USB-6229 5v Unstable

[Panorama]

USB-6229 is giving large swings in measured values when no signal is applied.

To investigate the problem, I connected a 100R resistor between AI0 and AI8 (differential voltage mode) ... problem persisted.

Measured 5V (pin 96) ... varies between 2.0v and 4.0v ... with sporadic noise.

Input power supply was measured at 12V constant at the input fuse.

Is there anything I can do for this ...  

[Panorama]

Further testing shows that the 5v is OK initially when power is applied but fades very quickly to 2v after less than one second.

Analog Outputs not functioning either.

This condition degraded gradually over one day.

Seems that some part of the internal regulator has suffered. I have not used the 5v output pin as a supply and do not think that the inputs have been overdriven ... however I did leave the DAQ turned on overnight and connected to a Current Transformer ... it is possible that the DAQ AI0 received an overvoltage. In which case think the 6229 might have died.  

[Panorama]

Latest update: I have concluded that I have overdriven my DAQ as a result of capacitive coupling from the mains via a CT.

Next time: Use two grounded Faraday shields ... one on the mains turn and earthed at the mains load and the other inside of the CT, earthed at the DAQ. Should have done this at the start.

Does NI supply replacement DAQ PCBs for the USB-6992? 

[johnsold]

Sorry you learned an expensive lesson: Computers and USB devices are not ruggedized to handle stray currents and voltages routinely encounterd in industrial and utility equipment.

Lynn

[Danny_Funk · Accepted solution]

Panorama,

You can check the Warranty and Repair page for replacement related questions

Warranty and Repair Services

Regards,

Danny F