Fix the high voltage fuse for the microwave. Ways to repair a microwave oven with your own hands. Microwave oven does not turn off after operating mode

There are more and more appliances in our homes, which makes life more comfortable. But any technology breaks down someday. In order not to wait for a technician, you can try to fix the breakdown yourself. In this article we will talk about microwave ovens and how to troubleshoot them. Repairing a microwave oven yourself mainly comes down to identifying the damaged unit and replacing it with a working one. Occasionally it is necessary to replace parts.

Repairing a microwave oven yourself will be easier if you have at least a little idea of ​​its structure and the functions of its elements. Knowing the operating algorithm and which part is responsible for what, it is easier to determine the causes of failure.

Microwave or microwave oven, microwave oven - it's all about one device

Magnetron power supply

First, let's look at the microwave operating algorithm. The main working element is a magnetron. It is he who produces the waves through which food is heated. But high voltage must be supplied to it, so power (220 V) is first supplied to a high-voltage transformer, the output of which already leaves 2000 W. After the transformer there is a diode and a capacitor, which double the voltage. About 4 kW is already supplied to the magnetron. This is where the generation of microwaves begins. To prevent the magnetron from burning out during power problems, a fuse is installed in the power circuit. If it burns out, the stove does not start working.

The waves emitted by the magnetron enter the working chamber, where, reflected from the walls, they are concentrated in the area where the dishes with food are installed. Since the magnetron gets very hot during operation, a fan blows over it. Warm air also enters the chamber, which speeds up heating.

To avoid overheating of the magnetron, which in this case may fail, there is a thermal fuse in its power supply circuit. If the operating mode is abnormal (the fan does not work or cannot cope with cooling), this fuse blows. Then a situation arises when the microwave works but does not heat. In this case, the plate spins, the light comes on, but the food does not heat up.

Door lock

The waves emitted by the magnetron can “heat up” everything that gets in their way. Therefore, the microwave oven should not be operated with the door open. All waves must remain inside the chamber. Therefore, locking buttons are installed in the transformer power circuit. They only close when the door is closed, the door latches close the contacts, and power is supplied to the transformer.

Sometimes the microwave does not turn on precisely because the door lock does not work. This could be a foreign object that has gotten into the door latch holes, burnt or loose contacts. In this case, repairing a microwave oven yourself consists of replacing the contact group. You can handle this on your own.

Movable table

To ensure that food is heated evenly in the microwave, a movable glass table is installed in it. At the bottom of the chamber there is a guide roller on which a glass tabletop-plate is installed. On the bottom of the tabletop there are certain shaped protrusions that cling to the protrusions of the guide roller. Since the tabletop plate is large, so that it does not warp, a plastic ring with small wheels is installed under it. It makes the table easier to move.

The microwave does not heat. One of the reasons is that the table does not spin

The roller is driven by a motor, which receives power when the door is closed. Sometimes the microwave works, but heats food unevenly because the table has stopped rotating. This can be seen through the closed door. The reason is failure of the motor, breakage of the ring with rollers. In this case, repairing a microwave oven yourself means replacing the motor or guide ring.

Rear view with cover removed

Knowing how a microwave works is not enough to repair it yourself. You also need to have an idea of ​​what the parts look like and where they are located. To begin repairing a microwave oven yourself, you will have to remove the casing. All elements are under it.

There are many models of microwave ovens, but the layout is usually the same. The magnetron and its power circuit are located on the right side (when viewed from behind). There is also a fan here. On the left there is a control unit, there are also locks and door locking devices. That's all, actually.

Do-it-yourself microwave oven repair

Now that you have an idea of ​​the structure of the microwave and the algorithm of its operation, you can begin troubleshooting. When working, you must follow several rules:

The rules are simple, but you must follow them. Otherwise, either the equipment will deteriorate or your health will be seriously harmed.

And one more piece of advice. During the disassembly process, take photographs of the area BEFORE starting work. Then it will be easier to restore.

Doesn't turn on at all

It is very unpleasant if the microwave does not turn on. But usually this problem is easily resolved. There are not many complex breakdowns. So, here's what could be causing it:

Fuse blown

The fuse is a glass tube with metal caps. A spring-loaded wire is stretched between the caps, which is soldered to the cap at one end. If there are problems with power supply, the wiring heats up and the solder softens. If the power does not return to normal for too long, the wiring is soldered off.

The fuse is a fragile thing that can be easily damaged and is hidden in a plastic case. It can have a different shape and appearance, but inside there is a glass tube with a wire inside.

The problem is usually visible visually - the wire is dangling. But there are times when the contact is broken, but this is not visible visually. Therefore, it is better to take a multimeter and ring the fuse or check for a break by measuring the resistance.

If the microwave does not turn on precisely because of a blown fuse, it needs to be replaced or restored to functionality. Replacement is simple - it is removed from its place, then a similar one is inserted. Another thing is that the same one can still be found. And it should be the same denomination (exactly) and size. Therefore, you will need to take the burned-out one with you to the store. It’s better to buy several pieces at once. Since fuses usually blow when there is some reason. And until you identify it and eliminate it, they can burn frequently.

The fuse can also be restored. To do this, carefully remove the metal cap from the side where the wire was unsoldered. Using tweezers and a soldering iron, solder it into place and install the cap back. Repairing a microwave like this yourself is possible if you know how to use a soldering iron. If not, it's easier to buy a fuse.

The light is on, the table rotates, but the food does not heat up

What should you do if the microwave is working, the lamp is on, the table is moving, but the food is not heating up? The reason may be in the magnetron power circuit, or perhaps the emitter itself has failed. But the same picture will occur if the mica plate that covers the magnetron output is damaged, or if the enamel in the chamber is chipped. If metal is exposed, it can cause the microwave oven to malfunction. Therefore, we inspect the camera, paint over all the chips with white enamel, and remove the stains. If all this does not help, and there is damage on the plate, then we begin the repair from there.

Problems with mica plate

The mica plate is gray-brown in color and looks very similar to metal. It covers the magnetron output and is located in the chamber on the right. We take a flashlight and carefully examine it. It should not be damaged or heavily soiled.

If there is no damage, clean it thoroughly using dishwashing detergents (non-abrasive). After drying, you can try turning on the microwave again.

