⬢Before you start, make sure the extruder on your printer is in the middle of both the X and Z axes.

⬢Unload filament from the printer and remove the spool holder.

⬢Remove the steel sheet from the printer.

⬢Power off your printer and disconnect it from the power.

⬢1.5mm Allen key

⬢2.5mm Allen key

⬢Torx key TX6

⬢Torx key TX10/8

⬢Needle-nose pliers

⬢Prusa lubricant (1x) supplied with your printer

⬢PG-assembly-adapter (1x)

⬢The gearbox might be greasy. We recommend preparing a paper towel for wiping off the excess grease and dirt.

⬢Take off the flexible steel sheet.

⬢Use any cloth or piece of fabric, which is thick enough and cover the heatbed. This will ensure you won't damage (scratch) the surface during the disassembly.

⬢Remove the loveboard cover on the extruder by lifting it up.

⬢Remove the M3x10 screw from the right side and remove the side cover.

⬢Remove the side cover.

⬢There are safety latches on the front of each connector. The latch must be pushed inwards in order to be able to remove the connector. In case you can't reach the latch with your nails easily enough, use an appropriate tool to press the latch while you pull the connector out.

⬢Disconnect the extruder motor connector.

⬢Disconnect the Loadcell connector.

⬢Disconnect the Filament sensor connector.

⬢Open the fan-door.

⬢From the other side of the extruder, disconnect the hotend heater connector. Note, the safety latch is in the front of the connector.

⬢Disconnect the heatsink fan connector.

⬢Disconnect both thermistor connectors. Note, the safety latch is on the left of each one.

⬢Resease the two thumb screws holding the hotend assembly.

⬢Release both the hotend heater and thermistor cables out of the groove inside the x-carriage.

⬢Remove the hotend assembly by pulling it down.

⬢Remove the two M3x18 screws holding the heatsink fan.

⬢Remove the heatsink fan.

⬢Remove the three M3x10 screws holding the heatsink.

⬢Carefully remove the extruder assembly from the printer. Make sure not to damage any of the cables!

⬢Remove the M3x4T grub screw using the short side of the T6 Torx key.

⬢Remove the NTC heatsink thermistor. Be careful not to damage the cables.

⬢Remove the two thumb screws on the side.

⬢Remove both the M3x30 screws with the springs.

⬢Remove the Idler-swivel assembly.

⬢Remove the M3x25 screws.

⬢Remove the PG-case, the plastic cover on the front of the gearbox.

⬢In case you have the "three screw" version of the Nextruder, remove the M3x25 set screw.

⬢Remove the Idler assembly.

⬢Remove the whole gearbox assembly: the printed main plate, the brass PG-ring and the gears.

⬢Clean all the parts of the gearbox from excess grease and dirt.

⬢Locate the metal washer that should be between the gearbox and the motor. It might be stuck to the gearbox assembly.

⬢Remove the extruder motor from the heatsink.

⬢Very carefully pull the filament sensor out from the heatsink using the needle-nose pliers.

⬢Insert the filament sensor assembly into the heatsink. Make sure the steel ball part is closer to the side of the heatsink.

⬢Push the assembly into the heatsink and make sure the filament sensor assembly is flush to the metal heatsink.

⬢Place the heatsink on the extruder motor. Note the orientation of both parts.

⬢Attach the main-plate on the heatsink. Note the orientation of the part. Use the cutout as a guide.

The following instructions need to be done correctly and carefully. Achieve better understanding and successful assembly by watching the video alongside the guide: prusa.io/PG-assembly

⬢Attach the PG-assembly-adapter on the PG-assembly. Note the pockets for the gears in the adapter.

⬢Slide the PG-ring onto the adapter.

⬢Grasp the entire assembly in one hand so that it can be rotated with the PG-ring.

⬢With the other hand, slide the PG-ring onto the PG assembly in a wobbling motion (move the PG-ring left and right repeatedly) - a quarter turn is enough.

⬢Stop when the surfaces of the gears are approximately flush with the surface of the PG ring.

⬢Maintain the position of the PG-assembly and attach it on to extruder motor shaft.

⬢Very gently and freely rotate with the whole PG assembly (PG-assembly-adapter, PG-assembly and PG-ring) until it drops down so that there is no gap between the assembly and the main-plate. Do not push on the assembly.

⬢Remove the PG-assembly-adapter.

⬢Attach the PG-assembly-adapter back on the PG-assembly again to verify that all parts are properly seated.

⬢Rotate with the PG-assembly-adapter. The PG assembly must be easy to rotate without having to exert much force.

⬢Remove the PG-adapter. You will no longer need it during assembly. We recommend keeping it for maintenance.

⬢Ensure that the PG-assembly is not sticking out above the PG-ring. It should be positioned lower than the level of the PG-ring's surface or at the same level as the ring.

⬢Ensure that the gap between the PG-ring and the Main-plate is minimal. If a significant gap is observed, disassemble the planetary gear assembly and reposition it.

