with heating elements or quartz grills, multifunctional (convection) and built-in devices, including ultra-modern appliances with Smart Inverter and i -Wave ". Our professionals have many years of experience in restoring the performance of microwaves of many domestic and foreign brands: Gorenje, Horizon, Supra, Midea, LG, Panasonic, Samsung, BBK, Bosch, Siemens, Hansa, Erisson, Haie>, Candy, Zelmer, Electrolux, Grunhelm, Whirlpool and etc.

Thanks to well-established cooperation with many manufacturers of equipment, we have a complete list of technical documentation for all models and brands of microwave ovens, receiving recommendations for their repair from the original source. This fact, combined with the availability of modern equipment, allows us to carry out high-precision diagnostics and technologically correct repairs in the shortest possible time. At the disposal of our engineers:

temperature-controlled soldering iron or microprocessor-controlled antistatic soldering station
digital ampere meter
microwave meter
electronic industrial thermometer
laboratory power supply (adjustable or programmable).

The cost of repairing microwave ovens at home

The key to success Service Center"A-Iceberg" is a combination of a well-developed flexible pricing policy and high level service. The masters provide a full cycle of services, including post-warranty service, prevention of malfunctions, spot and major repairs. The cost of services depends on the following factors:

the nature of the breakdown and the level of its complexity

type of microwave oven and the price of its spare parts

the need to replace components or provide additional services(cleaning the oven, restoring the inner coating of the chamber).

If you want to order an inexpensive microwave oven repair, contact our highly qualified specialists for help. They will quickly detect even hidden and prospective breakdowns of the device, eliminate malfunctions of any of its components and, if necessary, replace the failed parts with high-quality spare parts.

Original spare parts

We use only original spare parts, since the installation of universal units often leads to recurrent breakdowns. You do not have to wait long for the receipt of the necessary components, because in our warehouse there are always replaceable components for microwave ovens of all brands and models. Spare parts are purchased from the official representatives of the manufacturing plant in the territory of the Russian Federation. All parts undergo technological tests and a certification procedure, so their use is a guarantee of a significant extension of the service life of your equipment.

Warranty period up to 2 years

For a quarter of a century of successful practice, our masters have developed a unique technology for the rapid restoration of the operation of microwave ovens, which makes it possible to eliminate most typical malfunctions within 1-2 hours. We are confident in the quality of our service, therefore, we provide a guarantee for up to 2 years without fail. The equipment repaired by us rarely fails, but in the event of a repeated breakdown, you can count on free service within the above period.

Only professionals work for us

Our masters are specialists with a high level of professional training, who regularly undergo training in the official offices of leading world brands and are fluent in the skills of using diagnostic and repair equipment. They are always aware of all technological innovations and quickly implement their basic principles in the organization of their work. Within an hour, the craftsmen produce:

replacement power cord, thermal sensor, thermal fuse, high-voltage diode, antenna hood of the microwave generator, grill heating element, mica plate, sensor membrane, display, control panel buttons, microcontrollers and microswitches.

More time may be required to complete:

repair and replacement of magnetron, control module, transformer, inverter, fan, plate rotation mechanism motor

restoration of the integrity of power circuits.

The Technical Control Department is always open to constructive dialogue with clients and daily evaluates the quality of services provided by all employees of the A-Iceberg Service Center.

How to call a microwave oven repairman

A microwave oven is an oversized device, but still taking it to a workshop requires additional time and money, therefore, home repair of equipment is considered a convenient service. We work every day, so specialists go without delay to anywhere in the region according to the declared time of the visit. You can call the master by phone: 8 (495) 213-33-33 or by filling out the application form on our website. It contains the name and phone number of the client with a brief description of the nature of the problems encountered. Contacting you as soon as possible, our operator will clarify some details and announce the estimated cost of repair work. After that, the master will be ready to immediately go to the address.

Why you should trust the professionals

Self-elimination of malfunctions without special knowledge and relevant experience can provoke the simultaneous breakdown of two main elements of the microwave - the magnetron and the control unit. In this case, the price of the repair is practically comparable to the purchase of a new device. Entrust the repair of microwave ovens at home to the engineers of the A-Iceberg Service Center, and in a few hours you will be able to warm up or prepare your favorite meals using a fully functional device.

