Testing methods and steps for repairing LED display screens.

Nowadays, LED display screens are increasingly visible and closely related in our daily lives, and they also add a bright charm to people’s lives. However, we not only see the charm, but also the faults caused by LED display screens at critical moments, which is also the most headache for users. So how can we solve it? Firstly, we need to find out what faults often occur in LED displays? Issues such as LED brightness, black screen, flickering, and so on. So how will we repair the LED display screen and what should we pay attention to during maintenance? What are the basic steps for maintenance? These are all things that need to be clarified and targeted to address these issues!

The problems with LED display screens are also ever-changing, so it is not easy to provide a detailed explanation of which problem. So let’s talk about the detection methods and basic maintenance steps for LED display screen maintenance. If I can grasp this, I think if the LED encounters a problem at a critical moment, I can look at the reasons from these points and solve the problem.
1、 Testing methods for repairing LED display screens
The detection methods for repairing LED display screens include short circuit detection, resistance detection, voltage detection, and voltage drop detection. Let’s talk about these methods in detail.
1. Short circuit detection method: Set the multimeter to the short circuit detection position (usually with alarm function, if it is connected, it will emit a beep sound) to detect whether there is a short circuit phenomenon. If a short circuit is found, it should be resolved immediately. Short circuit phenomenon is also the most common LED display module fault. Some can be found by observing the IC pins and row pin pins. Short circuit detection should be carried out when the circuit is powered off to avoid damaging the multimeter. This method is the most commonly used method, simple and efficient. 90% of faults can be detected and judged through this method.
2. Resistance detection method: Set the multimeter to the resistance range to detect the ground resistance value at a certain point on a normal circuit board, and then test another circuit board at the same point to see if there is a difference between the normal resistance value and the same point. If there is a difference, the scope of the problem is determined.
3. Voltage detection method, by adjusting the multimeter to the voltage range, detects the ground voltage at a certain point in the suspected circuit, compares whether it is similar to the normal value, and can conveniently determine the range of the problem.
4. Voltage drop detection method: Set the multimeter to the diode voltage drop detection level, because all ICs are composed of a basic number of single components, which are only miniaturized. Therefore, when there is current passing through a certain pin, there will be a voltage drop on the pin. Generally, the voltage drop on the same pin of the same model of IC is similar, and according to the good or bad voltage drop value on the pin, it must be operated in the case of circuit power outage.
Next, we will talk about the steps of repairing LED display screens. Firstly, it is necessary to have maintenance tools
2、 Maintenance tools
1. 1 electric soldering iron and 1 suction gun each, with several soldering tin
2. 1 electric screwdriver for quick disassembly of modules or unit boards
3. Computer+sending card, used to send programs to receiving cards
4. A multimeter used to detect specific faults in a module or unit board
5. 1 pair of tweezers, scissors, and pliers each
6. Receiving card+HUB board, used to observe module or unit board faults
3、 Basic steps for repairing LED display screens
1. Determine the type of HUB board used by the module or unit board, so that the interface definition of the ribbon cable is the same
2. According to different models of modules or unit boards, sending corresponding programs to the receiving card to ensure that the modules and unit boards are displayed in the correct program is a prerequisite for identifying the cause of the fault. Generally, the model of the module or unit board is printed on the PCB board.
3. Observe the phenomenon of the module or unit board and determine the initial fault. For example, common blind lights, string dots, small squares, etc.
4. Using a multimeter to identify faults, the main method is to use the short circuit detection method above to detect between the chip and the lamp pin.
5. Retest
The above are the maintenance methods and fundamental steps for common faults that occur in LED display screens at critical moments. We hope to be helpful to everyone who makes LED display screens.