The LED display screen is made up of LED modules. Its basic structure：display part (light surface), PCB (circuit board), and control part (IC component).
Common faults in LED display maintenance include: partial "dead light", "caterpillar", partial missing color blocks, partial black screen, large area black screen, partial garbled characters, etc.
There are five tools that LED display repair guy always needs: tweezers, heat gun, soldering iron, multimeter, and test card. Other auxiliary materials include: solder paste (tin wire), soldering flux, copper wire, glue, etc.
1. Local "dead light" problem
Partial "dead light" means that one or several lights on the LED display screen do not light up. This kind of non-lighting is divided into full-time non-lighting and partial color non-lighting. Generally, there is a problem with the lamp itself. Either it is damp or the RGB chip is damaged. Our repair method is very simple, which is to replace it with the spare LED lamp bead provided by the factory. The tools used are tweezers and heat gun. After replacing the spare LED lamp bead, use the test card to test again. If there is no problem, it has been fixed.
2. The “Caterpillar” Problem
"Caterpillar" is just a metaphor. It refers to the phenomenon that when the LED display is powered on and has no input source, a long dark bright strip appears on part of the lamp surface, mostly in red. The issue of this phenomenon is leakage of the internal chip of the lamp, or short circuit of the IC line tube behind it. The former is the majority. When this happens, we need to hold a hot air gun and blow hot air along the discolored "caterpillar" with leakage. When it hits the lamp, it usually works normal, because the heat makes the internal leakage chip connections opened, but there are still hidden dangers. We need to find the LED lamp bead that is leaking, and replace the hidden lamp bead by the method mentioned above. If the line on the back of the IC is short-circuited, you need to use a multimeter to measure the relevant IC pin circuit and replace it with a new IC.
3. Local color patches are missing
When the LED display is playing normally, a small square block of different colors appears. This problem is usually caused by the burning of the color IC behind the color block. Well, the solution is to replace it with a new IC.
4. Partial black screen and large area black screen
Black screen means that when the LED display is playing normally, one or more LED modules show that the entire area is not bright. A few LED module areas are not bright, we call it a partial black screen, and more areas are called a large black screen. When this happens, we usually first consider the power factor. Generally, check whether the LED power indicator light is working normally. If the LED power indicator light does not light up, it is likely that the power supply is damaged. Just replace it with a new power supply of corresponding power. You should also check whether the power cord of the LED module corresponding to the black screen is loose. Many times, re-twisting the wires can solve the black screen problem.
5. Partial garbled characters
The problem of local garbled characters is more complicated. It refers to the phenomenon of messy, irregular and possibly random flashing color blocks appearing in local areas when the LED display is played. When this kind of problem occurs, we usually first check the signal cable connection problem. You can check whether the cable is burned, whether the network cable is loose, etc. In maintenance practice, we found that aluminum-magnesium wire cables are easy to burn out, while pure copper cables have a longer life. If there is no problem with the entire signal connection, then exchange the LED module in question with the adjacent module that plays normally. You can basically judge whether the LED module corresponding to the abnormal playback area is damaged. The cause of the damage is mostly IC problems. , maintenance will also be more complicated.
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