The repair of the microwave oven keyboard, which I describe in this article, is not my invention. I read it myself on the Internet. My contribution is how to disassemble the "microwave", because each of them has its own characteristics when repairing.
The strange behavior of the microwave oven forced me to start repairing. At one point, 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! And when the oven spontaneously turned on several times, and then it didn’t turn off at all (you close the lid - it turned on!) I had to take action.
On the Internet, on all sites, there is a talk about a magnetron, about high voltage, etc. I read it, and I was afraid, I thought - why not give it to the workshop? I found the material about the keyboard malfunction quite by accident, when I had already disassembled the microwave and already checked the high-voltage fuse, high-voltage capacitor and high-voltage diode. Well, at least I didn’t get to the magnetron!
Microwave ovens that have so-called "touch" keyboards do not actually have any touch keyboards. There are, however, no buttons. They have two films, on each of which conductive paths and contact pads are applied opposite each other. When you press the panel, it bends, and these areas are in contact. A closure occurs. If you approach the issue fundamentally, this is not a touch switch, since the capacitance of the human body is used in touch devices, which makes the switch. And here, the same closure as in a regular button.
Of course, it all looks very modern, cool. But there is one disease. Over time, when these films are deformed, the closure occurs by itself. At the same time, microwave ovens begin to live their own lives and either stop responding to keystrokes, or vice versa, they can start working spontaneously. Therefore, with the introduction of so-called "touch" switches in microwave ovens, keyboard failure 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 figure above). I don't describe how to remove the shroud here, because I don't think it's difficult - unscrew the screws you can 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 printed circuit board.Before that, disconnect the cable that goes from it to the "sensor". To do this, pull the top of the block up. It will rise by about 1 mm, after which the cable can be freely removed (see below).
And here is the panel in your hands. Now you need to "unstick" the keyboard. Carefully, with a sharp knife, lifts the lower corner opposite the train. "Tear off" the keyboard. In this case, you need to pay attention to whether the film with conductive paths has separated. It is necessary to make sure that it is separated and removed along with the keyboard. But the second film should remain in place. There is no need to "tear off" completely. Where the cable goes to the PCB, it is desirable that the keyboard with the film on the edge hold onto the panel, as shown in the figure below.
Now you need to glue some gaskets in between the contacts. For this, some craftsmen use rather thick sheets (for example, stickers from old compact cassettes). Then you have to diligently push the keyboard so that it starts working. 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. In this case, the gap between the films increases.
After that, you need to glue the outer film together with the keyboard to the panel, rolling your fingers over the surface. We collect everything. And turn on the microwave.
Sometimes technology starts to behave strangely. It turns on when it should not, 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 you do if the buttons on the microwave do not work?
The touch buttons are arranged 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 embarking on an independent microwave repair, 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 was the "Start" button that broke. For repairs you will need:
If the equipment needs repair, and you decide to disassemble the touch panel yourself, then start by unplugging the microwave from the outlet and follow the instructions:
Inspect the plates for the integrity of all conductive tracks. The problem may lie in the violation of one of them. If all the tracks are intact, then the problem is in the closure of the contacts.
So, we got to the problem area. All of the following steps must be taken as carefully as possible to prevent further damage to your microwave:
VIDEO
It must be understood that such manipulations with technology are only temporary solution Problems. The buttons of the microwave oven will continue to push in further, creating a new circuit. To get rid of this problem for good, you need to completely replace the sensor.
Repairing buttons with your own hands is a labor-intensive and not entirely safe process. It is better if you address your problem to the master, 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 heating, 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 tracks are applied - they conduct current. When the button is pressed, the impulse passes through the membrane along the track to the main board, after which the selected mode or other command is launched.
Most users prefer the touch 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 microwaves look stylish and modern. That's just not taken into account that the electronics are sensitive to power surges in the network. The voltage drop causes the contacts to burn out.
The sensor does not tolerate rough handling. Strong pressing 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 failure in Samsung, LG, Daewoo and others microwave ovens:
The device turns itself on and off.
Individual keys do not respond to pressing.
The door open button does not work.
Questions are often asked on the forums: how to open the door if the open button is broken? How to fix the product? In any case, you will need to remove the casing and inspect the internal parts to understand what's wrong.
cross screwdriver;
thin knife;
tweezers;
adhesive tape or electrical tape;
glue.
Before proceeding with the repair, unplug the microwave oven from the mains.
Important! Even in the off state, some parts of the microwave accumulate electricity. Therefore, repairs must be carried out carefully.
