First, the detection method of LED display repair
1. Short-circuit detection method, the transparent display adjusts the multimeter to the short-circuit detection block (generally with alarm function, such as the public announcement to announce the sound of the squeak, to detect whether there is a short circuit phenomenon, and immediately after the short circuit is found, the short circuit phenomenon is also the most common LED display module problems. Some can be found by investigating the IC pin and the header pin. 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 problems 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 check whether the same point test of another same circuit board is different from the normal resistance value. If it is different, the scale 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 scale of the problem.
4. The voltage drop detection method, the multimeter is adjusted to the diode voltage drop detection file, because all the IC is composed of many basic unit parts, only miniaturized, so when there is a current passage period 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, the basic steps of LED display repair
1. Determine the type of HUB board used by the module or the unit board, so that the interface definition of the cable is the same.
2. According to different types of modules or unit boards, the corresponding program is sent to the receiving card, and the transparent display ensures that the module and the unit board are displayed under the correct program, which is a condition for finding out the cause of the problem. The type of the module or the cell board is usually printed on the PCB.
3. Observing the module or the unit board phenomenon, and determining the initial fault. For example, common xenon lamps, string points, small squares, etc.
4. Using a multimeter to find out the problem, mainly using the above short-circuit detection method to detect between the chip and the lamp foot.
5. Check again
Post time: May-18-2020