I noticed under extrusion on a print and saw that the filament was grinding though at the drive wheel(?) I don’t know the official name. Anyway, I stopped the print and pulled on the filament to get it out of the channel and it wouldn’t budge, I pulled a little harder and is stopped at the wheel. So I got out the needle nose pliers and got ahold of the filament and literally lifted the Tax 5 off the table by the filament and it would not come out. Got out the Xacto knife and tried to leverage the filament out that way and the filament snaps again just below the hole in the top of the carriage. So I heated the hot end and removed it hoping to pull the filament out of the bottom, no luck. I used a wooden handled long Q-tip and tried to clean as much as I could with the temp at 200. Tried using the thin wooden handle to push the unmelted filament out of the top so I could get the pliers on it again and no luck. So now the only place there is any filament is below the surface of the top of the carriage and above the heating element, any ideas?
What kind of filament were you printing with? So you opened up the extruded idler latch and were unable to pull the filament out of the extruder—what temp was the extruder when you tried to do this? I’ve seen this happen where the tiny fan that cools the hexagon died. This caused the whole extruder assembly to melt and warp, causing the under extrusion and jam.
These are the instructions I got when I called LulzBot support. You could call them and see if they have any other solutions.
Try setting the nozzle temperature to the high end of the range for the filament you are using. Block the cold end cooling fan (the always on fan) so the heat creeps up into the cold end. After about 15 minutes, insert some new filament and attempt to push the old filament out. As soon as you clear things out unblock the cold end cooling fan and retract the new filament out of the extruder.
After everything cools down (i.e. the cold end is back to its “normal” temperature). You can try a cold pull or two to make sure any left over filament is cleared out. I use the eSun cleaning filament for this and I’m very happy with the results.