784x or 785x R Series Device Does Not Output 5V Signal

Updated Jan 23, 2018

Reported In


  • NI 784x R Series Modules
  • NI 785x R Series Modules

Issue Details

I am using the +5 V output source of NI 784x or NI 785x R series device to power my external circuitry and it does not power up. Hence, I measured the voltage drop across +5 V referenced to DGND with the help of multi-meter. However, my multi-meter reads 0V. What could be the issue?


The internal user-replaceable socketed fuse might be blown and hence it is not out putting +5V signal. To ensure if the fuse is working fine or not, set the Digital Multi-meter (DMM) to measure continuity, the meter should beep continuously as you hold the leads to the ends of the fuse. That means the circuit is complete. If it does not do so, the fuse is blown. Refer to Replacement Fuses for R Series Devices for replacing the faulty fuse.

Additional Information

All NI 784xR/785xR devices have a user-replaceable socketed fuse to protect the supply from overcurrent conditions. When an overcurrent condition occurs, check your cabling to the +5 V terminals and replace the fuse as described in the Device Fuse Replacement (NI 784xR/785xR Only) section.


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