Any technique fails and microwaves as well. Appearance can not file an issue signals. Cold or slightly warm food after heating - an alarming sign. You need to check a magnetron in a microwave oven.
Work units for heating of food is impossible without one internal component - a powerful vacuum tube. It is called a magnetron. It generates microwaves to act on the water molecules in food. This occurs due to the interaction of the magnetic field with the flow of electrons.
The frequency range 0.5 to 100GHz. In continuous mode, the power may begin with a few tens of watts and end kW, and be pulsed 10 W to 5 MW. Most stoves power 700-850 W for a glass of water bring to the boil for 2-3 minutes. In the magnetron microwave high efficiency - 80%. There are tunable and non-tunable devices. At first you can change the frequency response of up to 10%.
Principle of operation
Powered detail by inhibiting electrons in the coupled magnetic and electric fields. It is used in radar devices and microwave ovens. To heat the food energy is used the antenna - the exhaust tube with a tightly seated cap of metal. Ceramic cylinder insulates the housing from the magnetron antenna. The outer skin is formed with the flange yoke. It distributes the magnetic field emanating from the annular magnets. The radiator cools the item during microwave. Levels of penetrating radiation reduces the filter canister. Inductive conclusions form the high-pass filter together with bushing capacitors.
The scheme of inclusion
A magnetron for a microwave - a significant detail. It includes the following components:
- Antenna - radiation source;
- metallic cylinder, insulating the antenna from the working surface;
- magnetic core for the propagation of magnetic fields;
- magnets distributes the flow;
- a radiator, a cooling device;
- filters, providing a safe level of radiation;
- power connector with two contacts.
How to check for serviceability
Replacing parts is expensive, so many people prefer to buy a new microwave. But do not get rid of the old equipment. Check the magnetron of the microwave oven on serviceability to make his break. The main symptoms of the fault - smoke, sparks and sounds from the oven. In their absence, make a total examination or the diagnosis with a tester.
General examination
Turn off the microwave from the power supply. Unplug the power cord. Visual inspection of the inner furnace chamber must identify places melted, burnt or discolored portions. So it is possible to detect a blown fuse. If you do not notice, can not do without the instrument.
Test using a tester
Reveal a hidden problem checking magnetron tester. Diagnose is not connected to the microwave part.
Recommended incremental steps:
- Connect the tester probes to the terminals of the magnetron. If the heat otgorel will seem endless.
- Inspect the main PCB, which are embedded diodes, resistors, varistors, and more. To check not desoldering elements proring can be done directly on the circuit board.
- If the thermal fuse to ring at room temperature, it should issue a signal.
- High voltage capacitor is only checked at the breakdown. In the normal state, it indicates infinity. In defective - resistance close to zero.
- Diagnosis of high voltage diode. The series connection of diodes in its composition does not give an opportunity to examine it. High level of internal resistance to be measured. Make sure that in this respect there is no breakdown. This will help to Megger.
possible faults
Consider the details of internal pull down can only be a part of. Find the component that caused the problem. This information will help to eliminate damage.
The reasons for failure:
- Burned cap - one of the key elements. Controls the vacuum tube. It can spark. The problem is solved by replacing the cap on the other.
- Improper operation of the radiator, the item gets very hot.
- Broken filament due to overheating. To diagnose this problem is a special tester. Functioning thread outputs a voltage of 5-7 ohms. If the work is broken, the voltage will drop to 2-3 ohms. Overscan thread indicates when diagnosing infinity.
- Damage to the filter unit, in operation it will show infinity. In case of breakdown of feedthrough filter capacitors tester show numerical resistance. Defective capacitors can be replaced.
- Leakage of the magnetron due to overheating. Fix this problem can only be a specialist.
- Faulty high voltage diode.
- Missing contacts in the fuse, which protects against overheating. Decides to replace the fuse with a new, better brand manufacturing.
- Defective high-voltage capacitor.
But there are other problems that are difficult to find on their own. It requires special equipment and expertise. All of these problems, in addition to depressurization, it is possible to repair their own hands.
Installation and connection of the new magnetron
If it is impossible to repair the item, it is necessary to replace the magnetron. This applies to expensive models, in this case, the costs are justified. The best option would be to visit the service center, but can be replaced independently. Make sure that the exhaust part and a new match for the power and position of the holes.
Connect the new magnetron for the microwave oven is not difficult, it just two pins. All notation can be learned from the circuit. Pay attention to such moments:
- the length of the new part should be the same as in the old;
- antenna diameter in both devices must be the same;
- be sure to close contiguity to the waveguide.
Contacting a service center in the event of a problem should be a priority. If the equipment is not under warranty, self-examination and repair will save on the work of specialists.
