RoboRio 5V rail has no voltage

[tsieberg]

We have a RoboRio 1.0 and we have analog encoders plugged into the analog ports.  We noticed the readings on the analog encoders started to be way off, so after investigation, determined the Analog Input 5V rail has no voltage between the ground and 5V pins..

We investigated the wiring for a short, and found a ground wire that was rubbing on a gear and rubbed through the insulation to the bare wires.  We removed all wiring from the RoboRio other than power, and the power LED remains red and Drivers Station continues to show a fault after recycling power.  No metal shavings were evident in the ports, but I blew them out anyway.  Next I opened the RoboRio up and blew off the bottom of the circuit board.  It was pretty clean because we keep tape over all unused ports and this RoboRio has never been to a competition yet.

Is there something I can do to clear the fault?  Already tried re-installing firmware.

[mshafer · Accepted solution]

HI tsieberg,

Thanks for posting on the forums; I'm Matthew with ni.

Sounds like you've done a pretty good job of trying to identify the problem. The good news is that shorts aren't a sticky fault -> they are reset automatically on device reboot. I would suggest re-inspecting all the exposed pins and the back for any remaining shavings that may still be lodged (consider using a flashlight) and causing a short.

Please let me know whether or not this works for you so we can discuss what steps to take next.

[tsieberg]

Matthew,

The reason I did a thorough job was because I read about others having this issue and there attempts/successes at resolving it on this forum and ChielfDelphi.com.  

Our team meets again this evening from 6-8:30pm central.  We'll reinspect again during that timeframe, this time using a flashlight.  

Thanks for the info about the device reboot resetting the fault, that is information I couldn't find anywhere else, not even in the RoboRio manual.

Tim

[tsieberg]

An update - The RoboRio is working again.  The first time I took it apart, I only took the back off.  The circuit board stayed attached to the top cover.  This second time, I learned that by removing the power wire connector (using the two little screws) that the top cover then separates from the circuit board making it all accessible.  I never actually saw what the problem was, but blowing it off with high pressure air must have cleared something because it works now, the power light is once again green and the 5V rail works.