1. Short circuit test. Short circuit is one of the most common LED display faults. Use an electrician's multimeter to detect the short circuit condition and detect whether the components are short circuited. If the short circuit is found, take corresponding measures to solve it. Some can be directly observed. The short circuit test should be performed without power supply to avoid damage to equipment and personal safety.
2. Resistance test, first detect the resistance value of a certain point of the normal LED screen, and then check whether the resistance value of other points of other LED screens is the same as the normal resistance value. Those that are different are problematic.
3. Voltage test: first detect the voltage value of a certain point of the normal LED screen, and then check whether the voltage value of other points of other LED screens is the same as the normal voltage value. Those that are different are problematic.
4. Voltage drop test. The LED display screen is basically composed of many single components. When there is current passing through a pin of the single component, there will be a voltage drop. The voltage drop on the same pin of the same model is almost the same. Judge whether it is good based on the voltage drop on the pin.