"For the past few weeks, I've been having a problem with my new hot end. Basically, it shuts off in the middle of some/most prints.
I've used my multimeter to test the current at various points along circuit, and I thought I was having a problem with the hot end power cable, so I ordered and installed a new one.
Then again today, I had the hot end turn off in the middle of two prints. If I manually turn on the hot end and wiggle the connector at the hot end, I can see the temp drop until I wiggle it just the right way again, then I see the temp go back up.
The board is functioning fine and delivering ~12v to the hot end, and the new cable is in good shape, so this leads me to believe it must me a loose wire or bad crimp on the hot end itself.
Please let me know what we can do to solve this. Thanks!" -Brad
Answer: Great troubleshooting Brad. For those out there without a multi-meter, a good way to isolate the problem would be to try another hot end power extension. Generally, this kind of failure is a result of wire fatigue. An indication of fatigue would be that the problem corrects itself after wiggling the cable.
If you try printing the same model multiple times and see a failure in the exact same point in the print, the problem is likely with the g-code.
Alternatively, if the hot end (Ubis 13S or ceramic) fails in seemingly random points in various prints, it is likely caused by a break in the wiring somewhere.
If replacing the hot end power cable is unsuccessful, there may be an issue with the hot end itself.
Finally, if the hot end and power cable are found to be functional, the board would be the last thing to diagnose. Again, wire fatigue (either on the extension cable or the actual hot end) is the most common cause for this issue.