If there is damage, unscrew it. It is secured with screws or plastic clips. If the hole is through, it is advisable to replace the plate. If there are only traces of soot and the damage is not so serious, remove the plate and remove carbon deposits, soot, and greasy stains. If possible, we restore it to its original condition. We put it in place and try to start it.

If there is a hole in the mica plate and there is nowhere to get a new piece, you can turn it over for emergency repairs. We turn it upside down so that the hole is in a different place. Repairing a microwave like this yourself is only a temporary measure. But for some time the performance is restored.

Magnetron problems

If everything is fine with the mica plate and the chamber, but the microwave still does not work, most likely the problem is in the magnetron. But first of all, you need to check the power circuit. It consists of a high-voltage transformer, a capacitor, a high-voltage diode and a safety diode.

First of all, we check the protective diode. He is the one who “takes off” first. It is located in a plastic case near the magnetron. If there are traces of soot, it means it has burned out. It must be replaced with exactly the same one.

The next step is to check the continuity of the transformer windings. First, turn off the power, discharge the capacitor, and remove the terminals of the primary winding from the contact plates. Now you can measure the resistance of the transformer windings. The values ​​should be like this:

• primary winding - 1.5 Ohm;
• secondary - 110-120 Ohms;
• secondary filament winding - 0.1 Ohm or less.

If there are deviations, we change the transformer. We select exactly the same parameters.

If everything is fine with the transformer, put it in place and connect the terminals. Next we check the network filter. To do this, remove the terminals with which the magnetron is connected to the transformer. We measure the resistance between the removed terminals and the housing one by one. If the resistance of at least one of them is less than 50 Ohms, then the capacitors on the surge protector are broken. In this case, you can repair the microwave oven yourself by completely replacing the entire board assembly or replacing broken capacitors. Once again, please note that the denominations must be the same.

If the microwave still does not turn on, check the magnetron itself. It needs to be removed from its place and inspected. If the antenna cap is burnt out, it needs to be replaced. But the cost of a magnetron is comparable to the cost of a new microwave oven. So, if the equipment is old, it is easier to buy a new one.

Checking the door lock

If after all the manipulations the microwave still does not work, you need to check the door locks. First, let's check how tightly it fits. Take a sheet of paper and press it between the body and the door so that its edge sticks out. Using this edge we try to pull out a sheet of paper with the door closed. With normally functioning blockers, this is impossible or very difficult.

If the sheet is pulled out, adjust the door pressure. There are adjusting screws in the hinge area. By twisting them, we achieve tight and uniform pressure.

Next, you need to check the electrical part of the operation of the blockers. When viewed from behind, they are on the left. We take a multimeter and check their resistance in the open and closed states. If at least one of them is faulty, it is better to replace them all. They have almost the same degree of wear. If you replace only the one that has failed, the other one will fail after a short period of time. You will have to disassemble the microwave again and go through everything step by step.

The microwave is sparking. What are the reasons and what to do

If sparks often jump in the microwave oven chamber during operation, the mica screen is most likely damaged. During operation, grease and food particles fall on it, which gradually become charred. Sparks appear between these coals and the wall of the microwave due to the potential difference. They are akin to an arc discharge during welding. They occur under certain conditions and can cause significant harm. Therefore, it is advisable to solve the problem immediately.

The first method is to remove the mica screen and clean it thoroughly, removing all traces of soot and soot. The second option is to replace it with a new one. You can buy a suitable piece of mica at a service center. This is pressed mica. A piece of the desired size and shape is cut out of it, a hole is made in it using a screwdriver, and the edges are sanded with fine-grain sandpaper.

But if you are going to change it, it is better to make it out of special plastic. Such screens are also available in service centers, and they last longer because they do not absorb grease and are easy to clean.

Such deposits lead to the appearance of sparks during operation. Do-it-yourself microwave repair - remove carbon deposits, paint over metal

There are microwaves that already have a plastic screen. The paint in them burns where the waves emerge. This carbon deposit also causes sparking. The plastic screen is fixed on two clamps; removing it is simple - pry it off with a screwdriver and squeeze it out. To repair the microwave with your own hands in this case, use fine-grain sandpaper to clean off the deposits. It comes off along with the paint. We clean it well so that no traces remain. Paint over the resulting stain with white paint (enamel). You can use nail polish.

Do-it-yourself microwave repair: replacing the magnetron cap

Sometimes the furnace sparks due to burnout of the magnetron cap. In this case, remove the magnetron from its place and inspect the cap. If there is damage, do-it-yourself microwave repair consists of replacing this cap.

Carefully remove it and inspect the antenna. If the metal is intact, the device may be working. Then we find a cap of a suitable size and install it in place. It’s not easy to find a cap on sale - it costs a penny, no one messes with something like that. But you can make it from an old-style capacitor. It is important to find the appropriate diameter. Then a piece of the required length is cut, a hole is drilled in the center, and the edges and the entire surface are treated with sandpaper with very fine grain. It is then polished to a mirror finish. The efficiency of the microwave depends on how well the cap reflects the waves.

Causes of breakdowns

In most cases, the cause of microwave oven breakdowns is non-compliance with operating instructions. The first rule to remember is that no metal objects should get into the camera. Even a metallic rim on a plate - painted with paint that contains metal - can cause violent sparking in the microwave. The spark often “pierces” the magnetron, which then fails. In addition, it is when the microwave sparks that the protective plate is damaged and the elements of the power circuit may fail.

The second common reason is the use of cookware that is not intended for microwave ovens. If you heat food in a regular closed container, it may burst. In this case, the contents scatter in all directions, clog the waveguide, and the microwave does not work again. Turning it on in this state will again lead to burnout of the magnetron.

The last unacceptable mode is no load. If you turn on a microwave with an empty chamber, it is almost guaranteed to fail. And in this case the magnetron will also burn out.

There are not many technical reasons for the breakdown of microwave ovens. Firstly, these are changes in nutrition. This problem can be eliminated by installing a voltage stabilizer. Secondly, this is the physical wear of parts. This is true for equipment that has been in operation for more than 7 years. Thirdly, the use of low-quality parts. This is the problem with cheap technology. And fourthly, a manufacturing defect. And again, brands that have been on the market for many years have better quality control than brands that are unknown to anyone. The good news is that manufacturing defects usually work out during the warranty period.

We are 100% sure: it is enough to understand what is inside in order to repair the microwave. Let's start with the simplest model, inside of 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 when discussing a topic on the Internet, they either speak useless nonsense, or speak in too highly specialized language, difficult to understand.

