hal-9000

Let me first say that even though you have experienced issues with the printer and it looks daunting now, you're bound to experience these or a multitude of other problems with other brands too. The device is solid and I believe you'll be happy once you get over this hump. Now about your issue, from reading it seems like the issue outstanding is the Bowden tube and feeder, is that right? I can speak to issues with the U1 where I have had this problem if there is a slight build up on the knurled bolt or if the mechanism is too tight. You may also want to look at printing a replacement ring for under your Bowden clip as maybe your not in alignment (goes under the white plug where the tube enters). Have you also tried maybe re-seating the tube itself? I am thinking since you took it apart to fix the temp sensor and all it may not be all the way seated or seated incorrectly. Even before that I would email support and replace the cracked pieces so you can start clean.

I have an U1 with heated bed, LED lights (not off the board ... yet), dual extruder and upgrade fans. The last thing to change out would be the electronics and I'm wondering if the U2 board would work on this. Thoughts?