Issue

Your Centauri Carbon printer fails to extrude filament when you command it via the Prepare menu. It heats OK, but no filament comes out and the spool does not turn.

Cause

You likely have a piece of filament broken off inside the extruder gearbox and it is stopping the filament from moving down to the hotend. This can happen with softer filaments like TPU and brittle filaments, such as clear PLA.

Fix

Overview: You'll need to power off the printer, remove the shroud over the print head, remove the extruder gearbox, split it apart, and clear the clog.

Power off the printer, remove and unplug the front model cooling fan

Unscrew the two 2mm screws on each side of the shroud

Slide the shroud forward and take the shroud off

Press down on the PTFE tube connector and pull up on the tube to remove it

Remove the four 2mm screws around the edges of the extruder gearbox

Pull it forward and unplug the cables at the bottom of the hotend with tweezers or sidecutters

Remove the 2.5mm screws holding the hotend to the gearbox and pull the hotend off

Remove the three 2mm screws holding the gearbox together. Watch out for the cutter blade!

Separate the gearbox and clear any filament bits you find inside. 

You should be able to see all the way though the extruder gearbox from the filament PTFE push-fitting to the hole next to the cutter. If you can't, there's filament in the pathway, so use a thin Allen key to push out any broken filament pieces.

Brush out any debris, and reassemble the unit as a reverse of the steps above. 

Watch out for the cutter blade, you will need to press down on the extruder to overcome the spring tension when doing up the 3 gearbox screws.

If you didn't find any filament clogs in the Extruder, your hotend may be clogged, so once the printer is reassembled, heat the nozzle to 250 and see if you can poke a needle all the way through it from the PTFE tube fitting to clear it out. New nozzles and hotends complete are available to buy if unsuccessful.