The structural characteristics and principles of Galanz microwave ovens, common faults and troubleshooting

The microwave oven is a new favorite of modern kitchen appliances, which is increasingly popular. The microwave oven is really convenient to people’s lives with fast heating speed, power saving and no pollution. At present, there are many microwave products on the market, but the Galan Shi microwave oven has always been an exclusive show.


First, the recognition of Galanz microwave furnace model

Second, microwave oven structure characteristics and working principle

The microwave oven is mainly composed of several parts of the furnace cavity, the furnace door and the control circuit.

1. Furnace cavity: is a microwave resonant cavity, which is a space that can heat the microwave energy to the food. The glass turntable driven by the micro motor is installed at the bottom of the furnace chamber, and the heated food is placed on the turntable and rotates together, so that the high-frequency electromagnetic field in the furnace is relatively moved to achieve uniform heating in the furnace. .

2. Gate: It is the import and export of food. The furnace door consists of a metal frame and a viewing window. It is required to observe the heating of food in the furnace from the outside, and the microwave cannot be leaked. There is a metal microporous web in the glass interlayer of the viewing window, which can prevent microwave leakage through it. Since the metal mesh size is precisely calculated, the penetration of the microwave can be completely blocked.

3. Control circuit: The control circuit is shown in Figure 1, which is divided into a low voltage circuit, a control circuit, and a high voltage circuit.

The circuit after the secondary winding of the high voltage transformer is high voltage circuit, mainly including: magnetron, high voltage capacitor C, high voltage transformer T, high pressure diode D. The magnetron is the heart of the microwave, and the microwave energy is generated and emitted by it. Its work requires a high pulsating DC anode voltage and a filament voltage of about 3 to 4V. The multiplier rectifier composed of high voltage transformers and high voltage capacitors and high pressure diodes provides the magnetron to meet the above-described required operating voltages.

The circuit of the high-voltage transformer before the primary winding of the microwave oven is low voltage, and the circuit (also included control circuit) mainly includes: a fuse fu, thermal circuit breaker protection switch SW6, SW7, interlock switches SWL ~ SW3, lighting, Timer and power distributor switch SW4, SW5, turntable motor M3 and fan motor M2, etc.

The turntable motor and fan motor are synchronous motor, that is, the turntable motor rotates and drives the glass turntable when the microwave oven is operated, and the fan motor is simultaneously rotated, and the magnetron and other major components are cooled.

Third, not the discrimination of non-microwave furnace

Some phenomena that occur during the use of microwaves, some users often consider the microwave ovens by the microwave oven because the microwave oven is not well understood.

1. Trip

The power consumption of the microwave oven machine is large. The entire startup process is longer than the general home appliance, so the power consumption at startup is 5 to 6 times the microwave input power. When the start current of the microwave oven is 7A, the working current is around 5A. Some families are equipped with a limited capacity of the protective gates, and the trip occurs due to the current impact of the microwave furnace, it is preferable to be equipped with L0A or more protection brakes. In addition, when using a microwave oven to heat the food, it is best not to open the high-power electric appliance such as the rice rice pot.

2. Feel the sound

The sound of the microwave oven is mainly from the fan, and the high and low of the wind speed is proportional to the size of the sound. Galanz microwave furnaces use high-speed fan motors to increase the cooling effect of the host, extend the life of the magnetron and the host. It can be seen that as long as the sound is stable, no noise is normal.

3. Mechanical program controller microwave ovens have intermittent sound

The thermal adjustment of the microwave oven is controlled by the interruption of the relay, so that the magnetron has rules, thereby achieving the purpose of reducing firepower. The high fire is continuously generated high pressure, so the microwave oven is working in the firepower position above the high fire, which is a normal phenomenon.

4. When the microwave oven is working, there is a wind, leakage

According to the linearity of the microwave and the foldability of metals, the shield characteristics of the metal in the microwave and the homogeneous web, the junction of the door and the cavity is not controlled, the smaller, and as long as it is The gap is within the specified range, the more uniform gaps around the door. This makes the microwave to obtain an absolute shield within the cavity. In view of the above factors, a small amount of wind and light from the structural seam are completely normal due to the wind pressure of the cooling fan.

Fourth, the exclusion of common faults.

1. Start “three no” (light light, no sound, no microwave emission)

This kind of phenomenon is often caused by a variety of reasons. First check whether the power plug and the socket are poor contact, if it is not a power problem, check the following items. (1) If the 8A fuse is blown, if the new fuse is exchanged; (2) monitoring is turned off, causing short circuit; (3) interlock switch is not closed or the door hook is closed without contacting the interlock switch; (4) The primary and secondary short circuits; (5) capacitance breakdown or extreme breakdown.

