If the new screen is installed and powered on, it may be that the control card settings are not scanned correctly, or the cable is not inserted correctly (check the cable from the control card to the first board), and the wrong 5V power supply will also cause this problem.
If this phenomenon is suddenly discovered after using it for a period of time, in addition to the failure of the control card, the biggest possibility is that the board enters the water and burns the chip or the power supply.
You can also try to connect a monitor with a DVI interface to see if the signal at the DVI output of the graphics card is normal. In general, the card of Lingxingyu has a resolution of 1024*768 for the DVI interface. The cause of the LED display screen may be a graphics card problem or a driver problem. Try to unplug the network cable of the receiving card behind the display and press the debug button on the receiving card to see if the screen scan is normal.