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LED displays are versatile tools used for showcasing text, images, videos, and more. However, the proper functioning of LED displays relies on various factors, including the LED control card. These control cards play a pivotal role in illuminating the LED display screens, but problems can arise if they are not set up correctly. In this blog post, we will discuss common issues related to LED control cards and how to resolve them.

Hardware Connections

How to Determine if the Control Card is Functioning Properly?

When you connect the control card to the power source, the first thing to observe is the power indicator light. A red light indicates that the 5V voltage is connected correctly. If the light does not turn on, immediately disconnect the 5V power source and check for issues such as incorrect connections, voltage overload, reverse connections, or short circuits. Ensure that the control card receives a separate 5V power supply. If the red light remains off, it may need to be sent for repair.

Why is the Display Screen Not Working or Showing Irregular Brightness Levels Even with a Functioning Control Card?

When the control card is connected to the display driver, it defaults to a 16-scan mode. If the display is not working, check whether the data polarity and OE polarity settings in the control software are correct. If brightness levels are irregular or if a specific row is exceptionally bright, it indicates an OE setting issue. Correct the OE settings to resolve this problem.

Why Do I Get “Error Occurred, Transmission Failed” Messages When Transmitting Information to the Control Card?

Ensure that the communication interface is connected correctly and that the control card’s jumpers are set to the appropriate voltage levels. Check if all parameters in the “Control Card Settings” are configured correctly. Also, verify that the working voltage is above 4.5V using a multimeter.

Why Doesn’t the Display Screen Work Properly After Loading Information?

Check if the scan output selection in the “Control Card Settings” is correct.

Why is Communication Unreliable in a 485 Networking Setup?

Ensure that the communication cable connections are correct. Avoid connecting the communication cables of multiple screens to the computer interface simultaneously, as this can create strong reflection waves and interfere with signal transmission. Follow the correct connection methods detailed in the “Communication Interface Usage and Precautions” guide.

How to Resolve Communication Issues When Using GSM Data Transmission or Remote Dialing?

If communication issues persist after checking the MODEM, focus on the control card settings. Connect the MODEM to the control card, open the control card configuration software on the transmitting end, and click “Read Settings.” Verify that the serial port baud rate, serial port, and protocol settings are correct, and then click “Write Settings.” In the offline software, set the appropriate communication interface and parameters, and finally, send the script.

Software Applications

Why Does the Alignment of Text Not Match the Display Window?

If the alignment setting does not match the position of the text inside the display window, check for unnecessary spaces or carriage returns at the beginning or end of the text in the edit display text box, and remove them.

Why Does a Display Item Flash Briefly and Disappear?

If a display item flashes briefly during script preview or on-screen display, check if the display duration is set to 0 or 1. Increase the duration to resolve the issue.

Why Does Leftward Scrolling Text Appear Jerky?

For text items set to scroll to the left, if the scrolling motion appears uneven with regular pauses, check the scrolling speed settings and increase the scroll speed.

How to Clear the Content of Multiple Windows Simultaneously?

Use the “Clear Screen” button to clear the content.

How Can I Make a Display Item Stay on the Screen Permanently?

If you want a specific display item to remain fixed on the screen, avoid setting it to clear after display. Additionally, when adjusting the display window for other items, ensure that it does not overlap with the fixed item to prevent it from being covered.

How to Choose Animation Files?

When working with image files, select GIF animation files.


Troubleshooting LED display control card issues requires attention to hardware connections and software settings. By carefully addressing these common problems and following the provided solutions, you can ensure that your LED display operates smoothly, effectively showcasing your desired content. Whether it’s resolving hardware connection problems or fine-tuning software applications, these tips will help you make the most of your LED display system.