The device of a simple microwave oven

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

1. 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, which at times appears to be bare. The metal is coated with transparent lacquer insulation. The coil is located under the secondary windings.
2. There are two secondary windings. One is literally several turns of copper wire wound carelessly next to the primary: cathode heating. Provides 6.3V AC voltage to help electrons escape the surface. Above, in good, high-quality insulation, the high-voltage winding is located. Gives 2 kV going to the output, powering the magnetron.
3. 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 half-wave charges the capacitance. At the next half-cycle, the electrode will already be under double the voltage: that taken from the transformer and the discharge of the capacitor. The result is about 4 kV. Enough to start generation.

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

This results in an electrical layout:

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

The heating coil and cathode are electrically connected. The power of the magnetron is controlled by a timer, and to prevent sparks from occurring, a starting relay is added to the circuit. 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 lies a shaft equipped (in our case) with two cam disks. The first is responsible for powering the transformer that forms the power supply for the magnetron, the second is responsible for the quartz grill lamps. The buttons of two relays are controlled by cam mechanisms:

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

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

When the front forms a spark, the capacitance presents zero resistance to the differential, the inductance of the transformer is separated by open contacts. Large current does not flow! The capacitance begins to charge to a voltage limited by the zener diode. A diode turned in the right direction prevents the discharge. When the threshold value is exceeded, the relay is activated and a large current flows to the transformer and power supply to the magnetron. Due to a well-thought-out design, microwave oven timers with a protective relay almost never burn out. Now the programmer!

Equipped with a gear, toothed transmission that regulates the clock. Depending on this, the periods of operation and downtime of the magnetron change. The longer the rest, the less power is released. About the magnetron, let us add: the introduction of inverter control shifts the control of cycles from the timer to the sensor circuit for measuring temperature. The sensor evaluates the emission spectrum of the food and decides how to operate the microwave oven. It is not the downtime (operation) of the cycle that changes, but the duty cycle of the pulses. More frequent packets, more power. As a result, it becomes possible to flexibly adapt to the current situation.

Safety relays

Before talking about the grill, the magnetron cooling fan, the work compartment light bulb and the table motor, I would like to mention the protective relays. Contactors ensure 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:

1. The door is open, the relay buttons are released, the contacts that were initially normally closed are connected.
2. In this case, the power supply circuit must be broken twice.
3. But in the second relay the ground is shorted to phase.
4. The first relay worked - nothing bad happens, the circuit is already broken.
5. The first relay is stuck and the fuse will blow because the ground is shorted to phase.

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

Not a power fuse placed in the housing and hanging under the magnetron, but located on the electronic board. Consider the curious features of protective relays. One (third) supplies a phase to the starting relay. Without this, supplying voltage to the magnetron is in principle impossible. The power fuse estimates the energy consumption of the magnetron. If an emergency situation occurs, the protective element burns out, protecting the generator from damage. The described thing will happen if you turn on an empty microwave oven, or put a fork, spoon, or metal object inside. The only bordering golden ring of the plate can provoke an emergency situation.

Service Mechanisms

Typically, a swarm of units is connected in series in a microwave oven. Now we are discussing secondary mechanisms: fan motors, table motors, quartz grill lamps, backlight bulb. This is done to reduce the number of wires. Design changes simplify microwave repair to the maximum. Result: burnout of one element blocks the operation of the furnace. The magnetron threshes, as does the start relay. The noted effect is a characteristic sign of the cause hidden in the auxiliary mechanism. An equivalent result if the third relay breaks, 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 stated above), microwave oscillations will not be generated.

The above diagram is typical for microwave ovens; we believe there are other designs. Just take note of the designers' imaginations. The elements inside the microwave oven are powered by 220 volts. There are no other special sources inside. Models stuffed with electronics stand out sharply. An inverter requires a number of voltages to operate.

I would like to note that in microwave ovens with hybrid modes, you can test almost 100% of the component parts of the product separately. Study the design of the programmer. It is convenient to shine the light on the grill while the magnetron is turned off. Beginners are perplexed: how to regulate the power of the grill. We believe that the share of this component of the microwave oven is made up of energy not consumed by the magnetron. The microwave operates longer, leaving less time for other components of the electrical circuit.

Now let’s say a few words regarding the occurrence of a fire inside a microwave oven: thunder and lightning strike. 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 contributes to the breakdown of the insulation, resulting in a discharge inside. Be foolish enough to put a plug in the compartment - lightning will easily pierce the enamel coating. A black spot will remain; in the worst case, the wall will burn through.

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

Please note that microwave radiation is harmful to health. Therefore, repairing microwave ovens on a regular basis cannot be called the best job.

Typical breakdowns

In microwave ovens, the weak point is the inability of the owners to properly operate the product. Buyers are sure: plates with a gold rim cannot be placed inside, the dishes will break (the metal rim will peel off), not the microwave. Conventional thinking is wrong. If you place a steel spoon inside, there is a high probability of an electric arc; if the stream of ionized air does not burn 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 housing at the mica gasket. The magnetron, through a pin, supplies energy to the waveguide, which is sensitive to the presence of contaminants inside. Grease stains burn, spark, and interfere with the normal operation of the device. Therefore, the output of the waveguide is covered with mica cloth. The soft, flexible material, which is relatively inexpensive, is sold in large pieces; use scissors to form a piece into a suitable shape. The operating principle is based on the ability of mica to pass the 2.45 GHz frequency of microwave oven heating. Otherwise, the fabric will get very hot and burn out after a short period of use. Mica prevents the conductive walls from getting wet - this is important if soup is heated inside: flying splashes cause irreparable damage to the cleanliness of the compartment. It has long been noticed: water absorbs radiation at 2.45 GHz, which promises trouble. If liquid gets inside the waveguide, an emergency situation will immediately arise: evaporation of molecules, changing the dielectric properties of the air medium, instantaneous breakdown, burnout of the high-voltage fuse, in the worst case, the magnetron and other electronic components.

Why does the protective mica gasket become unusable? The housewife prepares food, often including fat, oil, and other substances among the ingredients in the recipe. The substances do not boil, they shoot out dirty drops. The fat gets onto the mica tissue and a conductivity bridge is formed. Separately, the natural mineral is a dielectric; it reliably isolates the waveguide from the housing; a single drop of oil that soaks the gasket can blow up this wall. An arc is instantly formed:

• between the walls of the waveguide and the mica fabric;
• between the mica fabric and the body.