2. Start the light, the turntable can turn, but does not heat

(1) The primary, secondary open circuit of the transformer is open. The 500-type meter is set 2500V AC block, a table base is connected to the transformer core, and the other table rods are second high-pressure slice, the secondary high pressure should be around 2100V, and if there is no voltage, the transformer is bad. If there is 2100V. Then check the transformer filament voltage, and the use of the universal LOV gear measurement filament electric pressure should be around 3.4V. If there is no voltage, the transformer is broken and should be sent to the same

Model transformer.

(2) The magnetron filament is open or the magnetic steel cracking. Using the multimeter R × 1 gear, measure the magnetron tube filament card, if the magnetron is broken, if the resistance value is small, the magnetoelectric steel is cracked.

(3) Diode breakdown. Using the multimeter R × 10k, the “+” terminal diode negative electrode, the table rod “-” ends the diode positive, and the reading should be about 150K. Multi-purpose table stick exchange location, measuring diode reverse resistance, multimeter reading should be big, 万 万 用 表 表 读, or close to short circuits, the diode breakdown should be sent to the same model new diode.

(4) The joint line is loose. Check if the plug is loose on the plug on the capacitor, if the plug is clamping.

3. Heating is normal, the fire is not bright in the furnace

Check if the plug falls off, and the stove light is burning.

4. The structural characteristics of the Galanz microwave oven and the maintenance dial are not turned or the fan is not turned.

Check if it is not due to the line, replace the new motor.

5. Automatically stop after 2 ~ 3 minutes

The cause of the fault is that the cooling failure or cooling is insufficient. The temperature of the thermal cutter automatically cuts off the power supply. Check if the fan motor winding is open, whether the fan fan is falling off, and the cooling airway is accumulated with many dust or dirt.

6. Do not open the door

Check if the door hook is broken, if it replaces the new door hook. In addition, the microwave oven is used for a long time. Due to wear and rust, the door shaft and the shaft hole are increasing, and the door is inclined. Then adjust the door hinge to re-correct the position.

I have a Galanz WP700L17L microwave. Open the oven door instant burning insurance during heating.

In an instant burning insurance in the open furnace door. The fault may be in the gate control switch section. The diagram of the gate composite switching circuit is shown in the drawings. When the door is closed, S3 is stepped first. After SL, S2 is turned on; the door is turned on, and the S2 is interrupted, and S3 is turned on, and the operation time gap is very short. If SL, S2, timing switch is opened due to a certain reason (such as contact sintering), it will leak microwave. Once this happens. The power supply will be short-circuited by S3 and the fuse is quickly blown to protect personal safety.

Removing S3 measurement is normal, it may be that the combined switching action is not hired. This dedicated switch cannot be found for a while. Therefore, it is temporarily disconnected to anyone wiring to apply. Because SL, S2, the timing switch is very small at the same time (of course, the best use of new parts). Burn insurance phenomenon in half a year after this treatment.

Another: circuit principle

The shutter door, S1 is closed, S3 is converted from the AC point to the ab point, and the S2 is closed, Q3 causes B extreme to change the low potential and positively biased, + 5V passed Q3 E, C poles, R7, R8 partial pressure plus To the 13 feet of the CPU (TMP47CA00BN-RH31), the CPU detects the gate signal, and is in the waiting state of the command state. When controlling the 15 pin of the CPU by the keyboard control, the high-resistance state (high) becomes a low-resistive state (low), Q4’s B is extremely converted to a low potential and is biased; and this, The 14 feet of the CPU also output a pulse signal. After the D11 rectification, R23, R20 is plugged to the B pole of Q13, triggering Q13 to turn on, Q13 is turned on, and Q14 is biased, +4V voltage is converted by RLL, R18 The pressure from the E, C of Q14 is applied to the B pole of Q13, which further turns the Q13, that is, the 16 foot of Q13, Q14, and CPUs constitute a lock state.

Since the T14 is turned on, the B exception of Q6 is high to be lowered to low potential. At this time, the current is generated by the E, C poles, Q6 E, C poles, D10 of the relay J2, R42, Q4. , S2-to-ground, J2, RY2 contacts, transformer TH to power work. When the barbecue is required, the 15 foot of the CPU restores high level, stops the microwave working portion; the 12 foot output of the CPU is low, control Q5 on, J3 is connected, 220V alternating current is directly added to the quartz fever Conduct heating. And at the same time, when the microwave oven enters the working state, the CPU’s 2 foot will automatically output a low level signal to Q7, so that Q7 is turned on, the relay J1 is bonded, RYL is turned on, so that the furnace light is lit, turntable, fan motor At the same time.

