Most often, the external signs of microwave failure are the appearance of sparks, smoke, stopping the movement of the plate, stopping of heating food placed in the oven. Or if you cannot turn on your microwave. It is dangerous to switch it on.
There are three main causes of electrical failure:
A blown fuse;
The mica plate burned out.
This is the most common cause of failure. There are two fuses in the microwave oven. The first, main fuse is on the input voltage of 220 volts in a microwave oven. Here it can burn out. In this case, the oven stops turning on and does not respond when you press any buttons. To diagnose this failure: remove screws from the oven’s back and open the protective panel. Do not forget to pull the plug out before starting repair work. Then it is necessary to forcibly discharge the filter capacitor. To do this, its inputs connected to each other by insulated wire. Be sure to keep the wire strictly behind the insulation. Then check for voltage on the line filter board and check that the microwave power cords are working.
If there are no faults in this part, should be inspected the diode in the rectifier circuit of the power supply. Most often it is the cause of a blown fuse in this type of failure. The fuse in the microwave should be checked for breakage visually or with an ohmmeter, if necessary, replace it with a working one and analyze the causes of burnout to avoid a recurrence of a similar situation, paying attention to various dark color of electrical elements indicating problems in microwave units.
The second fuse is after the high-voltage transformer in the magnetron circuit and is called high-voltage. It is “hidden” in a plastic case in the form of a tube and is located next to the transformer. This fuse fails due to the failure of a high-voltage diode or capacitor. It is better to replace the fuse with a new one, because it is calibrated to the required tripping current. It is necessary to replace the part that caused the fuse to burn out.
If the backlight in the oven works, the plate rotates, but the microwave does not heat the food, then the cause of the fault is a magnetron failure. Magnetron – a device that generates microwave radiation. That is why the oven does not heat.
The magnetron is located in a small rectangular metal case. Firstly it must be cleaned and then inspected visually. Next, inspect the magnetron unit. The integrity of the wires connecting the terminals and the case. Often the reason for failure of magnetron is failure of the capacitor. Then be sure to check the microwave control unit. Pay attention to burnt, smoky and dirty places. These parts will need to be replaced for further work of a microwave oven.
Mica plate burning
A sign of breakage of the mica plate – sparks that appear when it is turned on. The reason is improper operation of the oven, heating food with the lid open. In this case, drops of food are sprayed, falling on the plate. As a result, it gets wet and burns.
Mica plate is inexpensive and can be purchased at specialty electrical stores. If you find a mica plate of other sizes, you can make a plate of the right size with your own hands.
If you can’t find a replacement for this part, you can reuse the burnt plate. To do this, remove the plate and carefully clean it of dirt. Then turn it over with the damaged side inwards and carefully set it in place. This type of repair, of course, is difficult to call ideal, but it is quite suitable until the moment when you find a replacement for a damaged part.
If you have not been able to solve the problem even with our tips, and the oven still does not heat up, you can repair the microwave oven from special services or buy a new one.