Taz6 thermal runaway and replacement thermistor

Greetings folks - hoping I can get someone to help clarify something for me.

I have a Taz 6 with the original hotend (hexagon?) from when I purchased the machine.

I’ve gotten a Thermal Runaway error on two prints today, and after some examination, I think I have a bad thermistor. Following this post:

I checked the resistance on the thermistor. At room temp with a multimeter, it’s reading 19.6k ohm, and from what I can tell, it should read 100k or so.

Looking at the Lulzbot store, when I filter for Taz 6, this is the only thermistor I see:

But in the description, it doesn’t mention the Taz 6 or hexagon, so I’m assuming it’s the wrong thermistor. I started disassembling the hotend, but I’m having a tough time getting the thermistor out to compare against the pictured one, so I’m hoping someone can tell me if this is the right part? Or point me to the correct one?

Thanks much!

I believe this is the one you want.
https://www.lulzbot.com/support/100k-semitech-gt2-thermistor

The cartridge type thermistors won’t fit in the hexagon hot end.

I had noticed these thermistors before (I think they came up in a search result), but there doesn’t seem to be a way to order them. Is this one of those “contact Lulzbot support” issues? Is there an alternative I can use?

Thanks much!

Just about any 100k thermistor on Amazon. Overall it’s still not an easy process. You’ll have to splice the wires or get new terminal pins like these:


And crimp them on and remove the old terminal pins from the wiring harness.

In addition to that you probably won’t be able to get the old thermistor out of the heater block, it’s just very difficult due to the stresses involved with the high temperatures and cooling. It may be easier to replace the heater block and start new. Then you may or may not get the heating cartridge out. Fair chance you’ll accidentally break those wires too and need to replace the heating element.

Sorry to sound negative but this is the reality of it. Not impossible but not a walk in the park either. Good luck!