How to repair a microwave at home

Repair of microwave ovens with your own hands at home

To carry out the repair of the microwave, you must have a general idea of ​​how it works. Repair of the microwave oven begins with the removal of the upper cover. Before this, you should take care of a complete shutdown of the device from the power supply network, only then proceed to eliminate breakdowns with your own hands.

When these actions are successfully done, a transformer with two fuses will open for access: one is located directly on the details itself, it is fusible, the second is located near the HF oven body, made of ceramics. Also near the transformer there is a double.Stroke block, consisting of a thick capacitor and a diode. The entire set of these elements is a power supply chain of a microwave magnetron.

Important:

Carefully! Do not immediately touch the capacitor immediately after removing the upper protective panel. This element is able to maintain a voltage for a long time, which can easily lead to an electric shock. When repairing a microwave oven with your own hands, this factor should be taken into account.

It is important to know

The main element of the microwave oven is a magnetron, which is a transformer that transforms current into high-frequency voltage. And it is it that is extremely dangerous for a person.

Accordingly, when disassembling equipment or performing any work, it is necessary to carefully observe safety precautions.

• Be sure to de.Energize the microwave before repair.
• Be sure to use grounding.
• Do not disassemble the magnetron without proper experience and without the use of dielectric mittens.

Inside the microwave building, a screen is provided, which does not allow the penetration of microwave radiation to the outside. And it is for this reason that the stove cannot be turned on when the door is open. This is a kind of protective mechanism provided for by the manufacturer himself.

But when disassembling, there is a possibility of closing the door lock mechanism. In no case can you turn on an open microwave!

Search for a malfunction in a microwave

If the microwave oven has a digital display on which the error code in the form of the letter E with the number has appeared, then you need to find in the instructions for the operation of the furnace what fault means this code. Perhaps, having completed the instructions, you do not have to engage in serious repair.

Attention! When repairing a microwave, you should be careful. Touching the bare sections of the circuit connected to an electrical network can lead to electric shock defeat. Do not forget to remove the fork from the outlet and discharge the high.Voltage capacitor when checking!

Before starting the independent repair of the microwave oven, you need to remove the fork out of the outlet, turn out several screws fixing the lid and remove it, moving towards the posterior wall of the stove.

Further, all parts and nodes are carefully examined for the presence of mechanical or thermal damage in the form of darkening. The density of the planting of unit terminals is checked. If there are no visual defects, then according to the instructions in the table, the search is carried out and eliminated.

Where to buy the necessary spare parts for the microwave, how much they cost

If there are spare components, you can repair the broken furnace and save on the purchase of a new. Buy details in service centers, at manufacturers, specialized stores for the sale of household appliances and Internet sites.

How to replace high.Voltage fuses

The analogue element is selected according to the indicators indicated on the old fuse. Look at the case. Power is measured in amperes.

Keep in mind that if the face value is smaller, the furnace will constantly turn off, if more. There is a risk that the whole chain will burn.

The algorithm of actions when replacing the fuse:

• Find the location of the burned spare part. This is evident in the instructions attached by the manufacturer to the device;
• To access the details, remove the panel;
• Neatly, so as not to break the latches, the fuse is dismantled. The service centers use tweezers for this;
• According to the same scheme, a new element is carefully inserted in return for the burnt;
• Install the panel not its place and fix it with fasteners.

How to replace a cap with a magnetron

• Remove the microwave casing;
• Dismantle the nutrition terminals;
• Self.Tapping screws are unscrewed. They connect the magnetron with the waveguide;
• Remove the magnetron;
• Extract a burnt cap;
• Before installing a new one, they are convinced that the antenna retains integrity. If there are soot on it, contaminated places are carefully cleaned;
• Put a new part and assemble the opposite algorithm.

How to replace a burned protective mica

Replacing mica. Fairly simple manipulation. You can not even buy a new plate at the same time. They work according to the plan:

• Extract a damaged element;
• Process the charred area;
• Turn over the mica side with the burned side to the inner wall of the furnace;
• They are attached to the place of fixation and make marks, in the locations of the mounts;
• Make holes according to the marks;
• Reliably attach the fee back;
• The device is ready for further operation.