Galanz 750PS microwave electric schematic

After the input 220 AC is converted by the transformer TH, the secondary becomes 3.4V filament voltage and high pressure of 1.8 kV. 3.4V as a filament (cathode) voltage of the magnetron V.

Microwave repair method and skills

Microwave energy required for microwave ovens, and the microwave energy required for cooking food is produced by core components – magnetron. It is currently widely used for the microwave forced air-cooled magnetron, which is shown in the figure.

As can be seen from the figure, the magnetron is composed of a cathode (filament), an anode, a ring magnetic steel, a coupling ring, an antenna (ie, the microwave energy outputer), the radiator, and the filament plug. Among them, the anode is cylindrical, usually made of copper, and a plurality of flaps in the cartridge divide the anode into a dozen sector space. Each sector space is an anode resonant cavity, and its resonant frequency is the operating frequency of the magnetron. Generally 2450 MHz. The outer casing of the anode is nested a pair of annular permanent magnets, and the magnetic field formed by magnet steel is used to control the microwave oscillation energy in the anode cavity. The microwave energy output from the anode is transmitted to the antenna via a ring metal pipe (ie, coupled loops), and then transmits microwave energy into the furnace to heat food.

The wire operating voltage of the microwave arm magne control tube is generally 3.3V, and the current is about 10a; the anode (on the cathode) voltage is about 4000V. When the magnetron is energized, the filament is heated while forming a high voltage electric field between the cathode (filament) and the anode, under an electric field, the cathode transmits electrons, and the anode receives electrons to generate an anode current. When the electron is oscillated at each fan-shaped anode resonant cavity, the electron is perpendicular to the high voltage electric field due to the constant magnetic field generated by the ring magnetic steel, and below the magnetic field, the electron is along the cathode, the anode interval The tank curve movement forms a rotary electronic cloud that accumulate energy, and continuously delivers the anode to obtain a stable per second frequency of about 2450 million microwave oscillation energy on the anode.

The size of the microwave energy depends primarily on the high and low of the anode voltage, and since the magnetic field strength of the ring magnetic steel is constant, the microwave output power is mainly related to the anode voltage. However, if the magnetic steel is broken or the magnetic significant decline is reduced, the output power of the magnetron can be reduced, the microwave oven heating effect is deteriorated, the heating is slow, the firepower is faulty, and it must pay attention to this problem when repairing. The dynamic conduction in the magnetron is very small, and the fluctuation of the anode voltage has a great influence on the microwave output power, which will significantly affect the heating performance of the microwave. In order to avoid the operation of the microwave oven due to the fluctuation of the supply voltage, the magnetron anode voltage is typically provided by a power supply circuit composed of a leakage transformer, which can stabilize the anode current of the magnetron to maintain the microwave oven output power stabilizes.

The microwave conversion efficiency of the magnetron is about 70%, and the power of the remaining 30% of the remaining 30% is turned into heat, dissipated on the tube, high due to high power, high temperature rise, so the microwave furnace is set, The magnetron is forced to cool the air-cooled heat to prevent overheating damage.

Magnetron detection, repair or replacement

Filament cold resistance: use (universal table, the same) R × 1k gear test, normal less than 1 q (usually dozens of MΩ filaments and housing question resistance R × 10K gear measurement, normal is infinite. “Filament resistance is caused One of the common causes of magnetron output power. If the wire resistance is measured, it is not easy to judge that the magnetron is bad or aging. Practice shows that this situation is mostly a magnetron filament pin or socket oxidation The contact resistance formed after the fouling is also caused by the measurement mistake, usually the multimeter form pen and measuring point, or the contact resistance of the black and socket, and the problem of the magnetron itself is less, generally only the life of the life Over, long-term overloading or minority magnetron can happen this fault. So, when testing, the first merge should be normal, and the measurement method should be correct, and the magnetron should be placed or scratched. Remove dirt and oxides and then measure, if the measurement resistance is still large, it can be determined that the magnetron is poor.


Most of the filament is mostly damaged by the magnetron itself, which is generally changed from this to this, but the minority magnetron filament is turned from the lead in soldering. When repairing, the filament base can be opened, followed by clamping the lead and connecting piece with a wire pliers, and then using the soldering iron solder. Tables 1 and 2 show some of the main technical parameters of commonly used imported magnetrons and main parameters and reference transform models for maintenance and replacement. It should be noted that domestic magnetron uses more in early domestic microwave ovens, and the most imported and asset magnetron can be used, and its model may change. Some early magnetron have already or will be discontinued, so they must ask when purchased. Whether the clear can be changed.

