I have an Ender 3 V2. The other day it was printing along just fine and suddenly stopped printing, it acted like it was printing, but there was no filament coming out even though the extruder was running. When I checked the display it reported the hot end was at 215 which was the set point. but the nozzle was covered in blackened melted plastic and was actually cold to the touch. I cleaned it out, put a new nozzle on it and the hot end wouldn’t heat up. I figured the hot end was dead so I ordered and installed a new one.
Now the hot end temp constantly reports 522 c so obviously turning it on won’t cause it to heat since the printer thinks the hot end is far above the set temp.
My guess is something on the main board is shot and I need to replace that. Anyone got any other thoughts on things to try first?