When to Change DC Block on NI 5668

Updated May 12, 2020

Reported In


  • PXIe-5606
  • DC Block for PXIe-5668
  • PXIe-5668

Issue Details

My PXIe-5668 seems to be giving me an incorrect measurement, and I think it might be at the signal's connection. How do I know if this is the issue?


  1. Remove the DC Block and inspect for any physical damage. With damage, something similar to these images should be seen:
Worn Out Pin - Gaps in the rings
Broken Pin - pieces are separated or bent inwards/outwards
  1. If no damage is detected, reattach according to the Getting Started Guide and run the Self Calibrate in NI MAX. This is what a good pin will look like:
  1. Put a known signal into the device and compare the amplitude of the signals. If any part of the signal is not accurate, replace the DC Block.
This part is field replaceable; it can be ordered under PN 787672-01. Refer to the PXIe-5668 (5606) Getting Started Guide for removing the housing and changing out the block.