LED display repair and inspection is a time-consuming and laborious task, especially for different types of display repair, it is not the same, here I just share with you, some of the basics when repairing the display The methods and steps of maintenance testing are hoped to help everyone. First, the fault detection method 1. Short-circuit detection method, adjust the multimeter to the short-circuit detection block (generally with alarm function, such as the sounding when the conduction is made), detect whether there is a short circuit phenomenon, and find out the short-circuit phenomenon should be solved immediately, the short-circuit phenomenon is also the most common LED The display module is faulty. Some can be found by observing the IC pin and the pin header. Short-circuit detection should be performed in the event of a power failure to avoid damaging the multimeter. This method is the most commonly used method, simple and efficient. 90% of the faults can be detected by this method. 2. Resistance detection method, adjust the multimeter to the resistance file, detect the resistance value of a certain point of a normal circuit board, and then test whether the same point of another same circuit board tests whether the normal resistance value is different. If it is different, the scope of the problem is determined. 3. Voltage detection method, adjust the multimeter to the voltage file, detect the voltage to the ground at a certain point of the circuit suspected of having a problem, compare whether it is similar to the normal value, and conveniently determine the range of the problem. 4, the voltage drop detection method, the multimeter is adjusted to the diode drop detection file, because all ICs are composed of a basic number of unit parts, but miniaturized, so when there is current on one of its pins, There will be a voltage drop across the pin. Generally, the voltage drop on the same pin of the same type of IC is similar. According to the voltage drop value on the pin, it is necessary to operate under the condition that the circuit is powered off. Second, LED display repair essential tools 1. One soldering iron + one sniffer, some solder 2, 5V regulated power supply, power supply to the receiving card and maintenance module or unit board 3. One electric batch for quick disassembly of module or unit board 4, computer + send card, used to send the program to the receiving card 5, receiving card + HUB board, used to observe module or unit board failure phenomenon 6, a multimeter, used to detect module or unit board specific faults 7, one pair of tweezers, scissors, and cutting pliers Third, the basic steps of LED display repair 1. Determine the type of HUB board used by the module or unit board, so that the interface definition of the cable can be the same. 2. According to different models of modules or unit boards, send the corresponding program to the receiving card to ensure that the module and the unit board are displayed under the correct program. This is the premise to find out the cause of the fault. The model number of the module or unit board is printed on the general PCB board. 3. Observe the module or unit board phenomenon to determine the initial fault. For example, common xenon lamps, string points, small squares, etc. 4, use the multimeter to find the fault, mainly by using the above short-circuit detection method to detect between the chip and the lamp foot. 5. Test again.
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