Lost the print and the blob pulled a wire out
I was printing a part with tall angled legs (my own version of an infinity cube) and it broke off probably right after I went to bed. Woke up to a tangled blob of plastic and it says ERR: MINTEMP
After peeling most of the plastic off there's a wire left hanging with about 1.5" [38mm] of the end exposed.
Did I just bone the whole hot end?
No - just the thermistor
Buy two spare thermistor assemblies on the e-shop, one heater cartridge (just in case). Use one thermistor to replace the one that the wire is broken on. There are instructions in the documentation section - but basically the heat block (which is secured to the heat break by screw tension) is a pinch block. That screw in the very back (opposite the nozzle end of the heat block) tensions the split insmall size. the block, pinching the thermistor and the heater cartridge (the two sets of wires that go into the heat block - white ones are thermistor, red ones are heat cart).
With the hot end hot (try 250, 260) loosen that screw. The thermistor should then slide out. You should be able to push it from the opposite side with an allen wrench of small enough size. You'll have to loosen the loom on both ends - be careful that the nylon filament is pushed into the hole on both ends at the end of your fix since that keeps the loom from sagging. Reroute the thermistor wire carefully, and take great care not to break the wires on the heater cartridge (if you do, then you have that spare)
RE: Lost the print and the blob pulled a wire out
Thank you Mr Rogers. I've ordered 2 hotend thermistors and a heater cartridge like you suggested. Shipping was $15, but it didn't go up when I added a roll of Prusament so I guess it's a wash. I've already got the + kit for the pinda so it will be a good time to get that installed too. I'll have to go back through your instructions carefully when the parts arrive, but for now I feel good that my Prusa won't be down for too long. Thanks again for your assistance,
Buy two spare thermistor assemblies on the e-shop, one heater cartridge (just in case). Use one thermistor to replace the one that the wire is broken on. There are instructions in the documentation section - but basically the heat block (which is secured to the heat break by screw tension) is a pinch block. That screw in the very back (opposite the nozzle end of the heat block) tensions the split insmall size. the block, pinching the thermistor and the heater cartridge (the two sets of wires that go into the heat block - white ones are thermistor, red ones are heat cart).
With the hot end hot (try 250, 260) loosen that screw. The thermistor should then slide out. You should be able to push it from the opposite side with an allen wrench of small enough size. You'll have to loosen the loom on both ends - be careful that the nylon filament is pushed into the hole on both ends at the end of your fix since that keeps the loom from sagging. Reroute the thermistor wire carefully, and take great care not to break the wires on the heater cartridge (if you do, then you have that spare)
RE: Lost the print and the blob pulled a wire out
Got the parts. The machine just says ERR: MINTEMP
It won't let me into any menus to heat up the block. I think I have to beaver off the cold plastic and hope there's something that looks like it makes sense.
RE: Lost the print and the blob pulled a wire out
Plugged in the new thermistor and preheated the block. All the caked-on pla smoked and melted away. Pushed out the old one and pushed in the new one. It squawked about over temp hotend but I turned it off and let everything cool. Reassembled the fan and it's good as new. I even routed the thermistor wires up and over the heater wires so they won't get caught in a blog again.
Thanks for your help @Dan Rogers