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How to replace Nextruder heatsink (XL Single-tool)

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How to replace Nextruder heatsink (XL Single-tool)

How to replace Nextruder heatsink (XL Single-tool)
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Last updated 6 days ago
How to replace Nextruder heatsink (XL Single-tool)
 Difficulty
Moderate
 Steps
60
 Available languages
CSPLDEITFR
Introduction
Introduction
This guide will take you through the replacement of the Heatsink on the Original Prusa XL (Single-tool).
The following instructions are intended for XL Single-tool only, although most steps are common. If you have a Multi-tool XL, please go to How to replace Nextruder heatsink (XL Multi-tool)
Some parts might slightly differ. However, it does not affect the procedure.
All necessary parts are available in our e-shop prusa3d.com.
The following instructions require extreme attention. The procedure involves direct intervention in the planetary gearbox.
Tools necessary for this guide
Tools necessary for this guide
Tools necessary for this guide
For this guide, please prepare:
Torx TX10 key
Torx TX6 key
Torx TX8 key
2.5 mm Allen key
Universal wrench
Nose pliers
Side cutters recommended for cutting zip ties
Additional parts
Additional parts
Additional parts
For this guide, please prepare:
Prusa lubricant (1x) supplied with your printer
PG-assembly-adapter (1x)
The PG-assembly-adapter is not included in the box and needs to be printed. You can download the STL file from printables.com.
The STL file is located in Parts for maintenance section. Before proceeding, please ensure to review the recommended print settings provided in the caption.
DO NOT continue without the PG-assembly-adapter. It is necessary for the assembly!
Filament unloading
Filament unloading
Filament unloading
Filament unloading
The following step is only necessary if you have a filament loaded in the current toolhead.
Unload the filament from the hotend. On the screen, navigate to Filament -> Unload Filament and select the tool, you want to working on.
Remove the filament from the hotend. It is not necessary to completely remove it from the printer. Just a few centimeters (inches) above the extruder.
Cool down the printer to room temperature. On the screen, navigate to Preheat -> Cooldown.
CAUTION: Wait for the printer to fully cool down to room temperature before proceeding further.
Printer preparing
Printer preparing
Turn the power switch OFF (symbol "O").
From the rear side of the printer, unplug the PSU cable.
Protecting the heatbed
Protecting the heatbed
Before you proceed, it is recommended to protect the heatbed.
Make sure the heatbed is cooled down to ambient temperature. Place the empty cardboard box approximately to the front center part of the heatbed.
PTFE unplugging
PTFE unplugging
Turn the printer so the left side of the printer is facing you.
Gently push the black collet to release the PTFE tube.
Pull out the PTFE tube.
Wi-Fi antenna detaching
Wi-Fi antenna detaching
This step is only for the printer, which has a Wi-Fi antenna on the back of the printer.
Turn the printer, so the back side of the printer is facing you.
Unscrew the Wi-Fi antenna from the antenna connector and place it nearby.
Disconnecting the Nextruder cable
Disconnecting the Nextruder cable
Disconnecting the Nextruder cable
Disconnecting the Nextruder cable
Turn the printer, so the back side of the printer is facing you.
There is an antenna cable behind the antenna-holder, do not pull the connector!
Loosen two screws on the cover slightly. No need to remove them completely. Push the cover to the right and gently remove it from the screws.
Push the safety latch and disconnect the Nextruder cable from the connector "DWARF1".
Attach the antenna-holder to the screws and push the cover to the left. Tighten the screws.
Dock detaching
Dock detaching
Dock detaching
For older CoreXY back covers without hexagonal cutouts (honeycomb pattern), loosen the screw in the dock as instructed. The procedure remains the same.
Using a 2.5mm Allen key, untighten the screw inside the (middle hole) dock.
Keep the Nextruder cable bundle next to the printer.
Nextruder releasing
Nextruder releasing
Nextruder releasing
Turn the printer, so the front side is facing you.
Snap off the x-carriage-cover back from the X-carriage. Do not throw the parts away!
Using a T10 Torx key, remove two M3x12bT screws. Do not throw the parts away!
Nextruder detaching
Nextruder detaching
Nextruder detaching
Hold the Nextruder during disassembly.
Untighten two M3x12bT screws using a T10 Torx key. Do not throw the parts away!
Detach the Nextruder and place it nearby, we will rebuilt it in the next steps.
