my BIQU B1 has worked almost perfectly for months. Since yesterday, however, suddenly no printing has worked.
After some experimentation it looks as if the filament in the hotend does not become liquid, although the nozzle is hot and the temperature display shows the corresponding values normally. The fans all seem to work normally. The extruder also works normally until nothing goes on because no material is flowing out through the nozzle.
The hotend is not clogged and I also changed the nozzle.
If I remove the nozzle I can advance the filament and it will come out of the hotend as if it was never melted.
Even with PLA with 240 degrees I have the problem.
The printer is still original, so nothing has been modified.
I don’t know what else to try. I am grateful for any help.