Two kinds of faults in micro-wavelers microwave ovens

Most of the two faults commonly related to microcomputer microwaves are related to thin film switches or FPC printed lines, (1) Most of the key switches in the keyboard fail. Thin film switch or FPC is leakage is a common cause of this fault. The leakage is caused by the long-term moisture or moisture erosion of the microwave computer board, and it is difficult to determine whether or not to judge whether or not the electric leakage from the appearance of the circuit board, so it is necessary to directly Wipe or clean the film switches, FPC and computer boards with waterless alcohols, and it will have effect. Such a fault may also cause several discontinuous lines while the FPC printed line, but this is basically improperly maintenance, so it is more rare. When checking with the naked eye, you can use the naked eye to measure the meter, soon you can check the fault, re-weld the disconnection to troubleshoot. (2) Individual button switches in the keyboard fail. The FPC line disconnection or thin film switch contact with the failure switch is a major cause of this fault. The thin film switch and line corresponding to the failure switch can be found, and the fault can be excluded after processing the above method.

It must be noted that when repairing components such as computer boards and their keyboard circuits should be used with 20 ~ 25W iron iron, and the soldering iron shell should be reliably ground. If there is no condition, it is necessary to heat the soldering iron and then unplug the power plug. use.

Microwave fan motor and turntable motor structure and principle

The fan motor in the ordinary microwave oven uses a single-phase hood motor from 20 to 30W. Its action is to carry out a ventilation-dissipating J rotary electric machine for magnetron and high pressure transformers, furnace cavity, etc. to drive food in the furnace cavity. Heating is uniform. The turntable motor is typically composed of a permanent magnet synchronous motor and a reduction gear set, the rotational speed is 5 to 8 rpm, and the power is 3 to 5W. These two motors are not microwave special parts.

Microwave fan motor and turntable motor detection, repair or replacement

The winding electrical winding resistance is usually 10-20kΩ, and some of the earlier products have a resistance of less than 10kΩ, usually 4 to 8 kΩ. The cooling motor winding resistance is 100-250 Ω. The wind turntable motor and the winding failure of the motor is mostly the end of the tip dewatering or painted wire. Usually, it is not difficult to detect and repair. If it is open or short, the winding is removed or replaced by the winding.

The difference between the wind turntable motor is different, and the difference may be large. If it is difficult to judge according to the measured value, it can be powered up. As long as the gear set and the rotor are not being blocked, the motor will rotate; if the speed is normal and Turn 5 minutes The motor housing is not hot, and there is no problem. If the motor is not turned, the gear or rotor has problems, and a few may also be poorly contact, and the motor is required to be removed. Electric machines that are not normal or turned for a while will also be dismantled, and it is difficult to repair new parts. The turntable motor can be replaced by 3 to 5W Hongyun fan synchronous motors similar to the shape of the shape, and the characteristics are often used.


Microwave maintenance guide

Microwave ovens are a high-tech home appliance, and there is high voltage electricity. It should be careful when the microwave maintenance will be careful, and it will not cause human danger and damage to the microwave oven to cause personal hazards and damage to the microwave oven. In general, pay attention to the following matters when repairing the microwave:

(1) It is found that the microwave oven is abnormal or fault, and the microwave should be maintained through the manufacturer’s maintenance department or special maintenance point, do not need to be repaired or continued.

(2) Before checking the internal inside of the microwave, be sure to cut off the power switch first, first unplug the power plug.

(3) When repairing the microwave oven, do not paralysis due to the power supply has been cut, because the high-voltage capacitance of the rectifier circuit in the microwave oven high-pressure circuit has been charged, and there is still high voltage electricity, touch it will have a high voltage electric shock. The danger should be very payable.

(4) When repairing the microwave circuit, first use the ground wire to put the high voltage capacitance of high voltage capacitance, but in order to carry out microwave maintenance.

The microwave oven is often misunderstood, the microwave light is weak: if you do not use a lower fire to cook when cooking, the light of the microwave oven becomes weak and there is a sound generation, which is the normal phenomenon generated when the microwave is controlled. .

Microwave furnace timer and power regulator structure and principle

Ordinary microwave ovens generally use the timer and power adjustment (control), as a result of the same motor driven composition, simply referred to as timing power tuning. The timer is mainly composed of mini synchronous motors, reduced gear assemblies, and timing linkages. Since the linkage switch is connected in series in the microwave oven power circuit, the timer is mostly a power launch switch, except for the microwave of the start switch. When the operator is set, the timing switch is turned on and the microwave furnace is turned on, and the timer motor is rotated. When the time is reached, the switch is disconnected, the microwave oven stops working. Many timing will be turned off while opening a crisp ringtone to remind people to heat the work.

