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.
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.
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:
VIDEO
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:
If the oven door is open, the relay trigger is released.
In this operation, the power supply circuit has two breaks.
The second relay closes the ground on the phase.
When the first relay is energized, nothing bad will happen as the power supply circuit is in the open position.
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.
Many of us have forgotten about various stoves, hobs and completely trust the process of cooking microwave ovens. And this is not surprising at all: microwave ovens take up little space, have a rich set of different functions and significantly save time. Naturally, we get very upset when our microwave breaks down. The reasons for the breakdown and malfunction can be different. Consider what breaks down most often in a microwave oven. Often, if a microwave oven breaks down, it is necessary to contact a specialized master. After all, this is not the simplest device, so the repair is rather 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 the microwave on your own will not be difficult.
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:
Magnetron.
Transformer.
High voltage fuse.
Rectifier diode.
Capacitor.
Control block.
It is easy to distinguish them, because outwardly the design is not very complex. The magnetron is always installed in the middle, directed towards the food warming 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 is already flowing out of the element. Further, the negative half-wave goes to the diode, and the positive one charges the capacitor, which again leads to a twofold increase in voltage. After that, the generation of microwaves by means of a magnetron begins. The power of the magnetron is regulated by the control unit.
Therefore, in the event of a breakdown, it is worth paying attention to these elements. They carry the greatest load, so they are often the problem.
When disassembling the microwave, be sure to disconnect it from the mains.
Search for breakage in a microwave oven is based on "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:
The integrity of the power cord.
Door position and closing system.
Mains fuse and thermal relay status.
In the first case, the situation is elementary - there is no power supply due to damage to the 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, it is worth checking the operation and position of the door. The fact is that the operation of a microwave oven when the door is open is dangerous for others. Therefore, the design provides for the possibility of operation only when it is completely closed. If a latch, a locking system or a checking element is broken on the door, the protection system will not allow the device to start.
The last points also concern the protective systems of the oven. The fuse prevents damage to the device due to power surges, and the thermal relay provides a complete shutdown of the system when the door is open. Both can fail, it is quite easy to replace them.
It is also worth checking the voltage in the network and the number of devices connected to the outlet. The microwave oven is very demanding on power supply, therefore its slight deviations can interfere with the operation of the appliance.
Most models suffer from common problems and have similar, typical faults. For example, if the microwave works, but does not heat, then 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-spanner wrench, as well as a soldering iron with the necessary equipment.
When repairing a microwave microwave yourself, you should remember about safety measures. The two most important hazards in microwave oven repairs are high voltage in oven components and microwave radiation. Do not turn it on if the door is defectively locked or the mesh on the viewing window is damaged. Do not make independent holes in the case and introduce any conductive objects into the units and elements of the furnace. Never touch internal parts and assemblies while the microwave is in operation. Be sure to use a tester or other electrical meter to measure AC and DC current.
If the above reasons are not confirmed, then you need to disassemble the device for troubleshooting. Before that, be sure to turn off the oven from the network and wait a couple of minutes.
What should you look for when searching for breakdowns? There are several basic elements that often fail:
Circuit breakers.
Capacitor.
Diode.
Transformer.
Magnetron.
These elements are directly involved in the operation of the device and were mentioned earlier. First you need to check the health of the fuses.Their breakage can be seen immediately, because during combustion, the conductor inside is destroyed. If this did not happen, then it is worth looking further.
For further verification, you need to take a multimeter, because outwardly 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, then the part must be replaced.
It is impossible to check the high-voltage diode with a tester. It is recommended to replace it in case of breakage of other parts, because often the blow falls on it. It can be checked in a slightly different way - by connecting it to the network on the way to the light bulb. If the light is weak or blinking, then the part is working properly. If it burns brightly or does not turn on at all, then the diode must be replaced.
Next, the transformer is checked.
It is important to observe safety precautions, because
this element is able to hold a charge for a long time. It will take several minutes to discharge a serviceable transformer, and if the discharge resistor breaks down, it will take much longer. It is worth discharging it on the case or not touching it at all if there is no experience with such a technique.
