Bed thermistor issue - resistance in spec
I have a mk3s and started getting the MINBEDTEMP error. I probed the bed thermistor and it gave all the signs there was a break in one of the wires. I have a new one ordered but I also have a few prints with a bit of a deadline so figured it wouldn't hurt to try to fix it myself in the meantime.
I'd read somewhere that some people were replacing the wire with 14-16ga wire. I have some 16ga wire on hand so I cut the existing thermistor wire on the heated side and soldered/heatshrink the 16ga wire to it. I used the existing plug but new female connectors for the board side.
Powering the printer up I still get the same error. I probed for resistance at the connector and got 81k (spec is 80 kΩ - 125 kΩ). So it would appear my wiring fix addressed the problem but apparently not.
Electricity is basically magic to me. I’m just comfortable with the mechanics of wiring and connectors. Would have a section of the wire changed from 26 to 16ga still cause an issue with the signal the software is expecting?
RE: Bed thermistor issue - resistance in spec
the wire size will not cause an error.
there are three thermistor sockets, did you plug the thermistor into the correct one after the repair?
did you clean the nozzle with a brass brush? in which case, this may have damaged the thermistor circuit!
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Bed thermistor issue - resistance in spec
I made note of which socket it was before pulling it and then also referenced a how-to on the Prusa site, just to make sure. This is the bed thermistor so no issue with cleaning breaking anything. I also just swapped the bed and hotend thermistors to see if the problem followed the sensor or it was a board issue. The hotend reported 0 after the switch so it's not the board. The only thing I can think of is if the new female connectors I used aren't making contact with the pins on the board. When I have a chance, I'll try removing the female connectors from the connector and attach them to the board pins to see if that fixes the issue.
RE: Bed thermistor issue - resistance in spec
Good Luck!
Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Bed thermistor issue - resistance in spec
That was it. The metal female connectors were apparently not far enough in the locking connector. I replaced it with a different connector I had and it reads correctly and I can print again.