What is a microwave magnetron, how to check and fix it

The rapid heating that made the microwave oven so popular is possible thanks to the magnetron. When it breaks, the whole furnace fails. If you can find a magnetron in a microwave, are curious and like to check service centers for honesty and competence, then this article is for you.

What is a magnetron

This is a microwave generator in a furnace. The electromagnetic waves it emits heat the food by setting the water molecules in the food in motion. It turns out that the food is heated without thermal influence from the outside. Therefore, the operating temperature in the microwave cannot exceed 100 ° C – the boiling point of water.

How it works

Here we can recall a school physicist who rightly said that science would come in handy.

The principle of operation and the scheme of this electrovacuum diode resembles an ordinary electric light bulb. High voltage is applied to the case, which is the cathode. Power is connected, elementary particles – electrons – rush to the anode.

What is the anode made of? Copper sleeve (cylinder, tube, lamp) with vacuum sections inside and tungsten filament. Magnets are located on the sides, creating a magnetic field and setting a spiral trajectory for particles. Electrons, moving through the resonator at a breakneck speed, excite high-frequency currents. A powerful microwave flow arises, which enters the oven through a waveguide (antenna). The device is protected from overheating by aluminum heatsink fins.

If the food does not heat up, the magnetron needs to be checked.

Major faults

In many cases, the magnetron is beyond repair. But before you buy a new one, you need to understand the causes of the breakdown. You may be able to save money by replacing just one part.

1. Depressurization. The device needs to be replaced. It won’t work without a vacuum.
2. Broken filament. It’s like a light bulb – if burned out, then forever.
3. The cap on the antenna burned out. Can be repaired.
4. The magnetic system is out of order. It rarely happens, but if the top magnet bursts, it can be replaced.
5. Service life has ended. If the device is worn out, it is better to change it.
6. The capacitance of the transition capacitor is broken. Service departments in case of such a breakdown advise replacing the entire magnetron. But, having the right tools, you will find how to replace this part.

As you can see, there are few fixable cases, but they do exist. Before starting repairs, check the system for operability.

Diagnostics

Attention! In no case do not plug in the device that you pulled out of the stove body! This can cause irreparable harm to your health and those around you. Before disassembling the microwave, check how the power source works. Possibly low voltage in the electrical network is to blame. If the power supply is correct, conduct a thorough inspection with the tester.

The first check for serviceability is visual. Look to see if the antenna cap has burnt out, if there are any deformations, holes, traces of burning on the body, filter. Pay attention to the integrity of the magnets. This will help determine where the cause of the breakdown is. If there are no external signs of damage, you can ring the magnetron with a multimeter.

• Turn on the tester, set the mode to 200 ohms. Touch the probes to the leads. An integral winding has low resistance (approximately 0,5 ohms), you will hear a squeak or ringing.
• Nothing happens – it means that the filament has broken.

• To ring the through capacitor with a tester, set the largest measurement mode. With one probe, touch any of the contacts, and the second – to the body. If everything is in order, nothing will happen, the device will show “∞” – infinity.

The charge breaks through the case? Most likely, the capacitance of the capacitor is damaged.

Important! The use of special devices for diagnostics does not always guarantee the accuracy of the data.

How to fix at home

You can change the following details yourself:

• antenna cap;
• pass capacitor.

Cap replacement

This part can be bought at any radio market, made independently from an electrolytic capacitor or a thimble that is suitable in diameter. How to do it:

1. Turn off the power to the oven, carefully remove the power plug.
2. Disconnect the fasteners, pull out the device.
3. Check cap. If there is soot, clean with fine-grained sandpaper.
4. The cap is pierced by current, burned out – it needs to be replaced.
5. Remove it from the antenna, check its integrity. If the anode is in order, the device can be repaired.
6. Install a new part, insert the magnetron into place.

We change the capacitor

1. Remove the filter cover.
2. Bite off the throttle contacts with wire cutters.
3. Use a drill (3 mm in diameter) to drill holes around the capacitor.
4. Remove from filter housing.
5. Unwind one turn at each throttle. This will increase the length of the contact.
6. Clean the contacts with sandpaper, a knife.
7. Insert a new capacitor into the filter housing in place of the old one, screw it on.
8. Connect the contacts so that they do not touch the walls of the box.
9. Close the cover.

Ready! We have considered breakdowns that you are able to fix without the intervention of professionals. But if the magnetron is beyond repair, it must be replaced.

How to choose a new magnetron

Before you buy a new magnetron, check the specifications of the old one. On the outer wall of the device there is a label with the necessary information: model name, power, frequency, location of the power terminals. Full compatibility can be obtained by choosing a model that matches your microwave oven model. Because if you have a Samsung, then the LG brand generator will not work in many ways.

Now you have all the data to find the desired model in the browser search engine, find out how much it costs and where to buy.

connection

How to connect:

1. Insert the new device in place of the old one.
2. Securely screw in the mounting bolts (self-tapping screws).
3. Connect the wires.
4. Screw on the back wall of the oven.

With the necessary knowledge and skills, it is possible to repair even a complex, at first glance, electromagnetic system. But if you feel that you lack competence, do not take risks, trust the professionals.