How to use a multimeter to detect the problem of repairing various faulty circuit boards, sometimes it is necessary to flexibly master the use method and skill of the multimeter according to the fault phenomenon. For example, the following questions are listed below:
1. For example, if the digital meter is not energized, in the case of power failure of the circuit board, first dial the multimeter to the corresponding resistance file to check whether the insurance is damaged, varistor, and so on.
2. If the above measurement is normal, then turn the multimeter to the diode to check whether the diode is damaged. First, connect the positive electrode of the diode with the red pen and the negative electrode of the diode with the black pen. At this time, the normal diode should display 0.5mV~0.7mV. Normal, otherwise It is the bad tube, and the four diodes are measured by analogy.
3. If the above measurements are normal, then measure the voltage on the circuit, dial the multimeter to the corresponding DC voltage file, connect the circuit board with the black test pen, and connect the red test lead to the measured point. For example, measure the voltage after rectification and filtering. and many more.