The power regulator is also known as the fire reschedule, which is actually a time switch, and the function is constantly turning on and disconnects the magpoically controlled power supply during the working period of the microwave, so that the magnetron is regularized, and the work is Time and rest time have a certain proportional relationship, change this ratio, so that the working time of the magnetron in the microwave oven is changed accordingly, thereby acting as a result of adjusting the microwave output power. The power regulator is also driven by the same motor used by the timer.

When the actual work is set, the power regulator is set to control the magnetron to rest for a while and then constantly loop according to a certain cycle until the microwave oven ends. Here, it is assumed that the working time of the magnetron in – a cycle period is T1, the rest time is T2, then a cycle period T = T1 + T2, as shown in FIG. The power regulator controls the microwave output power from Fig. 6. The circulating cycle T is very particular, from the heating angle, considering the shortness of the short, but it will make the power adjustment switch frequently, affect the working stability and service life of the magnetron.

Usually the mechanical power regulator T is about 30s, and the practice proves to be more ideal. When t = 30s, if the magnetron working time t1 is 6, 12, 15, 24, 30s, respectively, the microwave output power of the corresponding 6S is an insulation power, which is 20% of the stove rated microwave output power Po. Also known as the temperature of the temperature. The corresponding 12S is a thawing power (40% PO, also known as low power or low-fire), corresponding to 15S is a medium power (50% Po, also known as a fire), corresponding 24S is medium and high power (80% Po, also known as Mid-fire), corresponding 30s is high power (100% PO, also known as high fire or full power). Most of the normal microwave furnaces have such a 5-speed power (firepower) adjustment gear, of course, the power settings of each gear may vary. A few microwave ovens have more power gear, up to 8 ~ 12, in order to adapt to cooking and thawing different foods.

Microwave furnace timer and power regulator detection, repair or replacement

Most of the electrical coil resistance reference value of common timing modulators: opening is 15 to 25kΩ; the closed form is 5 ~ 10kΩ, but there are also products not in this range. The inspection is mainly to measure whether the motor winding is broken or the resistance is large. If so, it should usually check whether the lead is poor contact, as in this respect, usually re-winding the coil or replacing the motor.

Timed modulators also have mechanical faults, more common are parts such as plastic regulatory hips by foreign objects or itself, when repairing, only disassembling foreign matter or repair, and exchange damaged components.

Microwave high voltage capacitor structure and principle

The general structure of the high voltage capacitor used in the microwave oven is shown in Figure 4. The rated operating voltage of the capacitor is usually 1800 to 2200V, the capacitance is 0.8 to 1.2μF, and the inside of the capacitor is then 10 ~ 12mΩ high resistance resistance, its effect is the electric charge on the capacitor after the shutdown.

The main function of the high voltage capacitance is to form a half wave pressure rectifier circuit and provide a DC anode high pressure for the magnetron. The secondary high voltage winding of the high voltage transformer outputs about 2100V, and after the high pressure capacitance and the high pressure diode are rectified, the DC high pressure supply magnetron of 4,000 V is extremely used. Due to the cathode of the magnetron, the anode is outside, for safety, the anode of the magnetron is always grounded, and the cathode is negative.

High voltage capacitors also have the effect of improving the efficiency of microwave oven. Because there is a lag currently inductive current, the efficiency is low; with high pressure capacitors, its advanced capacitor current will compensate for the lag leak current, so that the power factor of the circuit can be improved, efficient. rise.

Microwave high pressure capacitance detection, repair or replacement

The high-voltage capacitor can be measured by a multimeter R × 10K or R × 1K gear, and the table needle should be gradually returned to 9 to 12MΩ after swinging a certain angle. If there is a small conduction or resistance, it indicates that the capacitor breaks down or leakage. If the clinic is not swing, it indicates 9 ~ 12mΩ, indicating that the capacitor has been opened. Also measure the electrical resistance between the two ends and the outer casing between the capacitors, otherwise the capacitance and housing are insulated. The high voltage capacitor of the microwave oven, as long as the main characteristic parameters are the same or similar, the outer dimensions do not affect the installation, which is generally mutually replaced.

Galanz WD900ASL23-Z type microwave, sudden work 3 ~ 6 minutes after work


After 3 ~ 6 seconds, 1: 01, re-operating the phenomenon. This phenomenon may be too high of the working temperature of the magnetron, causing the thermal relay protection or thermal protector itself. It may also be poor power supply. In this end, it is very easy to make the principle, first check the power, and find that the power socket is hot, the fault is to contact the resistance too large connector to heat generation deformation, cause the instantaneous power failure. After replacing a power outlet of a load current 8A, troubleshooting.