We bring to your attention another article to help the home master. Its topic will be the repair of microwave ovens Samsung, LG, Panasonic, and others. popular brands... In the introductory part, we will briefly talk about the principle of operation and design features of microwaves. After that, we will give a list of typical malfunctions, an algorithm for diagnosing a breakdown and ways to solve the problem. Next, consider a real case of microwave repair, using the example of the LG-4022G model.

Device and principle of operation

We will consider this issue superficially so as not to get away from the main topic. The information will be simplified as much as possible, since not all home craftsmen have a deep knowledge of electrical engineering. Let's start with the description and purpose of the main structural elements, they are presented below in the figure.

Rice. 1. Microwave device

Legend:

Door latches serve both for fixing the latter and for the system of blocking operation in the open position.
A rotating tray on which the dielectric cookware is placed.
Separator equipped with rollers that drives the pallet.
The drive that rotates the separator.
Backlight lamp, turns on depending on the operating mode.
Ventilation (usually forced).
Magnetron - a microwave generator, in fact, is the main structural element. You can find out how it works and how it works by reading an article on our website dedicated to this issue.
Waveguide, provides the movement of microwave waves to the microwave chamber. It is a rectangular hollow metal tube.
High voltage diode.
Capacitor.
Waveguide power supply transformer and control circuits.
Control block.

We will not give a complete schematic diagram of the device, since they can be very different in different models of microwave ovens. In our case, the supply circuit of the magnetron will suffice. As a rule, it has a typical structure.

Let's briefly describe the principle of operation of the above circuit. Power to the primary winding of the transformer (I) is supplied from external circuit control that regulates the power and duration of microwave radiation. One of the secondary windings (II) supplies voltage to the magnetron filament. Winding II is made of 2-4 turns of a thick wire, since the current in the heating circuit can reach 10.0 A at a voltage of about 3 volts.

Another secondary winding (III), which supplies a high voltage level (up to 3.0 kV), is called anode winding. As can be seen from the figure, in this circuit, a rectifier and a voltage multiplier are built on the basis of a high-voltage diode (VD1) and a capacitor (C1). In this case, VD1 is turned on so that the opening occurs with a positive half-cycle, as a result, the capacitor begins to charge. When the negative half-cycle begins, the diode VD1 closes and the voltage is supplied to the magnetron M1 together with the charge accumulated on the capacitor. This leads to a doubling of the voltage and the formation of an electric field of the required intensity in the magnetron.

Resistance R1 in this case is necessary for C1 discharge. Typically, this resistor is located in the capacitor case. As for VD2, it provides protection in the event of an increase in voltage across the capacitor C1 or the occurrence of a short circuit in the magnetron M1.

Preparatory stage

Before proceeding with the repair, it is necessary to collect as much information as possible about the failed device. Ideally, this is a model-specific service manual. In this document, the manufacturer provides all the necessary data, starting from the assembly drawing (exploded view, literally from the English explosion-diagram) and ending with the troubleshooting algorithm.

If the documentation could not be found, and this will happen in most cases, do not worry, typical microwave oven malfunctions can be determined without a schematic diagram. It is enough to know what the main elements look like and where they can be located. A photo of the microwave oven with the cover removed will help you with this.

The intuitiveness of the process in most cases allows you to remove the casing and get to the main structural elements without an assembly drawing. But in this case it is necessary to remember the sequence of actions and try not to leave “unnecessary” parts after the reassembly.

What tools are needed?

In most cases, you can do with a Phillips screwdriver and. In some cases, you may also need a soldering iron. Accordingly, spare parts will also be needed, which ones will be clear after the diagnosis.

Typical malfunctions and ways to eliminate them

Before considering in detail the elimination of the malfunctions listed below, we consider it necessary to warn that before diagnostics and repairs, it is necessary to physically disconnect the device from the power supply, that is, pull the plug from the outlet.

No response to the power button.

In this case, diagnostics and repairs should be subject to the following algorithm of actions:

We check the presence of voltage in the power supply. If it is not there, we solve the problem with the power supply, otherwise go to the next step.
We check the power supply unit of the control module. We start with the fuse. If it is burnt out, we will replace it. After that, we turn on the device and try to heat, for example, a glass of water. If everything works, the repair is complete. If the fuse blows, the problem is in the control module, it should be repaired or replaced.

