Microwave Panasonic DIY repair

Microwave (microwave) Panasonic NN-G335 oven is a very successful model, both in design and in functionality. Until now, this model has not been discontinued, but only underwent a slight restyling. The oven has an exceptionally convenient handle for opening the door, equipped with a grill and electronic (touch) control. Despite the relatively high price in its class, the Panasonic NN-G335 microwave oven is in great demand among buyers. What is the furnace in operation in terms of the reliability of the electronic and mechanical components?

Corroded bottom of the chamber.

After about three years of operation, through corrosion of the bottom of the chamber formed. The high humidity and friction of the turntable wheels are likely to be the cause of the corrosion. Immediately after the discovery of such a defect in the chamber, the furnace was checked for radiation leakage with the help of a microwave detector. Everything turned out to be normal. The outer casing shields well despite the major destruction of the camera.
In the second year of operation, the camera illumination lamp burned out. The breakdown is not at all terrible and easily removable. You need to: open the oven (remove the cover), disconnect the wires on the lamp, remove the lamp and install a new one. However, the lamp there is used not ordinary, but a special one for microwave ovens (the base is not threaded, but in the form of two contacts). Buying a lamp is not particularly problematic. As a last resort, you can put an ordinary lamp, having come up with a way to fix it and connect the power wires.

Backlight lamp.
Shines through small through holes directly into the camera.

In the third year of operation, at one "fine" moment, the furnace refused to work at all (the display did not light up, there were no signs of life). After opening the case, first of all, the thermostats were checked, and a malfunction was immediately found - one of the thermostats was in a permanently open state. There are two such thermostats in the Panasonic NN-G335 oven, both operate to open when their body is heated above the nominal response temperature (indicated on the thermostat body). In order to replace a failed thermostat in any microwave oven, you need to know the response temperature of the failed thermostat, its operating current, the type of switching (on or off) and the type of case (appearance). We could not find the same thermostat (by fixings). This is not scary, the main thing is to ensure reliable thermal contact of the thermostat body with the body of the investigated object (details of the furnace structure on which it is installed).

"Live" thermostat in the standard setting (photo on the left).
Replaced thermostat. Installed with an additional pressure plate and self-tapping screws (photo on the right).

It is difficult to say what was the reason for the failure of the thermostat. Most likely, the reason is simply time, because everything has its own lifespan. If overheating took place, for example, due to the closing of the external ventilation slots by something, then after turning off the oven and cooling it down, a working thermostat should turn on again, which did not happen.
And the last thing I had to face was the blown fuse for power supply as a result of the operation of the protective diode.

Power board with blown fuse F1 removed (photo on the left).
Power board, speaker view (buzzer). The hole marked with a red circle can be sealed, for example, with electrical tape, and the microwave will not beep loudly (photo on the right).

Protective diode 2X062H mounted on a high-voltage capacitor 1 μF x 2100 V (photo on the left).
The inscription on the high-voltage capacitor (photo on the right).

In order to find the reason for the operation of the protective diode 2X062H and, as a consequence, the blown out of the fuse, the resistance of the magnetron heating circuit was checked, it turned out to be extremely small (about 0.1 Ohm), it was not possible to accurately measure it with an ordinary multimeter. According to the found reference data for this magnetron, such a low resistance was normal for a working magnetron, or rather, should be 0.07 Ohm. The resistance between the magnetron body and its terminals was also checked, the resistance turned out to be "infinite", as it should be. From these measurements, it was concluded that the magnetron was in conditional serviceability (for lack of the possibility of deeper testing). However, when dismantling the magnetron and removing the protective metal cover, traces of excessive local heating of the coils were revealed (the enamel of the insulation had darkening), but the wire itself was not damaged. To ensure the conditional serviceability of the high-voltage transformer, the DC resistances of all its windings were checked. The resistances roughly coincided with the reference data. The measurement results were written with a pen on the transformer itself for the possibility, if necessary, to re-check the measurements in the future.

Magnetron Panasonic 2M211 (photo on the left).
View of the furnace with the removed magnetron (photo on the right).

Magnetron.The slightly burnt insulation of the coil is visible (photo on the left).

Magnetron. The cover is removed (photo on the right).

