AF-3500 series display has dark lines around the perimeter of the module causing a grid pattern on the display face


  • Three or four rows of LEDs around the perimeter of the module look darker than the rest of the LEDs.
  • Black lines around each module.
    Dark lines module.jpg
  • When the module is moved to another location, the dark pattern follows the module.


  • Galaxy
  • AF-3500, AF-3550
  • Electronic Message Center (EMC) or Board (EMB), Marquee, Readerboard, Display


  • The theory behind why dust collects on the perimeter LEDs is that the display may have dirty, clogged filters. Ventilation may be pulling air through the modules instead of through the vents if filters are preventing good air flow. This may cause the LEDs to collect more dirt around the perimeter where air flows. Check for dirt/dust accumulation around the outer perimeter of individual modules.
    • Note: This issue could also be caused by loose louvers. Be sure to check the modules for loose louvers. If the louvers are loose please contact Daktronics at 1-800-325-8766.


Advise cleaning the display modules and replacing filters if needed. To Completely clean all the caked on dust off of the LEDs it may take a very thorough wash process or more than one display/module washing

  • Note: Use only the brush specified in step 4 below, Grainger scrub brush - Part #1DU76, for cleaning the module surfaces. Using anything other than the brush listed below could cause irreversible visual issues.
  • Note: Use only the concentrate specified in step 2 below, Crystal Simple Green (Hagemeyer Part #323056), for cleaning the module surfaces. 
  • Note: DO NOT use carwash and wax concentrate or spotting agent rinse as these leave a chemical residue on the LEDs.
  • Note: DO NOT use a Power Washer. The high pressure can cause damage to the LEDs and louvers. 
  • Note: If the parts listed below are not obtainable please contact Daktronics at 1-800-325-8766
  1. Turn power to the display off prior to cleaning.
  2. Use a ratio of 1 part Crystal Simple Green (Hagemeyer Part #323056) to 3 parts water.
  3. Fill spray bottle with solution and apply directly to the display face or to a clean scrub brush.
  4. Use a Grainger scrub brush, Part #1DU76.
  5. Wash the display from top to bottom in vertical columns
  6. Use horizontal brush strokes to loosen and remove dirt and grime.
  7. Use light pressure to prevent damage to LEDs.
  8. Apply additional cleaning solution to the display brush as needed.
  9. Clean only an area that is safe to reach from a lift or stage, then move on to the next section of modules.
  10. Rinse module surfaces thoroughly before the cleaning solution dries.
  11. After cleaning a section of modules, rinse it thoroughly using clean water under low pressure.
  12. Allow the display to air-dry completely.
  13. Check the display for uniform cleanliness.
  14. If the display still appears to be dirty, repeat the steps to wash and rinse the display.

KB ID: DD3456065

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