How to fix a timer, control module

Before starting the repair, the device is disconnected from the network. Further according to the scheme:

• To extract the part, the screws are removed;
• Dismantle the timer into the camera;
• Before disconnecting the wires, they photograph their location on the phone;
• Disconnect the wires from switching and timer modes;
• The position of the gears and regulators apply marks, everything is fixed. It will be easier to collect everything back;
• Before disassemble the timer, they rehabit all contacts step by step;
• Remove the timer cap. Fix the shaft of the cover and external gear with their hand. Note! If the position of the gears shifts, it will be difficult to establish their work then;
• Visualize the inner element. Chopped contacts are cleaned, visible cracks are soldered and shunt;
• Conduct a reverse assembly.

How to replace the capacitor in the furnace

In the presence of elementary skills in working with electrical appliances, all steps to replace the capacitor are performed for 20-30 minutes:

• Disconnect food;
• Remove the screws that hold the lid on the side frame;
• Shift the body;
• Keep in mind that the capacitor is the ideal place of dust, which negatively affects its work. In addition, a certain energy remains in the capacitor. Your task is to discharge it. Turn to the terminal with a screwdriver. If a spark appears, it is working. If not, proceed to the next stage;
• Using the multimeter, the power of the element resistance is determined;
• Turn over the microwave with a lid up;
• Remove the transformer. The capacitor is located under it;
• Dismantle the metal strip. It blocks the capacitor and change it to a new one;
• Collect the stove in the original state.

How to replace a cooler in a microwave

In most models, the fan is near the transformer. To get access to it, the capacitor is dismantled. How to do this step by step was considered in the section above.

To remove the cooler, you need a set of screwdrivers:

• Unscrew the lower fixers. They are dismantled without tools;
• The screws are unscrewed on top with a cross blade;
• Remove the transformer;
• Carefully disconnect the fan, test it and, if it is impossible to repair, change it to a new one;
• Collect the stove, screw the back panel.

How to repair a power supply unit

The power supply malfunction is diagnosed in 30% of the breakdowns. In modern microwave versions, instead of a transformer, manufacturers install a small pulse block. If he burns out, he is simply changed to a new.

Consider the older version of the microwaves, where the power supply is equipped with a transformer.

Repair of microwave faults yourself

Microwave repair is a feasible task for a novice electrician. If the problem is the breakdown of one of the constituent elements of the furnace, then the simplest and most correct solution is to replace it. The bottom line is that most of the details of this device are not subject to repair, but only a complete replacement with a new. This is especially true for fuses, diodes and capacitors. The main reasons for the failure of the device.

Replacing parts is carried out in a few steps:

• The microwave is turned off from the network.
• The transformer is discharged (5 minutes).
• The terminals are disconnected from the defective details, it is extracted.
• A working part is connected to the same place.

When replacing the part, you need to take into account two important factors. The first of them is compliance with the scheme. It is important to remember that each detail has its own characteristics selected for the performance of the entire electrical circuit. If this nuance is not taken into account after replacement, then this leads to new breakdowns. This is especially true for the transformer and capacitor.

The second important factor is to connect the part. It is necessary to correctly connect the replacement, preserving the previous location of the terminals. If you connect the device in the reverse order, then this can disable it, as well as several other parts in the system.

This will restore its microwave in most cases. If the breakdown is associated with the electronic part of the device, then you should contact the professionals. This will provide high.Quality repair and extend the operation of the device for a long time.

How the microwave works

Well, now you know about the microwave and microwaves is enough to decide whether to undertake to repair yourself. If such a desire remains, then in order to finally understand how the microwave oven works, where what can break in it and where what degree of caution should be shown during its repair, you will have to turn to the fundamental electrical circuit of the microwave. Its typical construction, used in many models of Samsung and other manufacturers, is given on the left in rice. Green is a network filter designed to not release microwave power supply to the wires (see. Further). Blue. Control module with the EMB system. Mustard. A device for the formation of power pulses for magnetron (UFI). Formally, Ufa enters the control module; Their components are located on one printed circuit board. But the malfunctions of UAS are specific, so it should be functionally considered separately. Pink indicated a power supply unit of the BPM magnetron.

