After changing the nozzle on 3mm-Extuder, because the filament frequently got stuck, there was no connection to the extruder again. LEDs were on, but the temperature was not displayed on the screen, also in extrude menu there were no options (extrude, feed, remove, etc.) and heating up does not work at all.
Changing the extruder for the dualhead, had the same issues. The second extruder worked normal (Q) but the other one (H) was not displayed again and did not heat up or appeared in the menu.
But selecting the option "Flushing Nozzles" both extruders moved, and also in printing both extruded, but the first extruder (H) without temperature (therefore also no filament)
Also updating firmware didn't help.
Sometimes the temperature of the extruder appears for a second on the screen: H=1053/000c
What could be the problem and what can i do to fix it?