Thunder and lightning are the first sign of impending microwave failure.

Proper grounding

If the device is not grounded, the situation is extremely dangerous. Enough to grab the kitchen faucet with your right hand (expose your palm to the stream of water), or accidentally touch the microwave oven with your left hand and you will die. It is appropriate to recall: devices connected near water sources operate in tandem with a differential circuit breaker. Grounding must be done correctly. Often it is not enough to neutralize the corresponding terminal. We look at two pitfalls:

1. Grounding resistance is negligible. Units, fractions of an ohm. 10 is already considered an unacceptable value. Therefore, the circuit often uses not wires, but tires (strips) of steel or other metal (alloy) of large cross-section. It is clear that such conditions cannot be provided for a home network.
2. The differential circuit breaker works by detecting the leakage current. The output and input quantities are measured and 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 burned by overload, and the magnetron in addition.

Differential protective devices often have fuse slots, but should not be confused with safety functions. The black humor of TV repairmen says:

• The fuse burns out last, when everything that could break has already broken.

This means that the differential protection device cannot save human lives. The microwave oven must be properly grounded. The devices belong to electrical safety class I. The terminal is on the plug. Install Euro sockets that are connected correctly. And this is primarily grounding; why has already been explained. Let us add that a regular outlet or fuses may not protect you from an accident. In the case of a microwave oven, the chance of a favorable outcome of the accident is high.

High voltage fuse

Regarding what has been said, many have a question mark in their heads the size of a mountain, what is a high-voltage fuse. Let's explain! The microwave oven device includes two fuses (minimum):

1. An ordinary small transparent (glass), white (porcelain) cylinder on an electronic board. Ensures the safety of hinged, integrated elements. The fuse is low voltage and belongs to the power supply circuit of the electronic board. It will burn out if the capacitor breaks, shorting the resistor located on the printed circuit board.
2. The magnetron has its own power generation circuit, formed by a step-up transformer, diode, and capacitor. The source applies a potential of several kilovolts to the cathode. Items are easy to find. The capacitor looks monstrous: a hundred gram steel can, to which a diode is attached at the end, the second leg is soldered (screwed) to the body. Nearby you will notice a ceramic or other dielectric chest (often brown). Inside the Egyptian sarcophagus there is a high-voltage fuse. Protects the magnetron against overheating. If the cathode current becomes too high (the mica gasket breaks through, or someone puts a spoon into the working compartment), the high-voltage fuse will burn out first. By the way, microwave oven repair technicians rarely complain about the power element. Therefore, it performs its duties properly (or, conversely, causes the magnetron to fail).

You cannot remove the high-voltage fuse from the electrical circuit and 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 and someone will be electrocuted.

Magnetron voltage generation circuit

Of course, you’ve heard about inverter microwave ovens. Firstly, the design is not very different from standard microwaves, and secondly, not everyone likes the flexible heating control mode; it is imperfect. The designers provide the ability to disable the option, and the cooks use it. To understand how a scientific-sounding inverter microwave oven works, consider the magnetron voltage generation circuit:

• The microwave oven starts with a power transformer. The input winding is below the secondary, assembled with copper wire with varnished transparent insulation (heat transfer to the outside by infrared radiation) for better cooling. Above there are a couple of sloppy turns that form the 6.3 volt voltage of the cathode filament. Finally, the step-up winding is located on top, from where a potential of 2 kV (amplitude) is supplied to the rectifier.

• The anode of the magnetron is placed on the neutral wire (not the housing). The cathode is additionally heated to make it easier for electrons to leave the emitter surface. 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 part of the electrical circuit.
• A mains voltage of 230 V is supplied to the primary winding of the transformer. In the case of inverter control, the duty cycle of the pulse sequence is modulated. As a result, the result is determined by the effective value. The farther apart the pulses are, the lower the level, and the less power the magnetron gives to the food.

Please note: the magnetron has two terminals and three wires. The single one powers the filament, while the double one supplies energy to the cathode and closes the 6.3 V circuit. The anode is connected separately, at the back of the ingenious design. To supply voltage to the transformer, the electronic circuit contains a relay. The measure protects the programmer (timer-controlled contacts) from sparking. A zener diode and a capacitor are connected in parallel to the relay, taking the shock of the front of the connected voltage. The armature is then released and 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 rod shaft contains a ring of different heights. By rotating the knob, we select a combination of states of the relay group. Depending on this, the microwave oven switches to the desired mode. It is clear that there is nothing to break here (and if it breaks, it is difficult to restore). We will check each relay if necessary; such steps are not required more often. The grill contact has failed and the lamps will go out. Let's say the same about the magnetron circuit.

The timer is more complicated. The shaft is lined with gears, each making (opening) a contact. In a microwave oven without inverter control, the timer sets the frequency of turning on (off) the magnetron. The relay mentioned above blocks the sparking of the timer contacts. With inverter control, there is an infrared radiation sensor in the compartment; according to the sensor readings, the duty cycle of the pulses (frequency) is controlled.

What can break. Imitating a clock mechanism, there is a spring inside the timer. If you notice a breakdown, you should replace the steel with a new one. The mechanism is durable, contacts rarely break. We described the main types of faults, of course, you need to start with the cord. A trivial breakdown, to blame in 20% of cases. Now readers understand a fair amount 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 literary sources it is written: the measurement method is in NVN 100 GOST 19308 - 80; Provides a graphic and useful information to guide the assessment process. The beginning of the paragraph is taken from a book on repairing microwave ovens, published in 2003. 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 he is invited to dance further. The book is a little outdated. The text cites increasingly less used microwave oven designs: radiation enters the working chamber from above. In an outlandish modern design move, it was supposed to create a uniform field throughout the volume. Today the waves enter from the right, repairs are carried out differently.

Hundreds of pages are already covered with breakdowns of capacitors, burnout of diodes and fuses. It seems that school-age children know what breaks. It is proposed to discuss an obscure aspect - microwave field, power, distribution of the tension vector, features and danger. When carrying out repairs, we often forget that the device is designed to help the family, and not destroy humanity. A Whirlpool could easily destroy the gene pool if proper safety precautions are not taken.

