The microwave keyboard repair that I describe in this article is not my invention. I read it myself on the Internet. My contribution lies in how to disassemble the "microwave", because each of them has its own characteristics when repairing.
The strange behavior of the microwave forced me to start repairs. One fine moment, when I came home, I found her in a working position. Who turned it on is not clear! But right away I did not consider it necessary to take any measures. I thought it wouldn’t turn on anymore. No matter how it is! And when the oven spontaneously turned on several times, and then did not turn off at all (close the lid - it turned on!), We had to take action.
On the Internet, all sites talk about a magnetron, about high voltage, etc. I read it, and was afraid, I thought - shouldn't I send it to the workshop? I found the material about the keyboard malfunction quite by accident, when I had already disassembled the microwave and had already checked the high-voltage fuse, high-voltage capacitor and high-voltage diode. Well at least I didn't get to the magnetron!
In microwave ovens that have so-called "touch" keyboards, in fact, there are no touch keyboards. There are, however, no buttons. They have two films, on each of which conductive tracks and contact pads are applied opposite to each other. When you press the panel, it bends, and these pads touch. A closure occurs. Generally speaking, this is not a sensory switching, since the capacitance of the human body is used in sensory devices, which makes the switching. And here, the same closure as in a regular button.
Of course, it all looks very modern, cool. But at the same time, there is one disease. Over time, when these films are deformed, the closure occurs by itself. In this case, microwave ovens begin to live their own lives and either stop responding to keystrokes, or, on the contrary, can start working spontaneously. Therefore, with the introduction of so-called "touch" switches in microwave ovens, keyboard breakdown is one of the most common problems.
So. First you need to remove the "touch" panel. To do this, unscrew the screw that secures the panel from the inside (in the picture above). I am not describing how to remove the cover here, because, in my opinion, it is not difficult - unscrew those screws that you see!
Then you need to open the door and then the panel rises freely (see above). All wires, before disconnecting them, sketch (or photograph). Remove the printed circuit board.Before that, disconnect the cable that goes from it to the "sensor". To do this, pull the top of the shoe up. It will rise by about 1 mm, after which the cable can be freely removed (see below).
And now the panel is in your hands. Now you need to "unstick" the keyboard. Carefully with a sharp knife lifts the bottom corner opposite the train. We "rip off" the keyboard. In this case, you need to pay attention to whether the film with conductive tracks has separated. You need to make it so that it separates and removed along with the keyboard. But the second film must remain in place. It is not necessary to “rip off” to the end. Where the ribbon cable goes to the printed circuit board, it is desirable that the keyboard with the edge of the film is held by the panel, as shown in the figure below.
Now you need to glue some spacers between the contacts. To do this, some craftsmen use rather thick sheets (for example, stickers from old compact cassettes). Then you have to push hard on the keyboard to make it work. Therefore, it is enough to stick double-sided (or even ordinary) tape. We cut it into strips (or squares) and glue it between the contacts. This increases the gap between the films.
After that, you need to glue the outer film together with the keyboard to the panel, rolling it with your fingers over the surface. We collect everything. And we turn on the microwave.
Sometimes the technique starts to behave in a strange way. It turns on when it shouldn't, switches modes or does not respond to commands. Of course, if you doubt your knowledge of electronics, it is wiser to contact a specialist. But what can be done if the buttons on the microwave do not work?
The touch buttons are designed in such a way that tracks with current are applied to two films. If you push the button, then it can create a contact closure.
Before starting to repair the microwave yourself, it is important to make sure that the button does not work, and not the control system itself. There is a separate technology for this. Let's assume that we are sure that it is the Start button that has broken. For repair you will need:
If the equipment needs repairs, and you decide to disassemble the touch panel with your own hands, then start by unplugging the microwave from the outlet and follow the instructions:
Inspect the plates for the integrity of all conductive paths. The problem may lie in the violation of one of them. If all the tracks are intact, then the problem is in the contact closure.
So, we got to the problem area. All the following actions must be performed as carefully as possible To avoid further damage to your microwave oven:
VIDEO
It is necessary to understand that such manipulations with equipment are only temporary solution Problems. The microwave buttons will be pushed in further, creating a new closure. To get rid of this problem permanently, it is necessary to completely replace the sensor.
Do-it-yourself button repair is a labor-intensive and not entirely safe process. It is better if you contact a master with your problem, who will completely change the sensor on your microwave and carry out its full diagnostics. In case of serious breakdowns, it will be cheaper to buy a new microwave oven.
