2023 Author: Philip Bishop | [email protected]. Last modified: 2023-08-25 07:54
- Microwave design
- Search for breakage
- Dismantling the microwave oven yourself
- Destruction of the cap on the magnetron
- Repairing microwave oven faults yourself
- Burnout of protective mica
- Other malfunctions
- Microwave repair video
Many of us have forgotten about various stoves, hobs and completely trust the process of cooking microwave ovens. And this is not surprising at all: microwave ovens take up little space, have a rich set of different functions and significantly save time. Naturally, we are very upset when our microwave fails. The reasons for the breakdown and malfunction can be different. Consider what breaks down most often in a microwave oven. Often, if a microwave oven breaks down, it is necessary to contact a specialized master. After all, this is not the simplest device, so the repair is rather complicated. But in fact, the design of a microwave oven is elementary and includes only a few basic elements. If you first familiarize yourself with frequent breakdowns, then repairing the microwave on your own will not be difficult.
Although the design of a microwave oven contains a lot of elements, most of them do not play a special functional role. To repair this device, you only need to know the basic elements of the circuit that ensure its operation. Among them:
- High voltage fuse.
- Rectifier diode.
- Control block.
It is easy to distinguish them, because outwardly the design is not very complex. The magnetron is always installed in the middle, directed towards the food warming unit. The transformer is located under it, representing a massive box with a protruding coil. The capacitor, diode and fuse are located to the right of it, and the control unit is often located near the input panel.
When the device is turned on, a voltage of 220 V is supplied to the transformer. Passing through the primary and secondary windings, a current of 2 kV is already flowing out of the element. Further, the negative half-wave goes to the diode, and the positive one charges the capacitor, which again leads to a twofold increase in voltage. After that, the generation of microwaves by means of a magnetron begins. The power of the magnetron is regulated by the control unit.
Therefore, in the event of a breakdown, it is worth paying attention to these elements. They carry the greatest load, so they are often the problem.
When disassembling the microwave, be sure to disconnect it from the mains.
Search for breakage
Search for breakage in a microwave oven is based on "symptoms". This allows you to gradually eliminate possible causes and find the real one. So, if the oven does not turn on at all, then it is worth checking the following points:
- The integrity of the power cord.
- Door position and closing system.
- Mains fuse and thermal relay status.
In the first case, the situation is elementary - there is no power supply due to damage to the power cord. A similar situation occurs when the outlet is damaged or overloaded. In this case, it is enough to replace this element, everything is in order with the microwave itself.
Next, it is worth checking the operation and position of the door. The fact is that the operation of a microwave oven with the door open is dangerous for others. Therefore, the design provides for the possibility of operation only when it is completely closed. If a latch, a locking system or a checking element on the door is broken, the protection system will not allow the device to start.
The last points also concern the protective systems of the oven. The fuse prevents damage to the device due to power surges, and the thermal relay provides a complete shutdown of the system when the door is open. Both can fail, it is quite easy to replace them.
It is also worth checking the voltage in the network and the number of devices connected to the outlet. The microwave oven is very demanding on power supply, therefore its slight deviations can interfere with the operation of the device.
Most models suffer from common problems and have similar, typical faults. For example, if the microwave works, but does not heat, then this indicates a malfunction of the capacitor, diode or magnetron. To repair a microwave oven yourself, you will need a simple set of tools: pliers, wire cutters, a screwdriver, an adjustable wrench and a five-spanner wrench, as well as a soldering iron with the necessary equipment.
When repairing a microwave microwave yourself, you should remember about safety measures. The two most important hazards in microwave repair are high voltage in the oven components and microwave radiation. Do not turn it on if the door is defectively locked or the mesh on the viewing window is damaged. Do not make independent holes in the case and introduce any conductive objects into the units and elements of the furnace. Never touch internal parts and assemblies during microwave operation. Be sure to use a tester or other electrical meter to measure AC and DC current.
Dismantling the microwave oven yourself
If the above reasons are not confirmed, then you need to disassemble the device to troubleshoot. Before that, be sure to turn off the oven from the network and wait a couple of minutes.
What should you look for when looking for breakdowns? There are several basic elements that often fail:
- Circuit breakers.
These elements are directly involved in the operation of the device and were mentioned earlier. First you need to check the health of the fuses. Their breakage can be seen immediately, because during combustion, the conductor inside is destroyed. If this did not happen, then it is worth looking further.
For further verification, you need to take a multimeter, because outwardly it is extremely difficult to find a breakdown on the remaining parts. To check the capacitor, you need to switch the device to ohmmeter mode, and then connect it to the part. If there is no resistance, then the part must be replaced.
The high-voltage diode cannot be checked with a tester. It is recommended to replace it in case of breakage of other parts, because often the blow falls on it. It can be checked in a slightly different way - by connecting it to the network on the way to the light bulb. If the light is weak or blinking, then the part is working properly. If it burns brightly or does not turn on at all, then the diode must be replaced.