In order to independently repair the control module, you must have certain skills in radio electronics; without them, it is not recommended to start self-repairing the control module.

The microwave oven does not turn off after working off the mode.

In most cases, this problem indicates a faulty door position microswitch. To eliminate the problem, we find, check and, if necessary, replace the switch.

If the microswitches are normal, then the problem may be with the relay supplying voltage to the magnetron supply circuit. We "call" the relay contacts with a multimeter, if they are "stuck", we change the electrical switch to a new one.

When no problems are found with the relay, it means that the malfunction is associated with the control unit, we change or repair it.

Weak heating.

Most often, this malfunction is associated with a voltage drop in the household power supply. If it falls below 205.0-210.0 V, a sharp decrease in the intensity of the microwave flow occurs. This problem is typical for private houses in rural areas, where voltage drops regularly and as a result.

If the multimeter shows acceptable level voltage of the household network, then you should check the power circuit of the magnetron, we will describe how to do this in the next section.

When the diagnostics of the magnetron circuit did not give results, then everything indicates a problem with the control module.

No heating.

Such a malfunction clearly indicates a malfunction in the magnetron power supply circuit. Diagnostics is performed as follows:

We check with a multimeter the presence of voltage on the primary winding of T1 (see Fig. 1). If not, the problem should be looked for in the control module.
The presence of voltage indicates that it is necessary to check the high-voltage circuit fuse, transformer T1, fuse, capacitance C1, diode VD1 and the magnetron itself. Checking the listed items is performed with the power off!
We call the fuse with a multimeter, switching it to the diode test or resistance measurement mode. If the device shows an open circuit, we replace the fuse.
We check T1, open circuit and short circuit of the primary and secondary windings.
We are testing the C1 capacity, it was described on our website.
"Calling" VD If anyone is unfamiliar with the diode testing technology, then you can familiarize yourself with it in a previously published article.
Checking the magnetron. There are certain peculiarities with testing it, so let's take a closer look at this process:

First of all, it is necessary to "ring" the filament, if the multimeter shows a resistance close to zero (see a in Fig. 6), then everything is fine with it, we continue testing. If the device shows an open circuit, check the contact of the filter coils (marked with yellow arrows in b Fig. 6). In case of problems with the contact of the mounting of the coils, the device can be restored, otherwise, everything indicates the need to replace it.
After testing the thread, we check the pass-through containers for breakdown. To do this, we transfer the multimeter to the “dialing” mode, touch the body with one probe, and touch the magnetron contacts with the second (b in Fig. 6). The normal indicator will be infinite resistance, otherwise everything indicates that the capacitance is broken, which means that it is necessary to replace the magnetron.
If the magnetron test fails, you must measure the input voltages on the device. If they are below the permissible parameters, then this may be caused by an interturn short circuit in a high-voltage transformer or a reduced power level in the household power supply.

Rice. 6. Checking the magnetron

Important! The magnetron must be changed to the same type. This is due to the fact that the parameters of the high-voltage transformer and the control circuit are calculated based on the specific model of the microwave generator.

Sparking is observed.

Such a malfunction can be caused by the following reasons:

Burnout of the mica plate, which insulates the waveguide from splashes and food pieces... The plate is located inside the chamber on the side of the magnetron. The condition is determined visually. If the problem is with the plate, it is sufficient to replace it.
During operation, the cover of the coupler burned out... This is a kind of plastic cap that rotates the pallet. In this case, only replacement will help. Naturally, it is necessary to install a coupler from the same type of model, since the design of such a cover may be different even from one manufacturer.
The "wrong" dishes are installed in the chamber... We remind you that metal appliances, as well as those on which metallized dyes are applied, cannot be used in microwave ovens.

The pallet does not rotate.

First of all, it is necessary to check that the pallet is not blocked by any foreign object, it is correctly installed or the separator. If everything is normal, then the reason lies in the drive. This may be due to the following reasons:

Jammed engine(determined tactilely) or breaking one (dialing is carried out) of the windings. In these cases, replacement of the drive is required.
Gearbox problem... In this case, it all depends on the design. In some cases, the gearbox can be repaired. But, as practice shows, it will be easier and cheaper to replace it.