Have you already put the dish on the reheat, but it turned out that the buttons on the microwave do not work? What to do? You can contact the service for help, or you can fix the breakdown yourself.
First, let's figure out what the keys on the sensor are. The mechanism consists of two films, on the surface of which the tracks are applied - they conduct current. When the button is pressed, the pulse passes through the membrane along the track to the main board, after which the selected mode or another command is started.
Most users prefer the touchscreen control panel because it opens up a wide range of possibilities. By pressing one button, you can select the cooking mode or heating time. These microwave ovens look stylish and modern. But it is not taken into account that electronics are sensitive to power surges in the network. A voltage drop leads to burnout of the contacts.
The sensor does not tolerate rough handling. Pressing firmly leads to pushing the button.
If the "Start" button or another key is not pressed, you can do the repair yourself.
What are the signs of panel breakage in Samsung, LG, Daewoo and others microwave ovens:
The device switches itself on and off.
Individual keys do not respond to pressing.
The door opener button does not work.
Often on the forums, they ask questions: how to open the door if the opening button is broken? How can a product be repaired? In any case, you will need to remove the casing and inspect the internal parts to understand what is wrong.
Phillips screwdriver
thin knife;
tweezers;
scotch tape or electrical tape;
glue.
Disconnect the microwave oven from the mains before proceeding with the repair.
Important! Even when turned off, some parts of the microwave accumulate electricity. Therefore, repairs must be carried out carefully.
How to repair a panel:
Unscrew the screws that secure the microwave case.
Pull the pins out of the connectors. It is advisable to photograph their location in order to connect correctly in the future.
Remove the cover plate bolts.
Dismantle the control module.
Use a thin knife carefully to detach the sensor.
Remove the top film-like layer from the control panel.
Inspect contacts and other elements for damage, burns.
How to fix the equipment if the problem is in the contact closure? Follow the guidelines:
To eliminate snapping, you need to create a distance between the two plates.
To do this, glue a piece of tape or insulating tape on the inside.
Connect the two parts and install the sensor in place, re-establish the connection.
If the keys work, then the repair was a success.
The described repair is a temporary measure. You need to understand: if the buttons began to push through, stick, sink, only a complete replacement of the panel will help.
Another problem is possible - oxidation of the tracks.
After disassembling the panel, wipe the oxidized area with solvent.
Use conductive adhesive to repair the damaged portion of the track. Apply a thin layer to the tear site. Wait until dry. Reassemble the panel in reverse order.
If that doesn't work, take note of one user's experience. After the repairs performed according to the described recommendations, the operation of the control did not recover.Then, instead of glue, aluminum foil was used.
Cut out a thin strip of foil.
Glue to the track with glue.
A detailed analysis of the repair is shown in the video:
VIDEO If you have not done repair work before, it is better to contact a specialist. The electronic controls are very sensitive, so use your microwave with care. To avoid problems with power surges, install a voltage stabilizer.
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.
The microwave oven is one of the most demanded household electrical appliances. Quite often, when purchasing a microwave oven, potential consumers opt for models equipped with a touch keyboard. As of today, this type of microwave oven is the most popular in the domestic market.
Microwave ovens with touch control differ from other models of microwave ovens:
stylish design;
intuitive controls;
the ability to program while cooking according to complex recipes;
storing favorite recipes in the device's memory, which can be called up by lightly pressing a finger on the corresponding sensor (microwave ovens of Samsung and LG brands);
the presence of fixed cooking programs (for example, in the Panasonic NN-ST342W, etc.).
However, such microwave ovens have one significant drawback - the control unit, equipped with a touch keyboard, requires careful handling during operation and does not tolerate power surges. ... Unfortunately, in modern conditions, it is practically impossible to provide gentle working conditions for microwave ovens, therefore, sensor control units (CU) often fail. Wherein cause of malfunction may be caused by the buttons on the microwave not working.
Sensory (sometimes called membrane) the keyboard is a compact three-layer membrane design without separate moving mechanical parts. On two films, in the places where the keys (buttons) are located, there are contact pads that are interconnected by conductive tracks. Between them is an adhesive mask with slots (holes) that allow the contact pads to touch when pressed lightly. The operation of the membrane keyboard is ensured by the high flexibility of the constituent elements.
The touch keyboard, with which the user controls the operation of the microwave oven, is the weakest point of such a sufficiently reliable electrical engineering. The microwave oven reacts with unpredictable behavior to the breakdown of the touch buttons. , for example, sudden switching of operating modes, lack of reaction to touching one or several sensors, as well as spontaneous switching on or off (breakdown of the "Start" button). At the same time, the problem can also suddenly disappear, and after a while it appears again.
