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How to adjust the LED display when the characters are reversed? Reveal the secret of polarity setting

2025-10-21 71

The newly installed LED screen suddenly displayed mirrored text. This picture made people dumbfounded as if looking into a mirror. Don't worry, this common fault is actually​ ​It can be done in three minutes​ ​, the key is to find the "secret switch" of the control system.


Three major culprits of display inversion

Let’s first investigate the source of the fault. These three places are most likely to cause problems:

How to adjust the LED display when the characters are reversed? Reveal the secret of polarity setting
  1. ​Data polarity reversed​ ​: The text is displayed in reverse white as if it were X-rayed
  2. ​OE polarity disorder​ ​: A specific number of lines shine abnormally, forming "zebra patterns""
  3. ​Scanning method incorrectly selected​ ​: The text is fragmented like a disorganized jigsaw puzzle.

There was a joke at the opening screen of a shopping mall last week - the promotional price "199 yuan" changed to "991 yuan", and the technicians checked and found that it was​ ​Data polarity is set to active high​ ​lead to. This kind of low-level error often occurs when the control card is temporarily replaced, and experienced drivers are also prone to overturning.


Four-step method for control software adjustment

Open the control system software and follow this process:

  1. ​Screen parameter settings​ ​ → Enter the general password 168 to enter the core parameter area
  2. ​Data polarity switching​ ​: Check "Low Valid" in the "Basic Parameters" column"
  3. ​OE polarity correction​ ​: Change the default high level drive to low level
  4. ​Scan verification​ ​: Select the 1/4 or 1/8 scan mode that matches the module

Notice! Be sure to click after modification​ ​Live preview function​ ​, observe the virtual screen display effect. Once, I installed a stage background screen in a theater. The preview was normal but the actual display was reversed. Later I found out that the control card firmware version was incompatible, which was solved in seconds after upgrading.


Three Hardware Troubleshooting Tips

If the software tweak doesn't work, you'll have to check the physical connections:

  • ​Cable plugging direction​ ​: If the 08 interface module is mistakenly inserted into the 12 interface control card, the phase will be reversed.
  • ​Signal line sequence check​ ​: Use a multimeter to measure whether the CLK clock signal is on pin 5
  • ​Power interference detection​ ​: Mixed bundling of strong and weak electricity will cause signal distortion.

Teach you a trick: add an additional installation on the output end of the control card​ ​signal isolator​ ​, which can effectively eliminate random phase reversal caused by electromagnetic interference. After the installation of LED fence screens in a sports venue, the bit error rate dropped from 3% to 0.02%.


Hidden skills of smart screens

Now high-end screens come with​ ​Fault self-diagnosis function​​:

  • Mobile APP displays the signal status of each node in real time
  • Abnormal polarity automatically pops up correction suggestions
  • Historical parameters are stored in the cloud and restored with one click

What's even more powerful is​ ​AI correction system​ ​, can capture the actual display effect through the camera, and automatically compare and correct it with the control signal. I heard that this technology is used in the transparent screens of some brand exhibition halls, and the installation efficiency is increased by 40%.


If the display is reversed, don’t rush back to the factory.​ ​80% of faults can be repaired on site​ ​. Remember this formula: software parameter adjustment is the foundation, hardware troubleshooting must be careful, and intelligent assistance is more worry-free. Next time you encounter "mirror text", take a deep breath and then open the control software - you are only three clicks away from perfect display.

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