How to Use a Multimeter to Troubleshoot Problems
If the device is not working, the first thing you think about is whether the device voltage is normal. You need to use the voltage range of the multimeter (choose AC voltage range or DC voltage range, it depends on whether your device is an AC device or a DC device) to measure. If the control circuit or secondary circuit is disconnected, even if you are familiar with the schematic, you need to use the voltage range to measure whether the voltage at a certain point is normal. If it is determined that the voltage at that point should not be there but is present, and what should be there is not, it indicates that there is a disconnection or poor contact at that point. In order to more accurately determine if there is a problem at that location, you also need to disconnect the power supply of the device. Use the ohm range of the multimeter to confirm if there is indeed a disconnection at that location, in order to troubleshoot the problem. Basically, it depends on your familiarity with the equipment and the accumulation of experience in your work.
How to use a multimeter to check for short circuits?
The short-circuit resistance value of the capacitor is zero; The resistance of the transformer and motor coil touching the shell is also zero;
Short circuit between two insulated coils, etc. Some short circuits cannot be detected, such as coil turn to turn short circuits.
Discussion:
Resistance has no polarity. Use a multimeter to measure the voltage of an electronic device. Connect the red probe to positive and the black probe to negative, and the multimeter will display a positive number. If it is negative, it can be determined by reading the multimeter. Turn the multimeter with a buzzer to the buzzer position for measurement. If the multimeter emits a beeping sound, it is judged that there is a short circuit
