DIY daewoo microwave touch panel repair

In detail: do-it-yourself daewoo microwave touch panel repair from a real master for the site my.housecope.com.

The more often we use household appliances, the faster they fail. In this regard, the microwave can be classified as one of the most demanded household electrical appliances in the kitchen. It is not by chance that they break quite often.

One of the weakest points of microwave ovens is the control panel. At one point, the technique begins to malfunction: the touch buttons for selecting programs stop responding to pressing or work every other time, the start button on the microwave does not work, and problems can also arise with the door opening button.

Fortunately, in most cases, you can fix all of the listed problems with your own hands, without asking for help from a service center.

First, you need to establish why the microwave does not respond to pressing some buttons.

This is most often due to:

damage to the conductive tracks on the board,
loss of contact in connectors,
sticking contacts.

The first thing to start with is checking the quality of the keyboard bus contacts in the control module connector.

If everything is in order with the contacts, the touch control panel itself will most likely have to be repaired.

If no touch buttons are pressed on the microwave, this indicates that the control board needs repair or complete replacement.

To carry out diagnostics and repairs at home, you must have the following tools on hand:

crosshead screwdriver;
stationery knife;
multimeter-tester;
contact cleaner or finest sandpaper;
alcohol or degreaser;
conductive adhesive for repairing boards.

Video (click to play).

The process of diagnostics and repair itself is carried out in the following sequence:

VIDEO INSTRUCTION

It should be understood that such manipulations allow you to get rid of the problem for a while. If microwave buttons are pretty worn out, it is recommended to completely replace the entire sensor.

Another common problem faced by owners of microwave ovens is the door refusing to open when the corresponding key is pressed. The first thing that comes to mind in this case is that the microwave opening button has broken.

In fact, the problem is not in the button itself, but in the part called the "microwave oven door latch." It is made of plastic and can wear out and break with prolonged use.

Replacing this part will help to solve the problem. Today, you can find and order on the Internet a "native" latch for almost any microwave oven, especially when it comes to a popular model.

However, in order to make sure that the latch is not jammed, and it really broke, you need to somehow open the door.

It is easy to do, you just need to remove the cover of the microwave oven housing by unscrewing several fastening bolts with a screwdriver, and squeeze the hook with your hand or with an improvised tool.

VIDEO REVIEW

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 voltage surges in the mains... 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 designwithout 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 provided due to 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 points of connection 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 the buttons that do not respond to a light touch. Image - DIY daewoo microwave touch panel repair

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 case 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.

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.

We fix the “touch” microwave keyboard with our own hands.

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.

The first is the replacement of “touch” devices. Quite a simple and quick way. If you can find these very devices, and they, unfortunately, are not so easy to find. Now people themselves are trying not to repair anything, but to hand it over to the workshops. Therefore, there are no spare parts in the stores.
The second is to mount conventional buttons instead of "touch" panels. In this case, you have to tinker, but there will be no more of these malfunctions. But again, there remains the difficulty in finding these very buttons. They are not in stores either, since there is no demand for them.

And the last thing. It turns out that the inquisitive mind of the Kulibins is capable of coming up with original solutions. As the saying goes: "The need for invention is great!" You just need to put, for example, an adhesive tape between these two films, then the gap between them will increase, and there will be no short circuit.

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.

View of the "touch" panel from the inside.

Author of the article "Do-it-yourself microwave touch panel repair" Sanych

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 you do if the buttons on the microwave don't 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:

Phillips screwdriver to open the panel.
Thin knife or sturdy scissors.
It's good if you have tweezers. This will greatly simplify the repair work.
Plain tape or special insulating tape.
Good glue.

Before you start repairing, do not forget to turn off the power microwave ovens. True, in the microwave there are parts that can accumulate electricity, so it is not always safe to work with equipment. It is better to entrust repairs to specialists.

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:

Unscrew the bolts that hold the microwave oven lid.
We take our time to disassemble all available connections. At this point, it is important to remember which part is connected to where. It will be good if you take a photo of all the contacts you have.
We find a special protective panel and unscrew the bolts on it.
We take out the control unit from the panel.
Detach the sensor plate using a knife or thin blade.
Divide the plate into two parts.

