MINTEMP error Catch 22 - Can't get to Thermistor to repair due to major filament glob monster on hot end.  

RE: MINTEMP error Catch 22 - Can't get to Thermistor to repair due to major filament glob monster on hot end.

I use a soldering iron, mine is temperature controlled so I turn it down to about 250C, to reduce the smoke! 

and I cover the build plate with paper to prevent mess on the build plate. 

last time I had a Blob, my Part Fan Shroud ended up, FULL of waste filament. 

After cleanup, I Printed a replacement in PETG, without a fan shroud on the printer. 

(I don't print ASA or ABS, for health reasons, PETG Fan shrouds are ok for PETG, TPU and PLA Prints.)

regards Joan

RE: MINTEMP error Catch 22 - Can't get to Thermistor to repair due to major filament glob monster on hot end.

Posted by: @graham-mcintyre

So I appear to be in a bit of a pickle with my MK3S.   I had a print failure where I lost adhesion part way through but did not notice it as I had stepped away for a bit.  When I came back, the print had hit an emergency stop due to MINTEMP. Rebooting, I came back up to a MINTEMP error, and 0 degrees on the hot end thermistor.   It looks like the extruder got so gobbed up due to the failure that it probably caused the thermistor wire to break..

Soo - I need to be able to melt off the filament blob to be able to get to the thermistor wire.  But I can't preheat the nozzle due to the MINTEMP error.  How do I get out of this mess?  Is there a way to force the hot end to heat anyway? Even if I disassemble the hot end I will only be able to get so far without melting out the filament.

 I will dig through my spares bin, I may have a spare thermistor I could plug in.  That may get me past the MINTEMP but it will be dangerous to preheat since I won't be able to know /  control the temp.  But maybe I can try it just to get the blob off as quickly as possible.

Or, maybe I could use a soldering iron to melt specific parts off (with a sacrificial tip).

Any other ideas?  Thanks in advance for any advice. 

 

You are not the first with this problem, but it can be solved with a little care. https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-hardware-firmware-and-software-help/recommendations-for-removing-a-massive-filament-blob-from-hotend/

I had a similar problem once and was able to remove the roughest part with a heat gun. After that, small work with brushes and sticks and replacing some plastic parts (also the Thermistor). I had a fanshroud on reserve, as this is a known wearing part.

good luck!

RE: MINTEMP error Catch 22 - Can't get to Thermistor to repair due to major filament glob monster on hot end.

Heat gun, soldering iron, hot knife, and if its just PLA and you can remove the the extruder from the printer you can soak/dip it in boiling hot water to soften it up. PLA begins to soften at 50C, boiling water is 100C then use pliers to remove the bulk of the material.

Good luck

RE: MINTEMP error Catch 22 - Can't get to Thermistor to repair due to major filament glob monster on hot end.

Or, just replace the thermistor.