1. high-voltage diode

Normal, measured with a multimeter rx10k block, forward conduction (with a certain resistance), reverse cutoff (resistance to infinity) ; with other resistance block to measure the forward and reverse resistance are not pass. High-voltage diode damage is mostly breakdown, that is, both forward and reverse pass. High-voltage diode damage caused by fault phenomena are: burn high-voltage insurance, or microwave oven operation does not heat, microwave operation does not heat and noise increases.

2. Magnetron

Normal, the measurement of the two terminals between the zero-point few ohms, the two terminals on the shell of the shell between not pass (resistance value infinity). Magnetron damage, some of the performance of the filament between the two terminals open circuit, some of the performance of the two terminals on the shell conductive path, some can not be measured directly. Magnetron damage induced by the phenomenon of: microwave oven running sound small, not heating, or burn power insurance, high voltage insurance, high voltage diodes and so on.

3. High-voltage transformer

Normal, the measurement of the resistance between the two inputs is less than 31, the filament winding resistance is also very small close to oq, the high-voltage winding resistance is larger in the 9011-150f1. High-voltage transformer damage to the high-voltage winding turn-to-turn short-circuit is mostly. Damage caused by the phenomenon are: running current increases the odor, or running without heating, smoke.

4. High-voltage capacitors

Its capacity in 1bf or so, there is a 9mq resistor in parallel. Normal, the pointer multimeter placed in the rx10k block, two pens were connected to the two poles of the high-voltage capacitor, the measurement of the beginning of a certain resistance value but not high, and then gradually rise to 9mq or so; two pieces of the shell resistance should be infinity. The actual maintenance of high-voltage capacitor failure is relatively low, the common form of damage is the pole piece or insulation wood fire, individual failure or breakdown. High-voltage capacitor damage caused by the phenomenon of burning power supply fuse or high-pressure fuse, microwave oven can run but not heating.

5. Mechanical timer / fire selector

Normal, measure the motor at both ends of the resistance, clockwise twist the time knob, timing switch contacts conduction. The fire contact is on and off when the motor is rotating. Timing switch contacts are damaged, causing the whole machine does not work; fire switch contacts damage caused by the microwave oven operation does not heat; motor damage caused by the microwave oven operation heating non-stop, or run without heating, not stop.

6. Door switch

The door switch contains several light touch switches. Under normal conditions, there is a tiny contact switching sound when the switch is closed. Damage to the fault performance: the whole machine does not work, running does not heat, open the door to burn the power supply fuse and so on.

7. Bidirectional diode

Pointer multimeter placed in the rxlok block, the two pens were connected to the two poles of the bidirectional diode, forward and reverse resistance should be infinity. Bidirectional diode breakdown, leakage, will generally cause the microwave oven does not heat or the power supply insurance burned out. Check if there is no such tube, can also be removed without removing the removal of the circuit has no effect on the work, but the opportunity to lose high-voltage overvoltage protection.

8. Thermal relay

Also known as thermal cutoff, temperature limit switch, thermal switch, etc., belongs to the automatic reset thermal protection components. The multimeter will be placed in the rxlo block, the two pens were connected to the thermal cutoff two terminals, room temperature resistance should be oi, high temperature and to reach its marked value resistance should be infinity, when the temperature drops to a certain value and automatically become 011. thermal relay damage, should be replaced with the same specifications of the parameters of the relay, such as replacement of the labeled temperature is too low will cause misprotection; replacement of the labeled temperature is too high to achieve the purpose of the protection.

Two: common troubleshooting

1. Power on the unresponsive, fuse fuse check the door switch, microwave high-voltage system (high-voltage transformer, high-voltage diode, magnetron, high-voltage capacitors), fan motor, turntable motor. After troubleshooting, the fuse can be replaced with a test machine.

Tips: Check the high-voltage transformer is mainly to observe the primary winding, high-voltage winding there are no traces of burning, there is no insulating paint burnt flavor.

