Partial black screen after LED display commissioning — receiving cards detected, what could be the cause?

Display Installation & Troubleshooting
1

I have recently completed the installation and basic configuration of an indoor LED display, but encountered an issue during final commissioning.

Project details:

Display type: Indoor LED screen

Pixel pitch: P2.5

Control system: NovaStar

Screen size: Approx. 4m × 2.5m

Issue description:

1.Sending and receiving cards are correctly detected in the software

2.Most of the screen displays normally

3.A small section remains completely black

4.Power cycling does not resolve the issue

Troubleshooting steps already taken: Reloaded configuration files；Replaced signal cables；Checked power supply.

The issue persists.
In cases like this — where part of the screen is black but the system detects all hardware — what should be checked first?
Any similar experiences would be appreciated. Thanks!

3

Thanks for contributing to LEDLightsWorld Community!

This issue is quite common in LED display projects. It’s best to troubleshoot from simple to more complex causes.

Step 1: Check module-to-receiving card connections

Even if the receiving card is detected, carefully inspect:

  • Ribbon cables for the black area (loose or reversed)

  • HUB board connectors for poor contact

This is the most frequent and often overlooked cause.

Step 2: Test receiving card output ports

Swap:

  • A signal cable from a working area

  • With one from the black area

If the black screen moves, the issue is likely related to the receiving card output or port mapping.

Step 3: Verify power supply to the affected area

Even when overall power is normal, check:

  • Whether a specific power line is missing

  • Voltage levels at the module level

Local power issues often cause complete blackout of a section.

Step 4: Configuration & scan settings

Confirm that:

  • Module resolution

  • Scan mode

  • Port mapping

Match the actual hardware layout. Mismatches between configuration and physical wiring can cause partial black screens.

Summary

When hardware is detected but part of the screen is black, over 80% of cases are related to cabling or power distribution, not software.

Start with physical checks before diving deeper into configuration.

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