What do status lights on NPN logic cards mean?


  • What do the status lights on NPN logic cards mean?
  • Why are indicator lights on NPN logic cards blinking rapidly or irregularly?


  • Product Family: NPN Series Displays (Narrow Pixel Pitch)
  • Product: NPN-4100, NPN-4101, NPN-4102, NPN-4150, NPN-4152
  • Components: Logic Card


  • Startup


    • Port A and Port B status lights synced and blinking rapidly immediately after powering the display on.
      • This is normal behavior during system boot-up.
      • Rapidly blinking status lights should both slow down to a steady blink after boot-up.

  • Normal Operation
Normal Operation.gif
    • Port A and Port B status lights both blinking steadily.
      • Status lights may or may not be synced, but steady blinking indicates normal operation.

  • Loss of Sync
Loss of Sync.gif
    • Port A or Port B status light(s) blinking rapidly indicate a Loss of Sync between logic cards.
      • Light on one port may blink rapidly, while light on other port blinks steadily, as shown above (the loss of sync is on Port B).
      • May also result in visual issues on the display.
      • When a Loss of Sync error occurs, remove and reconnect the Cat5 cable at both ends and verify status lights on both logic cards return to normal operation. If Loss of Sync error continues after reconnecting the cable, wiggle the connector within the jack on the logic card to ensure the cable is seated properly.
      • Further troubleshooting will be needed if reseating the cable does not resolve the issue.

KB ID: DD4611187

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