How to repair led display?

 How to repair led display

LED display is a valuable industrial product! If we do not understand the use and maintenance, will cause you big losses? So we have to learn how to repair the LED display, so that your LED display can be used normally! Please have patience to read this article, I will tell you the LEGESATECH led screen factory maintenance experience in detail!

1.What constitutes an LED display?

2.What tools do you need to repair the LED display?

3.How to repair LED display module?

3.1.What is the composition of the LED module?

3.2.What are the common problems of LED display module?

 4.How to repair the switching power supply of LED display?

5.How to repair the LED display receiving card?

6.How to replace LED screen lock?


1.What constitutes an LED display?

We need a detailed understanding of the structural components of the LED display and the function of each component, in order to better grasp the principle of the LED display, which is conducive to our more accurate interpretation of the problems that need to be repaired when maintenance. The LED cabinet is generally the basic component of the LED display, which is composed of the LED module arranged in accordance with certain rules. The overall composition of the LED box is shown in Figure 1-1.

LED display cabinet overall structure

Figure 1-1       LED display cabinet overall structure

(1)LED cabinet structure. The material is generally iron, die-cast aluminum and carbon fiber, etc., which is mainly used to fix the internal components of the LED box to facilitate the assembly of the LED display, and can also play a good protective role.

(2) Switching power supply. General LED display requires the use of DC low-voltage power supply, the commonly used DC voltage is 2.8~5V, China’s commonly used mains power is 220V/50Hz. In order to improve the application area of LED display, the switching power supply input voltage used in the general LED industry is AC100~240V and 50/60Hz, and the rated output power is mostly concentrated in 150~400W.

(3)LED module. It is the main luminous component of the LED box, and all components in the LED box are designed to ensure the normal and stable operation of the LED module.

(4) Receive the card. It is the control center of the LED cabinet display, which can output different control signals according to different driver chips and drive circuits of the LED box, so as to control the normal display of the LED cabinet.

(5) Transfer board. It can rearrange and combine the data control signal output of the receiving card according to the definition of the LED module signal input interface, and transmit the signal to the LED module by wiring or direct docking of the interface, and its size and shape are determined according to the internal structure of the LED cabinet.

2.What tools do you need to repair the LED display?

We have a complete understanding of the structure of the LED display. Next we need to get our repair kit ready. Only good maintenance tools can efficiently repair the LED display. Next, I will show the tools for repairing LED display through pictures. LEGIDATECH led screen factory can provide you with repair tools, you do not need to spend a lot of time to buy cumbersome gadgets.

2.1When repairing the LED screen  module,it can be used to replace the LED lamp bead and LED driver IC

soldering iron_QUICK 203【60W】


2.2  When you repair the small-pitch LED display, in order to better replace the LED lamp beads and LED constant current driver IC. Because the maintenance space is very small, under the premise of not destroying other LED display components, at this time we need to use this heat gun to heat the LED lamp bead and LED driver IC, after heating for a period of time, we can smoothly remove the bad LED lamp bead and LED driver IC.

heat gun-1

2.3.When repairing the LED display, because the LED components are very small, we can not use our hands directly to pick up the small components, at this time we have to use tweezers to pick up the LED display components.



2.4.If we want to remove the LED module from the LED display cabinet, we need to use a manual screwdriver.


2.5 .There are a very large number of small screws on the module of the LED display, and the small screws can only be removed with the help of an electric screwdriver.

brushless batch electric screwdriver


2.6. Flux and solder paste used to secure electronic components。

Solder pastetin cream


Learn these repair tools, you can already try to repair the LED display.

2.7.When you repair the outdoor LED display, it will destroy the waterproof function of the LEDm module. That’s where we get the water repellent.

waterproof glue


3.How to repair LED display module?

3.1.What is the composition of the LED module?

LED module, also known as LED light board, is the smallest detachable component of the LED display application level. LED module is generally composed of LED lamp beads, signal input/output interface, chip, kit, PCB substrate and power input interface. Figure 3-1 shows the basic structure of the LED module.

repair LED module

Figure 3-1

(1)LED lamp beads. That is, the light-emitting diode, which is the light source of the LED display. The images and videos of the LED display are displayed to the audience through the combination of different brightness of the LED lamp beads.

(2)PCB substrate. As a hub platform for signal transmission, its role is to connect the control chip, LED lamp bead, signal input/output interface, and power input interface through the PCB line. The PCB substrate after welding the components is a unit board that can be lit, which is commonly known as the LED module (light board). Figure 3-2 shows the PCB substrate.


Figure 3-2

(3) Kit. Usually made of plastic, it is mainly used for the fixation and protection of LED modules. It can fix the LED module to the LED box structure, or directly fixed on the steel structure for assembling the LED display screen. However, not all LED modules need to be fixed with a kit, and many LED modules will integrate bolts for fixing, so this type of LED module does not need a kit.

(4) Chip. The main function is to receive the control signal output by the card control system, and adjust the current size of the chip to control the PIN, so as to control the brightness and luminous intensity of the LED lamp beads. Through the precise control of tens of thousands of pixels on the LED display, the required image can be displayed. Conventional LED modules generally include power amplifier chip, decoding chip (including CMOS power tube), driver chip and so on.

Power amplifier chip: the commonly used power amplifier chip is generally 74HC245 power driver chip, its role is mainly signal drive, signal isolation (LED module between multiple groups of data generally use a signal and 74HC245 input channels, multiple output channels are independently output to different data control chip).

② Decoding chip: The commonly used decoding chip is 74HC138+4953, and the decoding signal controls the 74HC138 channel output and 4953 power tube conduction, so as to control the positive electrode and power supply of the LED module or a column of LED lamp beads. With the development of the LED industry, there have been many decoding line chips for LED display and driver integration, such as RT5958, DM7258, ICND2013, ICND2018 and so on.

③ Driver chip: with the control signal output of the control system to control the LED light beads on and off, to achieve the image display of the LED display. At present, the driver chips used are generally divided into universal driver chips, dual latch driver chips (MBI5124, ICN2038S, MY9868, etc.), PWM (pulse width modulation) driver chips (MBI5153, ICN2053, ICND2055, etc.).

(5) Signal input/output interface. The control signal output of the control system is connected from the receiving card to the LED module through the wiring, and the signal between the LED modules is connected through the wiring, which is used for the display control of the LED module.

(6) Power input interface. It is the input interface that supplies power to the LED module.

3.2.What are the common problems of LED display module?

There are two common problems in the maintenance of LED display modules: 1. Replace the lamp beads of LED display 2. Replace the module IC.

                                                                 Replace the lamp beads of LED display


Replace the module IC


4.How to repair the switching power supply of LED display?

Is the power supply broken? Use a voltage gauge to check whether the output voltage of the switching power supply is 4.2V-5V




5.How to repair the LED display receiving card?



6.How to replace LED screen lock?



To sum up, we need to understand the composition of LED display and LED module, and then learn the tools for maintenance of LED display. According to the video I provide common maintenance LED display, step by step to practice maintenance LED display. I believe you will learn how to repair LED display in a short time. I will continue to update the content of this article and videos, to provide you with better reference to learn some information. Thank you for your cooperation.

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