linuxcnc stopping constantly

Hello everyone, I have started running in to a really strange problem today. I have been running my machine happily for over a year now, I would guess there is probably 100 - 200 hours of runtime on it without any problems at all. Last night I was running a 2 hour job, and about 1:45 into it linuxcnc just randomly powered off (not estop, not crashed, just as if I had hit the "power" button). At the time I was able to just push power again and finish the job using run from line.

This morning when I went to run another job I can't even get the machine to stay powered on for more than 30 seconds. No alerts come up in the UI, no crashing happens, it really seems as if the software "power" button is just somehow getting pressed. I found this post forum.linuxcnc.org/38-general-linuxcnc-q...utting-off-toggle-f2 where the OP appears to be having a very similar issue, and I went through some of the troubleshooting steps suggested there. Unfortunately I am using a Gecko G540 which is also handling my limit switches so I can't as easily just unplug my drivers to test if they are the cause. I am certain it is not the spindle/VFD because the power offs happen without it running at all. I have started up linuxcnc in debug from the terminal and attached the results below. I assume the qtpyvcp errors are old news and not impacting to this particular issue, although I have never looked at this output before so I can't say that with certainty.

The only reasonable way I can think of to test if my drivers are causing the problem would be to leave the G540 powered on but unplug the stepper motors from the G540 unit, and I don't know if that is safe to do or not so I will wait for guidance here before going that route.

I have video of the issue happening but I am not able to post it from this computer. It is really only showing the power button spontaneously turn grey anyway so I don't know how useful that would be.

I greatly appreciate any help!

UPDATE: I believe I found the cause of my problem. Past me was trying to be smart so I connected the motors to the cables using terminal blocks that I screwed to the frame of my machine. Figured I might need to replace the motors some day and I'd make it easier on my future self. Well, I mounted the blocks vertically and somehow an aluminum chip was bridging two of the terminals intermittently.

I have absolutely no idea how that could possibly trigger a soft power off in linuxcnc, but it doesn't seem to be happening anymore since I cleared that out. I will consider this solved from my end but if anyone on here doesn't know why that was happening and there's anything I can do to help debug please let me know.

I attempted to run the job that was interrupted the first time this happened after clearing the chips and taping up my terminal blocks, but the stoppage happened again. It looks like the chips might have been part of the problem, but not the whole problem, so I'm back to square one. I will run through the troubleshooting steps again today to see if anything behaves differently than it did before.

Hopefully the final update: the chip issue above lead me to notice another issue; I had forgotten to heat shrink the end of one of my stepper cables. This was causing some of the shield strands to be exposed, and it looks like they might have been just barely touching my machine's frame. The sound of the motor noticeably changed when I intentionally touched these two things together, which makes me believe that this was the true cause of my issues. I suspect this was creating some sort of ground loop, because both the frame and the steppers are separately grounded to the star point in my electronics enclosure. After taping the end of that cable thoroughly I have run through a couple programs now (including the original that I couldn't get through before) without issue.

Hopefully this little saga helps someone in the future!