Electrical circuit diagram of the microwave oven

What is happening there

In the network filter there is a common fuse F1, which can burn out in many cases, see. Further. If the malfunction that caused its burning is eliminated, the new F1 must be set the same face value (on the same current, time and temperature of the operation) as the “native”. F1 exercises overall protection from overloads on current, therefore, if you have a thought of a “bug”, it is better to immediately switch it to a new microwave.

The heat.Subject (termchichka) is installed on the case of the most warming component. Magnetron. And is triggered repeatedly: it is restored by cooling. Turning off the microwave oven by overheating before the programmer is turned off. A sign that the exhaust fan of the magnetron cooling, its output grill or input pipe is clogged. If the fan motor at the same time works with a knock, a creak, and a big noise. Its mechanical wear is likely, which requires replacing the motor.

Microsematkers (micrics) SWA, SWB and SWCs make up the system of electromechanical locking. SWA and SWB are used by the upper mustache of the door latch, SWC lower. Since the microwave of the I hazard class I is often operated by abnormal (without grounding), a complex EMB system is used: double to open from the control for a short circuit. One of the principles of TB is implemented here: if it is impossible to avoid an invisible danger of 100%, you need to at least make it visible. The invisible danger in this case is the radiation of a microwave through a loosely covered door, and the visible. Combustion F1.

The diagram of electromechanical locking of the microwave oven (the door is closed)

Due to the importance of EMB for the safety of the furnace and its susceptibility to breakdowns due to the settlement of the child (see. Further), you need to consider the EMB scheme in more detail from the general already in the state when the door closed, (see. Rice. On right). As you can see, if SWA sticks with the door open, then the SWC will close the overall power circuit, which is why F1 will burn. So that there is no false power of EMB, it is necessary that the SWC switch a little slower than SWA. Therefore, firstly, to replace faulty SWA and SWC only with the same type.

Secondly, a situation is possible when all the EMB micrics call normally both with an open and with a door closed, but F1 burns out immediately when it is opened. This means that the children from the products penetrated the micrics, the times of their triggering “sailed” and the EMB was unbalanced by time. There is only one way out. Change immediately SWA, SWB and SWC, t.To. They are non.Graceful and are not subject to repair.

Note: the same microswitchchers of the electromechanical blocking of the door must be checked first if the furnace does not turn on when the door is closed. Very often their contacts simply do not close/switch from a child sticking to them.

Fat and Chad

With the role of fat and a child from it in the occurrence of malfunctions of the microwave, we collided immediately, and then there will be even more troubles from it. Fat in products in the microwave does not boil, as in a pan, but evaporates, and its pairs settled anywhere, forming a tall of a child. It violates the work of mechanics, causing complex problems (see. Further). A slightly wet children’s film has a noticeable conductivity, “confusing” the control automation, and dry breaks through a voltage of less than 500V, which is dangerous for the high.Voltage part. It is especially undesirable to get the child’s hide. The repair of the microwave of the furnace in this case is the most difficult and expensive.

To make sure the ubiquity of fat vapor vapors, you can do experience for which you will need a completely new pan with a lid. The lid is still removed away, and in the pan, any culinary fat is melted before spreading. Then they let him completely freeze in a pan, cover it with a lid and hold it like that at room temperature for a day or more. After that, the lid is Igravi turns out to be a sticky to the touch. On it the donkey fat. What will happen from fat in the furnace chamber at a temperature of 100 or more degrees. A rhetorical question. Fat child in the microwave is not dark, ash, as a kitchen, but almost transparent and therefore poorly noticeable, but no less harmful.

Automation of control

Suppose our stove is still working. The product is loaded, the door is closed. Power regulator (see. Below) set correctly. Turn the timer handle for the right time. SW1 will immediately close, turn on the backlight, rotation of the table, blowing the magnetron and convector. When they “accelerate”, SW2 will work and turn on the device for the formation of magnetron power pulses (UFI), the stove will begin to heat. When the timer returns to zero, SW1 and SW2 will open, turning off everything, and the call will call. In simple microwaves, its spring is soared mechanically when closing the door, and is released by a lever that pushes the timer cam.