⬢Insert the idler assembly between the PG-ring and the extruder motor. There is a cutout for the spacer in the main-plate. Line up the idler spacer with the hole in the PG-ring.

⬢Secure both parts with the socket set screw 3x25. Do not overtighten the screw! The screw protrudes from the PG-ring after tightening. 

⬢Apply a small amount of Prusa Lubricant all around the PG-ring and PG-assembly teeth.

⬢Using a paper towel, wipe off any excess lubricant on the front surfaces.

⬢Take the PG-case and make sure the Spacer 13x24x2,5 (plastic ring) is already inserted in the part.

⬢Cover the planetary gear and secure the PG-case with the M3x25 screws. Do not overtighten the screws!

⬢Attach the spring 15x5 on both M3x30 screws.

⬢Push the two screws with the springs through the holes in the protrusion on the heatsink. There are no threads inside.

⬢Attach the Idler-swivel assembly on the screws. See the correct orientation of the Idler-nut. The side with version marking must be visible. See the picture.

⬢Tighten both screws. Stop tightening as soon as the screw tips reach the front face of the idler nut.

⬢On the extruder motor side, insert the NTC thermistor into the hole in the heatsink.

⬢Secure it with the M3x4T grub screw. Screw it all the way in. Tighten gently, but firmly using two fingers and the short side of the T6 Torx key. Applying more force may cause permanent damage to the thread.

⬢Insert two thumb screws into the heatsink. Do not tighten them completely. Two turns are enough for now.

⬢Place the Nextruder onto the spacers on the X-carriage.

⬢Make sure the heatsink thermistor cable doesn't get pinched. It should be guided through the dedicated channel in the x-carriage.

⬢Make sure none of the cables is getting pinched behind the extruder.

⬢Align the heatsink holes with the spacers on the X-carriage and join both parts together with three M3x10 screws. Start with the middle one.

⬢Connect the Loadcell cable into the Loveboard.

⬢Connect the Filament sensor cable into the Loveboard.

⬢Connect the E-motor cable into the Loveboard.

⬢Connect the heatsink thermistor cable into the Loveboard.

Out of the two similar connectors, it goes to the connector on the right.

⬢Carefully tuck the heatsink thermistor cable into the groove in the X-carriage.

⬢Add the heatsink fan onto the extruder assembly. Make sure the cable is pointing to the left.

⬢Attach the fan using two M3x18 screws.

⬢Connect the heatsink fan cable to the Loveboard.

Out of the two similar connectors, the heatsink fan connects to the lower one.

⬢Tuck the fan cable into the groove on the X-carriage too.

⬢Make sure the thumb screws on the side of the heatsink are loose.

⬢Insert the hotend assembly into the heatsink from below.

Push it all the way up.

⬢Make sure the hotend assembly is fully inserted.

⬢Make sure the part of the hotend with the cables is pointing to the back of the printer, as seen in the picture.

⬢After the hotend assembly is positioned correctly, hold it in place and tighten the two thumb screws fully.

⬢Connect the hotend thermistor cable into the Loveboard.

Hotend / nozzle thermistor connects to the left of the two similar connectors.

⬢Tuck the cable into the groove on the X-carriage.

⬢Connect the hotend heater cable into the Loveboard.

⬢Finally, tuck the cable into the groove on the X-carriage.

⬢Once again, verify the thumb screws are tight.

⬢Curve and arrange the cables on the right side of the extruder as you can see in the picture.

⬢Cover the cables with the LoveBoard-cover-right.

⬢Secure it with the M3x10 screw.

⬢Push all cables to the extruder to make more space around them. See the picture.

⬢Slide the Loveboard-cover on the extruder. And push it all the way down. The cover must go behind the X-carriage-back.

⬢Ensure that the two plastic covers fit together perfectly.

⬢Remove the protective cloth off the heatbed.

⬢Attach the steel sheet back onto the printer.

⬢Connect the printer to the electricity and turn it on.

⬢The next step of the wizard will prompt you to touch the nozzle to test and calibrate the Loadcell. During this procedure, the parts of the printer are not heated up so that you can touch them. Click Continue.

⬢Do not touch the nozzle yet, wait until prompted by the Tap nozzle NOW message.

⬢Tap the nozzle from below. In case the Loadcell does not detect the touch, you will be prompted to repeat the step. Otherwise, you will see Loadcell test passed OK when it succeeds.

⬢Once you get to the Gearbox Alignment part, select Continue and follow the on-screen instructions.

⬢Undo the idler lock (swivel), then open the idler door.

⬢Loosen the three screws on the front of the gearbox by 1.5 turns.

The printer will go through the automatic gearbox alignment. This process can’t be seen from the outside.

⬢Once prompted, tighten the three screws in the pattern indicated on the screen.

⬢During the filament sensor calibration, you will need to use a short piece of filament. Prepare the filament and select Continue. There should be no filament inside the extruder before the start of the calibration process.

There should be no filament inside the extruder before the calibration process starts.

⬢Once prompted to, insert the filament end into the opening on top of the extruder.

⬢Remove the filament after the calibration finishes.