Next, the transformer windings are checked. It is necessary to remove the terminals and check the terminals of the device one by one with an ohmmeter. First, the primary winding is checked, for which the rate 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 the 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, just connect the tester to its power terminals. The tester switches to ohmmeter mode. If the resistance is 2-3 ohms, then this means a breakdown of the device. The situation is the same if the tester reads infinity. In both cases, the device must be replaced.
These items are the most common culprits in microwave oven breakdowns. However, the failure of the device is often associated with other malfunctions, 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 needed. Although it is much easier to simply replace a part if you are sure that it is broken.
There are frequent cases of breakage associated with the destruction of the cap on the magnetron. The thin aluminum body simply cannot withstand stress and is destroyed by microwave waves. This problem often occurs in older devices that are more than a few years old. The obvious symptoms in this case are noise and sparks during the 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:
Cap replacement.
Flip the cap.
The first option is a priority, it is enough to order a replacement or return 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 a microwave oven is a feasible task for a novice electrician. If the problem lies in the breakdown of one of the constituent elements of the furnace, then the simplest and 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 reasons for the failure of the device.
Parts replacement is carried out in several steps:
The microwave is disconnected from the network.
The transformer is discharged (5 minutes).
The terminals are disconnected from the defective part, it is removed.
A workable part is connected to the same place.
There are two important factors to consider when replacing a part. The first is schema compliance. 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 is especially true for the transformer and capacitor.
The second important factor is the connection of the part. It is necessary to connect the replacement correctly, keeping the previous arrangement of the terminals. Reconnecting the device in reverse order can damage it, as well as several other parts in the system.
This will restore your microwave in most cases. If the breakdown is related to the electronic part of the device, then you should contact the professionals. This will ensure quality repairs and prolong the operation of the device for a long time.
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 products leads to local burnout of the lid and to complete destruction.
Local burnout of the lid mica plate can be removed with alcohol or solvent 646. It is enough to gently wipe the burnout area.
If the mica plate of the lid is clearly in poor condition, is greasy or begins to paint, then it should be replaced. Removing the diffuser plate is a snap. This can be done using an ordinary 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. The best way to do this is with a knife - you can break the mica with scissors. We make holes in the new plate with a sharp screwdriver and process the edges of the fields of the plate with sandpaper. We install the new plate in place of the old one.
The question often arises, how to replace mica for microwave ovens? For these purposes, any dielectric with a similar dielectric constant is suitable. For example, PTFE or Teflon.
Common breakdowns in a microwave oven are also malfunctions associated with other elements of the oven. For example, such as the keyboard of the oven control unit, the microwave oven electronic control unit and the dissector. Less often, the high-voltage capacitor and transformer, the microwave waveguide plug and the rotating pan fail. The power supply and magnetron of the microwave oven are subject to wear and tear.
Knowing how to troubleshoot microwave ovens can save you significant repair costs. However, if you do not know how to repair the microwave yourself, then it is best to contact a specialist. Specialized service centers will help you to repair the microwave microwave. In addition, watch the video on microwave repair, perhaps there is exactly that breakdown that will help you fix your beloved household assistant.
VIDEO VIDEO VIDEO VIDEO
Do-it-yourself microwave repair: a detailed video on how to repair a microwave oven and fix a microwave
Simple DIY microwave repair: 5 solutions to basic problems
Rarely can a kitchen be imagined without a microwave. Recently, she is pr
If a microwave oven breaks down, you can immediately take it to a service center, or you can try to repair it yourself, while saving money.
But before you start repairing a microwave oven, you should understand that a person who has at least some knowledge in electronics and electrical engineering can qualitatively repair a microwave oven.
Also, when working, you must comply with all safety rules.
To repair microwaves, you need to know the following basic elements:
Energy converting transformer;
Magnetron;
Rectifier;
Fuse;
Fan;
Capacitor;
Control block.
It is quite easy to understand where and what is located. Right in the middle of the chamber is a magnetron and a transformer underneath. The fuse, capacitor and rectifier should be located to the right of it. As for the control unit, it is often located near the input panel.