Cable bundle removing
Cable bundle removing
Cable bundle removing
Cable bundle removing
From the front side of the Nextruder, using a T10 Torx screwdriver untighten two screws to release the cable support. Do not remove the screws completely!
Press the blue fitting and pull out the PTFE tube.
Press the secure pin and remove the Nextruder cable.
Nextruder body removing
Nextruder body removing
Nextruder body removing
Nextruder body removing
From the right side of the Nextruder, using a T10 Torx screwdriver unscrew two M3x20rT screws. Do not throw them away!
From the left side of the Nextruder, unscrew two screws using a 2.5 mm Allen key. Do not throw the parts away!
Pull out the Nextruder body from the Nextruder. Do not throw the parts away!
Dwarf door opening
Dwarf door opening
Dwarf door opening
Loosen the screw, just a few turns are enough to release the dwarf-cover-door. No need to removing the screw completely.
Open the dwarf-cover-door widely.
Heatsink fan removing
Heatsink fan removing
Heatsink fan removing
Heatsink fan removing
Gently remove the zip-tie using a pliers. Watch out for the cables! 
By pressing the security latch, remove the heatsink fan cable from the Dwarf board.
Remove the heatsink fan. Do not throw the parts away!
Nextruder idler opening
Nextruder idler opening
Nextruder idler opening
Push the idler-swivel upward.
Pull the idler-lever downward in order to release tension on the gearbox.
Gearbox & motor assembly removing
Gearbox & motor assembly removing
Gearbox & motor assembly removing
Gearbox & motor assembly removing
Fully loosen three M3x25 screws from the printed gearbox cover. Keep the screws in the assembly, don't remove them completely.
Carefully slide the gearbox assembly off. It is necessary to remove the entire assembly in one piece. This means PG-cover (top plastic cover), PG-ring (brass ring), PG-assembly (metal gears), and main-plate (bottom plastic plate), all joined by M3x25 screws.
Set the gearbox assembly and the extruder motor aside.
Pay attention to not lose the spacer from the motor shaft.
Hotend assembly removing
Hotend assembly removing
Hotend assembly removing
Hotend assembly removing
With a Torx TX 8 key loosen the grub screw in the extruder. Do not remove the screw completely. A few turns are enough to release the hotend assembly in the heatsink.
By pressing the security latch, remove the hotend thermistor cable from the Dwarf board.
By pressing the security latch, remove the hotend heater cable from the Dwarf board.
Carefully pull the hotend assembly out of the heatsink. Do not throw the parts away!
At the same time pull the disconnected hotend cables from below the heatsink.
Heatsink assembly removing
Heatsink assembly removing
Heatsink assembly removing
By pressing the safety latch, unplug all remaining cables from the Dwarf board.
Remove the heatsink assembly and set it aside.
Print fan removing
Print fan removing
Print fan removing
Remove the three M3x10 screws from the heatsink. Do not throw the parts away!
Separate the heatsink and the print fan assembly. Do not throw the parts away!
Idler-swivel removing
Idler-swivel removing
Idler-swivel removing
Remove the two M3x30 screws to remove the idler-swivel from the heatsink. Do not throw the parts away!
Remove the idler-swivel from the heatsink. Do not throw the parts away!
Using a universal wrench, remove the Fitting QSM-M5 by turning it counter-clockwise. Do not throw the parts away!
NTC thermistor & Hall sensor removing
NTC thermistor & Hall sensor removing
NTC thermistor & Hall sensor removing
NTC thermistor & Hall sensor removing
Using a T6 Torx key, remove the M2.5x6rT screw. Do not throw the parts away!
Carefully remove the Hall filament sensor. Do not throw the parts away!
Using a T6 Torx key, remove the set screw from the bottom of the heatsink to remove the NTC thermistor. Do not throw the parts away!
Pull out the NTC thermistor from the heatsink. Do not throw the parts away!
Filament sensor removing
Filament sensor removing
Filament sensor removing
Filament sensor removing
BE EXTRA CAREFUL when removing the filament sensor. The filament sensor contains a tiny parts (spring, magnet, steel ball) that tend to fall out when the sensor is removed.
Very carefully pull the filament sensor out from the heatsink using the needle-nose pliers.
CAUTION: Avoid gripping the part firmly, as this may cause irreparable damage.