No response to the control panel.

In modern electronic models, such a malfunction indicates a problem with the control module. In products with an electromechanical control system, it makes sense to check the mechanical relays and / or switches, if necessary, replace defective parts.

When turned on, the scoreboard does not work.

If, when turned on, the power indicator lights up, but the digital display does not work, then everything indicates problems with the control module. It needs to be repaired or replaced.

The fuse blows when the door is closed.

A characteristic indicator of faulty microswitches for door position. One of them is "stuck" and does not switch; as a result, a short circuit occurs in the control circuit. The repair consists in replacing or cleaning the microswitches.

An example of a step-by-step repair of a microwave LG MB-4022G

There can be a lot of reasons for breakdowns and malfunctions of a microwave oven, as you have already seen above. Most often, this is a failure of the magnetron itself, due to improper operation of the device, namely, the use of dishes that are not intended for cooking in a microwave oven. Also, various metal parts that may accidentally be inside during operation.

But sometimes there are minor breakdowns that can be easily eliminated without special tools and without spending a lot of money.

Below, in the article, one of such breakdowns will be described, and a way to eliminate this malfunction. The photo shows a stove that has stopped turning on and does not react in any way to manipulation of the control knobs.

Rice. 7. LG MB-4022G

Before removing the protective cover from the oven, carefully inspect the power cord and the plug itself for damage, breaks and cuts. If there are any, then the oven should be disassembled.

This requires a Phillips screwdriver.

We turn the stove with the back side towards us, and by unscrewing the two fastening screws, remove the ventilation cover. Next, remove the protective cover.

Rice. 8. Remove the protective cover

Rice. 9. Unscrew the screws

It is attached at the back with several screws. We unscrew them all.

When all the rear screws are unscrewed, go to the side, left side.

Rice. 10. Unscrew the side left side

There are three mounting screws, two on the bottom and one in the middle. They should also be unscrewed. As you loosen the screws, you can see the metal edges of the cover pull away from the chassis.

Rice. 11. We continue to unscrew the screws and remove the covers

Rice. 12. Lid from the inside

You can notice traces of carbon deposits that have formed due to the action of high temperatures.

The removed lid gives access to the main elements of the microwave oven (fig. 13). Above, you can see the elements for the grill - heating element located in a special case.

Rice. 13. The inside of the microwave

On the left is the magnetron itself (Fig. 14), namely its upper part.

Rice. 14. Microwave oven magnetron

At the bottom left is the power filter, from which the wires are pressed and network cable... Also on the top of the chamber, you can see two temperature sensors. They are attached to the body and react to changes in temperature. Two wires are connected to them.

Rice. 15. Power filter and 2 temperature sensors

When viewed from the side, other elements are revealed here. For example, a power transformer with a step-up winding.

Rice. 16. Power transformer

We also see the magnetron heatsink.

Rice. 17. Magnetron radiator

And we examine the power switch.

Rice. 18. Power switch

Time relay with sound signal, the role of which is played by a mechanical bell (Fig. 19).

Rice. 19. Time relay

Fan for blowing the magnetron radiator (Fig. 20). It prevents this important expensive part from overheating.

Rice. 20. Fan blowing magnetron

There is almost nothing on the right side (Fig. 21).

Rice. 21. Right side

Let's start with inspecting the power filter, because it is on it that the power cable comes, and then the voltage from the board goes to other elements of the furnace. Therefore, the place where the voltage "disappears" must be sought from the side of its supply, that is, the network cable.

So, on the power filter board, we find the terminals where the supply wires come, namely blue and brown (Fig. 22).

Rice. 22. Power wires

We plug the power cord into the network and measure the voltage on this section of the circuit. The device shows that the mains voltage - 220 volts comes to the board. This means that the power cord is one hundred percent intact, and this indicates that the problem is further down the circuit.

Rice. 23. We measure the voltage on the section of the circuit

A fuse is installed on the power filter board, which may be the reason that the voltage does not pass further.

Rice. 24. Checking the fuse

With a circuit tester, we measure the integrity of the fuse. This can be done without removing the fuse from the installation clamps, only before that it is necessary to de-energize the device by removing the power plug from the socket.