As a result, it was decided to replace the fuse with a higher current (10A), assemble and check the furnace in operation. As it turned out, this decision was correct. After the last repair, the microwave oven works perfectly, no extraneous noise or abnormal operation was observed. Of course, if repaired according to all the rules, then it was also necessary to replace the burnt out protective diode with a new one, but its far from the lowest price, the absence of radio supplies in the vicinity of the store and the extreme need for a kitchen in the oven outweighed the rest of the arguments. At the end of the article, you can see a few more photos of the repair process.

High voltage transformer. View of the nameplate (photo on the left).
The resistance of the high-voltage transformer windings was measured with a Mastech M-838 digital multimeter (photo on the right).

Contact to body one of the terminals of the transformer winding (during testing, it is necessary to check the presence of this contact with a multimeter).

Everything is connected.

Rectifier diode. Body contact (in red circle).

We bring to your attention another article to help the home master. It will focus on the repair of microwave ovens from Samsung, LG, Panasonic and other 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. As practice shows, in about 80% of cases of microwave failure, it can be restored by the efforts of a home craftsman.

We are so accustomed to microwave ovens that the failure of this kitchen appliance creates a lot of inconvenience. With its repair in the workshop, difficulties also arise, primarily related to transportation. Naturally, this raises the question of the possibility of repair on their own. In our article, we will provide a list of typical malfunctions and tell you about how to fix them. Before starting the repair of microwave ovens (Samsung, LG, Panasonic, etc.), we recommend that you familiarize yourself with their principle of operation and design features, this information will not be superfluous.

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 a description and purpose of the main structural elements, they are presented below in the figure.

Rice. 1. Microwave device

Legend:

1. Door latches serve both for fixing the latter and for the system of blocking work in the open position.
2. A rotating tray on which the dielectric cookware is placed.
3. Separator equipped with rollers that drives the pallet.
4. The drive that rotates the separator.
5. Backlight lamp, turns on depending on the operating mode.
6. Ventilation (usually forced).
7. Magnetron - a microwave generator, in fact, is the main structural element. You can find out how it works and how it works by reading the article on our website dedicated to this issue.
8. Waveguide, provides the movement of microwave waves to the microwave chamber. It is a rectangular hollow metal tube.
9. High voltage diode.
10. Capacitor.
11. Waveguide power supply transformer and control circuits.
12. 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.

Typical diagram of a magnetron power supply circuit

Let us briefly describe the principle of operation of the above circuit. Power to the primary winding of the transformer (I) comes from an external control circuit 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.

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.

Fragment of microwave explosion diagram

Unfortunately, manufacturers are in no hurry to share this information, distributing it only among the networks of certified service centers. If you manage to find the technical documentation for the repair, prepare for it to be in English.

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 appearance and location of the main elements in the microwave case

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.

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

As we promised, here is a list of common faults:

• No response to the power button.
• The device does not turn off after working out the mode.
• Weak heating.
• No heating.
• Sparking is observed.
• The pallet does not rotate.
• No response to the control panel.
• When turned on, the scoreboard does not work.
• The fuse blows when the door is closed.

Before considering in detail the elimination of the listed malfunctions, 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.

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

1. 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.
2. 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.

Example of fuse location on a control module

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 OK, the problem may be with the relay supplying voltage to the power transformer in 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.

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 power grid overvoltage occurs regularly, and, as a result, voltage drops.

If the multimeter shows the permissible voltage level of the household network, then the power circuit of the magnetron should be checked, as 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.

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

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.

Such a malfunction can be caused by the following reasons:

1. 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.
2. 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.
3. 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.

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:

1. Jammed engine (determined tactilely) or breaking one (dialing is carried out) of the windings. In these cases, a replacement of the drive is required.
2. 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.

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.

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.

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.

A kitchen assistant is not so complicated that, in case of minor malfunctions, go to a microwave oven repair shop. Repair of Samsung microwave ovens, MYSTERY MMW, Whirlpool, LG, Panasonic and other popular models is easy to do on your own. To determine the malfunction and replace parts, the knowledge gained at school and the ability to solder is enough.

To do home repairs of panasonic microwaves with your own hands, you need to know the basic elements that ensure its operation. Microwave, be it Mystery 2018g; or any other, consists of the following functional blocks:

• a magnetron connected to the camera by a waveguide;
• transformer;
• high voltage fuse;
• high voltage diode;
• capacitor;
• control unit.

The magnetron is located in the center of the compartment. A transformer consisting of a stacked metal core with a coil is placed below. On the right side of it is a board with a capacitor, a diode and a fuse. The control unit is usually located next to the operating mode setting panel.

