1, short circuit detection method, set the multimeter to short circuit detection block (generally with alarm function, such as the conduction of the sound), detect whether there is a short circuit phenomenon, find short circuit should be solved immediately, short circuit phenomenon is also a common LED display module fault.Some can be found by looking at IC pin and pin pin.Short circuit detection should be operated in case of circuit power failure to avoid damage to multimeter.This method is commonly used by *, simple and efficient.90% of the faults can be detected by this method.

2, resistance detection method, the multimeter set to the resistance, test a normal circuit board at a point to the ground resistance value, and then test another same circuit board of the same point test and the normal resistance value is different, if not, determine the scope of the problem.

3. Voltage detection method: adjust the multimeter to the voltage range to detect the voltage to the ground at a certain point of the circuit suspected to have problems, and compare whether it is similar to the normal value, which can easily determine the scope of the problem.

4. Voltage drop detection method: adjust the multimeter to the diode voltage drop detection file. Because all IC is composed of many basic elements, it is only miniaturized.Generally, the voltage drop on the same IC pin of the same model is similar. According to the voltage drop value on the pin, it must be operated in the case of circuit power failure.