Troubleshooting Partial Pixelation and Display Bleeding in LED Signs

Introduction 

Partial display issues on LED signs can be frustrating, especially when one section is working properly while other segments remain blank. Understanding what might be causing this can help you troubleshoot effectively and get your sign functioning as expected. This guide walks you through diagnosing and resolving issues when only one section of your LED sign displays content, and the rest does not.

Table of Contents

1. Initial Problem: Understanding the Issue
2. Troubleshooting Steps
3. Common Causes and Solutions
4. Conclusion
5. Additional Support

Initial Problem: Understanding the Issue

1. Initial Problem: The section labeled "TE" in the text display was not functioning, and the sign wasn't receiving a signal.
2. Solution Attempted: The power supply was replaced, resulting in both sides of the sign working.
3. New Issue: The next day, the left half of the sign stopped working.
4. Further Troubleshooting: Another power supply was replaced on the non-working side, which did not show a green light initially.
5. Current Status: The entire sign is now illuminated, but only the first section is receiving a signal.

Additional Observations:

• The fans are not operating, even though their connections appear intact.
• Multiple power cycles were performed over the past two days.
• Cat5 and ribbon cables were disconnected and reconnected during the troubleshooting efforts.

Overall: Despite replacing power supplies and checking connections, only part of the sign receives the signal, and the fans remain non-functional.

Troubleshooting Steps

If you encounter a similar issue, follow these steps to diagnose and potentially resolve the problem.

1. Check the Control Card

• Note: Since part of the screen is displaying content, the controller card is likely not the source of the issue and you may skip this step. If the screen were completely blank, the controller card would be a likely cause.
• Inspect the Ethernet Port: Ensure the controller card's ethernet port has activity lights. A functioning controller card should display:
  • A solid red light indicating power.
  • A flashing green light indicating signal transmission.
• Action: If the green light isn’t flashing, consider replacing the ethernet cable or the controller card itself.
• Verdict: The picture of the control card below confirms that it is functioning correctly.

2. Inspect Cat 5 Cables

• Check the Cat 5 Cables: Look for small tears or damaged connectors that could interrupt the signal. Ensure cables are properly plugged in and secure.

Note: Even minor tears in cables can lead to significant display issues.

3. Video Card: The Likely Suspect

The sign's video cards are integral to signal transmission and display. There are typically three video cards per side:

• Right (TE), Middle, and Left cards.

These cards are connected in a series, so if one fails, it can disrupt the signal flow to the others. In this case, while the TE card is functioning, the connection between TE and the middle card may be faulty.

You can also try replacing the Ethernet cable and connecting this card directly to the next one, bypassing any port connectors if used. This provides a direct connection between cards, helping to confirm whether the issue is with the card or the cable.

4. Fans Not Working

Fans play a crucial role in preventing overheating and ensuring the longevity of your LED sign. If the fans are not functioning, it can cause performance issues and potential damage.

• Check Connections: Verify that the fan connections are secure and properly plugged into the power source.
• Inspect for Damage: Look for any visible signs of damage or wear on the fans or their connectors.
• Order Replacement Fans: If the fans are damaged or not functioning despite being connected correctly, it is recommended to order and replace them with new units to prevent overheating and ensure optimal performance.

Common Causes and Solutions

• Damaged Cat 5 Cables: Replace any cables with signs of wear or damage.
• Faulty Video Card: Replace or repair any video cards that are not transmitting signals properly.
• Controller Card Issues: Reset or replace the control card if necessary.
• Overheating: Ensure fans are operational and that the sign is not overheating, as this could impact performance.

Conclusion

Diagnosing display issues on an LED sign requires a methodical approach. By checking the control card, inspecting Cat 5 cables, and troubleshooting video card connections, you can isolate and address the root cause of the problem. Regular maintenance and inspection of components can also help prevent future issues.

Additional Support

If you are experiencing any of the following problems, this guide above may help:

Problem 1: Sign Displaying Content on One Section Only Similar to the issue discussed, signs may sometimes display content only on one section while the rest remains blank. This can be caused by faulty connections, damaged cables, or malfunctioning video cards.

Problem 2: Pixelated Display on One Side A pixelated display on one side of the sign often indicates problems with the video cards or poor cable connections. Ensuring all components are functioning and properly connected is crucial for maintaining a clear and vibrant display.