Microwave / wavef oven lock switch and anti-microwave leakage device detecting microwave oven during use and maintenance, the furnace door is often frequently switched, even collisions, tapping, etc., easy to cause damage or failure of the gates, door hooks and door seals; additional, use After a long time, the aging deformation of the plastic doors, the displacement of the door hinge can increase the gap of the door, which may cause the amount of microwave leaks to increase, and the maintenance personnel and users may cause damage, so do not fall lightweight .

It is mounted on the outer casing of the magnetron, and the upper surface and the magnetron of the upper cover are in direct contact, and when the magnetron is operating, the temperature change is conducted to the heat sensing sheet through the upper surface end surface. Within the normal temperature range, the motion, static contacts of the protector are in contact with the on state. When the abnormality such as cooling fan is stopped, the magnetron temperature rises and reaches the numerical (protected), and the thermal sensing sheet is thermally deformed, so that the top rod moves, press the spring sheet, so that the contact Detained from the static contact, so that the circuit is cut off, the magnetron stops working, and the temperature begins slowly. When the magnetic controlled temperature drops to a certain value, the thermal sensing film is active, restored the original shape, makes the moving, the static contacts, the circuit is turned on, and the magnetron is re-operated, which is self-recovery.

Microwave oven high pressure diode test and substitute

The conduction threshold voltage of the high voltage diode is high. If the inner battery voltage is 1.5V, its forward resistance is measured, the measurement resistance may be large, and the gauge is mostly not moving. This cannot be judged that it is good, so The R × 10K gear measurement of the metric meter with an inner battery is greater than 6V, and the measured forward resistance is about 20-300kΩ; the reverse electrical resistance is infinite. like. Measurement with a mega Europe, the forward resistance is normal than 2kΩ; the reverse resistance is infinite. If there is no above the above instrument, the R × 1k gear measurement of ordinary meter is also used, but it is necessary to measure the 6 ~ 9V battery on a table pen, then measure the battery, and the battery is positive and the battery is negative. Red table pen is used for measurement.

When measuring, the two measurement is not shorted, or it is not necessary to measure the high pressure diode or other component of the known internal resistance (too small), so as not to pass the head and damage the table needle; reuse. The measurement resistance determination criteria can refer to the value of the normal high pressure diode measured by the same method. Of course, according to the general experience, it is more convenient, and most reliable, 鼹鼹 Just detect that the reverse resistance is infinite, the forward resistance is not infinite or large (the needle deflection is angled, not a micro-motion), indicating that the diode is basically good. For asymmetric protective diodes used in some microwaves, 10K gear measurements can be used, and the normal positive and reverse resistance should be infinite.

The high pressure diode of the microwave oven, as long as the main characteristic parameters are the same or similar, the dimensions do not affect the installation, which is generally replaced with each other.

Galanz WP700 microwave furnace is turned on, and the turntable is normal, but does not heat.

Analysis of the cause may result in non-microwave output for high voltage circuit failures or magnetron failure.

Open the housing check and find that the high pressure fuse has been burnt. According to the machine circuit diagram (see Figure), the high-pressure fuse is blown, indicating high voltage current overload, may be due to high pressure capacitor C breakdown, high pressure diode D breakdown or magnetron breakdown. Check the high pressure diode normally, then check the high pressure capacitance C, find the breakdown, replace the test machine, troubleshooting.


Galanz microwave oven WD700A WD750B WD800B WD900B Electrical Map

Microwave furnace element detection

First, magnetron detection method:

1) Test between the magnetron filament terminals, the resistance value should be less than 1 Ω;


2) Test between any filament terminal and magnetron (ground), the resistance value should be infinite; if the resistance is small or zero, then the magnetron should be replaced.

Second, high voltage transformer detection method: detect three windings:

1) Primary windings, about 1.45Ω

2) A secondary winding, about 112Ω

3) Filament windings, less than 1Ω

If the measured reading does not meet the above data, the high voltage transformer may have faults and should be replaced.

Third, high voltage capacitor detection method:

1) The measurement instrument needs to be set in the highest resistivity;

2) Normal Phenomenon: A. Test the two terminals of the capacitor, showing on a short time (real), then the resistance after the charge is approximately 10mΩ; B, the electrical resistance of the terminal and the outer casing should be infinite;

3) Abnormal phenomenon: A, short-circuit capacitor is always turned on; B, the open circuit capacitor always displays about 10MΩ resistance value due to its 10mΩ internal resistance; C, when the internal line wiring in the high voltage capacitor, an infinity is displayed. resistance.

Fourth, high voltage diode (also known as one-way diode or high pressure rectifier assembly) detection method:

1) Set the instrument to the highest resistance (note: The battery of the measuring instrument must also have a voltage of 6V, otherwise an unlimited large resistance is displayed in both directions).

