LED black screen: how to quickly locate and solve?
March 24, 2022
How to locate the LED black screen problem and what are our solutions? Before you have the ability to locate and solve such problems, you must understand some points. Now, let's get started!
Warm up - do you remember the structure of the LED control system?
What can the LED receiving card tell us?
Black LED Troubleshooting
What should I do if the LED full screen is powered off?
What if part of the LED screen is black?
Warm up - remember the structure of an LED control system?
Before we discuss today's topic, let's review the basic structure of an LED control system that we introduced to our readers in our last article: LED Display Connections.
The basic structure of the LED control system is divided into three parts: control computer, LED display and LED display controller.
A control computer will be connected to the LED controller via a USB cable or Ethernet cable for sending control commands. And will use a signal cable such as HDMI to connect the controller in order to transmit the video signal.
After that, there will be a network cable connected to the LED display. In this way, we get the basic structure of the LED control system.
Sometimes, an LED display processor is involved to process the input source, so that the screen can display the entire picture, or achieve some effects such as rotation and scaling. Now, we can get a picture like this:
So why are we referencing this concept again? That's because they can both be factors that cause the screen to black out! Therefore, for further discussion, we retrieve it again for preparation. Now, let's get straight to the point.
What can the LED receiving card tell us?
The receiving card will be installed in the LED cabinet. Typically, one cabinet will be equipped with one receiving card. By paying attention to the status of the LED receiving card, we can know the running statue of the screen. Let's take the Novastar control card as an example:
Note the green light in the picture, this is a signal resource you can use to diagnose if the receiving card is working properly or where the problem is. There are several situations you need to be aware of:
(1) The indicator light flashes once per second: In this case, the receiving card is working normally.
(2) The indicator light flashes four times within half a second, and then flashes again four times after half a second interval, indicating that the receiving card is working normally, but in backup mode.
(3) The indicator light flashes slowly, only once for five seconds, in this case, there may be some problems with the network cable.
(4) The indicator light flashes rapidly, and flashes three times within half a second, which means that there is no signal input. So maybe we need to replace the signal wire or reconnect it.
After understanding the four conditions of an LED receiver, we can now move on to the next chapter.
Troubleshooting a Black LED Screen
Types of LED black screen
There are two kinds of power outages for LED displays, including full-screen outages and partial screen outages.
The power failure of the screen part may occur in a specific cabinet, a specific LED display module, and a specific sending card output area.
Why does the dose LED screen go black?
As we mentioned before, any part of the LED control system can be the cause of an LED screen power outage. Here, we list the reasons and corresponding solutions.
(1) Screen power
One. The screen is powered off. Just power on the LED display, then the problem will be solved.
B. Insufficient power supply. Please replace the power supply to replace the power supply.
(2) Receipt card
One. rcfgx file error. Send the original rcfgx file or recreate it and send.
B. Firmware error. Please upgrade the correct firmware.
(3) Video source
A. Black source. Just check and change the video source.
B. Disconnected, loose or damaged cable. Please reconnect or replace the cable.
C. The video source is not compatible with the LED display. If there is a problem with our sending card firmware program file, please upgrade the correct firmware.
Sometimes it comes from the wrong video source, so replace the correct video source.
(4) Sending card
One. The sending card is not powered. Please turn on the power of the sending card.
B. Input errors. Please select the corresponding input source, such as HDMI or DVI.
C. There is an input source interface failure. Change another interface or change the sending card.
(5) Brightness value
A. 0% brightness. Please increase the brightness, this value is usually 50%.
B. The screen controls are powered off. You can adjust the screen controls to normal.
(6) Ethernet cable
The ethernet cable may be loose or damaged, then reconnect or replace the ethernet cable.
Now that we've got the gist, let's talk about the system approach for now.
What if the LED full screen is powered off?
We can make a preliminary judgment from the red indicator light of the card.
One. If the red light is off, it means there is no power. Then, check or replace the power supply.
B. If the red light is on, there may be a problem with other points. Check for other possible causes.
If the case is B, then check the green light as we discussed earlier.
One. If the green light flashes slowly, only once for five seconds. Please check the sending card and ethernet cable.
B. If the green indicator flashes three times within half a second and flashes three times again after a 0.5 second interval, please check the video source input as there is no signal input.
C. If the green indicator light flashes once per second, it means the receiving card is working normally, then please check the firmware program file of the receiving card or rcfg file to see if there is any problem with these two files. Also, you can check if the brightness value is set to 0%.
What if part of the LED screen goes black?
There are three parts of the black screen of the LED screen, including the power failure of a specific module, a power failure of a specific cabinet and a power failure of a specific output port area.
(1) LED module level:
One. The LEDs indicate that the module is powered off. Replace the power supply unit or power cord.
B. Hub board failure. Change to a different connector or change to a new hub board.
C. Loose or defective flat cable. Please reconnect or replace the flat cable.
(2) LED cabinet level:
A. The power supply unit is faulty. Please replace the power supply unit.
B. Loose or faulty Ethernet cable. Just replace with a new ethernet cable or reconnect.
C. There are problems with the receiving card, including wrong rcfg file, firmware and failure of the receiving card.
Just do the corresponding fix, like reading the rcfg file from a normal receiving card and sending it to the receiving card.
For wrong firmware, please upgrade the correct firmware. And the wrong receiving card can be handled by the new LED receiving card.
D. Hub board failure. Please replace the hub board with a new one.
(3) LED sending card output level:
A. Loose or faulty Ethernet cable. Just reconnect the ethernet cable or replace it.
B. The output port of the LED sending card is faulty. Please change the sending card.
C. LED screen power failure. Replace the power supply or reconnect the power supply.
The above are the potential causes of LED black gravel, and what to do about them. If you encounter any of these situations, just follow the suggestions to locate the problem and fix it quickly!
Now, let's wrap things up here.
First, we learned about the different conditions of the green light of the receiving card. We must know four situations.
(1) If the indicator light flashes once per second, it means the card is working properly.
(2) If the indicator flashes 4 times quickly at 0.5 second intervals, it is in backup mode.
(3) If it flashes once every 5 seconds, it means the network cable is disconnected.
(4) If the indicator light flashes 3 times at 0.5 seconds, it means there is no signal input.
Then, we talked about today's topic - LED black screen. It can be divided into two cases, including full LED screen black screen and partial screen blackout.
For a full black LED display, first check the red indicator light of the receiving card to make sure it is powered on. If yes, check the other points we mentioned above based on the condition of the green lights (eg ethernet cable and receiving card files).
In addition, for the part where the LED screen is black, there are three levels, including the LED module level, the LED cabinet level and the output port level. Please resolve the issue based on what we listed above.
In this article, we discuss a common problem that confuses users and technicians of LED displays - LED black screen. We discussed methods of proving the conditions for receiving the card, because the information we get from it can tell us many clues. Then, we introduce you to two kinds of screen power outages, including full LED screen power outage and partial screen power outage, and solutions!