How to check the microwave transformer for serviceability

Sometimes when the microwave oven is operating, excessive noise is heard, the housing heats up and a burning smell comes from it. In this case, there is a high probability that certain problems have arisen with the voltage converter. And in order to be convinced of this, it is necessary to identify its serviceability.

How to check the microwave oven transformer for serviceability

The serviceability of the converter is checked by determining the voltage on the windings. But with parts that contain high voltage, this method is unacceptable. The thing is that the voltage on the secondary coil reaches a dangerous 2 kV. That is why the manufacturers of this equipment advise checking the integrity of the converter by measuring the inductor resistance.

Its integrity can be determined in another way. The bottom line is that they check the no-load current. To do this, disconnect the wires that connect to the device and remove it from the housing. In parallel with this, an ammeter is installed on the first coil. Food is supplied through it.

Important! If the converter is corrected, the following data will be displayed on the tester indicator; on the working part, the current in idle mode will be in the range from 0.3 to 0.5 A. If the numbers are higher, then most likely the transformer is faulty.

Check the transformer yourself

There are two ways to determine its performance - safe and under voltage. More on this below.

Safe diagnostics: how to check a microwave transformer with a multimeter

A safe study is carried out using a tester (multimeter). The essence of the study is to look for any problems. The sequence of actions is as follows:

1. The device is configured for measurement by setting the required measurement limits.
2. After this, check the resistance of the coils - primary and secondary.

Important! Before taking measurements, the converter must be removed from the housing.

If the number “1” appears on the tester panel, a break has occurred. If there is a closed circuit on the first coil, the indicator should show a value of the order of 4 - 4.5 Ohms, on the incandescent coil 3.5-8 Ohms, on the high-voltage coil 140-350 Ohms. The multimeter is set to a measurement range within 200 ohms. When taking measurements, the results should not go beyond the shown limits.

Important! If the measurements are outside the specified limits, then most likely there is a short circuit between the turns of the winding.

It is advisable to take into account the error of the measuring device. In order to check the condition of the device, there is no need to take the oven to a service center. If the user has knowledge of basic electrical engineering, he will be able to test the voltage parameters.

Test under voltage

If the circuit has been checked, but the product still does not operate normally, then it makes sense to determine the condition of the secondary choke.

Attention! This is a dangerous process, and safety precautions must be followed when performing the work.

The algorithm for checking a device under current is as follows:

1. The product is supplied with 220 V.
2. Using a device that allows you to carry out work from 2 kV, check the voltage at the outputs of the windings.

The voltage on the filament coil should be within 3 kV, on the high-voltage coil - 2 kV.

Reverse check

This method of checking a transformer is probably the easiest. 220 V is supplied to the secondary winding, 24 V will be removed from the primary winding. If 12 V is supplied to the primary winding, then the potential on the secondary will reach 109 V.

If the device heats up during idle operation, then most likely there is a short circuit between the turns of the winding. If it heats up during operation, but when turned off it stops heating, then you need to look for problems further.

Precautions when checking the microwave transformer for functionality

You may receive an electric shock while taking measurements. Moreover, its consequences are unpredictable. By following simple rules you can avoid such troubles:

• When determining data on a working furnace, it is unacceptable to touch the parts installed in the furnace.
• To carry out measurements on the tester, install the so-called alligator clips and connect to the circuits with their help.

If it becomes necessary to touch parts, perform the following manipulations to avoid shock from the capacitor:

1. disconnect the product from the network;
2. jumper the magnetron leads to the furnace body.

The standard circuitry of a microwave oven provides for the presence of a resistor that absorbs the discharge of the capacitance, but it cannot completely eliminate the danger of electric shock. The resistor may burn out. In this case, an electric shock can be fatal. Be careful!