When the furnace is turned on, 2 voltages appear on the secondary windings of the transformer - 6.3 V and 2 kV.

A low is fed to the filament of the magnetron, and a high is fed to a voltage doubler, consisting of a diode and a capacitor, and then to the anode. The result is microwave radiation that ovens use to heat and cook food. Microwave power is regulated using the microwave control unit.

Each breakdown is accompanied by its own symptoms:

1. Something sparkles, pops and shoots inside the oven. This phenomenon is observed when the mica lining that closes the exit of the waveguide into the chamber is destroyed. This also happens when the protective cap of the magnetron burns out.
2. Food placed in the chamber is not warmed up. The pallet rotates, the lighting works. The problem arises from a blown high-voltage fuse or capacitor breakdown.
3. The microwave does not heat well. This is due to low voltage in the mains or loss of emission from the magnetron.
4. The oven does not turn on. First, the integrity of the power cord, fuse and the presence of voltage in the outlet is checked. Then the state of the interlocking microswitches that turn on when the door is closed. If everything is in order, the reason is the oxidation of the contacts of the thermal relay located on the magnetron body.
5. The pallet does not rotate. The clutch connecting the engine shaft to the pallet is cut off or the motor is faulty.
6. During operation, the oven, in particular Mystery mmw, emits a loud hum. Defective transformer or fan.
7. Typed commands are not executed. Perhaps, due to the high temperature, the contacts of the control unit are burnt.
8. No indication or timer is displayed. Microprocessor malfunctioning. In this case, the repair of the touch control panel should be entrusted to the master.

To make repairs with your own hands, you need to open access to the elements under the casing on the back wall. To remove it with a Phillips screwdriver, 6 bolts are unscrewed. When removing the elements, it should be borne in mind that they are secured with hidden locks, so there is no need to waste time looking for screws or bolts. To remove any element, you must press the corresponding tab. There can be several fasteners, so make sure that they are all removed before removing.

Unplug the power cord from the outlet before removing the cover.

Since capacitors retain their charge for a long time, it is necessary to discharge them immediately by bridging the terminals with a piece of insulated wire.

It is better to repair a microwave oven with your own hands using a functional diagram. It is universal for all ovens and reflects all elements in sufficient detail. Do-it-yourself lg microwave repair can be done in accordance with the recommendations below.

Electrical schematic diagram of a microwave oven.

Microwaves are equipped with 2 fuses. The first in a glass case is installed at the voltage input from the outlet. Integrity is checked visually or with an ohmmeter. The second, high-voltage, in a tubular plastic casing is located near the transformer. Burns out when a diode or capacitor fails in the high-voltage circuit of the magnetron. Do not replace them with bugs, as this could lead to a fire. Before installing new fuses, it is useful to analyze the causes of the blown so that the situation does not recur.

This is what a blown fuse looks like.

In the process of heating and cooking food, drops of fat and pieces of food inevitably fall on the mica pad, causing sparks and crackling in the chamber. In this case, the magnetron has to work with overload, which leads to failure. Mica sheets are sold at radio stores, and anyone can cut a plate of the right size. If there is no possibility of replacement, then temporarily, after cleaning, an old plate is used, which is installed with the damaged side inside the waveguide.

Burnout of the cap, accompanied by noise and sparking, occurs due to old age, or due to the destruction of the mica plate. Therefore, when replacing the lining, it is imperative to check its condition. The part is cheap and easy to change. But it can also be repaired by simply turning the cap 180 °. In the new position, it will serve for a long time.

A conventional tester is not suitable for diagnosing this part, since it does not have a sufficient measuring range. The check can be carried out using an ordinary light bulb, connecting it through the tested diode to the 220 V network. If the part is in good working order, the light does not glow at full intensity. With a bright glow or its absence, the diode is replaced.

Capacitors, including high-voltage capacitors, are checked by measuring their resistance with an ohmmeter. If the device shows infinity, everything is in order. When readings are 0 or several ohms, the part is replaced. If, when checking the high-voltage capacitor, the resistance is 1 MΩ, it means that a discharge resistor is installed in it and it is suitable for use.

The check is carried out with an ohmmeter, which measures the resistance of the windings. In the primary, depending on the microwave oven model, it should be in the range of 2 - 4.5 ohms, the resistance of the high-voltage winding is from 140 to 350 ohms. The norm for a filament winding is a value range of 3.5 - 8 ohms.

