Thermistor failure?  

Re: Thermistor failure?

If the thermistor is disconnected or damaged in a way that the board can no longer measure its resistance, then the printer has no way of telling if the hotend is working at all. Thus, it throws the MINTEMP error and won't even attempt to heat.

Thermistors can be fragile but the cartridge style here do pretty well. Support can walk you through the troubleshooting and they'll likely send you a new one without any fuss. It's like a 5$ part.

Re: Thermistor failure?

What should the resistance value be for the MK3 Thermistor?

Re: Thermistor failure?

What should the resistance value be for the MK3 Thermistor?

https://www.mouser.com/ProductDetail/Semitec/104GT-2?qs=wgO0AD0o1vvQ2Rm%2FPgvFdg%3D%3D

100k at room temp

Re: Thermistor failure?

what are the readings on your lcd for temperature are they 0/0? or 20/0? or something else?

Re: Thermistor failure?

What should the resistance value be for the MK3 Thermistor?

https://www.mouser.com/ProductDetail/Semitec/104GT-2?qs=wgO0AD0o1vvQ2Rm%2FPgvFdg%3D%3D

100k at room temp

Thank you Curtis.c2. I was certain that was the case, however most sites don't call out the 100k value, and only call it a "E3D V6.1 Thermistor". I know there are different values of thermistors for different applications and I just wanted to make absolutely certain.

what are the readings on your lcd for temperature are they 0/0? or 20/0? or something else?

Curtis.n6... Several things to note that I'll itemize rather than make this all overly wordy...
* Printer is the MK3
* I'm seeing a reading of 288/0 at the hot end
* Measured resistance is 105k

This is what happened to get me to this point
* To clear a severe jam in the nozzle I had to disassemble the hot end and body (I think this design is a little tedious to service)
* The heater cartridge wires were severed in the process
* The thermistor cartridge was also damaged and is now reading 236k (I was seeing a zero temp warning)
* Replaced one of the 5A fuses that had blown (not sure if this is in any way related to the cartridge change but this has not repro'd)
* I replaced the hot end (sync, block, nozzle, thermistor and heater cartridge) that was recovered from my MK2s after upgrading it with the MMU
* The thermistor resistance is 104k (room temp is constant @ 25c)

Thank you,
Leo

Re: Thermistor failure?

what are the readings on your lcd for temperature are they 0/0? or 20/0? or something else?

Curtis.n6... Several things to note that I'll itemize rather than make this all overly wordy...
* Printer is the MK3
* I'm seeing a reading of 288/0 at the hot end
* Measured resistance is 105k

This is what happened to get me to this point
* To clear a severe jam in the nozzle I had to disassemble the hot end and body (I think this design is a little tedious to service)
* The heater cartridge wires were severed in the process
* The thermistor cartridge was also damaged and is now reading 236k (I was seeing a zero temp warning)
* Replaced one of the 5A fuses that had blown (not sure if this is in any way related to the cartridge change but this has not repro'd)
* I replaced the hot end (sync, block, nozzle, thermistor and heater cartridge) that was recovered from my MK2s after upgrading it with the MMU
* The thermistor resistance is 104k (room temp is constant @ 25c)

Thank you,
Leo

First, Chris not curtis 🙂

second.... i was responding to op but i can understand, since i did not quote them how you might make the mistake. good luck with your printer

Re: Thermistor failure?

I've had my printer (PRUSA assembled, not kit) for about a week and a half. Have done around 90 hours worth of successful prints. When I tried to print something this morning, I got a MINTEMP bed failure. Did some research, which suggested it might be a bad thermistor. Okay. Doesn't seem too hard of a fix.

Decided to run self test. Self test fails at the hotend check, telling me that the hotend heater/thermistor is not connected. Never even made it to the bed check.

Is it likely for both of these to fail at once? Or do I have something else going on?

I'm super frustrated given that I paid the extra money to have PRUSA assemble it... wasn't expecting to have failures this soon...

Nicholas,
what do you see for temps in the top left? 0/0 or 20/0 or something else?

Re: Thermistor failure?

First, Chris not curtis 🙂

second.... i was responding to op but i can understand, since i did not quote them how you might make the mistake. good luck with your printer

Sorry Chris, the appended alpha-number kicked my sly-dex-ya into overdrive. 🙂 And you are correct, I jumped the gun a little on my response, my bad. I saw that there hadn't been any traction from the previous poster, a few days, and assumed your question was directed at me.

I'll start a new thread with my inquiry.

BR,
L