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 reproductive function. Cell phones and other gadgets operate on a wavelength of 1-2 GHz (approximately).

Microwave field distribution inside a microwave oven

In expensive microwave ovens, the tray is motionless; the design of the chamber creates conditions for a constant and uniform field pattern. Readers already have a question mark in their head the size of a house! If the light bulb is on, it’s dark behind the closet, but it’s light under the chandelier. It is not difficult to understand the sequence of light and shadow. Ilyich's light bulb does not emit a fixed frequency - a band! As a result, the interference pattern escapes the eye. Coherent waves can add and subtract better. Same frequency. Let physicists avoid criticizing the review for being too loose in its interpretation of the concept of coherence, an overlooked aspect of the phase of electromagnetic oscillation.

The wave enters the working compartment and 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 exactly the opposite (light, shadow).

In the first case we see double the power, in the second – zero! If the human eye noticed a frequency of 2.45 GHz, the working chamber of a microwave oven would appear to the individual as dotted with spots, stripes of light and shadow. It is important to prevent food from being found in the zero field.

After repair, if work was carried out on the magnetron and waveguide, the picture will be unpredictable. Knowing Russian craftsmen, we are sure that in the country there will be a dozen microwave ovens containing a radar magnetron. Indeed, what a difference it makes on the microwave runway and in the microwave kitchen. In this case, it is recommended to check the parameters using the methods indicated below to assess the security of people operating the device. There is probably no special equipment at home, so it is suggested to simply place glasses of water on this side of the door and wait to see if it heats up. Now the measurement technique is in accordance with GOST R IEC 60705-2011.

Checking parameters

The process begins with general measurements and settings:

1. The room temperature should be 20 ± 5 ºС.
2. The temperature of the transformer and magnetron should not be higher than the ambient temperature by more than 5 ºС. Or wait 360 minutes after using the microwave. In the room, of course, where the measurements take place.
3. To measure power, water is taken from the tap.
4. The dimensions of the microwave oven are determined according to the figure below. The useful radius is the distance from the center of the axis of rotation of the work table (or the center of the working chamber) to the nearest wall or door, and the useful height is measured from the surface of the rotating table to the nearest limit point from above. The useful volume is expressed in liters and is equal to the product of the useful height, depth, width.
5. If there are several mains voltage ranges, the one generally accepted in the given country is taken.

Measurements are taken in a cylindrical borosilicate glass bowl 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 the water will retain its original shape. If anyone thinks that it is impossible to get borosilicate glass, then this is a mistake. Glassware for microwave ovens is made from the specified material. We are inclined to think that the cook will find at home what he needs to take measurements.

The water temperature at the beginning is 10 ºС. Then an electronic scale is taken, a bowl is placed on top, and 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 you don’t have electronic scales, 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 turned on (in the mode for which power measurements are carried out), microwave radiation operates until the liquid is heated to 20 ± 2 ºС. Wait with the chamber closed for 1 minute and record the final temperature of the water in the bowl. Please note: the liquid is stirred before measurement. Subtle point. You cannot perform a technological operation with an iron spoon. For example, a plastic ladle from a multicooker will do. So that the liquid does not lose some of the heat. Steel has high thermal conductivity, which is why the room seems colder than objects made of plastic. Although the temperature difference is zero. The power of the microwave oven in the selected mode is determined according to the formula:

m w, m c – mass of water, container; Т, Т1, Т2 – ambient and water temperatures at the beginning and end of measurements, respectively; t – 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 power of your microwave oven, hardworking readers are in for a major surprise. They have already said that it would be a good idea to place a bowl near the door on the outside, and another one inside. Using a similar method, evaluate the quality of the protective mesh. If you disturb it, whirlwinds of microwave energy will burst into the kitchen and fry anything in its path. 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, anyone applying for a specific job undergoes additional examinations and is paid extra for harmfulness. Has the cook's family already passed the medical examination?

Take the trouble to evaluate the microwave leakage from the chamber. The reason for poor insulation quality lies in the lack of grounding. Most microwave ovens belong to electrical safety class I. The plug is equipped with a ground loop petal. Contact hanging in the air disrupts the normal operation of the microwave oven. Try grounding according to the recommendations of the standards, and re-evaluate the leaks.

Ideally, if you put a cell phone in a switched off microwave oven (the plug of which is in a grounded socket) and call it, the call should not go through. This means that the metal mesh on the door truly copes with its responsibilities 100%. For jokers, let’s add that outside the microwave oven, the signal must pass confidently, responding with a cheerful call to the request of the communication towers.

When starting to repair a microwave oven, remember safety precautions. Usually women and children are in the kitchen. Why is there a harmful factor there? It would also be a good idea to thoroughly know the structure of a microwave oven. According to our recollections, if the screen is not grounded, 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 was installed incorrectly. In conclusion, we wanted to give a couple of pictures from the standard. Everyone can look at, read the text, and measure the values ​​at their leisure. In this case, we will be talking more about the distribution of the field (we wrote about this at the beginning). Well, for example, if you need to heat up beer, it will become clear where to put it! And never heat milk in baby bottles in microwave ovens. The dangers of this approach have already been covered (as corrupt officials would say) in a review. Don't forget to watch the video instructions in our article!

Many of us have forgotten about various stoves and hobs and completely trust the cooking process to microwave ovens. And this is not at all surprising: microwaves take up little space, have a rich set of different functions and save a lot of time. Naturally, we are very upset when our microwave breaks down. The causes of breakdown and malfunction may be different. Let's look at what breaks down most often in a microwave oven. Often, if a microwave breaks down, you need to contact a specialized technician. After all, this is not the simplest device, so repairs are quite complicated. But in fact, the design of a microwave oven is elementary and includes only a few basic elements. If you first familiarize yourself with frequent breakdowns, then repairing a microwave oven yourself will not be difficult.

Microwave design

Although the design of a microwave oven contains a lot of elements, most of them do not play a special functional role. To repair this device, you only need to know the basic elements of the circuit that ensure its operation. Among them:

1. Magnetron.
2. Transformer.
3. High voltage fuse.
4. Rectifier diode.
5. Capacitor.
6. Control block.

It is easy to distinguish them, because outwardly the design is not very complex. The magnetron is always installed in the middle, aimed at the food heating unit. The transformer is located under it, representing a massive box with a protruding coil. The capacitor, diode and fuse are located to the right of it, and the control unit is often located near the input panel.