How to repair the panel:
Loosen the screws securing the microwave housing.
Pull the contacts out of the sockets. It is advisable to take a picture of their location in order to connect them correctly in the future.
Unscrew the bolts of the protective panel.
Remove the control module.
Gently use a thin knife to pry off the sensor.
Remove the top layer in the form of a film from the control panel.
Inspect contacts and other elements for damage, burns.
How to fix the equipment if the problem is in the closure of contacts? Follow the guidelines:
To avoid shorting, you need to create a distance between the two plates.
To do this, glue a piece of adhesive tape or insulating tape on the inside.
Connect the two parts and put the sensor back in place, restore 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 squeeze, stick, sink, only a complete replacement of the panel will help.
Another problem is also possible - oxidation of the tracks.
After disassembling the panel, wipe the oxidized area with a solvent.
To repair the damaged part of the track, use conductive glue. Apply it in a thin layer to the gap. Wait for it to dry. Assemble the panel in reverse order.
If this does not help, take note of the experience of one user. After the repair according to the described recommendations, the operation of the control was not restored.Then aluminum foil was used instead of glue.
Cut out a thin strip of foil.
Stick to the track with glue.
A detailed analysis of the repair is shown in the video:
VIDEO If you have not done repairs before, it is better to contact a specialist. The electronic controls are very sensitive, so operate the microwave with care. To avoid problems with surges in the network, 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 Major Problems
It is rare that a kitchen can be imagined without a microwave. Recently, she
If the 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 proceeding with the repair of a microwave oven, it should be understood that a person who has at least some knowledge in electronics and electrical engineering can repair a microwave oven in a quality manner.
Also, when working, you must follow all safety rules.
To repair microwaves, you need to know the following basic elements:
Energy-converting transformer;
Magnetron;
Rectifier;
Fuse;
Fan;
Capacitor;
Control block.
Understanding where and what is quite simple. Right in the middle of the chamber is a magnetron, and underneath it is a transformer. 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 network!
If the breakdown consists in the failure of one of the main elements, then it will be easiest to replace it. The fact is that many parts of the furnace 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 you should perform the following steps:
Disconnect the oven from the mains;
Discharge the transformer (it will take about 5 minutes);
Disconnect the desired part from the terminals and remove;
Put the work piece in place.
When replacing, you need to pay attention to the correspondence of the diagram 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 high-quality repair of the microwave oven.
The fact that the furnace has broken down or is not working, as a rule, is signaled by some signs. According to them, the cause of the breakdown is determined.
So, what could it be, in more detail:
This is how the most common malfunctions that you can do yourself look like. When working with electricity and checking the elements of the furnace, one should not forget about safety precautions.
The microwave oven may have a touch or conventional control panel, which may be affected by exposure to high temperatures.
As a rule, problems with this part occur after 3-4 years of intensive use, and are expressed in the failure of the “obey commands” buttons. At the same time, some error can be displayed on the scoreboard. The oven can turn itself on 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, with a thin sharp knife, you need to pry off the touch film, while trying not to damage the membrane. It is best to start from the bottom or top corner on the left.
After removing the membrane, you need to check the operation of the panel by closing the contacts. Inside the oven, you can put a container with water. 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 exclude the possibility of a short circuit, you need to glue these places with pieces of electrical tape or adhesive tape.
Next, the upper membrane is put in its place, after which the operation of the microwave is checked. If something doesn’t work again or hardly responds to pressing, you should again turn off the stove, peel off the membrane film and remove the electrical tape or add it somewhere (depending on what doesn’t work). Do this until the buttons work as they should.
A touch panel repaired in this way can work for about six months, but it may continue to bend further, after which it will again have to be “straightened” or bought a new one.
If the microwave oven sparks, stops heating food or takes too long, the problem is most likely in the magnetron, which is the main heating element of the microwave device.
By the way, changing the magnetron in a microwave oven that has been serving for more than 5 years is unprofitable from an economic point of view.
As a rule, this device is "planted" on the terminals and screws that fix it to the base of the stove. However, replacement of the magnetron is required in rare cases. 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 descaled and rotated 180 degrees;
A new cap is made from a suitable capacitor housing;
It will also not be superfluous to replace the mica plate, which is exposed to harmful rays.
Actually, there is nothing complicated in repairing a magnetron, but if the problem is not in a burnt 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 the safety measures and proceed with caution. Knowing the main elements of the device device, you can calculate the cause of the breakdown yourself and eliminate it.
The microwave oven is one of the most used 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 ovens is the most popular in the domestic market.
