The Samsung microwave circuit differs little from similar devices. Many people will be interested in reading its description. This is useful for owners of microwave ovens from Samsung and other manufacturers. Some are just curious to know how this or that device works. For others, knowledge of the design will help not to make mistakes during operation. Still others are interested in the scheme in order to fix the stove on their own.
Content
- Microwave design
- Electrical diagram
- Additional elements
- Special parts
- Safety regulations
-
Repair features
- If there is no reaction to launch
- Light without heating
Microwave design
One of the most important parts that turns a compact camera into a microwave oven is the magnetron. This is the name of a vacuum tube capable of reproducing microwave waves. It is microwave waves that heat food. Electromagnetic waves with a frequency of 2.45 GHz affect water molecules in food, causing them to move faster and increasing friction between them. This warms up the food from the inside. Closely related to the principle of operation of the microwave oven is the diagram of the device.
In the microwave, one of the largest elements is the metal chamber.in which food is placed. The door is equipped with a special glass that reflects high-frequency waves. A rotating platform is used to heat food more evenly. It is driven by an electric motor gearbox.
The microwave oven circuit also includes the following elements:
-
ventilation holes; - frame;
- metal chamber;
- door;
- door latches;
- air duct openings;
- glass stand;
- guide roller;
- a heating element;
- clutch clutch;
- control Panel;
- display.
Any microwave oven has locking holes for door latches, because direct exposure to high-frequency waves negatively affects any body.
Microwave radiation is reproduced by a magnetron, and enters the chamber through a rectangular waveguide. This will heat up the device. For cooling, the case has a fan that blows cold air to the magnetron. After heating, it enters the chamber with food. Excess air and water vapor is discharged through the holes. They are also equipped so as not to emit radiation.
Some of the models from the lineup of any leading manufacturer are equipped with a dissector. It is installed inside the camera from above. Although outwardly the device looks more like a fan, it is necessary to evenly heat food. This is achieved through the correct distribution of microwave waves.
Electrical diagram
Microwaves use different electrical circuits, but the overall layout is the same. Electronic parts can be divided into control and executive. The first includes the following elements:
- microcontroller;
- control Panel;
- display;
- electromagnetic relays;
- buzzers.
When they are combined, a kind of "brain" of the microwave oven is obtained - a power and control board. A step-down transformer of small dimensions is used to supply power to the control part. The microcontroller uses transistors to drive three electromagnetic relays. Turning them on and off directly controls the algorithm of the device.
The microwave oven magnetron belongs to the executive part. It also includes the glass stand motor, cooling fan, backlight and other elements. One of the most important circuit participants is a high-voltage transformer. This is the largest element of the microwave, which is capable of receiving a power of 1.5-2 thousand. watt. Of these, about 500-850 are the useful part. The magnetron consists of the following parts:
- antenna;
- braid;
- chassis;
- radiator;
- connector.
An alternating current with a voltage of 220 volts is supplied to the primary winding of the transformer, and an outgoing voltage of 3.15 volts is supplied to the filament winding of the magnetron. Because of this, the emission of electrons occurs. The current consumption can reach ten amperes.
And there is also a secondary winding. Together with a voltage doubling circuit, in which a high-voltage capacitor and a diode are involved, it forms a current of 4 kW, which powers the magnetron. Its strength is small - about 0.3 A.
The electrons produced by the filament winding begin to move in a vacuum along a special trajectory. This is how microwave radiation arises, which comes from the magnetron to the chamber through the antenna and the rectangular waveguide. The camera itself in this simple scheme plays the role of a resonator. UHF waves bounce off the walls many times, passing through the food again.
In part, the control elements can be called defense mechanisms. For example, thermal switches prevent possible overheating. Normal operating temperature is 80 to 100 degrees. One of the thermal switches is installed on the magnetron. Two more control the temperature of the duct and grill.
If one of the sensors detects a critical value, the thermal switch opens the circuit. Electricity stops flowing to the magnetron. This usually happens at 120-145 degrees - this temperature is still safe.
Three switches are built into the right end of the microwave oven, opposite which the door is located. The main and secondary close contacts when the furnace is closed, and the control one opens. If even one switch fails, the fuse will trip and the device will not turn on.
To reduce the noise occurring in the mains, there is a surge protector.
Additional elements
There are several complementary parts in the microwave. Often, a microwave oven is equipped with a grill in the form of heating arcs or infrared quartz lamps. The convector works in tandem with it. These elements are quite reliable and break in exceptional cases.