If a malfunction is not detected, and the microwave does not heat up, they begin to check the magnetron.To do this, remove the top cover, disconnect the terminals from the wires and measure the resistance between the terminals.

If the ohmmeter shows several ohms, the filament is intact, at infinity it is cut off and the magnetron must be replaced. If the glow is intact, and the magnetron does not work, it is necessary to check the serviceability of the feed-through capacitors located next to its terminals and, if necessary, replace these capacitors.

The cause may also be a violation of contact in the soldering points of their terminals.

To remove a faulty magnetron, you will have to remove the transformer and waveguide and unscrew 4 bolts. For replacement, it is not necessary to use exactly the same type, any other (for example, from the Mystery mmw microwave) with similar power characteristics will do.

The source of the hum is determined first. If it is a transformer, then it is replaced with a similar one. A working fan usually hums due to overheating of the system. To make it silent, it is enough to move the stove away from the wall or clean the blades.

To determine the cause of the malfunction, remove the pallet. If the coupling connecting it to the motor shaft is not folded, the wire coming from the motor is checked. It might be disconnected or a plug that needs to be cleaned and reinstalled in place.

These methods will allow you to repair Whirlpool microwaves, repair Panasonic, Samsung, or other ovens. But if something is not clear, you should watch the training video on repair. The video teaches on the principle - look and repair.

In the video, tips for repairing Whirlpool microwaves at home:

The algorithm for starting the inverter is as follows:
1. The control unit (CU) issues a control signal (“meander”, the duty cycle is determined by the selected power value) through the IC701 optocoupler to the inverter driver;
2. The driver turns on the inverter - voltages are formed: filament and anode. If there are no start-up attempts (there is no voltage on the inverter or it is significantly damaged) - after 3 seconds, the control unit turns off the furnace;
3. If the filament current is for a long time more than twice the nominal 10A, the driver turns off the inverter. Four attempts are made to start this way, it takes about 10 seconds. If you disconnect the anode voltage from the magnetron, then the current consumption of the 220V furnace is about 1A (that is, only when the heating is running);
4. As soon as the driver considers that the inverter is working normally, a feedback signal is issued through the second optocoupler IC702. If there is no signal, the control unit stops working after 23 seconds.
5. During normal operation, the current consumption through the 220V network is about 5A.

For those who wish - inverter circuit:

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To repair a microwave oven, you need to have a general idea of ​​how it works. Microwave oven repair begins with removing the top cover. Before that, you should take care of completely disconnecting the device from the power supply, only then proceed with the elimination of breakdowns with your own hands.

When these steps are successfully completed, a transformer with two fuses will open for access: one is located directly on the part itself, it is fusible, the second is located nearby on the very body of the microwave oven, made of ceramics. Also next to the transformer is a doubler block consisting of a thick capacitor and a diode. The whole set of these elements is the power supply circuit of the microwave oven magnetron.

Carefully! Do not touch the condenser immediately after removing the top cover. This element is capable of holding voltage for a long time, which can easily lead to an electric shock. When repairing a microwave oven with your own hands, this factor should be taken into account.

The peculiarity of microwave ovens is that all parts are connected in series. First, you should pay attention to the above magnetron and its power supply circuit.After removing the protective housing, a transformer with a large capacitor located next to it becomes accessible. There will also be a ceramic, low-melting fuse, a diode. The magnetron operates according to this high voltage circuit. Under no circumstances should you get into it with your hands, tools. After a complete de-energization, the capacitor will lose its residual voltage, the likelihood of an electric shock will decrease.

1. The primary winding of the micro-transformer takes over 220V. As a rule, its location is at the bottom. You can recognize it by the coils of copper wire, which in appearance will be bare. However, it is not. It is covered with a transparent insulating film. The location of this coil is under the secondary winding.
2. The microwave oven has two secondary windings. On one of them, several turns of a simple wire are usually not neatly wound. This heats up the cathode. Here the AC voltage is only 6.2V so that the electrons can be lifted from the surface. But where there is good insulation, there is a high voltage winding. About two kV directed towards the exit.
3. A capacitor shunted by a diode is located at the output of the circuit. The action of the negative half-wave falls on the cathode, the action of the positive half-wave charges the capacitance. Further, the electrode is subjected to double voltage, which is removed from the capacitor and the micro-transformer. As a result, approximately 3.5-4 kV is created. This power is enough to start the generation process.