Timer

The microwave timer is an electromechanical cam programmer driven by the timer itself: a tape spiral spring with an hourly mechanism or a micromotor with a gearbox. Several discs with fists, closing and opening contact groups are planted on the timer shaft.

The most common breakdowns and their ways to eliminate them

Farting a high.Voltage fuse. It is very simple to determine such a malfunction, since the microwave stops responding to the inclusion and pressing of any buttons.

To conduct diagnostic measures, the capacitor of the high voltage should be discharged, then remove the metal case, unscrewing the mounting bolts.

After that, you need to measure the voltage in the network filter of the device with a multimeter.

• Typically, the diode is on the power supply board.
• If this electronic node burned down, then it must be replaced by new to restore the performance of the microwave.
• After replacement, it is important to find out why the fuse failed.
• Such problems usually appear after the power management board begins to work incorrectly, so it should be inspected and tested.

Note! Before disassembling a household device in a hurry, first of all, you should find instructions for repairing the microwave of your model. So you will disassemble in the correct order, which means that you can entirely collect the microwave back without additional damage and fragmented parts.

Magnetron malfunction

This is the most common malfunction that is found in many owners of microwaves. If the stove has stopped warming up food, then you need to understand the functioning of the magnetron.

If you do not see mechanical damage on the walls of the case, then you should remove the plate on the left side of the compartment. For cleaning the plate and other internal parts, it is worth using dry clean rags and isopropyl alcohol. If you have found darkened or scorched components on the control board, then they need to be replaced.

Upon completion of cleaning all surfaces, you can proceed to the diagnosis of the operation of the ECU. To establish a malfunction, it is necessary to inspect the quality and condition of the insulation between the device body and the main feeding contacts. If necessary, replace the sections of the wire, while it is important to take conductors with similar resistance.

The mica plate burned

This malfunction is also often puzzled by the owners, you can determine this breakdown by spark that forms in the wave canal zone.

The mica plate is usually damaged from the liquid and other spray, which are formed during the operation of the device. Therefore, do not forget to cover the heated dishes with a special microwave cover.

If the mica plate was thoroughly burned out, then do the following:

• Prepare the following tools and materials: scissors, knife, sandpaper, awl and small file.
• Dismantle the top cover and door of the microwave.
• Remove the old plate with the magnetron, then separate the plate from the magnetron body.
• Process the gap of the waveguide.
• Eliminate all pointed pieces of the metal side of the waveguide using a file.
• Clean thoroughly the wave canal from sunken parts, pollution and dust.
• Inspect the magnetron body for damage. If the mica layer is too stained with waves of breakdown, then then the cap will have to be replaced, it is worth.
• Next, install the magnetron in place.
• Also put the door to the right place of the electrical appliances.
• Circle the outline of the future plate on a cardboard sheet.
• And then cut a new mica plate and set in place.

The main malfunctions associated with the work of the door.

In some furnaces, especially the old types of design, increased background radiation is observed. In most cases, this is caused by an increase in the gap between the door and the front of the camera. The normal gap is commensurate with the thickness of the typewritten paper sheet. Therefore, the aforementioned sheet can serve as a kind of tool with which we can easily determine whether the gap corresponds to the required parameters.

If the leaf passes between the door and the camera with an effort or does not pass at all, then everything is in order, if the sheet enters is freely, then it is necessary to reduce the gap. Measuring the size of the gap must be carried out around the entire perimeter of the door.

Immediately make a reservation that the door adjustment can only be carried out if there are devices that allow you to measure the value of background radiation. To do this blindly not only pointless, but also dangerous. If not for life, then for vision.

There are only two points where there is the possibility of adjusting the gap.

Firstly, at the place of fastening of the door to the camera. If an increased background is observed from the side of the mount, you need to loosen the screws that attach the door, move it to the camera to eliminate the gap, and squeeze the screws.

