The microwave oven is a great helper in the kitchen. She cooks, fries, defrosts and reheats food. It becomes sad if it suddenly stops working. How to be? Take it to the workshop? There, unequivocally, they will ask for a lot of money. Microwave repair often costs a little less than the cost of a new device. What to do? Try doing your own microwave repair.
Repair at home of the furnace begins with the disassembly of the device. So, what is included in this rectangular device?
- chamber with a plate for products;
- door (the element has a seal);
- power cord;
- magnetron (generates energy);
- high voltage fuse;
- a device that converts energy (transformer);
- rectifier (high voltage diode);
- grill lamps;
- fan motor;
- backlight lamps;
- pallet motor.
These elements are connected in series. Opening the lid of the device, the main element, the magnetron, will be visible to the eye. It is powered by the following high voltage circuit: a transformer, a fuse, a huge capacitor, a diode.
Principle of operation
- The primary winding of the transformer (wound copper wire) is located at the bottom. It has a voltage of 220 V.
- Further in the circuit are two secondary windings. One of them (cathode heating) is a wound copper wire near the primary. It has 6.3 V. This AC voltage stimulates the electrons to move off the surface. The other winding is located a little higher. Here 2 kV. The voltage goes out.
- The output of the circuit is blocked by a capacitor shunted by a diode. Such an analogy of the arrangement of elements gives the following effect: a negative half-wave goes directly to the cathode element, and the other, positive, charges the capacitance. Gradually, a voltage of 4 kV is obtained, and the generation process begins.
- The cathode receives voltage from the secondary heating winding of 6.3 V. The magnetron anode is connected to ground. The coil, which performs the heating function, is electrically connected to the cathode. The power of the magnetron element is controlled by the device’s timer.
- The programmer controls the operation of the device. It has a gear train that regulates the time. The longer the element of the magnetron device works, the more power is given to the dish. And vice versa, if the magnetron works a little, then it produces the same amount of power.
- Opening the door stops the operation of the device. A protective relay is responsible for this process.
- A high-voltage fuse protects against idle operation and the ingress of tin objects. In case of an accident, it burns out.
- The above secondary mechanisms are connected in series. This fact makes it easier to repair microwaves with your own hands. Since, if at least one element does not work, then the entire device does not perform its functions. The exceptions are the starting relay and the magnetron.
Popular causes of breakdowns
Device cannot turn on
Why did it happen? Because an element such as a fuse has broken.
How to repair a microwave? Replace with a new fuse. After the specified action, check the safety diode of the transformer and the transformer itself for serviceability.
How to find the fuse in the device? This is a glass spray with a thin wire and a small spring inside. In working condition, the spring is stretched. Protects the fuse sleeve made of plastic.
How to check if it works? Disconnect the fuse from the circuit and check with a car battery and an incandescent lamp of the marker lights. The lamp is on – the element is working, off – it is not working.
The clock on the display works, but the device does not heat up
Why? It’s a broken door switch.
How to decide? Replacing a broken item with a new one or (if possible) repairing.
The device turns on intermittently
How to accurately recognize the problem? The device will first turn on, and after a few minutes, it will turn off. The process is repeated in a circle.
It’s the cooling fan that stopped working. The switching relay may break in it or the ventilation holes may be closed.
Solution: replace the element with a new one.
Sparks are visible from the camera and it smells of burning
The reason lies in the contamination of the mica gasket. The dirt caused the element to burn out.
In this case, you will have to repair the device by replacing the burnt element.
Microwave does not heat food
The device cannot heat food due to low mains voltage or loss of magnetron emission.
Repairing a breakdown will require special equipment (for example, a voltage stabilizer). Question: Is it worth it to repair a broken microwave oven yourself? Everyone must answer it on their own. With a positive decision, it will be necessary to increase the number of turns or completely replace the magnetron.
Microwave display not working
In the event of a breakdown, the display does not show the values completely, with spots. Most likely, the processor is damaged and needs to be replaced. The fact that the device does not turn on speaks in favor of the processor.
Another option: the breakage of the screen itself.
Control panel not working
The touch panel displays the operating time of the machine. If it does not work, then the tracks that conduct current are damaged.
Repair of the touch panel comes down to the complete replacement of broken elements or to the imposition of wires.
Tray does not spin smoothly
If the plate inside the microwave turns unevenly, with jerks, then the grooves of the rollers are dirty. Another reason: the engine broke down.
Exit: clean the grooves of the rollers from contamination or replace with a new engine. Also read the article what to do if the plate in the microwave is not spinning.
The light inside is on, the plate is spinning, but the food is not heated.
Causes: large voltage drop, changes in the power circuit, failure of the magnetron.
How to decide? It is necessary to ring the transformer circuit and fix the problems found. Second solution: replace the alternator.
Control panel buttons not working
With this breakdown, do-it-yourself microwave repair comes down to a careful check of the circuit with a tester, replacing broken buttons and soldering the contacts.
Extraneous hum at work
The reasons for the breakdown of the following elements: fan, transformer, diode.
How to decide? Replace elements.
Microwave won’t turn off
Diagnostics: The device is constantly running and cannot turn off.
What’s broken? The reason is a malfunction of the supply relay.
How to eliminate? Replace relay. Before doing this, check for damage with an ohmmeter. There may also be a reason in the processor itself or the control circuit.
Broken elements can be easily replaced with new ones? Where can you get these items? Any specialized store. If you are at a loss with the name of the element, disassemble the device, take the broken part to the store, show it to the seller. He will help you make the right choice.
Interesting to know: what is convection in a microwave.