When the device is turned on, a voltage of 220 V is supplied to the transformer. Passing through the primary and secondary windings, a current of 2 kV already flows at the output of the element. Next, the negative half-wave goes to the diode, and the positive half-wave charges the capacitor, which again leads to a doubling of the voltage. After which the generation of microwaves begins using a magnetron. The magnetron power is controlled by the control unit.

Therefore, in the event of a breakdown, it is worth paying attention to these elements. They bear the greatest load, so the problem often arises in them.

When disassembling the microwave, be sure to unplug it.

Troubleshooting

The search for a breakdown in a microwave oven is carried out on the basis of “symptoms”. This allows you to gradually eliminate possible causes and find the real one. So, if the oven does not turn on at all, then it is worth checking the following points:

• Integrity of the power cord.
• Door position and closing system.
• Condition of the mains fuse and thermal relay.

In the first case, the situation is simple - there is no power due to a damaged power cord. A similar situation occurs when the outlet is damaged or overloaded. In this case, it is enough to replace this element, everything is in order with the microwave itself.

Next, you should check the operation and position of the door. The fact is that operating a microwave oven with the door open is dangerous for others. Therefore, the design allows for operation only when it is completely closed. If the latch, locking system or testing element on the door is broken, the protection system will not allow the device to start.

The last points also concern the furnace protection systems. The fuse prevents damage to the device due to power surges, and the thermal relay ensures complete shutdown of the system when the door is open. Both can fail; replacing them is quite easy.

It is also worth checking the voltage in the network and the number of devices connected to the outlet. The microwave is very demanding on power supply, so minor deviations can interfere with the operation of the device.

Most models suffer from common problems and have similar, typical faults. For example, if the microwave operates but does not heat, this indicates a malfunction of the capacitor, diode or magnetron. To repair a microwave oven yourself, you will need a simple set of tools: pliers, wire cutters, a screwdriver, an adjustable wrench and a five-point wrench, as well as a soldering iron with the necessary equipment.

When repairing a microwave microwave yourself, you should remember safety precautions. The two most important factors presenting danger when repairing a microwave oven are high voltage in the oven components and microwave radiation. Do not turn it on if the door lock is faulty or the mesh on the viewing window is damaged. You cannot make independent holes in the housing and introduce any conductive objects into the units and elements of the furnace. Under no circumstances should you touch the internal parts and components while the microwave is operating. Be sure to use a tester or other electrical measuring instruments to measure DC and AC current.

Disassembling a microwave oven yourself

If the above reasons are not confirmed, then you need to disassemble the device to troubleshoot. Before doing this, be sure to turn off the oven from the network and wait a couple of minutes.

What should you look for when looking for breakdowns? There are several main elements that often fail:

1. Circuit breakers.
2. Capacitor.
3. Diode.
4. Transformer.
5. Magnetron.

These elements are directly involved in the operation of the device and were mentioned earlier. First you need to check the serviceability of the fuses. Their breakdown is immediately visible, because when burned, the conductor inside is destroyed. If this does not happen, then you should look further.

For further checking, you need to take a multimeter, because externally it is extremely difficult to find a breakdown on other parts. To check the capacitor, you need to switch the device to ohmmeter mode and then connect it to the part. If there is no resistance, the part must be replaced.

It is impossible to check a high-voltage diode with a tester. It is recommended to replace it if other parts break, because often it also gets hit. It can be checked using a slightly different method - by connecting it to the network on the way to the light bulb. If the light is dim or blinking, then the part is working properly. If it lights up brightly or does not turn on at all, then the diode must be replaced.

It is important to follow safety precautions, because

This element is able to hold a charge for a long time. It will take several minutes to discharge a working transformer, and much longer if the discharge resistor breaks down. It is worth discharging it on the body or not touching it at all if you have no experience working with such equipment.

Next, the transformer windings are checked. You need to remove the terminals and check the device terminals one by one with an ohmmeter. First, the primary winding is checked, for which the norm varies from 2 to 4.5 Ohms. For the secondary winding, the limits are 140 and 350 Ohms. It is also worth checking the filament winding by connecting the terminals leading to the magnetron to a multimeter. The norm here varies from 3.5 to 8 ohms.

All previous tests have failed, then the problem may lie in the magnetron.

To test the magnetron, simply connect the tester to its power terminals. The tester switches to ohmmeter mode. If the resistance is 2-3 Ohms, then this means the device is broken. The situation is the same if the tester shows infinity. In both cases, the device must be replaced.

The listed elements are the most common culprits of microwave oven failure. However, device failure is often associated with other problems, such as problems with the electronic control unit, timer and other electronic parts. Here simple checks with a multimeter will not help; the help of a qualified technician is required. Although it is much easier to simply replace the part if you are sure it is broken.

Destruction of the cap on the magnetron

There are frequent cases of breakdowns associated with the destruction of the cap on the magnetron. The thin aluminum case simply cannot withstand the loads and is destroyed by microwave waves. This problem often occurs in older devices that are more than several years old. Obvious symptoms in this case are noise and sparks during operation of the device.

To check, it is enough to remove the transformer, because the cap is located towards the food chamber. If the cap is destroyed, then there are 2 options:

• Replacing the cap.
• Flipping the cap.

The first option is a priority; it is enough to order a replacement or send the magnetron for repair. The second option is considered a temporary alternative that allows you to extend the life of the device indefinitely. It is enough just to rotate the cap 180 degrees around the axis, because the load falls on only one half.

Repairing microwave malfunctions yourself

Repairing a microwave oven is a feasible task for a novice electrician. If the problem is a breakdown of one of the constituent elements of the furnace, then the simplest and most correct solution is to replace it. The bottom line is that most of the parts of this device cannot be repaired, but only completely replaced with a new one. This especially applies to fuses, diodes and capacitors - the main causes of device failure.

Replacing parts is carried out in several steps:

1. The microwave is disconnected from the network.
2. The transformer is discharging (5 minutes).
3. The terminals are disconnected from the defective part and it is removed.
4. A working part is connected to the same place.

When replacing a part, there are two important factors to consider. The first of these is compliance with the schema. It is important to remember that each part has its own characteristics, selected for the performance of the entire electrical circuit. If after replacement this nuance is not taken into account, then this leads to new breakdowns. This especially applies to the transformer and capacitor.