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 possibleTo prevent further damage to your microwave oven:

To increase the distance between the plates and prevent shorting, it is necessary to stick an adhesive tape or insulating tape on the inside of the plate.
Now we connect the two plates and connect the ribbon cable to them.
We glue the sensor in place.
We assemble the microwave in the reverse order.
We check our device for the functionality of the buttons.

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 for your microwave and carry out its full diagnostics. In case of serious breakdowns, it will be cheaper to buy a new microwave oven.You can download movies, clips, episodes, trailers for free, and you do not need to visit the Youtube site itself.Download and watch an ocean of endless video in high quality. Everything is free and without registration!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 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 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. The 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, use a Phillips screwdriver to unscrew 6 bolts. 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 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 a 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 may be disconnected or a plug is clogged and needs to be cleaned and secured in place.The above methods will allow you to repair Whirlpool microwaves, repair Panasonic, Samsung, or other ovens. But if something is not clear, you should watch the training video on repair. The video teaches on the principle - look and repair.In the video, tips for repairing Whirlpool microwaves at home:Found on the Internet. Works for sure.Often the following malfunction is observed in microwave ovens, the oven begins to "live its own life." Does not respond to keystrokes, spontaneously starts, and all this manifests itself chaotically and randomly, it can recover and work normally for some time.
The reason for this disgrace is that the insulation between the conductors of the keyboard deteriorates. It is impossible to check this with a multimeter, the test voltage is too low, but for some reason the controller is enough.
Often masters decide that the processor is faulty, and it is completely in vain. The best solution is to replace the membrane keyboard, if there is, if not, then you can restore the old one. The keyboard consists of two films, on which conductive tracks and contact pads are applied, opposite each other. There is a mask between them, with slots opposite the contact pads, it is still very sticky and sticks together the films.For repairs, you need to glue the keyboard, the main thing here is not to make sudden movements, and not to pull not evenly and too hard. We remove the electronic unit.
We take a table knife with a round tip and carefully pry off the edge of the films so that you can grab the top one with your fingers, and then the main thing is not to bend or tug. There is no need to glue or tear off the outgoing loop of conductors, and it is more coastal with it. You need to glue it so that the upper film is separated, and the sticky mask and the lower film remain on the body. After several attempts, it will turn out nicely and neatly.
Next, next to the body, we put a book of suitable thickness, turn it off, as it were, open the unsticked film with the contacts up (the book is for ease of use). We take scotch tape and glue the entire surface of the film, except for the contact pads, it is better to use a narrow 6-8 mm, it is more convenient to work.
We return everything to its place, put the electronic unit in place, assemble it, check it and, hurray, everything works.
In this way, more than a dozen of all kinds of microwave ovens were restored, most of all Samsung (just the most in use), there were DEU and Shivaki.
All of the above does not apply to the GoldStar ovens of the MA 651 and MA 851 models in them COP444 really dies, however, it is successfully treated by “frying” (in 50% of cases), but that's another story.eximdnepr, this method saves from 2 months to a year maximum - then you still need to change the keyboard. Image - DIY daewoo microwave touch panel repair

If a person agrees, then we conjure.

Before opening the membrane, you should turn it off and with a piece of wire (preferably with a resistor of about 1 kOhm), by closing the connector contacts, simulate pressing the buttons.
As a rule, there is a defect in the loop-to-connector junction, or in poor insulation (less than a hundred megohms) -leaks between the tracks. This can be checked using a conventional multimeter (DT9208A, DT9502, etc.) with a low test voltage and a measurement limit of 200 MΩ.
Next, you should try to close with a connected membrane. It is useful to look at the signals with an oscilloscope to find the “pressed” button, which may be virtual and not present on the keyboard.
The connection with the broken track can be restored with the MGTF wire. To do this, I put the end of the wire, stripped by a few mm, between the two films on the track of the panel itself, and solder the second to the connector. Up to five tracks can be corrected in this way. If everything is torn, it is better to put buttons under the film.
Cracked paths in open areas are repaired with conductive varnish.

Good afternoon, I have a very long experience with microwave ovens.
Here is a specific piece of advice for you: he unfolds the keyboard (gently pry the top maple on which the buttons are written on the edge with the tip of the noch, and pull it towards ourselves slowly), after gluing the keyboard, we take the HARDEST SIMPLE PENCIL for example 4M and rolls over the contact pads, while removing the excess graphite dust with cotton wool with a swab, glues everything back and try, everything works with a light touch and for a very long time. Use on health