IM becoming crazy! I just bought UM3 Extended and everything works perfectly with the first print core.
I am trying to print with PLA using ONLY the 2nd print core, but nothing to do. I leveled by hand, then I made numerous active levelings, but the result is always the same: the nozzle of the second print core, after producing the blob correctly, does not print because it is too tight to the glass plate.
If I try the first one core and everything is perfect.
I searched for an offset Z, but there is nothing ...
Can you help me understand what to do?