The device shows the circuit, which means that the fuse is intact and the problem is not in it.

Rice. 25. Brown wire

Here, this device is responsible for disconnecting the microwave oven from the network, if the temperature of the case is critical, that is, it is more than 150 degrees. At this temperature, the bimetallic contacts in the device case open and break the circuit. After the case has cooled down, they return to their original position.

You can check its integrity with the same device that measures the continuity of the circuit (Fig. 26).

Rice. 26. Checking the temperature sensor

To do this, remove one end of the wire from the terminal so that the circuit does not introduce false readings. We connect the probes of the device with the sensor leads and look at the result. As you can see, the device shows an open circuit, which means that the sensor is inoperative.

To restore the operation of the sensor, sometimes it helps to sharply shake or hit it with some object, for example, pliers or the tip of a screwdriver. But even if the device recovers, there is a risk that in the event of a critical overheating, it will not work, and the consequences can be dire.

Therefore, in order not to risk it, it is better to replace the device with a new one, especially since its cost is about two dollars. You can easily find it in one of the online stores. Rice. 28. Temperature sensor: rear view

This thermostat is bimetallic KSD 201.

The marking indicates that it turns off at temperatures above 145 degrees and recovers when the temperature drops below 60 degrees.

It is not difficult to remove the sensor (fig. 29), it is enough to pry out one of the fastening lamellas with a screwdriver, and it can be easily removed. Before removing it, you need to disconnect the wires. If you mix up the wires when installing a new sensor, this will not affect its operation in any way.

Rice. 29. Remove the sensor

After purchasing this device, we install it in its original place, and connect the wire from the filter board to it. We do not connect the second wire yet. The sensor head should fit snugly against the camera body. We connect the device to the terminals of the temperature sensor and check its integrity.

Now the device shows the circuit (Fig. 30), which means that it is intact. Next, we connect the second wire and check the quality of the connection by twitching it.

Rice. 30. We check the integrity of the new sensor

Now we turn on the power plug to the network and check with the voltage indicator whether the voltage is coming to the sensor. To do this, we connect one probe of the device to the blue wire on the power filter board, and the second to the sensor - the near end - to which the brown wire comes.

Rice. 31. Check if the voltage comes to the sensor

If the result is positive, and in the photo (Fig. 31) this is exactly the case, then we measure the voltage at the sensor output (Fig. 32). The device shows that it is also present, as in the first case.

Rice. 32. We measure the voltage at the output of the multicooker temperature sensor

Although it is undesirable to do this without putting on a protective casing, we apply voltage to the oven, and after setting the minimum temperature, we turn on the device.

The oven has started up and is running (fig. 33).

Rice. 33. Checking the performance of the microwave oven

We quickly turn off the device and put on a protective metal casing.

The housing cover must be installed in the reverse order, that is, by inserting its front part into the grooves and fixing the rear part to the screws.

The microwave has become an indispensable assistant in the kitchen and offices. It saves time when heating ready-made meals and defrosting semi-finished products. We are so accustomed to the existence of a microwave oven that we instantly panic if any difficulties arise in its operation. Let's try to figure out what malfunctions can occur in a working microwave, and what ways to fix this problem exist.

Before trying to find a breakdown on your own, you should study the device of the device and understand how it works. A microwave oven consists of: a chamber, a door with a seal, a magnetron responsible for generating energy, an energy converter - a transformer, a diode, a capacitor, a fan. The auxiliary elements of the microwave are grill and pan lamps, fan and pan motors.

Microwaved food is heated by exposure to electromagnetic radiation high power.

Magnetron - a diode that generates electromagnetic waves when the flow of electrons interacts with magnetic field... A rod cathode with a channel filament is located in the center of the copper anode in the form of a cylinder, and it is this cathode that releases electrons. The standard power supplied by the magnetron is 800 Watt.

Due to the fact that the magnetron generates a lot of heat during operation, its case must be placed in a plate radiator, constantly blown by the air coming from the fan. Also, for reasons of protection, the magnetron is equipped with a special thermal fuse to prevent overheating.

Another important component of any microwave oven is fan... The fan creates a blowing of the magnetron, the grill, the chamber itself, from which, thanks to the action of this device, air and water vapor come out. With the help of air ducts located inside the oven, air is circulated, received by the fan from the outside.