Don't lose the small parts! You will need them again later. Keep them aside in a safe place.
Using a T6 Torx key, remove the hotend grub screw from the heatsink. Do not throw the parts away!
Now, you can throw the old heatsink into the bin.
Heatsink: parts preparation
Heatsink: parts preparation
Heatsink: parts preparation
Heatsink: parts preparation
For the following steps, please prepare:
Heatsink (1x)
Hall filament sensor (1x)  removed in previous steps
M2.5x6rT screw (1x) removed in previous steps
Hotend grub screw (1x) removed in previous steps
Filament sensor assembly 1x) removed in previous steps
BE EXTRA CAREFUL. The filament sensor contains a tiny parts (spring, magnet, steel ball) that tend to fall out when the sensor is removed.
Hall sensor installing
Hall sensor installing
Hall sensor installing
Place the Hall filament sensor into the similarly shaped pocket in the heatsink.
Fix it with M2.5x6rT screw. Tighten it very carefully, you can crack the electronics board.
Insert the grub screw into the slot closer to the bottom of the heatsink. See the picture.
Filament sensor installing
Filament sensor installing
Filament sensor installing
Insert the Prusa ball holder assembly into the heatsink. Make sure the steel ball part is closer to the side of the heatsink.
Note the correct orientation of the Prusa ball holder assembly. There is a protrusion on the part. The protrusion must be facing down.
Push the assembly into the heatsink.
Idler-swivel & NTC thermistor: parts preparation
Idler-swivel & NTC thermistor: parts preparation
Idler-swivel & NTC thermistor: parts preparation
For the next steps, please prepare:
Idler-swivel assembly (1x) removed in previous steps
M3x30 with spring screw (2x) removed in previous steps
NTC thermistor (1x) removed in previous steps
NTC thermistor grub screw (1x) removed in previous steps
Idler-swivel securing
Idler-swivel securing
Idler-swivel securing
The color of the idler-swivel may be different. The part is the same. 
Tighten the idler-swivel with two M3x30 screws.
Note the correct orientation of the part. The screw heads on the idler-swivel must be facing up (like in the picture).
The tip of each screw should be flush with the plastic part on the other side.
NTC thermistor securing
NTC thermistor securing
NTC thermistor securing
On the extruder motor side, insert the NTC thermistor into the hole in the heatsink.
The NTC thermistor must be placed in the centre of the heatsink. See the picture.
Insert and firmly secure the M3x4T grub screw using a T6 Torx key. Screw it all the way in. Applying more force may cause permanent damage to the thread.
Heatsink placing
Heatsink placing
Heatsink placing
Double-check that the spacer is still in place on the motor shaft!
Carefully place the heatsink assembly onto the motor assembly. Look at the picture.
Gearbox disassembling
Gearbox disassembling
Gearbox disassembling
Dismantle the gearbox assembly into its component parts:
PG-ring (1x)
PG-assembly (1x)
PG-front-case (1x)
Make sure there is a plastic spacer inside the case. It can be black or white. Do not remove the plastic spacer from the case.
Main-plate (1x)
M3x25 screw (3x)
Using a paper towel clean all the parts from grease.
Gearbox assembling
Gearbox assembling
Gearbox assembling
In the following steps, we will reassemble the entire gearbox assembly to ensure proper installation.
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
The video is for MK4, but the procedure is identical.
After watching the video, follow the steps in this guide.
Attach the PG-assembly-adapter on the PG-assembly. Note the pockets for the gears in the adapter.
PG-ring assembling
PG-ring assembling
PG-ring assembling
Do not assemble the gearbox without the PG-assembly-adapter. This tool is intended to ensure that the gears are correctly fit together.
Slide the PG-ring onto the adapter.
Note there is a chamfer on one side of the PG-ring teeth. This side must be facing down (to the PG-assembly).
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.
Gearbox inserting
Gearbox inserting
Gearbox inserting
Gearbox inserting
Proceed very carefully in this step.
Attach the main-plate on the heatsink. Note the orientation of the part. Use the cutout for the socket screw as a guide (lower left corner).
Maintain the position of the PG-assembly and attach it on to extruder motor shaft.
Make sure the PG-ring perfectly fits on the socket set screw.
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 minimal gap between the assembly and the main-plate. Do not push on the assembly.
Remove the PG-assembly-adapter.
PG assembly alignment
PG assembly alignment
PG assembly alignment
PG assembly alignment
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.
There must be no gap between PG-ring and the Main-plate. If you see a gap, remove the planetary gear assembly and repositon it again.
Gears lubricating
Gears lubricating
Gears lubricating
Open the Prusa Lubricant. Using the opposite side of the cap, puncture the hole in the opening of the tube.
Apply a small amount of Prusa Lubricant all around the PG-ring and PG-assembly teeth.
Tip: apply a small amount of lubricant to the tip of the zip tie and then spread the lubricant over the gears.
Using a paper towel, wipe off any excess lubricant on the front surfaces.
Gearbox covering
Gearbox covering
Gearbox covering
Gearbox covering
Place the PG-case on the gearbox.
Insert three M3x25 screws into the PG-case, but do not tighten them completely. They will be tightened later.
Close the idler-lever and lock it in position with the idler-swivel.
Nextruder cables connecting
Nextruder cables connecting
Nextruder cables connecting
Plug the load cell sensor cable into the Dwarf board.
Plug the filament sensor cable into the Dwarf board.
Plug the heatsink thermistor cable into the Dwarf board.
Print fan assembly & fitting: parts preparation
Print fan assembly & fitting: parts preparation
Print fan assembly & fitting: parts preparation
For the next steps, please prepare:
Print fan assembly (1x) removed in previous steps
M3x10 screw (3x) removed in previous steps
Fitting QSM-M5 (1x) removed in previous steps
Starting from September 2024, you may receive a new black Fitting M5-4. The assembly and functionality remain identical to the blue one.
Print fan assembly securing
Print fan assembly securing
Print fan assembly securing
Print fan assembly securing
Align the three metal spacers with the holes in the heatsink, make sure the board and fan cables are guided below the top spacer before you attach the heatsink, so that they are not pinched.
Don't pinch any cables!
Insert and secure three M3x10 screws. Don't pinch any cables!
Connect the print fan to the print fan connector.
Fitting securing
Fitting securing
Fitting securing
Starting from September 2024, you may receive a new black Fitting M5-4. The assembly and functionality remain identical to the blue one.
Mount the Fitting QSM-M5 on the top of the heatsink.
Gently tighten the Fitting QSM-M5 with a uni-wrench.
Hotend & nextruder body: parts preparation
Hotend & nextruder body: parts preparation
Hotend & nextruder body: parts preparation
Hotend & nextruder body: parts preparation
For the next steps, please prepare:
Hotend assembly (1x) removed in previous steps
Hotend fan (1x) removed in previous steps
M3x20 screw (2x) removed in previous steps
Nextruder body (1x) removed in previous steps
M3x40 screw (2x) removed in previous steps
Nozzle assembly securing
Nozzle assembly securing
Nozzle assembly securing
Nozzle assembly securing
Insert the heater and the thermistor cable under the heatsink. Look at the picture.
Insert the nozzle into the heatsink and push it all the way into the heatsink.
Rotate the heaterblock as in the picture. There must be approximately 35° - 40° angle to avoid damaging the hotend cables.
Do not use extra force while tightening, it may damage the hotend tube.
Maintain the position and using the TX 8 Torx key carefully tighten the grub screw to secure the hotend.
Nextruder body securing
Nextruder body securing
Nextruder body securing
Close the dwarf-cover-door and turn the Nextruder.
Attach the nextruder-body to the Nextruder.
Insert and secure two M3x40 screws.
Hotend fan securing
Hotend fan securing
Hotend fan securing
Hotend fan securing
Mind the orientation of the fan.
Insert the hotend fan between the heatsink and the extruder body. Look at the picture.
Insert and secure two M3x20rT screws.
Connect the hotend fan cable to the Dwarf board.
Connect the hotend thermistor cable to the Dwarf board.
Connect the hotend heater cable to the Dwarf board.
Dwarf door closing
Dwarf door closing
Dwarf door closing
Close the dwarf-board-cover on the Nextruder.
Gently tighten the screw.
Cable bundle securing
Cable bundle securing
Cable bundle securing
Cable bundle securing
Attach the cable connector into the top of the Nextruder.
Insert the semi-transparent PTFE tube into the fitting on the Nextruder. Push it all the way in.
Hook up the keyhole openings in the flexible plate of the cable bundle onto the screw heads and push it up to correct the position.
Using a T10 key tighten the marked two screws.