I was about 30 minutes into a print when it stopped extruding. I thought I had another clogg then noticed the temp reading 175 and not the preset 230. I watched it slowly drop. Now I have this error message “MINTEMP” on the screen instead of “TAZ ready”. I took the head off and checked all the connections and traced the wire back and check all junctions and everything looks good. The nozzle simply will not heat up. I have been having a horrible time over the last couple months trying to get through all the demons of this machine. First it was bad filament (not lulzbots problem in any way). Then it was slic3r having issues (finally switched to MatterControl with Cura) and my issues went away. I have had over 30 straight prints fail and FINALLY today I got 2 back to back perfect prints. I was super excited to finally have this machine dialed in like my other 2 printers and now it’s dead. This time it’s not a filament or software issue. This was supposed to replace my old Makerbot and newer Duplicator 4. It has the bigger print volume and much more impressive hardware numbers. I thought I would be able to use this TAZ3 as my new workhorse and the other two printers for small side projects. So far it hasn’t been up to the task. I could REALLY use some advice on what to do next. I need this machine running badly.
it sounds like your temperature sensor Thermistor died. That or the heater module. The Thermistor is this piece: https://www.lulzbot.com/products/100k-honeywell-axial-thermistor
The heater midule is this piece https://www.lulzbot.com/products/heat-resistor-47-ohm
There are some threads in this section of the forum that describe methods to check the thermistor for proper continuity with a multimeter if you have one available. That will at least let you narrow down which one is broken. If the machine is still under warranty you also might want to give Lulzbot tech support a call, they may be able to get you back up and running with a replacement part.
Thanks for the info. Unfortunately I’m 3 weeks outside of my warranty. The nozzle had to be replaced about 4 weeks ago and now the heater block isn’t working. I wonder if the part itself has any warranty, because 4 weeks of use with MANY failed prints and only 2 successful prints just sucks. Do you know where the axial thermistor is located? I see it’s only a few dollars but I would like to locate it on my machine and check it out first before I go and buy unnecessary parts.
The thermistor is installed in the heater block just above the nozzle on the hot end.
We’ll still cover it, if something failed. Email email@example.com to get a ticket started.
It is very rare that the thermistor itself fails. If you get a mintemp error, that means you have an open in your hotend thermistor circuit. The good news is this can often be fixed with a pick and some pliers. Disconnect the four pin buda connector (two red wires, two orange) the orange wires are the thermistor leads, the red are heating element leads. Check the resistance between the thermistor leads. It should be around 100k ohms at room temp. If it reads OL or nothing, then you probably have an open due to crimp failure. If you read 100k ohms, then the issue is somewhere else.
Here’s where the pick comes in: poke the two silver tabs on the side of the black connector that correspond to the thermistor wires. Then, when the retaining tabs are pushed in, gently pull and wiggle the thermistor leads until they come out of the black connector. Inspect the crimps. There needs to be good connection between the crimps and the wire. On the female crimp, there are two tabs that bend inward and make contact with the male crimp. Poke those inward with the pick. Use the pliers to crush the crimp tightly around the wire if it is not already. Check the resistance of the thermistor circuit. If it is reading about 100k ohms, then carefully bend the retaining clips back out and re-install the crimps into the connector.
If you’ve confirmed the heater resistor is blown… how do you go about removing that and replacing it with a new one?!
The heater resistor will slide out. If the resistor feels like it’s stuck, and if it reads open when tested for resistance/continuity, you can pull it out with impunity. You’ll also want to send in a message to firstname.lastname@example.org to let us know (thanks for doing that, this is for everyone else’s benefit if they come across this thread).
The replacement resistor that I got from Aleph has a smaller diameter than the housing that the failed one came out of. What should I use to transfer the heat to the housing?
You can use aluminum foil to take up any space and provide better contact with the heater block. Just wrap the resistor making sure to stay away from the leads. It does not need to be wedged into the heater block, as it’s held in place by the stiff wire leads.
I used some thermal paste. It seems to be working well.