The second important factor is the connection of the part. It is necessary to connect the replacement correctly, maintaining the same terminal arrangement. If you connect the device in the reverse order, it may damage it, as well as several other parts in the system.

This will allow you to repair your microwave in most cases. If the breakdown is related to the electronic part of the device, then you should contact a professional. This will ensure high-quality repairs and extend the operation of the device for a long time.

Burnout of protective mica

The most common malfunction is the failure of the waveguide cover in the microwave oven chamber. This is caused by splashes from cooking. This starts sparking between the magnetron antenna and the protective cover. Untimely removal of burnt food leads to local burnout of the lid and complete destruction.

Local burnout of the mica plate of the lid can be removed using alcohol or solvent 646. It is enough to carefully wipe the burnt area.

If the mica plate of the lid is in clearly poor condition, is greased or has become discolored, it should be replaced. Removing the diffuser plate is not difficult at all. This can be done using a regular sharpened knife. Usually the mica plate is attached with a self-tapping screw or rivets. Carefully place the old plate on the new template and cut out a new one. It is best to do this with a knife - scissors can break the mica. We make holes in the new plate with a sharp screwdriver and sand the edges of the plate fields with sandpaper. We install the new plate in place of the old one.

A microwave oven, regardless of the manufacturer’s brand or year of manufacture, is almost the same. Accordingly, spare parts are interchangeable. The main thing is to correctly diagnose the breakdown.

The table below will help with this:

Microwave oven design:

The microwave consists of fairly simple parts:

1. food heating chamber
2. magnetron
3. waveguide
4. transformer
5. Control block

The camera and magnetron are connected to each other using a waveguide. In addition, a transformer and its winding are also installed in the furnace. The operating principle is as follows: when the microwave oven is turned on, voltage is supplied to the primary winding of the transformer. At the same time, energy is also supplied to the secondary winding, which is responsible for heating the cathode. Both windings are very well insulated. In a microwave oven, everything is usually connected in series. Let's start with the magnetron power circuit. After removing the cover, pay attention to the transformer, next to it is a large capacitor and a diode. This is a high voltage generation circuit to power the magnetron. Do not put your hands or a screwdriver in there under any circumstances!!! We believe that the capacitor will slowly discharge, and if the plug is removed from the socket, then an electric shock is unlikely.

How it all works:

Schematic diagram of a microwave oven

typical electrical diagram of a microwave oven

The primary winding of the transformer receives 220 V. It is usually located at the bottom and is wound with copper wire, which may appear bare. It is actually covered with clear insulation. This coil is located under the secondary windings. There are two secondary windings. One of them is literally several turns of ordinary wire, which is not very neatly wound next to the primary. This is cathode heating. There is 6.3 V AC voltage here, which helps the electrons leave the surface. But above, in good, high-quality insulation, there is a high-voltage winding. There is approximately 2 kV that goes to the output. At the output there is a capacitor, which is shunted by a diode. It turns out that the negative half-wave passes to the cathode, and the positive half-wave charges the capacitance. At the next half-cycle, the electrode will already be under double the voltage: that taken from the transformer and the discharge of the capacitor. The result is something on the order of 4 kV. This is enough to start generation.

Troubleshooting

The search for a breakdown in a microwave oven is carried out on the basis of “symptoms”. This allows you to gradually eliminate possible causes and find the real one. So, if the oven does not turn on at all, then it is worth checking the following points:

• Power Cord Integrity
• Door position and closing system
• Mains fuse and thermal relay status

In the first case, the situation is simple - there is no power due to a damaged power cord. A similar situation occurs when the outlet is damaged or overloaded. In this case, it is enough to replace this element, everything is in order with the microwave itself. Next, you should check the operation and position of the door. The fact is that operating a microwave oven with the door open is dangerous for others. Therefore, the design allows for operation only when it is completely closed. If the latch, locking system or testing element on the door is broken, the protection system will not allow the device to start. The last points also concern the furnace protection systems. The fuse prevents damage to the device due to power surges, and the thermal relay ensures complete shutdown of the system when the door is open. Both can fail; replacing them is quite easy. It is also worth checking the voltage in the network and the number of devices connected to the outlet. The microwave is very demanding on power supply, so minor deviations can interfere with the operation of the device.

Disassembling a microwave oven yourself

If the above reasons are not confirmed, then you need to disassemble the device to troubleshoot. Before doing this, be sure to turn off the oven from the network and wait a couple of minutes.

What should you look for when looking for breakdowns? There are several main elements that often fail:

• Circuit breakers
• Capacitor
• Transformer
• Magnetron

These elements are directly involved in the operation of the device and were mentioned earlier. First you need to check the serviceability of the fuses. Their breakdown is immediately visible, because when burned, the conductor inside is destroyed. If this does not happen, then you should look further. For further checking, you need to take a multimeter, because externally it is extremely difficult to find a breakdown on the remaining parts. To check the capacitor, you need to switch the device to ohmmeter mode and then connect it to the part. If there is no resistance, the part must be replaced.
It is impossible to check a high-voltage diode with a tester. It is recommended to replace it if other parts break, because often it also gets hit. It can be checked using a slightly different method - by connecting it to the network on the way to the light bulb. If the light is dim or blinking, then the part is working properly. If it lights up brightly or does not turn on at all, then the diode must be replaced. It is important to follow safety precautions, because this element can hold a charge for a long time. It will take several minutes to discharge a working transformer, and much longer if the discharge resistor breaks down. It is worth discharging it on the body or not touching it at all if you have no experience working with such equipment. Next, the transformer windings are checked.

How to check a microwave transformer:

You need to remove the terminals and check the device terminals one by one with an ohmmeter. First, the primary winding is checked, for which the norm varies from 2 to 4.5 Ohms. For the secondary winding, the limits are 140 and 350 Ohms. It is also worth checking the filament winding by connecting the terminals leading to the magnetron to a multimeter. The norm here varies from 3.5 to 8 ohms. All previous tests have failed, then the problem may lie in the magnetron.
To test the magnetron, simply connect the tester to its power terminals. The tester switches to ohmmeter mode. If the resistance is 2-3 Ohms, then this means the device is broken. The same situation occurs if the tester shows infinity. In both cases, the device must be replaced.

