First off, I own a KITTAZ, but since there are more TAZ owners, I wanted to find out if anyone else has had this problem, or if anyone can recommend a solution.
I am using Pronterface, I set the extruder temperature, usually between prints, i.e. i’m taking one print off the bed, the temp was set to 0 when the print finished, I set it back to 185 for PLA, take off the print, something locks up and the temperature reading out on Pronterface says 185 or close to it, but in reality it is in a heat run-away ultimately resulting in the heat resistor burning out. This takes about 20 seconds. I usually notice it when I see PLA start leaking out (due to it being too hot). Once I see it, I turn off the printer immediately in an attempt to save the resistor, but I think I was only successful at doing this once, it just happens too fast.
This has happened to me 6 times now. So I am pretty proficient at replacing the heat resistors now. Lulzbot has been very responsive and has shipped me the 4 replacement heat resistors for free. (started with 2, one in extra flexystruder)
Things to Note that may help with diagnosis:
- The heat bed is also on a heat run-away, but it just doesn’t fry out.
- The thermistor is functioning correctly - when I turn the printer back on, the temp will refresh correctly and I can watch it fall (highest I have seen was ~247).
- It usually happens inbetween parts, not during the print (except once).
- Happens sporadically, first time was Dec-11, happened twice back to back, then worked for a month, then on Jan 14th, and 15th, then again on Jan 23rd/24th. I printed about 20 hours of objects between the 15th and the 23rd. And about 8 hours of objects on the 24th, so it’s not like I installed it and then it burned out, I usually get to print for a while first…
- I had a theory that it had to do with loading a part into pronterface while the temp was ramping, but have had it happen without loading a new part, so i’m not sure on that anymore.
- I have another theory that it might have to do with running Slic3r (generating Gcode) while setting the temp, as I was doing this last time it burned out and I might have been on previous burn outs but I can’t remember. Not sure exactly how this would have an impact, and it isn’t consistent, but I definitely think it is SW based.
- I have updated the FW with the latest without any modifications.
- I will upload my pronterface logs. If anyone has advice on how to make these more verbose, or if there are other logs that I can look at, that would be great.
1_22_resistor_burned_out_log.txt (9.27 KB)
1_23_resistor_burned_out_log.txt (4.73 KB)