When it comes to fixing LED displays, the first thing to know is what the most common failures are. Some common issues include ” Moiré,” local “dead lights,” local color block missing, local garbage, local black screen, or a large area of black screen, and so on.

Common LED display faliature issues

If you’re repairing LED displays, you’ll need a few essential tools: tweezers, a hot air gun, a soldering iron, a multimeter, and a test card. Other useful materials include solder paste (tin line), solder promoter, copper wire, glue, and so on.

The ” Moiré” problem

The ” Moiré”  refers to the LED display that’s under power conditions and has no input source. Part of the light surface appears as a long dark bright strip of phenomena, and it’s mostly red. This usually happens because of a chip in the lamp that’s leaking, or a short circuit behind the IC surface line tube line.

The former is more common. In most cases, all you need is a hot air gun to blow on the color-changing ” Moiré” to make it go away. The heat from the gun should collapse the internal chip connection, but there are still some risks. You just need to find the LED lamp bead that’s causing the problem.

If you follow the above steps, you should be fine. If the IC behind the surface of the line tube line short circuit, you’ll need to use a multimeter to measure the relevant IC pin circuit and just change a new IC.

Localized “dead light” problem

Partial “dead lights” means that the LED display lights on the surface of one or more lights don’t light up. This can be either the whole light doesn’t light up or just part of the color doesn’t light up.

In this case, it’s likely that the light itself has a problem. It could be moisture or it could be damage to the RGB chip. Either way, the repair is simple. Just use the LED lamp bead spares to replace it. You’ll need tweezers and a hot air gun. Then, just replace the spare LED lamp beads with a test card and test again. If everything looks good, you’re all set.

Local color block missing problem:

This is bit more complex. It’s about the LED display screen playing back a local area in a chaotic, irregular, and random flashing color block phenomenon.

First, we’ll check the signal line for any issues ,such as looking for are burned out lines, loose network cables, and so on. We’ve noticed that aluminum-magnesium wire tends to burn out more easily than pure copper wire.

If you’ve checked the signal connection and it’s fine, try swapping out the LED module and the one next to it. That should help you figure out if the problem is with the module or somewhere else.

Most of the time, the issue is with the IC, which makes things more complicated.

Localized black screen or large black screen problem

We need to go through the right steps to investigate and then solve the problem. Normally, four things can cause a localized black LED display screen: you can check one by one:

1) First of all, we should check to confirm whether the serial line used to connect the controller is loose or shedding. If the screen goes black at the start of the loading process, it’s probably because the communication lines are loose and there are interruptions

Don’t assume the screen body isn’t moving or that the line is fine. Check the lines first to rule out any issues. This will help you solve the problem quickly.

2) Make sure the LED screen and the main control card connected to the HUB distribution board are properly connected. Also, check that the plug is not reversed.

If you’re having issues with the power supply, double-check that all the hardware, including the control system, is properly powered up. The power supply lights aren’t flashing, so the power supply itself isn’t faulty. It’s worth noting that a poor-quality power supply is usually prone to this problem.

3) Check issues with the LED unit board connections.

1) A few boards in a row aren’t lighting up. Check the power supply in that column to see if it’s working.

2) If several consecutive boards in the horizontal direction aren’t bright, check that the normal and abnormal unit boards between the rows are connected properly, or that chip 245 is working correctly.

4) The software settings or lamp problems

If there’s a big difference between the two, it’s probably the software or settings. If it’s a smooth transition between the two, it could be a lamp issue.

How to repair LED display module beads

Here’s how the overhaul process works:

If you find the LED display module on the lamp bead is not bright or abnormal, Just prepare a suitable normal lamp bead beforehand.

You’ll need to remove them so that the LED pin is clearly exposed in the line of sight. Use tweezers on your right hand to clamp the lamp beads and a soldering iron (temperature of about 40 degrees or so) on your left hand to make contact with the pins at the solder.

And then wait for about three seconds. If it’s still not disassembled after that, let it cool down and try again. Otherwise, you might have burned out other parts, which could affect the solder on the pins. Use tweezers to remove the bad LED beads.

Next, we’ll get the normal, suitable lamp beads in the right holes on the PCB circuit board (LED lamps have a long foot for the positive pole, a short foot for the negative pole, a “square hole” for the LED positive pin jack, and a “round hole” for the LED negative pin jack).

Then, we’ll solder the LEDs to the PCB. A little solder wire melted and stuck to the soldering iron head. Use tweezers to adjust the direction of the lamp beads so that it is smooth. Then, solder the solder wire to the LEDs and PCB.

Finally, use the same type of gel to seal the LED display.

How to use a multimeter to check if the lamp bead is damaged?

The LED light beads go on the display. The long foot goes on the positive pole, and the short foot goes on the negative pole. The PCB “square hole” goes on the LED positive pin jack, and the “round hole” goes on the LED negative pin jack.

Here’s how to test a light: Use a multimeter set to resistance X1. Connect the black pen to the LED’s positive terminal and the red pen to the negative terminal. (If it’s a digital table, use the black pen on the negative and the red pen on the positive.) If the LED is bright, the light is good. If it’s not bright, the light is bad.

2. If the LED screen module isn’t bright and it’s a black screen, the main thing to check is whether the module on the power cord plug is loose or has poor contact.

If the module is showing color confusion or inconsistency,

If that doesn’t work, you can just plug the data cable back in or replace it. If the replacement cable still doesn’t work, it might be a problem with the cable interface.

3. If the LED display group is not bright or looks abnormal, check the signal direction of the first abnormal module. Make sure the power lines are in good contact. If the display module is black, it may be that there’s no power input.

If the screen module is displaying colors or has color confusion in bright spots, it shows that the module has signal input problems. Then you need to check whether the wires are plugged in well. In this case, you need to check whether the wires are plugged in properly or replace the wires with new ones.

Conclusion:

To sum up, fixing an LED display is a process that requires a lot of experience. If you are interested in second-hand LED display screen, you can check out the brands used LED video wall, which will help you save more money and get greater returns.