Any malfunctions due to which the touch keyboard has stopped working, can be divided into three groups :
sticking of membrane contacts, due to which the buttons of the touch panel are not pressed;
breakage of current-carrying conductors;
violation of contacts at the connection points of the loop and the connector on the control unit.
All these breakdowns the owner of the microwave oven can easily fix it on his own ... The exception is models produced by Daewoo, in which the appearance of the facade is disturbed when the touch panel is removed. Such microwave ovens are recommended to be repaired in a certified workshop, where they can replace sensors with ordinary buttons.
Important! When starting to repair a microwave oven, you should remember that even when the equipment is turned off, you can get under the influence of an electric current. This is due to the presence of components operating under a voltage of about 5 kV and capable of accumulating a certain amount of electricity.
To repair a keyboard with touch buttons, you will need:
Screwdriver Set;
tester (multimeter);
stationery knife;
tweezers;
pencil type "Constructor 4M";
electrical tape or ordinary narrow tape, about 6 mm wide;
fine-grained sandpaper;
a degreasing liquid such as alcohol;
conductive adhesive such as Kontaktol or its analogs;
PVA glue or similar.
Before starting repairs with your own hands, the microwave oven must be disconnected from the power supply ... Further, the microwave needs to be disassembled ... To access the touch keyboard, you need to separate the front panel from the case by unscrewing all the screws that secure them. Such screws can even be located on the bottom.
Then it is necessary dismantle the control box ... To do this, unscrew the protective panel and remove the control unit from it. This will open access directly to the touch keyboard, which is connected to the control unit with a special loop. Having disconnected the cable, you can start repairing buttons that do not respond to a light touch.
Disassembling the keyboard must be done very carefully and carefully.
First of all, you need stratify three-layer "sandwich" ... To do this, pry the corner of one of the films with a clerical knife, intercept it with your fingers and smoothly separate the layer from the base.
Before starting repair operations, it is necessary to visually inspect films for the detection of traces of oxidation of the contact pads and damage to the conductive tracks. Particular attention is paid to checking their status in the area where the buttons are not working. If it was not possible to visually detect damage, it is necessary to check (ring) the integrity of the tracks using a multimeter.
Having found a break in the conductive track, proceed to its rebuilding ... To do this, it must be thoroughly degreased, and then a layer of special glue is applied to the damaged area.
Important! When working with conductive adhesive, it is necessary to comply with the requirements set out in the instructions for its use.
After the adhesive mixture is dry, a tester is used to check the conductivity of the tracks.
Advice! In the absence of conductive glue, you can use a soft pencil, carefully sketching the damaged area with a lead.
Sticky buttons can be caused by a number of reasons, among which the most common is excessive finger pressure on the button and contamination of the contact pads. Eliminate the causes of "sticking" by slight increase in the distance between the upper and lower films ... To do this, first, both films are thoroughly degreased, and then the inner surface of one of them is carefully sealed with tape or tape. In this case, it is necessary to ensure that the contact pads remain open. After finishing work, you need to make sure that the buttons do not stick and provide reliable contact with a light touch.
The contact at the point of attachment of the loop is most often disrupted due to oxidation of the corresponding tracks ... Therefore, the first thing to do is to degrease them thoroughly. Sometimes destruction of the tracks is found, which also leads to a breakdown in contact. In this case, the end of the cable must be carefully cut with scissors by a few millimeters, then put back into the connector and make sure that the contact is restored.
After restoration work the keyboard is assembled by performing all operations in reverse order ... If the adhesive mask remaining on the films is not enough for reliable bonding of the layers, then additionally PVA can be applied, excluding the ingress of glue on the contact pads of the buttons.
Advice! It is not recommended to use adhesives such as "Superglue", as it will not be possible to re-disassemble the keyboard that has broken.
Having assembled the keyboard, it is installed on the front panel and the microwave body is assembled, placing all the removed parts in their places. After that, the oven is plugged into a power outlet and the buttons are checked for functionality.
VIDEO
The best way to avoid damage to the touch keyboard when using the microwave is to install it away from vapors that accompany the cooking process on a gas (electric) stove. ... It will also help to extend the life of the sensor, following these rules for using the microwave oven:
accurate pressing of the keys (buttons);
regular cleaning of the front of the microwave, while avoiding flooding the touch panel with cleaning fluids.
Note! It is recommended not to turn on the microwave oven to the power supply without a voltage stabilizer. This will avoid voltage surges that could damage the conductive parts of the touch keyboard.
VIDEO 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:
