I have been having this frustrating occurrence with my Ender3 where the machine will get stuck at Extruder Heating, before it begins the printing process and just sit there. I looked up solutions for the problem and I read more than once that it was a failed MOSFET that would have to be replaced or swap out the main board. This would make the third time I have had to replace this board due to some sort of component failure.
I bought another board and within a few prints, I was back to the same problem. I was quite livid and ready to push the 3D printer in front of a passing train. I did not do that, however, I put too much time and effort into making this the perfect 3D printer for me. I started to think, could be the Official Sprite Head causing issues? I was very limited as to which firmware seems to work with the Ender3 plus the Sprite Head. It’s a bit hacky but what I am doing works.
Also note, I have the same problem whether I am printing using OctoPrint or directly from the SD Card. It also wasn’t after every print.
In short, the quick fix for when the Ender3 is stuck at Extruder Heating. Go into the menu, Select Tune.
Select Nozzle to adjust the temp up or down a degree. Sometimes you may have to do it a couple times but this will kick the print off.
I don’t know why there is this issue of having to nudge the printer by adjusting the nozzle temperature but here we are. I can deal with this but this sort of fiddling is rather irritating.
Going to start looking at other boards to drive the 3D printer or possibly just look to getting something a bit more industrial. When I need my printer I need my printer and faffing around with it for it to do its most basic function can get a bit frustrating. I love my Ender3 but sometimes it just doesn’t love me back.