You should be extremely careful, the output winding is always parallel to the magnetron, which has two output options. But the grounding of the anode is done in a separate way.

Thus, this is what happens:

• the heating coil has 6.3V;
• at the cathode stays up to 4.2 kV, grounded by the anode.

All microwave ovens have an electrical connection for the cathode, heating coil. Each microwave oven is equipped with a timer that controls the magnetron power. The use of a start relay is used in order to avoid the occurrence of a spark. Next, you should pay attention to the front panel.

The most likely breakages occur in the area of ​​the mica plate. Energy is supplied from the magnetron to the waveguide along the rod. The latter is highly sensitive to the presence of various food debris. All these contaminants begin to ignite, emit sparks, thereby disrupting the stable operation of microwave ovens. To avoid unforeseen situations, the developers decided to close the waveguide with a mica plate. It has soft, flexible properties, relatively affordable pricing. It will not be difficult to fix such a breakdown with your own hands. You can buy material of any size, cut the corresponding segment. The peculiarity of the mica plate is that it transmits a frequency level of 2.45 GHz without obstacles. It is at this frequency that the microwave oven operates.

Also, mica plates do not get wet. This is a very important factor if liquid is heated inside microwave ovens. After all, water very quickly absorbs the radiating frequency of 2.45 GHz, there is a danger of serious damage. If the water reaches the waveguide, a big accident is created, which will not be easy to repair with your own hands. The high voltage fuse will blow instantly. If everything gets worse, the magnetron itself burns out, other electronics that power the microwave oven.

What factors influence the destruction of the mica plate? Most reheated food contains a lot of fats, oils, and other such ingredients. They differ in that instead of the usual boil, they shoot out greasy drops. Once such a drop hits the mica plate, a small wire bridge is created. An electric arc is formed: from the waveguide to the mica plate, then from it to the body of the microwave oven.As soon as pops and sparks, uncharacteristic for the operation of stoves, appear, this is a sure sign that the stove will soon need to be repaired.

Anyone who has tried to fix a microwave oven with their own hands wondered about the high-voltage fuse. The mechanism of microwave ovens of this kind triggers at least two fuses:

1. If you look at the electronic board of the microwave, this part appears as a small white or transparent cylinder. Its task is to protect integrated, wall-mounted microwave oven components. This small cylinder is also part of the power supply circuit. Its burnout occurs in the event of a capacitor breakdown, a resistor short circuit.
2. The circuit that forms the power supply of the magnetron includes a diode, a transformer, and a capacitor. Through them, about two or three kilovolts approaches the cathode. These details are not difficult to find. It is difficult to confuse the appearance of the capacitor with anything else. This is a huge detail in the form of a jar weighing up to one hundred grams. One diode leg is attached to it, the other is fixed to the body. Nearby is also a small barrel, often ceramic, painted in brown. It is this barrel that contains a high-voltage fuse inside it. Its task is to prevent overheating of the magnetron. When a mica plate breaks through or a metal spoon is placed in the microwave oven, the high-voltage fuse immediately burns out.

It is best not to try to assemble the high voltage fuse with your own hands or remove it from the electronic board. This practice is extremely dangerous for people. The microwave oven may stop working and there is a high risk of fire and electric shock.

Before you start talking about repairing a fan that cools a magnetron, grills or an illuminating lamp in a microwave oven chamber, you should also pay attention to the protective relay. Their task is to turn off all operating systems at the moment when the chamber door is in the open position. Two relays usually break the power supply circuit. And one relay will be controlled by the functionality of the second. The work is carried out as follows:

1. If the oven door is open, the relay trigger is released.
2. In this operation, the power supply circuit has two breaks.
3. The second relay closes the ground on the phase.
4. When the first relay is energized, nothing bad will happen as the power supply circuit is in the open position.
5. When the first relay sticks, the fuse kicks out. This is due to the fact that the ground was short-circuited by a phase.

The fuse is not meant to be on top of the magnetron or inside the case, but on the board. To fix a microwave oven with your own hands, you should check the operation of the protective relay. Without this functionality, access to the power supply to the magnetron is practically impossible. The task of the power fuse is to take into account the movement of current in the magnetron. In the event of a dangerous situation, the protective element burns out, the generator breakdown is excluded. A similar situation occurs when the microwave oven is idle or there is some kind of metal thing in its chamber.