2. Power on the unresponsive, the fuse is not damaged

Mechanical control store type microwave oven two can check the mechanical timer, magnetron temperature limiter. Computer-controlled microwave oven: observe the computer board fuse, check the computer board power transformer, magnetron temperature limiting protector. After troubleshooting, you can replace the insurance test machine.

3. Repeatedly burn the power supply fuse first check the door switch, high-voltage transformer, and then check the microwave system in other devices, such as high-voltage diodes, high-voltage capacitors, bidirectional diodes, magnetron, etc..

4. can run, but the microwave does not heat the first measurement of high-voltage transformer primary power supply, and then according to the results of the measurement to determine the scope of maintenance. If the measured high-voltage transformer primary no ac220v power supply, mechanical control of microwave ovens, should check the timer, door switch; computer-controlled microwave ovens, should check the door switch, computer board fire relay and drive transistor. If the measured high voltage converter primary ac220v power supply, then check the high voltage transformer, high voltage insurance, high voltage diode, protection diode.

5. Microwave does not heat, increased noise or vibration. Focus on checking the microwave system, such as high-voltage diodes, high-voltage transformers, high-voltage capacitors, bidirectional diodes, magnetrons.

6. Microwave heating is slow, the fire is significantly reduced compared to the previous failure is usually the magnetron aging, a few power control selector switch or power relay contacts are bad.

7. Barbecue does not heat up to check the grill with or without ac220v power supply. If the turtle is normal, replace the barbecue tube; if there is no supply voltage, check the barbecue control circuit, such as barbecue temperature limiter protector, barbecue t switch (some mechanical control microwave oven is set in the fire control, the foot of the device), for computer-controlled microwave ovens. Also check the grill relay and drive transistors and other components.

8, after turning on the liner fire f in the case of confirming that the user does not use metal utensils, check whether the mica sheet is burnt, whether the liner is too humid.

9. Start or stop button failure

Generally seen in computer-controlled microwave ovens, check the membrane switch.

10. Computerized microwave oven power on the display, but does not start to check the door switch and panel switch.

Tips: Individual models have special operating methods, such as: HP microwave ovens powered on the first start, you must first open / close the door once, the purpose is to prevent users from not into the food on the start of the machine caused by dry burning; Sharp microwave ovens powered on the first must be pressed to "cancel the key", the other key to play a role.

11. Sometimes do not start, sometimes automatically switch functions, buzzer error

Measure the cpu 5v, reset, clock oscillation pin voltage, replace the crystal.

The resistance value should be infinity when the labeled value, when the temperature drops to a certain value and automatically become 011. thermal relay is damaged, should be replaced with the same specification parameters of the relay, such as replacement of the labeled temperature is too low will cause misprotection; replacement of the labeled temperature is too high can not achieve the purpose of protection.

Here's a look at the reasons why the Grants microwave oven does not heat up:

1, the second door interlock switch is bad: this two door interlock switch is damaged. The reason is due to frequent operation, poor contact, electric shock destruction caused by 220-volt operating voltage can not work properly. Solution: first check whether the fuse is blown, and then see whether the monitoring switch is normal, if it is normal, it means that the interlock switch is bad. Replace the switch on it.

2, high-voltage transformer damage: many friends have encountered such a problem, that is, the high-voltage transformer is bad. After the boot if the lights are on but the turntable does not move, it means that it can not be heated, if it is normal to replace the high-voltage transformer can be.

3, the magnetron is bad: magnetron is bad mainly in the boot light but does not heat, generally this is due to the magnetron inside the aging filament broken. Solution: Speak during the inspection of high-voltage capacitor discharge, test filament winding, the normal is 0 ohms, if it is not so, it means that the magnetron is bad, change can be.

4, high-voltage diode is bad: this situation also occurs frequently, the disk is rotating, but does not heat, if this is the case in the overhaul of the filament winding should be measured to see if it is normal, if it is normal to look at the high-voltage diode to see if it is normal, if the test is infinity, this time to change the high-voltage diode.