Thermistor fail after smoke/melted plastic smell emitted from extruder
I'm having problems with my new MK2S. I got it up and printing it did one print before I started having problems. For no apparent reason (I hadn't change anything since the first successful print) there was a thermal runaway and smoke started emitting from the extruder as well as the smell of burning plastic. A small amount of PLA started bubbling from the hotend tip. I made sure the firm ware was updated and disassembled the extruder to make sure everything was in working order. Nothing was melted or showed any signs of damage, including the white plastic tube inside the extruder. The nozzle itself has been cleaned as well. When I put the extruder back together, the selftest fails and says there is a problem with the heater thermistor. The hotend still gets hot, as does the heatbed.
I've spent hours trying suggestions from the forum and am at a loss. The only thing I can think of is that the white material covering the small space where the thermistor cables attach to the hot end has flaked off a little bit. Could this be the cause?
If not, has anyone had a similar problem / any suggestions?
Anxious to get printing!
Re: Thermistor fail after smoke/melted plastic smell emitted from extruder
Have you had a word with Prusa Chat! they probably know best!
it's possible the hot end thermistor has gone bonkers
what is the extruder temperature when the printer is first turned on? (before trying to print anything!
does it show near enough the same as the heatbed?
if it's significantly lower then the thermistor may have gone open circuit, or high resistance
if so, change the thermistor.
it's also possible the rambo has gone bonkers... changing the thermistor will not help in this case
does the hot end start heating up without being asked to preheat, or start a print?, it could be that the heater drive FET has gone faulty. if this happens turn the printer off immediately.
there is a way to substitute the two thermistors and check the rambo port... but it could lead to overheating the printer again so I will not doccument it... if you are not confident in working this out, get help from someone who is confident
I would unplug the heatbed heater cable and the hot end heater cable for safety... again, there is a possibility that this may cause a poor connection on the associated molex connectors, so playing with this is at your own risk
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