Any oven has shielded chamber protected by a metal casing that prevents the penetration of radiation to the outside. The metal mesh on the glass of the microwave oven door is also not accidental - it does not transmit 2450 Hz rays. The door itself must adhere very clearly to the body, it is important to exclude any even the smallest distortion. In a naturally formed gap that retains its geometric shape, a so-called standing wave of electromagnetic pulses is formed, it takes on a value equal to 0, exactly here, and this prevents radiation from penetrating beyond its limits.

The control unit is designed to maintain the set power and turn off the device after the set time. These are the two main parameters of the functionality. In modern models, however, the functionality of the unit has significantly expanded, and now microwave ovens may have a built-in clock, a power indicator, standard cooking or defrosting programs, an end-of-work signal and some other functions.

Causes

So, the main malfunctions of the microwave are considered to be:

lack of mains voltage or its failure;
the oven door switch is out of order;
the mains, high-voltage or transformer fuse has burned out;
the doubler is faulty;
lack of interaction between the transformer and the control panel - no voltage is applied;
malfunction of the magnetron.

Troubleshooting methods

Consider ways to solve the most common breakdowns of a microwave oven.

The device does not turn on

The microwave fuses can be changed independently, it is advisable to coordinate the elimination of other malfunctions with specialists.

Periodic on / off stove

Most likely, the matter is in the fan - either the relay is broken, or the ventilation holes are inaccessible. The fan needs to be changed.

Termination of lighting

The microwave backlight, located inside, turns on when you open the door of the device and during the operation itself. The standard reason this doesn't happen is because replacement light bulbs... Less often, the reason lies in backlight malfunctions. It is quite possible to replace the light bulb inside the microwave on your own, in other cases it is better to contact a specialist.

Sparks and burning smell

The point is the mica plate, burnt out from dirt or improper use. The plate is punctured due to strong fat deposits, as well as when the oven chamber is washed abundantly with water. Using utensils with a metallic "shiny" coating will also almost certainly disable the microwave. If you continue to use the oven at the wrong time, you can "wait" for more serious breakdowns, which will be difficult and costly to eliminate. More detailed information is provided in the article).

Enamel defects

They can appear both in the chamber itself and on the microwave door. Associated with either a factory defect or careless use of the device. Without eliminating such defects, you cannot continue to use the oven.

There is no warm-up

Maybe it's a fuse that burned out as a result of a short circuit or a transformer, or a capacitor breakdown (all the reasons are in the article). The magnetron has its own definite useful life, due to the gradually decreasing possibility of the cathode to be emitted, this term also reduces the unstable voltage. All manipulations with the magnetron are recommended to be carried out in a specialized service center.

Display does not work

The designations on the microwave display are "torn". This usually means that the processor is damaged. Possibly, there is contamination of the loop contacts, or the loop itself has moved away. If the board is damaged, similar symptoms are also possible. It is recommended to contact the service.

The pallet spins jerkily or does not spin at all

During normal operation, the pan in the microwave chamber should rotate very smoothly, if this does not happen, then the grooves are dirty. It is quite possible to cope with this breakdown on your own by cleaning them, and at the same time the video itself. If we ignore this problem, then over time, the motor coil will fail, because, with the difficult rotation of the shaft, the load on the coil increases significantly.

Microwave buttons do not work

Excessive noise, hum during operation

Due to ventilation problems resulting in overheating. It happens that the fan fasteners move away from the attachment point or dirt gets under the wheels that drive the pallet, as a result, they create noise. If neither one nor the other is relevant, then the matter is in the magnetron - its repair is required.

The device does not turn off

It is necessary to replace the supply relay, which is probably out of order. However, do not forget that in most models there is a function for removing excess moisture with a fan, which starts from time to time. In practice, this means that the microwave continues to operate in ventilation mode, there is no heating, and then it turns off on its own. This is not a malfunction, but a common technical need.

Thus, the list of possible malfunctions that can befall your microwave oven is quite extensive. Some breakdowns can be dealt with without much effort, and the failure of individual elements, the repair or replacement of which is associated with both risk and a certain complexity, requires the attention of professionals. A microwave oven can serve you for many years if you use it properly, observe and pay attention to the slightest malfunction in the system.