The LED display screen is faulty. How to repair it?

Sep 16,2021| LED Knowledge

As a commonly used LED screen, full-color LED display screen has been applied in many activities, such as dinner, wedding banquet, stage program, square display screen, etc. when the display screen is the most important modern display equipment, the following is a simple analysis of several key points of maintenance.

The tools needed are multimeter, electric soldering iron, blade and tweezers.

To judge the problem, we must first deal with the primary and then the secondary, deal with the obvious and serious problems first, and deal with the small problems later. Short circuit shall be the highest priority.

1. Observation method: observation method and visual observation. Sometimes the circuit breaking can be seen by eyes. For example, PCB circuit is broken due to scratch, red and black wire is loose, etc

2 comparison method: The comparison method is very important and key. Sometimes we can't see whether the IC is faulty with the naked eye and can replace it with a good IC. Sometimes we don't remember whether the signal is connected. We can take the unit board and measure the corresponding position! Contrast is the key!

3 troubleshooting:Sometimes there are many reasons for a fault. We can deal with it one by one. If we don't remember, we can look at the treatment of common faults in front and eliminate them one by one!

4 resistance detection method: adjust the multimeter to the resistance gear to detect the ground resistance value of a certain point of a normal circuit board, and then detect the same point of another same circuit board to test whether the resistance value is different from the normal resistance value. If it is different, the scope of the problem is determined

5 voltage detection method: adjust the multimeter to the voltage level, detect the ground voltage at a point of the suspected circuit, and compare whether it is similar to the normal value, otherwise the range of the problem is determined.

6 short circuit detection method: adjust the multimeter to the short circuit detection gear (some are diode voltage drop gear or resistance gear, generally with alarm function) to detect whether there is a short circuit. If a short circuit is found, it should be solved first so that it will not burn other devices. This method must be operated when the circuit is powered off to avoid damaging the meter.

7 voltage drop detection method: adjust the multimeter to the diode voltage drop detection gear. Because all ICs are composed of many basic single components, they are only miniaturized. Therefore, when a current passes through a pin, there will be a voltage drop on the pin. Generally, the voltage drop on the same pin of an IC of the same model is similar. According to the voltage drop on the pin, it must be operated when the circuit is powered off. This method has some limitations. For example, if the detected device is high resistance, it can not be detected.
Welding pins of LED display

The maintenance points are summarized as follows:

First Point 1: short circuit

There are many examples of this phenomenon. If there is a short circuit fault, it needs to be checked in time.
Welding pins of LED display

Second point: open circuit

As the name suggests, open circuit is signal interruption. We just need to reconnect the line where the signal is interrupted.

Third point: IC damage

The abnormal display in a small area is likely to be the failure of the drive. Timely replacement is the top priority solution

The simple maintenance of LED display screen is also one of the advantages of display screen. Whether professional technicians or maintenance personnel, the above basic maintenance points and methods can help you better solve the problem

  Article KeyWords:LED display screen repair method


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