Is this the G1 model that updates ended last year?
The review on Amazon for the “HP Chromebox J5N50UT” (listed in the specs page) are from 2016 so it (most likely) is an older model.
If this is the G1 version support ENDED on Sep 2019.
When turning on the unit, I got the attached error message that the HP power supply unit, which was sent along with the Chromebox, was not providing enough power. (“The connected power supply does not have enough power to run this device. Chrome OS will now shut down.”) However, the output listed on the PSU was correct, according to the information on the back of the Chromebox. My research turned up this post where user boulder described the same issue. The resolution that he found was that the pin inside the plug for the PSU was bent to the side. I looked, and the PSU that had been shipped with the device had the same issue with the very small pin at the center of the plug. After bending the pin back to straight using a paperclip (make sure to unplug unit from wall first!) the Chromebox unit was able to power up normally and the error resolved. I wanted to post this here in case anyone else encounters the same issue.
Excellent post. Thank you for sharing!