⬢This guide will take you through the Print fan replacement on your Original Prusa MK4S or MK3.9S.
⬢All necessary parts are available in our eshop prusa3d.com.
Note that you have to be logged in to have access to the spare parts section.
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- How to replace a print fan (MK4S / MK3.9S)
How to replace a print fan (MK4S / MK3.9S)
Menu
- Printer maintenance
- How to replace a Heatbed Thermistor (MK4/S, MK3.9/S, MK3.5/S)
- How to replace the Prusa Nozzle (MK4S/MK3.9S)
- Filament Guide addon (MK4S/MK4)
- How to replace Loveboard (MK4S/MK4/MK3.9S/MK3.9)
- How to replace a hotend assembly (MK4S / MK3.9S)
- How to replace the silver PSU with the black PSU
- How to install the Nextruder V6 Nozzle Adapter (MK4S/MK3.9S)
- How to replace a print fan (MK4S / MK3.9S)
- 1. Introduction
- 2. Tools necessary for this chapter
- 3. Preparation
- 4. Removing the covers
- 5. Disconnecting the hotend
- 6. Removing the hotend
- 7. Removing the print fan
- 8. Print fan disassembly part 1
- 9. Print fan disassembly part 2
- 10. Print fan blower: parts preparation
- 11. Print fan assembly
- 12. Assembling the fan shroud
- 13. Mounting the print fan blower assembly
- 14. Connecting the print fan blower
- 15. Inserting the hotend assembly
- 16. Connecting the hotend cables
- 17. Attaching the Fan-door-cover
- 18. LoveBoard: Wiring check
- 19. Covering the LoveBoard: top cover
- 20. Finished
How to replace a print fan (MK4S / MK3.9S)
⬢For this chapter, please prepare:
⬢2.5mm Allen key
⬢Torx key T10/8
⬢Before you start, make sure the extruder on your printer is in the middle of both the X and Z axes.
⬢Unload a filament, if it is loaded.
⬢Power off your printer and disconnect it from the power.
⬢Remove the Loveboard-cover from the extruder.
⬢Remove the M3x30 screw holding the Fan-door-hinge part.
⬢Remove the Fan-door-hinge plastic part.
⬢
Disconnect the hotend heater connector.
Dislodge the cable from the groove in the x-carriage part.
Note that there is a safety latch which must be pressed in order to remove the connectors. Proceed carefully to prevent damaging the connectors.
Proceed carefully to prevent damaging the connectors.
⬢
Disconnect the hotend thermistor connector.
Dislodge the cable from the groove in the x-carriage part.
⬢Remove the thumb screws fixing the hotend in place.
⬢Remove the hotend assembly from the extruder.
Be careful not to damage the cables.
⬢Disconnect the print fan connector.
Note that there is a safety latch which must be pressed in order to disconnect the connector.
⬢Dislodge the print fan cable from the groove in the x-carriage part.
⬢Remove the four M3x5rT screws from both sides of the fan-holder.
⬢Remove the print fan assembly from the extruder by sliding it out. Watch out for the cable.
⬢Remove the M3x5rT screw hoding the fan-shroud.
⬢Remove the fan shroud.
⬢Remove the two 3x8sT screws.
⬢Remove the fan-case-cover.
⬢Remove the old print fan and its cable from the plastic part.
⬢For the following steps, please prepare:
⬢New MK4S Print fan blower (1x)
⬢Insert the MK4S print fan blower into the print fan blower case.
⬢Guide the print fan blower cable through the cable channel in the Fan-case.
⬢Close the fan with Fan-case-cover.
⬢Secure the cover with two 3x8sT screws.
Attach the Fan-shroud to the print fan blower assembly. Notice two teeth on the fan shroud and two rectangular holes in the blower assembly.
⬢First, insert those teeth into the rectangular cutouts.
⬢Close the Fan-shroud and secure it with the M3x5rT screw.
Use reasonable force to avoid breaking the parts.
⬢Take the print fan blower assembly and guide the fan cable through the cutout on the left side of the fan holder.
Use the same cutout through which the heatsink fan cable already guides.
⬢Slide the side pockets of the print fan blower assembly onto the two “forks” of the fan holder.
⬢Ensure that the holes of both parts are aligned.
⬢Secure both parts together using four M3x5rT screws.
⬢Guide the print fan blower cable through the cable channel in the X-carriage and plug the connector to the middle slot on the LoveBoard.
⬢Insert two thumb screws into the heatsink. Do not tighten them completely. Two turns are enough for now.
⬢Look closely at the underside of the heatsink and find the hole for the hotend assembly.
⬢Insert the hotend assembly tube in the hole and slide the whole thing into the heatsink.
⬢Push the hotend assembly all the way into the heatsink. There should be approximately a 2 mm gap between the heatsink and the brass part of the nozzle.
⬢While pushing the hotend assembly in, firmly tighten both thumb screws.
Avoid pinching any cable between the screws and the heatsink!
⬢From the underside, check that the hotend is oriented correctly. It must fit between the cutouts in the X-carriage.
⬢Guide the hotend thermistor through the cable channel in the X-carriage and connect it to the LoveBoard.
⬢Guide the hotend heater through the cable channel in the X-carriage and connect it to the LoveBoard.
⬢Attach the Fan-door-cover hinge to its counterpart in the X-carriage. Holes in both parts must be aligned.
⬢Insert the M3x30 screw in the hinge on the fan-door. Fully tighten the screw, then loosen it by a quarter turn. The fan-door must move freely!
Before covering the electronics, check the connection of all cables. Click on high-resolution preview in the top left corner.
⬢Close the idler mechanism if you haven't already done so.
⬢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.
Be careful not to pinch any cables.
⬢Ensure that the two plastic covers fit together perfectly.
⬢The fan replacement is finished. Verify your extruder is assembled as seen in the picture.
⬢To test out the fan functionality, visit the menu Control > Calibrations & Tests > Fan test.
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