2) Normal resistance is infinite in one direction, and in another direction is more than 100kΩ.

V. Two-way diode (also known as protective diode) detection method:

1) Set the instrument to the highest resistivity;

2) Disconnect the wire and separate the protective diode from the circuit;

3) The normal phenomenon should be two ends of the protection diode from both directions, and the resistance value is infinite. If it is damaged, the conductivity will be exhibited in one or both directions.

Note: The detection of δ or more metals is cut off the power and discharges the capacitance, unplug each related wiring.

Brand microwaves:

Samsung M9G88 microwave furnace is full screen display, and all function keys have no effect.

Checking the CPU + 5V, the reset signal, and clock oscillation are not abnormal. The peripheral components of the circuit are no bad. If the operation board has problems, the focus check IC1 (HD404316B38S) {26} ~ {35} script machine key control selection pulse end and diode The control level and resistance value of the CON03 to thin film are tapped by CON03 to thin film, where the cDn03 {2} foot and {5} foot does not have a TP signal output, normal, using the MF30 type 10,000 meter R × 10K transmission measurement, Table Positive The {5} foot, the negative electrode picks the {2} foot, and the end should have a resistance change value of 500mΩ to 200mΩ when any key is pressed, but the measured key has no change, indicating that the electrode has deteriorated. Since the conductive electrodes are bonded from self-adhesive, it can be regenerated and repaired, and the plastic film can be carefully removed, and it can be seen that the bond coating contacts have been black. Try rubber rubber, its contacts are intact, and then bonded to the test machine, each functional operation key is restored to normal, troubleshooting.

Idea WD800-A type microwave electric system diagram

Leap microwave overest

The check power distributor has been placed in high power gear, such as heating slower in low fire blocks. Due to the wind turbine, the turntable motor is operating normally, the power control system and the transformer are normal; measure the forward resistance of the high pressure diode 150kΩ, the reverse resistance is infinite, normal. Put a cup (glass) water, the water temperature is measured at 21 ° C, and the microwave oven setting the fire is heated. After one minute, take the cup to measure the water temperature only 26 ° C, normal, the temperature difference value should be between 9 ° C to 16 ° C, that is, it should be reached About 30 ° C ~ 36 ° C, according to this, it is determined that the magnetron output power is low. The magnetron pipe connection plug has been rusted so that the contact resistance value is increased, and thus the heating power is lowered. Remove rust, sand is scraped and then test machine, normal work, troubleshoot.

Sharp R-5880 microwave, the furnace light is on, the turntable, the fan is running normally, but the running noise is greater and can smell a little bit of sculid, the food in the furnace can’t be heated

Downtable open cover check. There is an avocium, and it is judged that a piece of short circuit is short-circuited. Initially, the electrical components have not seen an abnormality. Turn the magnetron, open the two-speed wire terminal, and measure the flame resistance of the wire with the multimeter R × 1 unit, then use R × 10K to measure the resistance of the magnetron housing Small. Intuitive discovery of one of which is short to the housing. Remove the magnetron, open the plastic cover of the pin with a screwdriver, see the carbonization phenomenon caused by the internal insulator, scraping all the carbonized moieties, and then fill the encapsulation with an epoxy resin, and replaced the magnetron after curing. Insert the terminal. The power-on heating is normal, and the magnetron can be repaired.


Samsung M9G88 microwave no screen display, according to each function key.

From the perspective of the fault, no screen is generally poorly in the LCD fluorescent display, no filament voltages or external control voltages are not in place. Checking the CON01 has an AC220V input. The control transformer secondary filament voltage is normal, and the measurement voltage is negative voltage, and there is no driving level input, the circuit IC1 (HD40316B38S) {21} is + 5V voltage, {8 }, {9} The oscillation voltage is 2.8V, 2.1V, and is normally, and the failure is between the drive circuit and the CPU circuit. If only the drive circuit is faulty, it will only make a selection in the display. . The voltage of IC1 {22} foot and IC2 {4} foot and IC2 (SWM002) are periphery in the CPU, where {4}, {7} ~ {12} is controlled by CPU, the IC2 {4} foot is not The voltage input (normal end voltage should be 3.5V), when the IC1 {22} foot-connected IC1 {22} is found, the feet have a duel, and the voltage is normal, the voltage is normal, and the troubleshooting is eliminated.

Little Swan W6001 baking microwave no response

Carefully remove the casing, first check the power supply circuit. Remove the 8A / 250V blow, from the appearance of the appearance, the use of multimeters have been disconnected, and it is not a serious short circuit. It should not be applied immediately after replacement, and the cause of the blower should be found. After investigation, the door chain switch LXW1-10B16 (0.3A / 250V) has been detached from the positioning slot, and one of the ends of the sheets have been broken. The switch is returned and repaired, and the tester is turned on, the fan tray is turned, the light is on, but does not heat.