Microwave ovens with touch controls differ from other models of microwave ovens:
stylish design;
intuitive control;
the ability to program when cooking according to complex recipes;
storing in the memory of the device the recipes you like, the call of which is carried out by lightly pressing a finger on the corresponding sensor (microwave ovens of Samsung and LG trademarks);
the presence of fixed cooking programs (for example, in Panasonic NN-ST342W models, etc.).
However, such microwaves have one significant drawback - the control unit, equipped with a touch keyboard, requires careful handling during operation and does not tolerate power surges in the mains . Unfortunately, in modern conditions it is almost impossible to provide gentle working conditions for microwave ovens, so sensor control units (CU) often fail. Wherein cause of failure may be caused by the buttons on the microwave not working.
Sensory (sometimes called membrane) the keyboard is a compact three-layer film construction , which does not have separate moving mechanical parts. On two films in the places where the keys (buttons) are located, there are contact pads connected to each other by conductive paths. Between them, an adhesive mask is applied with slots (holes) that allow the contact pads to touch when lightly pressed. 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 fairly reliable electrical engineering. The microwave oven reacts to the breakage of the touch buttons with unpredictable behavior , for example, sudden switching of operating modes, lack of response to touching one or more sensors, as well as spontaneous switching on or off (breakdown of the "Start" button). In this case, the problem may also suddenly disappear, and after some time it will appear again.
All malfunctions due to which the touch keyboard stopped working, can be divided into three groups :
sticking of the membrane contacts, due to which the buttons of the touch panel are not pressed;
breakage of conductive conductors;
broken contacts at the junction of the cable and the connector on the control unit.
All these breakdowns the owner of the microwave oven may well eliminate it on his own . The exception is models manufactured 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 conventional buttons.
Important! When starting to repair a microwave oven, it should be remembered that even when the equipment is turned off, you can get under the influence of 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 "Designer 4M";
electrical tape or ordinary narrow tape, about 6 mm wide;
fine-grained sandpaper;
degreasing liquid, for example, alcohol;
conductive adhesive type Kontaktol or its analogues;
PVA glue or similar.
Before starting repairs with your own hands, the microwave oven must be disconnected from the power supply . Further, microwave needs to be taken apart . To gain access to the touch keyboard, you need to separate the front panel from the case by unscrewing all the bolts that secure them. Such screws can even be on the bottom.
Then you need dismantle the control unit . 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 cable. By disconnecting the cable, you can start repairing buttons that do not respond to a light touch.
Work on disassembling the keyboard must be carried out very carefully and carefully.
First of all, you need stratify a three-layer "sandwich" . To do this, pry off 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, visually inspect films for detecting traces of oxidation of the contact pads and damage to the conductive tracks. Particular attention is paid to checking their condition in the area where the non-working buttons are located. If it was not possible to visually detect damage, it is necessary to check (ring out) the integrity of the tracks using a multimeter.
Having found a break in the conductive path, proceed to it restoration . To do this, it must be thoroughly degreased, and then applied to the damaged area with a layer of special glue.
Important! When working with conductive adhesive, it is necessary to comply with the requirements set forth in the instructions for its use.
After the adhesive mixture dries, the tester checks the tracks for conductivity.
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 are excessive finger pressure on the button and contamination of the pads. Eliminate the causes of "sticking" by a slight increase in the distance between the top and bottom films . To do this, first, both films are thoroughly degreased, and then the inner surface of one of them is carefully sealed with adhesive tape or electrical 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.
Contact at the point of connection of the loop most often disrupted due to oxidation of the corresponding tracks . Therefore, the first thing to do is to thoroughly degrease them. Sometimes the destruction of the tracks is detected, which also leads to a violation of the 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 PVA can be additionally applied, eliminating the ingress of glue on the contact pads of the buttons.
Advice! The use of adhesives such as "Superglue" is not recommended, since it will not be possible to re-disassemble a broken keyboard.
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 the power outlet and the operation of the buttons is checked.
VIDEO
The best way to avoid damage to the touch keyboard during microwave operation is to install it away from the fumes that accompany the cooking process on a gas (electric) stove . It will also help to extend the life of the sensor by observing the following rules for using a microwave oven:
accurate pressing of the keys (buttons);
regular cleaning of the front of the microwave, while avoiding flooding the touch panel with washing liquids.
Note! It is recommended not to turn on the microwave oven without a voltage stabilizer. This will avoid power surges that can damage the conductive parts of the touch keyboard.
