With the popularization and application of LED display screens and LED full-color screens, LED display screens have become a beautiful scenery in today's information society, especially when night falls, LED display screens bloom with brilliant images, allowing people to feel the colorful world. However, with the continuous expansion of the application scope of LED display screens, there are also more and more problems with LED display screen malfunctions. So, how to test for LED display screen malfunctions?

1. Resistance detection method, adjust the multimeter to the resistance mode, detect the ground resistance value of a certain point on a normal circuit board, and then test whether there is a difference between the same point on another identical circuit board and the normal resistance value. If there is a difference, the scope of the problem is determined.

2. Voltage detection method, adjust the multimeter to the voltage range, detect the ground voltage at a certain point of the suspected problematic circuit, compare whether it is similar to the normal value, otherwise the range of the problem is determined.

3. Short circuit detection method, adjust the multimeter to the short circuit detection mode (some are diode voltage drop mode or resistance mode, usually with alarm function), detect whether there is a short circuit phenomenon, and solve it first after discovering the short circuit, so as not to burn out other components. This method must be operated in the event of a power outage in the circuit to avoid damaging the meter.

4. Voltage drop detection method, adjust the multimeter to the diode voltage drop detection mode, because all ICs are composed of numerous basic single components, only miniaturized. Therefore, when there is current passing through one of its pins, there will be a voltage drop on the pin. Generally, the voltage drop on the same pins of ICs of the same model is similar. Based on the voltage drop value on the pins, the operation must be carried out with the circuit powered off. This method has certain limitations, for example, if the device being tested has high resistance, it cannot be detected.