The high-pressure diode T01 (14512) and high pressure capacitance CH85 (0.85 & micro; f / 2100ac) were normal. Extraction measurement high voltage transformer Y600STC primary no voltage (TS01 and CH85 should be removed before power-on detection, so that the high frequency circuit does not control), the problem may be on the timing switch. Timed switch wiring pile feet from left to right: 1 foot-connected fan motor, 2 foot-connected power supply, 3 foot contact MT, 4 foot lump light, 5 foot, 6 foot pick-up tray motor. After investigation, it is poor contact between the 2 feet and the plug, and the plug is polished and fastened to the electric test machine, the microwave oven is restored to normal.

Beautiful microwave furnace can’t be heated

First break the power, open the cover, discharge high-pressure capacitor, measure the capacitor, high-pressure diode, magnetron, and high voltage transformer, when the high-pressure insurance is measured, after changing high-pressure insurance, the boot work is normal.

Samsung brand RE-630D microwave fuse.

This fault may be caused by a short circuit of a component. Replace the burned fuse, unplug the transformer high-voltage end plug, power up, the furnace light is on, the pallet and fan are normal, indicating that the transformer and primary circuit are normal. It is determined that the high voltage capacitor breakdown, replacing the capacitor, troubleshooting.

Idea WD800-A microwave furnace energized rear machine has an ambitious and a non-smoke

Cut the power immediately and turn on the cabinet check (see the accompanying drawings),

The F / 8A is in good condition, the T (magnetic saturated transformer) upper layer, the secondary high-pressure wire pack has been burned black. When the maintenance is maintained, the T secondary is first connected to the plug of the high voltage capacitor C, and the insulation is wrapped with a high pressure tape, which is broken. Then the test machine, the indicator light on the panel lights, and the screen count is displayed, and there are twice “Hello, thank you for the use of the Hewage Electric Appliance”. Note the low voltage part of the primary winding, voice prompt, and electronic control is intact. The high-voltage microwave generator sections were meticulously overhaul with the MF-47-type pointer mills and DT890D digital multimeters, respectively. The t-type high pressure winding resistance is 100Ω, the wire winding resistance is 1 Ω, normal; the asymmetric insurance diode D1 is positive, the reverse resistance is infinite, the high pressure rectifier diode D2 forward resistance is 150kΩ, the reverse resistance is infinite, normal . Finally, measure the high pressure capacitor C first discharged, and it is intact. At this point, it is possible to determine that the machine fault is done due to the T secondary high pressure winding insulation, and the turns is formed, and the heat is burned. So after replacement of new transformers dedicated to a 900 W type microwave oven (note that the same name terminals of the transformer cannot be received) The microwave oven has returned to normal.

Anbao Road MC-2318 Mechanical BBQ Microwave Circuit Diagram


The Sharp microwave oven turntable does not turn, the furnace light is not lit and cannot be cooked (no microwave output).

If a microwave oven is harmful to the human body, only the electrical lock and mechanical locking device specially used in the microwave oven is normal, and the relay J2 in the Sharp microwave control circuit can control the high voltage transformer. It is normal to check the lock device.


If the cooling fan and the turntable are not turned, the furnace light is not bright, so it is determined that the fault is in the negative power supply, the cooling fan, and the turntable control circuit. The triode BG2E is extremely normal and the B-pole voltage is normal, and the C-pole voltage is zero, the BG1 is not saturated. Remove the BG1 to check the C, E Extraction, and reboot the microwave oven after replacement to the new tube.


Samsung RE-563T type microwave, the furnace light is on, the tray is running normally but cannot heat the food.

The furnace light is on, the pallet is also turned, indicating that the primary line is normal, the fault is in the secondary circuit, the high voltage portion, as long as it is a leak-magnetic transformer, high voltage capacitor, high pressure silicon stack, magnetron, etc., it will cause no Microwave output, it is not possible to heat food. Unplug the transformer secondary high-voltage end plug off the high voltage circuit, compress the fault range, and the maintenance is also safer. Power-on inspection transformer secondary voltages are 1800V, 3.15V, normal. Use a multimeter-resistant blocking to check the high-pressure capacitance, high pressure silicon stack and magnetron, check, the magnetron filament is open, and the magnetron can be replaced according to the regular. However, in order to find the reason for the opening of the filament, the magnetron filament base is opened, and the filament lead is discharged, clamping it with the pliers, welding it with the soldering iron, and works normally.


Anbao Road MA-2318 Mechanical Microwave Circuit Diagram

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