The listed elements are the most common culprits of microwave oven failure. However, device failure is often associated with other problems, such as problems with the electronic control unit, timer and other electronic parts. Here simple checks with a multimeter will not help; the help of a qualified technician is required. Although it is much easier to simply replace the part if you are sure it is broken.

There are frequent cases of breakdowns associated with the destruction of the cap on the magnetron. The thin aluminum case simply cannot withstand the loads and is destroyed by microwave waves. This problem often occurs in older devices that are more than several years old. Obvious symptoms in this case are noise and sparks during operation of the device. To check, it is enough to remove the transformer, because the cap is located towards the food chamber. If the cap is destroyed, then there are 2 options:

• Replacing the cap
• Flipping the cap

The first option is a priority; it is enough to order a replacement or send the magnetron for repair. The second option is considered a temporary alternative that allows you to extend the life of the device indefinitely. It is enough just to rotate the cap 180 degrees around the axis, because the load falls on only one half.

Repairing microwave malfunctions yourself

If the problem is a breakdown of one of the constituent elements of the furnace, then the simplest and most correct solution is to replace it. The bottom line is that most of the parts of this device cannot be repaired, but only completely replaced with a new one. This especially applies to fuses, diodes and capacitors - the main causes of device failure. Replacing parts is carried out in several steps:

1. The microwave is disconnected from the network.
2. The transformer is discharging (5 minutes).
3. The terminals are disconnected from the defective part and it is removed.
4. A working part is connected to the same place.

When replacing a part, there are two important factors to consider. The first of these is compliance with the schema. It is important to remember that each part has its own characteristics, selected for the performance of the entire electrical circuit. If after replacement this nuance is not taken into account, then this leads to new breakdowns. This especially applies to the transformer and capacitor. The second important factor is the connection of the part. It is necessary to connect the replacement correctly, maintaining the same terminal arrangement. If you connect the device in the reverse order, it may damage it, as well as several other parts in the system. This will allow you to repair your microwave in most cases. If the breakdown is related to the electronic part of the device, then you should contact a professional. This will ensure high-quality repairs and extend the operation of the device for a long time.

Whirlpool Microwave Error Codes

The most common kitchen appliances that fail are microwave ovens, so people try to repair microwave ovens on their own. In such devices, problems occur that are quite easy to fix with your own hands, especially if a person is familiar with the operating principles and operational capabilities of the microwave.

Safety regulations

The most common cause of breakdown is improper operation of the device or negligence. Also, devices break down due to manufacturing defects, but usually they are still under warranty, so you don’t need to disassemble them, you just need to take them to a service center, where they will repair them for free or replace them with a similar one.

Before repairing microwave ovens, It is worth familiarizing yourself with the safety rules:

Internal organization

The device itself contains a large number of elements, most of which do not perform any functional role. To repair a microwave with your own hands, It’s enough to know the main parts that make it work:

• magnetron located in the middle and directed to the heating block;
• fan;
• the transformer installed just below the magnetron looks like a massive box;
• the fuse and capacitor are always located to the right of the transformer;
• the control unit can be found near the panel;
• rectifier diode.

Mostly, breakdowns occur in these elements, which is why experienced craftsmen advise paying attention to them first.

Troubleshooting

You can find the malfunction by “symptoms”. This allows you to quickly and easily recognize a breakdown. During the inspection process, it is necessary to exclude possible causes and leave only the real one.

First, it is worth considering the option when the microwave device does not start. For this It is necessary to inspect the following elements:

If irregularities are found on the power cord, then the problem is simple - the device is not powered. The same troubles can happen if the outlet is damaged. The situation can be corrected by replacing the cord; in this case, the microwave oven is absolutely working.

Then they move on to checking the door. All such devices operate exclusively with the door closed. And if it is not closed tightly or there are any malfunctions in the latch or locking system, then the protective system will simply not allow the oven to operate; it will not turn on.

Next you should pay attention to the fuse. The fact is that this element simply turns off the device during power surges in the electrical network. And the thermal relay, in turn, will not start it if the door is open. These parts fail very often, but they are fairly easy to replace with new ones.

In addition, you need to check the voltage itself, and also see how many devices are connected to the outlet at the moment. The fact is that a microwave oven is extremely demanding on power supply, and even minor fluctuations or deviations will not allow it to function normally.

Types of faults and solutions

Almost all models have the same problems and malfunctions. It happens that the appliance seems to work, but does not heat the food. This may indicate a breakdown of the capacitor, magnetron or rectifier diode. To fix the microwave, need to prepare:

All these tools may be needed when carrying out repair activities. In addition, it is necessary to comply with safety requirements, since the work involves high voltage, which is life-threatening.

It is strictly forbidden to make any holes in the device body or connect conductive elements to it. Do not touch internal parts if the device is in operating mode.

Cap failure

Very often the furnace stops functioning due to the destruction of the cap located on the magnetron. The fact is that it has a very thin and unreliable aluminum body that simply cannot cope with the load. And constant exposure to microwave waves leads to its destruction. This problem is especially common in old microwaves that have been in use for a long time. This problem can be identified by the characteristic noise and sparks that occur during operation.

To check the device, you need to remove the transformer and inspect the cap, In case of destruction, the problem can be solved in two ways:

• install new;
• flip the element.

The first method, of course, is better; you can place an order for a new element or simply take the magnetron to a service center where it will be repaired. The second method involves temporary use, although in this case the part can last quite a long time. To do this, you need to rotate the element 180 degrees, and it will work again. This is explained by the fact that the entire load falls on only one half of the cap.

Burnout of protective mica

Such a breakdown occurs from splashes entering the waveguide cover. After this, the magnetron antenna and the protective cover begin to spark among themselves. And if there are crumbs or food stains in the device, they begin to burn, and this leads to local burns appearing on the lid. You can get rid of them using medical alcohol or solvent.

If the condition of the mica plate is very poor, it will have to be changed. It is not difficult to dismantle it; just unscrew the screws using a regular kitchen knife, and in some models the lid is even secured with rivets. After the element is removed, it needs to be laid on the prepared material and outlined with a pencil, and then cut out with the same knife. It is not recommended to use scissors as they can break the mica.

The necessary holes can be made with a sharp screwdriver and then sanded with sandpaper. The material can be absolutely any dielectric, it can be Teflon or fluoroplastic.

By understanding the structure of a microwave oven, you can easily identify a malfunction, and self-repair can save a lot of money, since the services of service centers are expensive.