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How do you fix a MicroLite card with non-functional LED indicator lights?

How do you fix a MicroLite card with non-functional LED indicator lights?

Posted by Ed Gurski on 17th Jan 2017

On a MicroLite ROM card (also known as the "black handled card") the top LED indicator light should be flashing and the bottom LED indicator light should be on at all times.  When the LED indicator lights are in this state, then the card should be operating normally.  If the LED indicator lights on the ROM card are out, then there may be an issue with the Pico fuses in the card.


Where did the LEDs go on the front of my MicroLite relay system? Typically this is caused by bad Pico fuses that are located on the ROM card (the black handled card).  If these fuses blow, then you will be missing LEDs on the front of the card. Consequently, you will not be able to turn the lights on or off on your MicroLite system.

Replacing the Pico fuses in the MicroLite ROM card is quite easy.  

1.  Power down the panel using the on/off switch located on the front of the transformer.  

2.  Slowly and carefully pull out the ROM card using the black tabs. 

3.  Once the card is out, then locate the fuses at the top right of the card.  

The picture below shows you where to find these fuses on the card:


4.  Use a pair of needle nose pliers and take out the fuses. 

5.  Once the ROM card is removed, then remove the non-functioning Pico fuses.

6.  Then, cut the new Pico fuses down to size and put the bare ends of the fuses back into the same spots.  

7.  Once those are replaced, then slide the card back into the panel and restore power to the panel.  

8.  The LEDs should come back to life, and in turn you will be able to operate your lights again. 

9.  If the LED's don't come back to life, then call Knight Sound & Lighting for further troubleshooting.  You could have a bad backplane, a bad relay, etc.  

Please call us at 330-940-4078 to get the correctly rated Pico fuses.  If you put the wrong Pico fuses into the system, then you could damage the system.  Knight Sound & Lighting (GoKnight.com) is a factory certified MicroLite service agency.  We are happy to answer any questions that you may have about your MicroLite lighting system.