Contents

• 1 The principle of operation of the microwave microwave power supply circuit
• 2 Protection equipment
• 3 Basic malfunctions and repairFirst visually check the integrity of the fuse. If it is blackened or a disconnected hair is visible in the glass case, then a replacement is required. The primary winding of the transformer is located below and visually it can be viewed and measured the incoming voltage at its terminals.

  A few more turns of wire can be seen near the primary winding, this is the secondary winding of the cathode heating. It gives a voltage of ~ 6.3v, necessary for the normal operation of the cathode. Above is the secondary winding of the transformer, which produces about 2kv of voltage applied to the doubler. The high voltage winding of the transformer is well insulated with several layers of insulation.

  

  Doubler is a capacitor with a parallel diode. It doubles the incoming voltage of 2kv to 4kv, which is fed to the cathode of the microwave microwave magnetron. The cathode is preheated with an alternating voltage of ~ 6.3v, coming from the secondary winding of the cathode. The anode of the magnetron is connected to earth.

  Magnetron is controlled by a relay and a timer using the set parameters on the front panel of the microwave. The parameters of the microwave oven microwave are set by the programmer. The programmer is equipped with a gear or gear, responsible for adjusting the clock. The longer the intervals of operation of the magnetron, the more power is allocated to cooking. Accordingly, the longer the rest intervals, the less power the magnetron produces.

  In the new models of microwave ovens, inverter power control of the microwave generator is used. In this case, the cyclical nature of work and rest of the magnetron is managed by a temperature measurement sensor. By its signal, the pulse repetition rate increases or decreases. For high temperature, the pulses go very often, more power is expended and more energy is released for cooking. For a lower temperature, their cyclicity decreases, which allows flexible control over the entire process.

  

  Protection equipment

  Protective microwave oven relays are responsible for the simultaneous shutdown of all systems when the door is opened while the magnetron is operating. Two protective relays at the same time break the voltage supply in phase and zero. In addition, one of them necessarily controls the correct operation of the second protection element. There is also a third protection relay opening the power contacts when the microwave oven door is open and the warm-up process start button is not turned on.

  High-voltage fuse blows, providing protection for the microwave generator from emergency situations:

  • idle;
  • hitting metal objects on the pallet.

  The secondary mechanisms of the microwave oven:

  • fan motor;
  • engine pallet;
  • backlight lamp;
  • lamp grill.

  Since all the secondary elements are connected in series, if one of them fails, nothing works except the magnetron and the starting relay.

  This makes it easy to repair your own microwave oven.

  Major malfunctions and repairs

  The list of faults of microwave ovens is not exhaustive, it only reflects the most common breakdowns. You can repair all the listed faults with your own hands.

  Problem	Possible causes
  solution not turned to mills	Power supply fuse triggered, only	replacement After replacing the fuse, the operability of the transformer and transformer safety diode of the
  transformer turned off.the oven is periodically turned off and on at intervals of several minutes	Cooling fan malfunction, relDo not turn on the fan, close the air vents	Minor repairs or replacements
  Sparks are visible and smell like	when broken Mica pads are broken due to contamination of	Replacing
  Microwave does not heat	low voltage or loss of magnetron emissionApplying an	voltage stabilizer Do-it-yourself repair by increasing the number of turns or replacing an
  magnetron LCD display does not display all segments, highlights and spots	The screen or processor is damaged. If the microwave also does not work, then exactly the	processor Replacing the
  Touchpad stopped working	conductive paths are damaged	Do-it-yourself repair by wiring or replacing
  The pallet rotates with jerks	Roller grooves are not tied, problems and drivers have to work;replacement of the engine
  The light is on, the pan rotates, the microwave does not heat	A strong voltage drop in the network, breakdown in the power supply circuit of the transformer, magnetro is broken	Installing a voltage regulator, repairing a transformer supply circuit with a tester, troubleshooting, replacing an
  microwave generator The buttons on the	control panel do not turn on Do it yourself repair by checking a tester, pinning the contacts, or replacing the
  buttonsbuilding fan, doubler diode or transformer	Replacing
  Microwave works without shutting down	Faulty voltage supply relay( contact sticking)	Disconnectpower, replace. There may also be a problem in the processor or relay control circuit. Independent repair by checking with an ohmmeter, if the circuits are in order, replacing the processor module

  You can repair the microwave oven with your own hands, but you can properly use it and thereby significantly increase the term of impeccable service.

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