Hello everyone. It has been a while since I have hopped in here.
I am back for some advice. I have all of sudden started receiving this error very early on in my prints, normally while it is still in the bed leveling sequences.
Disassemble the hotend and test the HT-NTC100k thermistor. I pulled it out of the heatblock so it is exposed to ambient temperature. I then checked the connector where it plugs into the SKR with a multimeter to check its resistance. Per the datasheet, it should read 100ohms at 25C. I was getting 104ohms so I believe that checks out.
I also performed a few PID autotunes on the hotend (E0) just to make sure its not acting funny. Nothing weird happened there.
Any other ideas or things I should check?
It is at the very limits of my wifi reach and I think sometimes the Pi/Octoprint loses internet. But that shouldn’t affect anything once it is already printing, right?
I have removed the thermistor and reinstalled it. So I have resnugged the thermistor set screw now. I think that is good. I will try moving the printer to a different location to test that theory. I have also ordered a couple new thermistors, so we will try that idea out too.
Something that may be worth noting is that each time this happens, the bed comes crashing down. Is it problematic that the board is energized by the steppers as it crashes down? Would that cause any issues with the thermistor header on the board?
Here is the temp graph during the print. Never made it to the printing, got the error during leveling which is consistent now. Nothing clear in the graph, no drops. The last recorded temp was right where it should be.
As for power supply, I am using a 12V 30A supply and the printer has used it for a year or so now. Not sure what could be wrong there.
I had a thermistor once on my TAZ which had a crack inside it (it was a glass bead one). It would work reliabley most of the time, but for some reason when homing the printer it would often times go open during the point in the homing sequence where the head gets close to the bed. How weird is that?- it took me forever to find it.
I also had a thermistor on my Qidi FFCP clone which had a broken wire in the harness, and again it worked most of the time, except if the carriage was in a little-used part of the build area. (Back right corner of the build plate). In that case, I’d get similar temp errors during many but not all prints.
I also suspect a broken wire or thermistor. The homing may be moving things in a position where an intermittent wiring issue gets aggravated. Try homing with the hot end is cold and see if that shows up with something weird in the graph. I would also be preemptively ordering a new thermistor and wire.
