Microwave oven principle and maintenance, microwave oven maintenance methods and skills

The microwave oven is composed of a power supply, a magnetron, a control circuit and a cooking chamber. The power supply provides about 4000 volts of high voltage to the magnetron, which is excited by the power supply to convert the electrical energy into microwave energy, which emits microwave energy at a frequency of 2450MHz, passes through the waveguide system, and couples into the cooking chamber. The water molecules placed in the chamber of the microwave oven oscillate at a frequency of hundreds of millions of times per second, and the molecules collide and rub against each other to produce heat energy, resulting in the heating of food.

This is how a microwave oven works.

The common faults of microwave ovens are: no start, no heating, slow heating (insufficient fire), turntable does not rotate, intermittent work, open flames, unadjustable fire, etc., after unplugging the power plug, power off, and then discharging the high-voltage capacitor for maintenance.

Three ways to judge the microwave oven for quick repair: 1. The light does not turn on after starting, the stove fan does not rotate, and the door is switched, focusing on the one on the outside. 2. Open the door and burn the insurance, check the one inside (door switch) above.

3. After the light is turned on, the stove fan rotates to work, listen carefully to whether there is a large boom sound, the sound is generally bad for the magnetron, and the sound is generally bad for the high-voltage diode.

The microwave oven is very simple, a transformer that produces high voltage is one-third of the weight of the entire microwave oven, a high-voltage capacitor, a ground diode, a microwave generator, and the rest is a variety of switches and protections, and the general faults are in the first four.

The principle is that microwaves are generated to force water molecules and the like in food to rub against each other to generate heat.

Microwave ovens are mainly composed of magnetrons, high-voltage transformers, high-voltage diodes, high-voltage capacitors, door interlock switches, monitoring switches, cooling fan motors and turntable motors. There is high voltage, high current and microwave radiation during working hours, so the maintenance of microwave ovens is more special and complex than other household appliances, especially the safety issues are more prominent. With this in mind, the following is a summary of safety precautions when repairing microwave ovens, followed by tips for repairing them.

Safety issues (find microwave ovens to China Easy Repair Network for repair).

A microwave oven is a special household appliance that not only has high voltage and high current, but also emits microwave radiation when working. If the maintenance method is improper, not only will there be a lot of detours, but more importantly, the maintenance personnel may be subjected to high-voltage electric shock and microwave radiation, endangering personal safety, and may even bring irreparable damage to the user's body due to long-term excessive microwave radiation. Therefore, the prerequisite for repairing a microwave oven is to fully understand its basic principles and have the relevant knowledge to prevent excessive microwave leakage and high-voltage electric shock.

If you haven't already done so, you have to study hard and fix the microwave once you're sure. In general, the safety issues that must be taken into account when repairing a microwave oven are as follows.

First of all, before disassembly and maintenance, the safety-related parts must be inspected, mainly to see whether the furnace door can be closed, whether the gap of the door is too large, whether the window is damaged, whether the solder joints on the furnace cavity and furnace shell are desoldered, and whether the furnace door gasket is defective and uneven. This is mainly to check if there is a possibility of excessive microwave leakage. If a problem is found, it should be fixed first; If it cannot be repaired temporarily due to missing parts or other reasons, other faults in the machine can be repaired first, but after repairing other faults, do not use it reluctantly, let alone deliver it to the user, and only deliver it after the safety hazard is completely eliminated.

Find a microwave oven for China Easy Repair Network to repair)

Second, if you need to check the internal circuitry, you should usually disassemble the microwave after a power outage. After disassembling the machine, use a screwdriver with a plastic insulated handle to short-circuit and discharge both ends of the high-voltage capacitor to avoid accidental electric shock during maintenance. This is because there may still be high voltage on the high-voltage capacitor after the microwave oven has been cut off, especially in a short-term microwave oven, so don't assume that it is safe to cut off the power.

Thirdly, in addition to checking such as measuring the 220V power supply voltage, we should try not to do ** inspections when we are not too sure. If a power-on check is really required, the high-voltage circuit must be disconnected to prevent the magnetron from working, and then the magnetron must be turned on for inspection to ensure personal safety. For the inspection of the magnetron and its power supply circuit, unless you have the necessary expertise and experience in equipment maintenance, you should use the power-off inspection method to ensure safety.

Practice has shown that as long as the relevant skills are mastered, the power-off inspection is not much worse than the power-on inspection, and the speed of judging some faults is even faster than the power-on inspection. Find a microwave oven for China Easy Repair Network to repair)

Microwave oven is a special household appliance, there is not only high voltage, high current, but also microwave radiation in the working time, if the maintenance method is improper, not only will take more detours, more importantly, the maintenance personnel may be subjected to high-voltage electric shock and microwave radiation, endangering personal safety, and may even bring long-term excessive microwave radiation to the user's body and cause irreparable damage. Therefore, the prerequisite for repairing a microwave oven is that you must fully understand its basic principles and master the relevant knowledge of preventing microwave over-leakage and high-voltage electric shockIf you have not already done this, you must study hard and be sure before repairing the microwave oven. In general, the safety issues that must be paid attention to when repairing a microwave oven are as follows.

First, before dismantling and repairing, it is necessary to inspect the safety-related parts and components, mainly to see whether the furnace door can be closed, whether the door gap is too large, whether the observation window is broken, whether the solder joints on the furnace cavity and shell are desoldered, and whether the furnace door gasket is defective and uneven. This is mainly to check if there is a possibility of excessive microwave leakage. If a problem is found, it should be repaired first; If it cannot be repaired temporarily due to lack of parts or other reasons, other faults in the machine can be repaired first, but after repairing other faults, do not use it reluctantly, and cannot be delivered to the user, and must completely eliminate potential safety hazards before delivery.

Second, if you need to check the circuitry inside the machine, you should usually disassemble the microwave oven after the power is off. After dismantling, use the plastic insulating handle to change the cone to short-circuit and discharge the two ends of the high-voltage capacitor to avoid accidental electric shock during maintenance. This is because after the microwave oven is powered off, there may still be a high voltage on the high-voltage capacitor, especially if the furnace is powered off not long ago, so don't think that it will be safe after the power is off.

Third, in addition to measuring the 220V mains voltage and other inspections, in the case of not being very sure, we should try not to do the power on live inspection. If you really need to power on for check, you must first disconnect the high-voltage circuit to prevent the magnetron from working, and then turn on the check to ensure personal safety. As for the inspection of the magnetron and its power supply circuit, unless you have the necessary professional knowledge and experience in repairing equipment, you should use the power-off inspection method to ensure safety.

Practice shows that as long as the relevant skills are mastered, the power-off inspection is not much worse than the power-on inspection, and the speed of judging some faults is even better than the power-on inspection.