VIDEO The kitchen assistant is not so complicated that in case of minor malfunctions, contact a microwave repair shop. It is easy to repair Samsung, MYSTERY MMW, Whirlpool, LG, Panasonic and other popular models on your own. To determine the malfunction and replace parts, it is enough to have the knowledge gained at school and the ability to solder.
To make home repairs of panasonic microwave ovens 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 chamber by a waveguide;
transformer;
high voltage fuse;
high voltage diode;
condenser;
control unit.
The magnetron is located in the center of the compartment. The transformer, consisting of a type-setting 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.
Low is applied to the magnetron filament, and high is applied to a voltage doubler consisting of a diode and a capacitor, and then to the anode. The result is microwave radiation used by ovens to heat and cook food. The microwave power is controlled by the microwave control unit.
Each breakdown is accompanied by its own symptoms:
Inside the furnace, something sparkles, crackles and shoots. This phenomenon is observed during the destruction of the mica lining that closes the exit of the waveguide into the chamber. The same thing happens when the protective cap of the magnetron burns out.
The food placed in the chamber is not warmed up. The pallet rotates, the backlight works. The problem occurs due to a blown high-voltage fuse or breakdown of the capacitor.
The microwave does not heat well. This is due to low voltage in the mains or loss of emission by the magnetron.
The oven does not turn on. First, the integrity of the power cord, fuse and the presence of voltage in the outlet are checked. Then the state of the blocking 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 housing.
Tray does not rotate. The coupling connecting the motor shaft to the pallet is cut off or the motor is faulty.
During operation, the oven, in particular the Mystery mmw, emits a loud buzz. Faulty transformer or fan.
Typed commands are not executed. It is possible that the contacts of the control unit burned out due to the high temperature.
No indication or timer is displayed. The microprocessor is broken. 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, keep 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 protrusion. There may be several fasteners, so before excavating, you must make sure that they are all removed.
Before removing the cover, unplug the power cord from the outlet.
Since capacitors retain their charge for a long time, it is necessary to immediately discharge them by jumping the leads 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 furnaces and reflects all elements in sufficient detail. Do-it-yourself lg microwave repair can be done in accordance with the recommendations below.
Electric circuit diagram of a microwave oven.
Microwave ovens are equipped with 2 fuses. The first one in a glass case is installed at the voltage input from the socket. Continuity is checked visually or with an ohmmeter. The second, high-voltage, in a tubular plastic case is located near the transformer. It burns out when a diode or capacitor in the high-voltage magnetron circuit fails. Do not replace them with "bugs", as this can lead to a fire.Before installing new fuses, it is useful to analyze the causes that led to the blown so that the situation does not happen again.
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 lining, which causes sparks and crackling in the chamber. In this case, the magnetron has to work with overload, which leads to failure. Sheets of mica are sold in radio stores, and anyone can cut a plate of the desired size. If there is no possibility of replacement, then temporarily, after cleaning, the old plate is used, which is installed with the damaged side inside the waveguide.
The burning 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 necessary 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 last 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 by connecting it through the tested diode to a 220 V network. If the part is in good condition, the light bulb does not glow at full heat. With a bright glow or its absence, the diode is replaced.
Capacitors, including high-voltage ones, are checked by measuring their resistance with an ohmmeter. If the device shows infinity - everything is in order. With readings of 0 or several ohms, the part is replaced. If, when checking a high-voltage capacitor, the resistance is 1 MΩ, then a discharge resistor is installed in it and it is suitable for use.
The check is made with an ohmmeter, which measures the resistance of the windings. In the primary, depending on the microwave 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 the value range of 3.5 - 8 ohms.
If a malfunction is not detected, and the microwave does not heat, proceed to check the magnetron. To do this, remove the top cover, disconnect the terminals with wires and measure the resistance between the terminals.
If the ohmmeter shows several ohms - the filament is intact, at infinity - it is broken 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 at the soldering points of their conclusions.
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 will do (for example, from the Mystery mmw microwave oven) with similar power characteristics.
First, the source of the buzz is determined. If it is a transformer, then it is replaced by a similar one. A healthy fan usually hums due to system overheating. To make it silent, it is enough to rearrange 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. Perhaps it is disconnected or the contact is clogged, which needs to be cleaned and fixed in its original place.
The above methods will allow you to repair Whirlpool microwaves, repair Panasonic, Samsung microwaves, or other ovens. But if something is not clear, you should watch the training video for repair. Video teaches on the principle - look and repair.
Video (click to play).
In the video, tips for repairing Whirlpool microwaves at home:
