The drive rollers on the printhead can get caked with filament if a jam course; if the hot end is clear and filament still does not feed, the feed rollers may need to be cleaned.
This operation should be done with the print head removed
Tools required:
2.5mm Allen key
torque screwdriver - 1.5 nm
small paint brush
tweezers
Remove the pivot bolt with a 2.5mm allen key, and apply pressure with your thumb to the tensioner arm pivot to unload the spring.
Remove the pivot and the tensioner arm.
Clean out debris from the roller area and make sure that the serrations on the feed rollers are clear of plastic gunk. During a jam, the rollers can eat away at the filament and fill the divots in the serrations with plastic. If things are really stuck, fine tweezers can be used to clear out the roller serrations.
Rotate the roller using the back of a paintbrush or a similar plastic/wood tool, ensuring the whole circumference is clean.
Clean the drive roller mounted in the tension leaver in the same way.
When clean, reassemble the lever and align the spring seat of the tension lever with the spring.
Apply pressure across the pivot of the tension lever to align the pivot hole, then hand thread the pivot bolt into the print head,
Please do not force the pivot back in place. This can damage the threads on the extruder body. When everything is aligned, it shouldn't take much force to start the threads.
Torque the pivot to 1.5nm (13. lb-in)