After purchasing LED display screen and related accessories, we need to assemble the display screen and control software operation. In this process, you may encounter some control problems, such as failure to send information to the control card, unsuccessful loading of information, and abnormal display. Don’t worry, the following five steps teach you how to repair the LED display control card problem.

1、 Judge whether the control card works normally
After the control card is powered on, observe the power indicator. If the red light is on, it means that the 5V voltage has been connected. If it is not on, please turn off the 5V power supply immediately. Check whether the 5V working voltage is connected well, whether it is overvoltage, reverse connection, failure, output short circuit, etc. Please use a separate 5V power supply for the control card. If the red light is not on, repair is required.
2、 Is there no display or abnormal brightness on the display screen
When the control card is normal, sometimes the display screen does not display or the brightness is abnormal. At this time, power up the connection between the control card and the display driver. The default is 16 scan. If there is no display, please check whether the polarity of data and OE in the control software are correct; if the brightness is abnormal, a line is particularly bright, indicating that the OE setting is reversed, and then set OE correctly.
3、 The system prompts “error, transfer failed”
Sometimes, when you send information to the control card, the system will prompt “error, transmission failed”. Why? First of all, please check whether the communication interface connection is correct, whether the jumper on the control card jumps at the corresponding level position, and whether the parameters in the “control card settings” are correct. If the working voltage is too low, please use a multimeter to ensure that the voltage is above 4.5V.
4、 Information loading display screen cannot display normally
After the information is loaded, the display screen cannot display normally. Please check whether the scan output selection in “control card settings” is correct.
5、 Block detection communication failure
So, when using GSM data transmission or remote dialing, how to solve the problem of blocked communication? When the communication is not smooth after connection, if you are not sure where the problem is, you can take the method of segmented detection.
First check whether there is a problem with the modem. Disconnect the modem connected to the control card and connect the modem with another computer. In this way, the modems at the sending end and the receiving end are connected to the computer and detached from the control system.
Download a software named “serial debugging assistant” from the Internet, and use it to set and debug modem after installation.
First, set the modem of the receiving end to auto answer. The setting method is: open the serial port debugging assistant at both ends, and input “ats0 = 1 enter” in the serial port debugging assistant of the receiving end. This command can set the modem of the receiving end as automatic response. If the setting is successful, the AA indicator light on the modem will be on. If it is not on, the setting is not successful. Please check whether the modem is connected to the computer correctly and whether the modem is powered on.
After the automatic response is set successfully, input “atd6515780 (receiver telephone number) enter” in the sender’s serial port debugging assistant to dial to the receiver. At this time, some information can be transmitted from the sender to the receiver, or from the receiver to the sender. If the information received by both ends is normal, the communication connection has been established. At this time, the CD indicator on the modem On. If all the above processes are normal, it proves that modem communication is normal and there is no problem.
If the problem of control card is solved, it can help you to use LED display normally.