An infrared heater is usually made in the form of two quartz lamps connected in series. With their power of 500-600 watts, they consume 115 volts of current. Unlike microwave heating, the grill does this from the top layers to the inner layers. Although this takes more time, otherwise the crust will not be fried.
The convector is essential for proper air circulation. This helps the food to warm up evenly.
Special parts
There are special elements in the power supply circuit of the magnetron, the properties of which must be taken into account when repairing yourself. This primarily concerns the high-voltage capacitor. A resistor is built into it, which is necessary for the discharge. The capacitor is energized up to 2 kV during operation. However, after finishing work, it may not be discharged. This will happen if the internal resistor is burned out. Therefore, there is an important safety measure: before starting the repair of the microwave oven, the capacitor must be forcibly discharged.
A large high voltage diode consists of many small ones. By connecting them in series, the combined element can operate with high voltages. However, this excludes the possibility of checking the diode by a standard technique, because the device has a high resistance both during direct and reverse switching on.
For many diodes, the highest possible forward voltage is 11 volts, which is achieved by connecting a dozen smaller parts in series. With this combination, the maximum constant reverse voltage reaches 12 kilovolts.
The bi-directional high voltage suppressor is a protective diode installed in parallel with the high voltage capacitor. It is necessary for overvoltage protection, but it often fails. However, the microwave will work even without it - during the repair, the protective diode can simply be removed. If possible, it is better to replace it with a new one - this way the high-voltage capacitor will last longer.
It is better to look for a detailed diagram of a microwave oven of a specific manufacturer in the native instructions. You can find it on the manufacturer's website. The manual should contain recommendations for checking the elements, a list of incoming parts, diagrams and the order of disassembly.
Safety regulations
When using and repairing any household appliances, you must follow safety rules. Their violation can not only disable the device, but also harm the health or life of a person.
It is easy to use the microwave correctly:
- If the door is open, the oven cannot be turned on. This is possible if the waveguide or door interlock system is damaged.
- The removed magnetron must not be connected, it is life-threatening.
- Do not operate the oven with a broken fan, otherwise it will lead to damage to the magnetron.
- Any actions with the parts of the microwave are permissible only after the high-voltage capacitor is disconnected from the network and completely discharged.
- When the repair is complete, all objects, regardless of their size, must be removed from the waveguide.
- The oven must not be turned on without load. If you need to work it out in idle mode, then you must definitely put some food. It can be replaced with a container of water.
When disassembling, you should photograph each step. If you have problems with the assembly, then you can use the existing photos. It is advisable to capture the initial position and attachment of all parts using mobile phones or digital cameras.
Repair features
One of the most common malfunctions is associated with the fact that the microwave does not react in any way to opening the door and actions with the equation panel. It often happens that the stove does not heat, although it shows signs of working capacity: the lights are on, the glass table is rotating.
If there is no reaction to launch
First you need to check if current is flowing to the power filter. To do this, the casing is removed, and the high-voltage capacitor is forcibly discharged. Use a multimeter to check the power cord. All wires from the outlet to the terminals must ring. The grounding terminal must ring to the chassis.
If the wire is intact, then it is necessary to check the condition of the mains fuse. It can be found on the filter board. In the event of a malfunction, you will have to install the same one. It is important to take into account that a more serious malfunction led to the blowing of the fuse - it will not be superfluous to inspect the microwave.
For visual inspection, it is better to use a flashlight and magnifying glass. The following factors signal the problem:
- breakdowns and abnormal holes in the elements;
- darkening, similar to burning;
- swollen capacitors or deformation of other elements.
The sense of smell will help diagnose the malfunction. The smells of burnt insulation, faulty printed circuit boards or transformer oil are quite vivid, so they can be easily detected. If you understand where the smell comes from, then you can localize the problem.
Light without heating
This is often caused by high-voltage circuit or magnetron faults. But before checking these components, you need to inspect the camera. You need to make sure that there are no burnt holes, dirt and worn out enamel anywhere. The rectangular plate of radio-transparent dielectric, located on the left, must be removed and especially carefully examined. To do this, you will have to rinse it with alcohol.
If the plate has through holes or darkening, then it will have to be replaced. Most likely, this happened due to the fact that metal dishes were placed inside the oven or they forgot about timely cleaning.
The safety diode must be checked in the magnetron circuit. If it burns out, then it is enough just to put a new one. The part must have original parameters.
A burnt-out antenna cap indicates the need to replace the magnetron. The same applies to breakdowns in the case. If the microwave oven has been in service for more than five years, then the repair may be impractical - it is more economically profitable to buy new equipment.