Next, the transformer is checked.
It is important to observe safety precautions, because
this element is able to hold a charge for a long time. It will take several minutes to discharge a serviceable transformer, and if the discharge resistor breaks down, it will take much longer. It is worth discharging it on the case or not touching it at all if there is no experience with such a technique.
Next, the transformer windings are checked. It is necessary to remove the terminals and check the terminals of the device one by one with an ohmmeter. First, the primary winding is checked, for which the rate varies from 2 to 4.5 ohms. For the secondary winding, the limits are 140 and 350 ohms. It is also worth checking the filament winding by connecting the terminals leading to the magnetron to the multimeter. The norm here varies from 3.5 to 8 ohms.
All previous tests have failed, then the problem may lie in the magnetron.
To test the magnetron, just connect the tester to its power terminals. The tester switches to ohmmeter mode. If the resistance is 2-3 ohms, then this means a breakdown of the device. The same situation if the tester shows infinity. In both cases, the device must be replaced.
These items are the most common culprits in microwave oven breakdowns. However, the failure of the device is often associated with other malfunctions, such as problems with the electronic control unit, timer and other electronic parts. Here, simple checks with a multimeter will not help; the help of a qualified technician is needed. Although it is much easier to simply replace the part if you are sure of its breakage.
Destruction of the cap on the magnetron
There are frequent cases of breakdowns associated with the destruction of the cap on the magnetron. The thin aluminum body simply cannot withstand loads and is destroyed by microwave waves. This problem often occurs in older devices that are more than a few years old. The obvious symptoms in this case are noise and sparks during the operation of the device.
To check it, it is enough to remove the transformer, because the cap is located towards the food chamber. If the cap is destroyed, then there are 2 options:
- Replacing the cap.
- Flip the cap.
The first option is priority, it is enough to order a replacement or give the magnetron for repair. The second option is considered a temporary alternative that allows you to extend the life of the device indefinitely. You just need to rotate the cap 180 degrees around the axis, because the load is only one half.
Repairing microwave oven faults yourself
Repairing a microwave oven is a feasible task for a novice electrician. If the problem lies in the breakdown of one of the constituent elements of the furnace, then the simplest and correct solution is to replace it. The bottom line is that most of the parts of this device cannot be repaired, but only completely replaced with a new one. This especially applies to fuses, diodes and capacitors - the main reasons for the failure of the device.
Parts replacement is carried out in several steps:
- The microwave is disconnected from the network.
- The transformer is discharged (5 minutes).
- The terminals are disconnected from the defective part, it is removed.
- A workable part is connected to the same place.
There are two important factors to consider when replacing a part. The first is schema compliance. It is important to remember that each part has its own characteristics, selected for the performance of the entire electrical circuit. If, after replacement, this nuance is not taken into account, then this leads to new breakdowns. This is especially true for transformer and capacitor.
The second important factor is the connection of the part. It is necessary to connect the replacement correctly, keeping the previous arrangement of the terminals. Reconnecting the device in reverse order can damage it, as well as several other parts in the system.
This will restore your microwave in most cases. If the breakdown is associated with the electronic part of the device, then you should contact the professionals. This will provide quality repairs and prolong the operation of the device for a long time.
Burnout of protective mica
The most common malfunction is the failure of the waveguide cover in the microwave oven chamber. This is caused by splashes from cooking. This starts sparking between the magnetron antenna and the protective cover. Untimely elimination of burnt products leads to local burnout of the lid and to complete destruction.
Local burnout of the lid mica plate can be removed using alcohol or solvent 646. It is enough to gently wipe the burnout area.
If the mica plate of the lid is obviously in poor condition, is greasy or begins to paint, then it should be replaced. Removing the diffuser plate is not difficult at all. This can be done using an ordinary sharpened knife. Usually the mica plate is attached with a self-tapping screw or rivets. Carefully place the old plate on the new template and cut out a new one. The best way to do this is with a knife - you can break the mica with scissors. We make holes in the new plate with a sharp screwdriver and process the edges of the plate fields with sandpaper. We install the new plate in place of the old one.
The question often arises, how to replace mica for microwave? For these purposes, any dielectric with a similar dielectric constant is suitable. For example, fluoroplastic or teflon.
Common breakdowns in the microwave are also malfunctions associated with other elements of the oven. For example, such as the keyboard of the oven control unit, the microwave oven electronic control unit and the dissector. Less often, the high-voltage capacitor and transformer, the microwave waveguide plug and the rotating pan fail. The power supply and magnetron of the microwave oven are subject to wear and tear.
Knowing how to troubleshoot microwave ovens can save you significant repair costs. However, if you do not know how to repair the microwave yourself, then it is best to contact a specialist. Specialized service centers will help you to repair the microwave microwave. In addition, watch the video on microwave repair, perhaps there is exactly that breakdown that will help you fix your favorite household assistant.
Microwave repair video
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