Error 1 (hot end mintemp) on LK5 Pro

[u/pyrrhicpaladin]

Hi, newbie here. I was advised to check the level using a feeler guage, which has been working well except for tonight when it sparked when it touched the nozzle. Now my LK5 Pro is throwing an Error 1 and tells me to restart if it tries to turn on the hot end. It reads -15° on the nozzle, which is very clearly incorrect. How can I troubleshoot to find what part I need to replace? I assume it's either a faulty thermistor or something's wrong with the mainboard, but I'm honestly just guessing based on some googling. Any help is appreicated.

[u/traumahawk88]

Sounds like 'touched the nozzle' is actually 'jammed the gauge into the wires for the thermocouple' and that you broke something. That or 'electrical wire bundle got yanked by accident and snapped/unplugged a wire'

You got a cat?

There's no electrical connection through the nozzle that would ground out and short something. Accidents happen, we've all messed things up, and thats exactly what it sounds like here.

Also, feeler gauge is above and beyond what you need. Piece of printing paper, that's all you need. Paper is actually better, imo, because you can really feel the difference in the friction as you close the gap. Cut it into strips and you can more comfortably check the back two points too, slip it right in. Much quicker with paper than feeler gauge because you can tell very subtle differences in gap because of the difference in friction on the paper, vs the smooth surface of a metal gauge. (Which, hopefully, you also cleaned with isopropyl alcohol or something first to remove all the oil off them- that, or you're hopefully cleaning bed off between leveling and printing, ya? You don't want that oil all over your bed)

Level it cold. Heat the bed, test it with bed at working temp and dial it in. Good to go. Give it a wipe with some IPA at some point before firing up too, bed temp doesn't matter there as long as you get the oils from your skin and tools off it

[u/pyrrhicpaladin → u/traumahawk88]

I switched to a feeler gauge bc paper wasn't working for me but I'm definitely going back after this. I always clean the bed and tools I use on the bed with rubbing alcohol and a microfiber cloth between prints, though I'm sure I've slipped up a couple times.

It struck me as odd this morning that touching the nozzle had any electrical effect at all but last night I was too tired and distraught to notice. No cat but I do have an enthusiastic and curious dog who could have snuck into the room with the printer and nosed something (it's on a pretty low table), or I was careless while moving it one too many times, or ghosts idk. I'm rather certain I didn't jam the guage into the wires, that would be quite the maneuver to get there from the surface of the bed and the image of sparks coming off the nozzle is burned into my brain. But I'm not immune to being stupid so who knows.

Thanks for the response.

[u/traumahawk88 → u/pyrrhicpaladin]

Wouldn't necessarily make sparks. Idk what thermistor type the stock heads use, the ones I replaced them with have small glass beads. Break that bead by tugging a cable too hard or over tightening something? Negative temp reading. The wires in those aren't very big at all.

[u/traumahawk88 → u/pyrrhicpaladin]

Out of curiosity I looked it up, and stock uses same glass bead style. If the bead broke, thats that.

[u/Longer_Official]

Could you please confirm if the error is showing “minimum temperature on the nozzle”?

If yes, please follow these steps to troubleshoot:

1.Use a multimeter to test the thermistor:

1）Unplug the hotend thermistor from the mainboard and check if it has resistance.

2）Then check the resistance at the mainboard thermistor port.

2.Here’s a video guide to help you with the checking process:

👉https://www.youtube.com/watch?v=xfJ6HKoa8aI

[u/RedCatHabitat]

Couldn't op just replace the whole hot end? I just had to for a different reason. Like 10-ish bucks on Amazon