All operations are best done with a door closed, otherwise you can overdo it and, eliminating a large gap on the one hand, get even more, from the opposite. From the side of the control unit, the adjustment of the clearance can be carried out by the displacement of the latch mechanism deep into the body. To do this, weaken the screws attaching the specified mechanism, shift it in the right direction and squeeze the screws again.

In principle, the latch does not have any grooves that allow it to move it in an arbitrary direction, but since the value of the required displacement does not exceed several tenths of millimeters, the existing backlash between the screws and the holes for them allows them to do this. It is also important not to overdo it and make sure that after all the manipulations the door closes well, and both constipation is turned on the locking microswitchchers.

In some Russian.Made furnaces, an increase in the gap is associated with a skew of the door. It happens that in one or two corners the gap is higher than the permissible, and in the rest are normal. Any door adjustment leads only to the fact that the situation is changing mirror. Such a skew sometimes manages to eliminate. To do this, squeeze the screws that fasten the oen.Colored metal window, slightly bend the door in the opposite skew direction and, without letting go of the door, squeeze the screws.

The largest part of the malfunctions of the door is associated with the operation of constipation, fixation mechanism and the door opening mechanism. As a rule, this is purely mechanical breakdowns and repair is reduced to the manufacture and replacement of a broken part.

Sometimes between the door and the walls of the camera there is sparking. The reason for this lies in damage to enamel on the inner surface of the door. Eliminating this is quite simple, you just need to paint the damaged area with a thin layer of varnish or enamel.

The main malfunctions of the microwave oven

• When turning on, the microwave does not work at all. The fuse burned in the furnace itself, as a result of closing in the stove or throwing voltage in the outlet. If the replacement of the fuse (the same face value) did not help, then the possible reason for the closure of the transformer or safety diode hv diode, which serves to protect the transformer. Reference: Magnetron power supply produces the following supply voltages: anode voltage UA. 4000 V., current. 300 mA. Voltage of the intensity U. 3.15. 6.3 V., current. 10 A (depending on the type of magnetron).
• The clock is working, but the microwave does not warm. A possible malfunction does not work a switch of the open door (the hooks that close the door to the switch or one of them are broken off. The door is not tightly closed).
• The oven works for several minutes and turns off, after a while the process is repeated again. Poor cooling of the magnetron: the Wintying holes of the microwave are closed, the clamping fan of the magnetron, the fan turning relay (if installed in this model) does not work. The microwave is built into a kitchen niche. There is little space for heat exchange, especially when the grill is turned on!
• In those microwave furnaces where the magnetron is located with a short wavelength, you can observe a breakdown of mica gasket. Signs: Sparks are visible in the microwave chamber (on the right on the wall) and the smell of Gary is heard. As mentioned above, this happens as a result of pollution.
• The microwave warms poorly. Possible reason for the underestimated voltage in the outlet or loss of emission (magnetron. Like any lamp can lose its emission), as a result of which the power of the generated energy is reduced. To restore the emission, you can harvest the floor of the voucial winding. Reference: network voltage ~ 220V, magnetron voltage fluctuates from 3.15 to 6.3 volts.
• On the display, not all segments are displayed, spots (in the LCD displays) are randomly blink or a possible cause is damaged by the screen or processor. The latter is damaged if the microwave itself does not work in addition to the display.
• The touch panel does not work. Damage to conductive tracks in the touch panel. It usually happens with a strong press on the touch buttons. Either replace the touch control unit, or gently sprinkle the touch panel and apply segments of an uninsulated wire on the damaged tracks.
• Some buttons do not work on the control panel. Check faulty buttons with an ohmmeter, if necessary, replace the worn buttons. Perhaps a simple buttons.
• The plate rotates, the light burns in the nuts, but the stove does not warm. Possible reason: magnetron is faulty, the circuit of turning on the magnetron power transformer or the voltage in the outlet is strongly underestimated.
• The rotating plate moves jerking, inhibits. You need to clean the microwave, remove the garbage under the plate, grooves of the roller mechanism or malfunction of the engine rotation engine.
• The dish on the one hand was burnt, but on the other, it didn’t even heat. The engine rotation engine is faulty.

Repair of current.Passing paths of the touch panel

(A malfunction this method is also suitable for repairing computer keyboard