Before starting repairs, be sure to disconnect the device from the mains!
If the breakdown consists in the failure of one of the main elements, then the easiest way will be to replace it. The fact is that many parts of the stove cannot be repaired, but only new ones can be bought. This is especially true for capacitors, fuses and diodes.
If the replacement is real, then the following actions should be performed:
Disconnect the oven from the mains;
Discharge the transformer (this will take about 5 minutes);
Disconnect the required part from the terminals and remove;
Replace the work piece.
When replacing, you need to pay attention to the correspondence of the circuit and the new part. If the new element and the circuit are incompatible, then this can lead to new breakdowns.
In the event of a failure of the electronics, it is still better to seek help from professionals who will carry out a high-quality repair of the microwave oven.
The fact that the stove is broken or does not work, as a rule, are signaled by some signs. According to them, the cause of the breakdown is determined.
So, what can it be, in more detail:
This is how the most common malfunctions look like, which you can do yourself. When working with electricity and checking the elements of the furnace, one should not forget about the observance of safety measures.
The microwave oven may have a touch control panel or a conventional control panel, which may not work due to exposure to high temperatures.
As a rule, problems with this part occur after 3-4 years of intensive use, and are expressed in the refusal of the buttons "obey the command". At the same time, the display may display some kind of error. The stove can turn itself off or off. The main reason for such phenomena is the closure of the panel contacts.
Self-repair of the touch panel of the device consists of the following steps:
First, you need to disconnect the microwave oven from the mains and disassemble the panel - the latter consists of a film with buttons painted on it and two membrane gaskets with contacts.
Next, you need to pry off the sensor film with a thin sharp knife, while trying not to damage the membrane. It is best to start at the bottom or top left corner.
After removing the membrane, you need to check the operation of the panel by closing the contacts. You can put a container with water inside the oven. If everything works, you can start repairing the panel.
Again, you need to disconnect from the network and wipe all contacts with alcohol. To increase the gaps between them and eliminate the possibility of short circuits, you need to glue these places with pieces of electrical tape or tape.
Next, the upper membrane is put in place, after which the operation of the microwave is checked. If again something does not work or reacts with difficulty to pressing, turn off the stove again, peel off the membrane film and remove the electrical tape or add it somewhere (whichever does not work). This should be done until the buttons work as expected.
A touch panel repaired in this way can work for about six months, but it may continue to bend further, after which it will have to be "straightened" again or bought a new one.
If the microwave oven sparks, stopped heating food, or started doing it for too long, the problem is most likely in the magnetron, which is the main heating element of the microwave device.
By the way, it is unprofitable from the economic point of view to change the magnetron in the microwave, which has been serving for more than 5 years.
As a rule, this device is "set" on terminals and screws that fix it to the base of the stove. However, replacement of the magnetron is rarely required. Basically, problems in its operation begin when the protective cap of the element burns out.
In this case, there are several options for solving the problem:
The cap is manually cleaned from scale and rotated 180 degrees;
A new cap is made from a suitably sized capacitor body;
It will also not be superfluous to replace the mica plate that is exposed to harmful rays.
Actually, there is nothing difficult in repairing a magnetron, but if the problem is not in the burned-out cap, but a little more serious, then it is better to entrust such repairs to specialists.
VIDEO
You can repair a microwave oven yourself if you have some knowledge of the operation of electrical appliances. However, there is nothing complicated in such a procedure. The main thing is to remember about safety measures and proceed with caution. Knowing the basic elements of the device, you can calculate the cause of the breakdown yourself and eliminate it.
A 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:
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.
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.
The microwave does not heat well. This is due to low voltage in the mains or loss of emission from the magnetron.
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.
The pallet does not rotate. The clutch connecting the engine shaft to the pallet is cut off or the motor is faulty.
During operation, the oven, in particular Mystery mmw, emits a loud hum. Defective transformer or fan.
Typed commands are not executed. Perhaps, due to the high temperature, the contacts of the control unit are burnt.
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.
Video (click to play).
In the video, tips for repairing Whirlpool microwaves at home:
