Page 1: Table Of Contents
Table of Contents 1. Introduction ........................................Step 1 - Preparing the upgrade kit ................. Step 2 - Getting the necessary tools ..............Step 3 - Additional utilities for this guide ....................Step 4 - Labels guide ......................Step 5 - Spare bag ................
Page 2 ..............Step 24 - Removing the X-axis bearings ..............Step 25 - Removing the X motor pulley ..............Step 26 - For new users of black PSU ..................Step 27 - Parts summary I..................Step 28 - Parts summary II..................
Page 3 ......................Step 18 - Haribo ......................Step 19 - It's done! 3. X-axis & X-carriage assembly ..............................Step 1 - Tools necessary for this chapter ............Step 2 - X-axis assembly: parts preparation ..............Step 3 - Assembling the X-end-motor ..............
Page 4 ..........Step 12 - Assembling the X-axis and smooth rods ..............Step 13 - Installing the X-axis assembly .............. Step 14 - Assembling the trapezoidal nuts .......... Step 15 - Installing the Z-top parts: parts preparation ................Step 16 - Placing the Z-top parts ..............
Page 5 ..............Step 27 - Inserting the hotend assembly ..............Step 28 - Connecting the hotend cables ........Step 29 - Assembling the fan-door: parts preparation ................Step 30 - Assembling the fan door ................Step 31 - Assembling the fan-door .................
Page 6 ..........Step 35 - Guiding the power cables (Silver PSU) ... Step 36 - Power panic extended cable (Silver PSU): parts preparation ........Step 37 - Extending the power panic cable (Silver PSU) ...... Step 38 - Y motor cable adapter (Silver PSU): parts preparation ......
Page 7 ..............Step 40 - Assembling the Y belt holder ............. Step 41 - Assembling the Y belt tensioner ............Step 42 - Assembling the Y belt tensioner ................Step 43 - Tensioning the Y belt ..................Step 44 - Belt tension check ..................
Page 9: Introduction
1. Introduction Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 10: Step 1 Preparing The Upgrade Kit
STEP 2 Getting the necessary tools The package includes: Needle-nose pliers (1x) Philips (PH2) screwdriver (1x) Universal wrench (1x) Wrench size 13 mm (1x) Torx key set Allen key set Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 11: Step 3 Additional Utilities For This Guide
Print it at 100 %, don't rescale it, otherwise, it won't work. For PRUSA veterans: Fasteners are divided into individual bags according to its type. Not into packages for individual chapters, as it was with previous printers. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 12: Step 5 Spare Bag
STEP 6 Printed parts - versioning Most of the 3D printed parts on Original Prusa MK3.9 are marked with their version. E, F and Gx series (e.g. E1) - those parts are printed on Prusa Research farm and are distributed with the kit.
Page 13: Step 7 Printed Parts - Self Printing
For printing individual parts it is recommended to use PrusaSlicer with 0.2 mm layer height, GRID infill at 15 %, no supports! Fan-shroud must be printed from ASA/PC/ABS only!!! We include this part in the upgrade package. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 14: Step 8 Printable Parts - Silver To Black Psu
For this replacement, the following parts need to be printed in addition: PSU-cover (1x) Download the part from xLCD category on prusa.io/printable-parts-mk4 Print the parts according to the prescribed print settings in the description on Printables.com. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 15: Step 9 Printed Parts Post-Processing
Check the parts for straightness. For example, by placing it on a clean table surface. Bent parts can cause problems during installation and subsequent use of the printer. Do not modify any parts unless instructed to do so. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 16: Step 10 We Are Here For You
Lost in the instructions, missing screw or cracked printed part? Let us know! You can contact us using the following channels: Using comments under each step. Using our 24/7 live chat here at help.prusa3d.com Writing an email to info@prusa3d.com Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 17: Step 11 - Pro Tip: Inserting The Nuts
When you browse the guide on help.prusa3d.com, you can view the original images in high resolution for clarity. Just hover your cursor over the image and click the Magnifier button ("View original") in the top left corner. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 18: Step 13 Important: Electronics Protection
Be extra cautious in rooms with carpets, which are often a source of electrostatic energy. Clothes made of wool or certain synthetic fabrics can easily gather static electricity too. It is safer to wear cotton clothing for the assembly. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 19: Step 14 Reward Yourself
Please consult a professional in the closest candy store. Hide the Haribo for now! From our experience an unattended bag with sweets will suddenly disappear. Confirmed by multiple cases all around the World. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 20: Step 15 How To Successfully Finish The Assembly
Use a reasonable force, the printed parts are tough, but not unbreakable. If it doesn't fit, check your approach twice. Most important: Enjoy the build, have fun. Cooperate with your kids, friends or partners. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 21: Step 16 Prepare Your Desk
Prepare something to contain the plastic bags and the removed packing materials so you can recycle them afterwards. Make sure there are no important parts being discarded. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 22: 1A. Parts Check
1a. Parts check Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 23: Step 1 Introduction
Filament is unloaded from the extruder. Spool holder is removed from the printer. Flexible steel sheet is removed from the heatbed. Printer is turned OFF end the power cable is unplugged from the PSU (power supply unit). Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 24: Step 3 Heatbed Inspection
Likewise, if the smooth rods are scratched or the bearing travel on the rods is not smooth (they really stutter), we recommend ordering new LM8UU bearings as well. Buy new LM8UU bearings in our eshop. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 25: Step 5 Y-Axis Smooth Rods Inspection
(bent, broken) with a new one. All parts are available in our eshop. Any scratches and scuffs are of no significance for the upgrade. In this case, it is up to your discretion to replace the parts. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 26: Step 7 Can I Open The Haribo
This dose of energy is primarily for printer assembly. Wait until you are prompted to open it. STEP 8 Let's get started Everything checked? So, let's start with disassembling the printer. Go to the next chapter. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 27: 1B. Printer Disassembly
1b. Printer disassembly Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 28: Step 1 Tools Necessary For This Chapter
2.0 mm Allen key for heatbed screws 2.5mm Allen key for all M3 screws STEP 2 Opening the electronics box Loosen the screw on the Einsy-base. Open the Einsy-door to access the electronics. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 29: Step 3 Disconnecting Cables
From the opposite side of the Einsy-base, locate the screw behind the cooling fins and loosen it, no need to remove it. Grasp the Einsy-base and slide it out of the printer frame. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 30: Step 5 Removing The Einsy-Door
We recommend placing the heatbed temporarily on a piece of clean cloth or other soft pad. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 31: Step 7 Dismantling Cable Management
Carefully remove the LCD cables from the extrusion. Place the printer back on its feet. Release four M3 screws securing the LCD assembly in the front plate. Remove the LCD assembly from the printer. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 32: Step 9 Dismantling The Y-Axis: Removing The Belt
Release and remove two M3 screws securing each Y-rod-holder in the rear plate. Remove the entire Y-axis assembly from the printer. Do not remove any parts from the assembly at this time. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 33: Step 11 - Removing The Z-Axis-Tops
And two zip ties on the underside of the cable-holder. Some MK3 units may have a rubber spiral wrap instead of the textile sleeve. Loosen the M3 screw securing the cable-holder. Remove the cable-holder from the extruder. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 34: Step 13 Removing The X-Axis Assembly
Release four M3 screws from both Z-bottom securing the Z-axis motors. Remove the motors by pulling them out from underneath. Do not discard the Z motors! Keep them aside. You will ned them for the MK3.9 upgrade. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 35: Step 15 Removing The Z-Axis-Bottoms
Loosen both grub screws in the pulley and remove the pulley from the motor. Keep the Y motor for later. The upgrade kit includes a new pulley. Keep this old one aside to avoid mixing them up. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 36: Step 18 Disassembling The Y-Carriage: Belt
MK3 has a different-looking part Y-belt-holder. However, the procedure is the same. The Y-carriage part may differ from the picture depending on your printer model. Remove the belt assembly from the Y-carriage. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 37: Step 19 Dissasembling The Y-Carriage: Rod Holders
New bearings are not part of the MK3.9 upgrade kit. If the bearings have been functioning properly thus far, retain them for the MK3.9 upgrade. However, if they have significant substantial wear, it is advisable to purchase new bearings from our eshop. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 38: Step 21 Disassembling The X-Axis: Removing The Pulley
Note that the screw position may vary depending on the printer model. Release three M3 screws securing the X-axis motor. Pull the X-axis motor and pulley out of the belt and remove it from the X-axis. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 39: Step 24 Removing The X-Axis Bearings
Alternatively, you can use the LM8UU bearings from the X-ends that have not been subjected to so much stress during the printing. However, removing them is more difficult. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 40: Step 26 For New Users Of Black Psu
For new users of black PSU If you've bought the black 24V 240W PSU, visit the dedicated installation guide here:How to replace the silver PSU with the black PSU. Don't forget to get back to this manual afterwards. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 41: Step 27 Parts Summary I
LM8UU bearing (6x) from X and Y-axis The list continues in the next step... STEP 28 Parts summary II. Heatbed assembly (1x) X motor (1x) Y motor (1x) Z motor left (1x) Z motor right (1x) Trapezoidal nut (2x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 42: Step 29 Don't Throw Away
Can I take a gummy bear yet? No gummy bears yet? Please hold We do not want to keep you waiting, but the correct dosage of gummy bears is very important for the whole procedure. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 43: Step 31 Well Done
1b. Printer disassembly STEP 31 Well done Go to the next chapter 1.c Part preparation Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 44: 1C. Parts Preparation
1c. Parts preparation Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 45: Step 1 Tools Necessary For This Chapter
Remove the cover. Release the screws fixing the heatbed power cables and remove the cables from the heatbed. From the underside, grasp the M3nN nuts with the pliers while loosing the screws. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 46: Step 4 New Heatbed Thermistor: Parts Preparation
Pay attention to the instructions! The "yellow" Kapton tape tends to curl up and you won't be able to restore its initial shape!! All the necessary parts can be found in the Heatbed thermistor set bag. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 47: Step 5 Preparing The Heatbed And Thermistor
Peel or bend the tape slightly, to reveal the tip of the thermistor. STEP 6 Covering the thermistor Maintain the thermistor position and cover it with aluminum tape. Ensure that the whole thermistor sensor is covered with the tape. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 48: Step 7 Fixing The Thermistor In Place
Pay great attention to sticking the tape everywhere. Finish gluing the tape to the heatbed. Double-check the entire surface is properly connected. STEP 8 M3nEs nuts: parts preparation For the following steps, please prepare: M3nEs nut (2x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 49: Step 9 Inserting The M3Nes Nuts
Use this method for both M3nEs nuts. The exact position of the nuts doesn't matter at this time. STEP 10 Cable clips: parts preparation For the following steps, please prepare: Cable clip (7x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 50: Step 11 - Installing The Cable Clips
"click" in. STEP 12 Installing the cable clips Install three clips to the long extrusion. Install two clips to the short extrusion. Turn the frame, install two clips to the second short extrusion. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 51: Step 13 Pg-Front-Case: Parts Preparation
Note the correct orientation of the washer. The side of the washer with the three circles must not face up! Otherwise, the planetary gear won't work properly. Make sure the washer is pushed evenly into the printed part. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 52: Step 15 Stickers And Labels: Parts Preparation I
STEP 16 Stickers and labels: parts preparation II. For the following steps, please prepare: All the stickers and labels can be found in the UPDATE STICKERS bag. Safety label (1x) Cleaning pad (1x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 53: Step 17 Xlcd-Cover Sticker (Optional)
Start slowly peeling off the application layer. Lightly press the layer onto the lettering as you peel it off. Observe whether all the letters are glued on. After peeling off the application layer, check that the final look matches the picture. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 54: Step 19 Pg-Case Sticker (Optional)
Start slowly peeling off the application layer. Lightly press the layer onto the lettering as you peel it off. Observe whether all the letters are glued on. After peeling off the application layer, check that the final look matches the picture. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 55: Step 21 Sticking The Serial Number Label
Please note that the following pictures in the manual were taken with a previous (yellow) version of the safety sticker. This is because they were taken before the new sticker was available. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 56: Step 23 Parts Summary I
The list continues in the next step... STEP 24 Parts summary II. Heatbed (1x) X motor (1x) Y motor (1x) Z motor left (1x) Z motor right (1x) Trapezoidal nut (2x) All the parts you printed for the upgrade. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 57: Step 25 Don't Throw Away
Keep them aside to avoid mixing with new parts. STEP 26 Still no sweets? Please don't open the bag yet. But you are getting close to your first taste ;). Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 58: Step 27 That's It
1c. Parts preparation STEP 27 That's it Once you have all of the parts listed, proceed with upgrading your printer. Enjoy the assembly. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 59: Frame Assembly
2. Frame assembly Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 60: Step 1 Tools Necessary For This Chapter
Thermal pad 40x12x2.2 mm (1x) Thermal pad 12x12x2.2 mm (2x) M3x6 screw (9x) M3x10 screw (2x) The list continues in the next step... Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 61: Step 3 Mounting The Xbuddy Box: Parts Preparation
Insert two M3x10 screws into the M3nE nuts in the second short extrusion. Turn them only 3-4 times by using a 2.5mm Allen key, just for the screws to be kept in place. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 62: Step 6 - Mounting The Xbuddy Box
Fully tighten all four M3x6 screws to secure the xBuddy box. Be careful when tightening the "rear" top screw. Use the shorter side of the Allen key for final tightening. Fully tighten both M3x10 screws in the M3nE nuts. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 63: Step 8 Mounting The Xbuddy Board
A few turns are enough for now. Put aside your instinct and leave the hole on the bottom right empty. Fully tighten all five screws. But very carefully, otherwise you can damage the electronics board. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 64: Step 9 Attaching The Zip Ties
Do not discard the X-holder. You will need it later again. Place the printer back on its "feet". STEP 10 Preparing Y-belt-idler (part 1) For the following steps, please prepare: Y-belt-idler (1x) M3x10 screw (2x) M3nS nut (2x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 65: Step 11 - Preparing Y-Belt-Idler (Part 2)
Arrange the frame so that the longer extrusions are facing you. Attach the Y-belt-idler from "inside" to the front plate. Note the correct orientation of the part. Secure the Y-belt-idler with two M3x10 screws. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 66: Step 13 Assembling The Y Motor: Parts Preparation
Ensure you are using the correct motor, there is a label on the bottom of the casing. The reason is, each motor has different cable length. GT2-16 pulley (1x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 67: Step 15 Assembling The Y-Motor-Holder
And align the pulley with the Allen key. When the pulley is aligned, tighten the grub screw in the pulley against the flat part of the shaft. Then rotate the pulley and tighten the second grub screw. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 68: Step 17 Attaching The Y-Motor-Holder
Ensure the correct orientation. The pulley must be facing towards the PSU. Attach the Y-motor-holder by using two M3x10 screws. To keep the Y motor cable safe during the assembly, temporarily hide it in the extrusion on the xBuddy box side. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 69: Step 18 Haribo
Compare the final look of the assembly with the picture. So that was an easy start, wasn't it? Good job anyway! Now, let's play with the next chapter: 3. X-axis & X-carriage assembly Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 70: X-Axis & X-Carriage Assembly
3. X-axis & X-carriage assembly Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 71: Step 1 Tools Necessary For This Chapter
Permanent marker (not included in the kit) STEP 2 X-axis assembly: parts preparation For the following steps, please prepare: X-end-idler (1x) X-end-motor (1x) M3x25 screw (1x) M3x16 screw (4x) M3nS nut (7x) M3n nut (6x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 72: Step 3 Assembling The X-End-Motor
From inside the oval opening, insert the M3nS nut into the X-end-motor. From the side, insert the second M3nS nut into the part. Do not put too much pressure on the nut to avoid damaging the opposite printed wall. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 73: Step 5 Assembling The X-End-Idler
There is no thread in the plastic part, no nut. The screw cuts a thread into the plastic when tightened. Insert and tighten the second M3x16 screw from the "top" side of the part. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 74: Step 7 Assembling The X-End-Idler
From inside the oval opening, insert the M3nS nut into the X-end-idler. STEP 8 Mounting the bearings: parts preparation For the following steps, please prepare: LM10UU linear bearing (2x) X-end-clip (2x) Rubber pad 20x10x1 mm (4x) M3x30 screw (6x) M3x18 screw (2x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 75: Step 9 Mounting The Bearings: Parts Preparation (Lubricating)
It is necessary to lubricate all 4 rows of balls inside the bearing. Open the lubricant and pierce the hole in the tube with the tip in the cap. Screw the tube into the applicator. Carefully slide the entire bearing onto the applicator. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 76: Step 11 - Lubricating The Bearing
STEP 12 Inserting the bearings: X-end-motor Insert and push one LM10LUU bearing all the way into the X-end-motor. Position the bearing like in the picture. The ball rows must be oriented to "X". Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 77: Step 13 Inserting The Bearings: Bearing Pads
Hold the X-end-clip slightly raised from the bottom surface of the X-end-motor. Pushing on the X-end-clip from the top may deform the rubber pads inside the part. Insert four M3x30 screws into the X-end-clip. Tighten the screws diagonally. Tighten the screws completely, but diagonally. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 78: Step 15 Inserting The Bearings: X-End-Idler
Smooth rod 8x370 mm (2x) the longest couple Wipe off the preservative oil from the smooth rods with a paper towel or a piece of cloth. LM8UU bearing (3x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 79: Step 17 Assembling The X-Axis: Marking The Bearings
Prusa lubricant applicator 8mm (1x) Prusa lubricant (1x) for LM8UU bearings Several paper towels to wipe oil and grease from the bearing surface. Each bearing must be lubricated before mounting on the printer. Follow these instructions carefully. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 80: Step 19 Lubricating The Bearing
Wipe off excess grease on the outside of the bearing with a paper towel. Use this procedure for all three bearings. The bearings may leave excess grease on the smooth rods after their installation. Wipe off any residue with a paper towel. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 81: Step 21 Assembling The X-Axis: Inserting Smooth Rods
STEP 22 Assembling the X-axis: mounting the X-end-motor Carefully slide the X-end-motor fully onto both smooth rods. Through the inspection hole check if the smooth rods are in touch with the screw. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 82: Step 23 Assembling The X-Carriage: Parts Preparation
STEP 24 Assembling the X-carriage Locate the protrusions on the X-carriage part and insert three M3nS nuts into the square holes. From the "bottom" of the part, insert five M3nS nuts into the part. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 83: Step 25 Attaching The Spacers
Push two M3x10 screws through the X-carriage From the "front" side of the X-carriage, attach two hex spacers on the protruding M3x10 screws in the same way described in the previous step. Tighten the screws. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 84: Step 27 Assembling The X-Carriage-Clip: Parts Preparation
For the following steps, please prepare: X-carriage-clip (1x) M3x10 screw (4x) Rubber pad 20x10x1 mm (2x) STEP 28 Assembling the X-carriage-clip Place two rubber pads into the rectangular pockets inside the X- carriage-clip. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 85 Rotate both bearings so that the marking is facing you (down). Cover the bearings with the X-carriage-clip and secure it by four M3x10 screws. Do not fully tighten the screws at the moment. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 86: Step 30 Attaching The X Motor: Parts Preparation
Make sure that the "tension" screw on the X motor side does not fall out during handling. Position the motor so that the screws are at the inner end of the oval holes. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 87: Step 32 Attaching The X Motor: Mounting The Pulley
Rotate the pulley and tighten the second grub screw. STEP 33 Guiding the X belt: parts preparation For the following steps, please prepare: X belt (1x) Pin H8 2.9x20 (1x) GT2-20 Idler pulley (1x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 88: Step 34 Guiding The X Belt: X-End-Idler
Allen key. Push the "lower" end of the belt through the belt channel in the X-carriage. Guide the belt through the X-end-motor around the pulley and back to the X- carriage. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 89: Step 36 Guiding The X Belt: X-Carriage
After you ensure that the movement is smooth, fully tighten the screws on the X- carriage-clip in this order: Upper left screw Lower right screw Upper right screw Lower left screw Move the X-carriage several times to both sides and check the movement is still smooth. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 90: Step 38 Haribo
"little rubber bears" in German. STEP 39 It's done! Compare your assembly with the picture. Everything is OK? Nice job, you just successfully assembled the X-axis assembly. Let's go the next chapter: 4. Z-axis assembly Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 91: Z-Axis Assembly
4. Z-axis assembly Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 92: Step 1 Tools Necessary For This Chapter
Tools necessary for this chapter For this chapter, please prepare: 2.5mm Allen key Needle-nose pliers STEP 2 Assembling the Z-bottoms: parts preparation For the following steps, please prepare: Z-bottom left (1x) Z-bottom right (1x) M3x10 screw (6x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 93: Step 3 Assembling The Z-Bottoms
Z motor left (shorter cable) use the one you removed from the printer Z motor right (longer cable) use the one you removed from the printer M3x10 screw (8x) Rubber pad 42x42x2 mm (2x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 94: Step 5 Attaching The Rubber Pads
The motor cables must guide under the frame to the PSU (right) and xBuddy Box (left). Push each motor through the Z-bottom and secure it with four M3x10 screws. Do not tighten them completely at the moment. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 95: Step 7 Z Motor Cable Adapter: Parts Preparation
Motor cable adapter (2x) STEP 8 Connecting the Z motor cable adapters Guide both the Z motor cables under the frame towards the xBuddy Box. Plug both Z motor connectors to the motor cable adapters. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 96: Step 9 Connecting The Z Motors
STEP 10 Mounting the X-axis assembly: parts preparation For the following steps, please prepare: Trapezoidal nut (2x) M3x10 screw (4x) Smooth rod 10 x 325 mm (2x) X-holder (1x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 97: Step 11 Mounting The X-Axis And Smooth Rods
It is important to place the X-holder at the center of the frame and the X-axis. If not, the centering results could be inaccurate. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 98: Step 13 Installing The X-Axis Assembly
There may be a small gap between the trapezoidal nut and the printed part. Tightening the two screws will cling the nut completely to the part. In the same way, install the second trapezoidal nut on the X-end-motor (left threaded rod). Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 99: Step 15 Installing The Z-Top Parts: Parts Preparation
Repeat this step on the other side of the frame with Z-top-right printed part. Rotate both threaded rods in parallel to move the X-axis assembly a few centimeters higher to release the X-holder. Remove the X-holder from the printer. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 100: Step 17 Loveboard: Parts Preparation
Move the X-carriage approximately to the center of the X-axis. From the back of the printer, guide the extruder main cable to the front of the printer through the gap between the belt and the upper rod. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 101: Step 19 Connecting The Extruder Main Cable
Very gently pull on the extruder main cable bundle to reduce the bundle on the connector side. There must be a minimal loop. Otherwise, the cable will interfere with other parts in the next chapter. The cables must not interfere with the extruder motor compartment. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 102: Step 21 Connecting The Extruder Main Cable: Parts Preparation
Push the M3x40 screw through the X-carriage-cable-holder. Attach the X-carriage-cable-holder to the X-carriage underneath the extruder main cable and tighten the M3x40 screw. Do not pinch any wire of the extruder main cable! Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 103: Step 23 Covering The X-Carriage: Parts Preparation
After the nylon filament holds in the X-carriage, check that it inclines upwards as seen in the picture. If it is pointing down instead, re-install the nylon filament into the X-carriage by the other bent end and check again. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 104: Step 25 Attaching The X-Cover-Back
Place the X-carriage-back on the X-carriage and arrange the main cable wires like in the picture. Be careful, no wire must be pinched! Secure the X-carriage-back with two M3x18 screws. Insert and tighten the M3x10 screw into the upper hole in the X-carriage-back. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 105: Step 26 Guiding The Main-Cable: Parts Preparation
The ends of the textile sleeves are heat-sealed at the factory to prevent ripping. To open them, the sealed end joints must be cut or torn. Zip tie (2x) X-carriage-cable-holder-cover (1x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 106: Step 27 Wraping The Extruder Main Cable
Wrap the textile sleeve around the extruder main cable and nylon filament. Proceed in a spiral motion around the bundle so that it is tightly bound together. Hold the cable bundle upwards while wrapping and continue until it is fully wrapped. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 107: Step 29 Ext-Cable-Holder: Parts Preparation
Ext-cable-holder-a (1x) Zip-tie (1x) M3x18 screw (2x) M3x10 screw (2x) M3nS nut (2x) The list continues in the next step... STEP 30 Ext-cable-holder: parts preparation Textile sleeve 5x300 mm (1x) Motor cable adapter (1x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 108: Step 31 Wrapping The X Motor Cable
Insert two M3nS nuts all the way into the Ext-cable-holder-a. Take the bent end of the nylon filament. And locate the hole in the Ext-cable- holder-a. Push the bent part of the nylon filament into the hole in the Ext-cable-holder-a. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 109: Step 33 Assembling The Ext-Cable-Holder
Cover the cables with the Ext-cable-holder-b and secure it with two M3x18 screws. Secure the Ext-cable-holder together with the zip tie in the groove. Tighten up the zip tie and cut off the excess of the zip tie. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 110: Step 35 Connecting The X Motor Cable Adapter
Leave the cables free in the xBuddy box for now. We will connect them later on. According to the third picture, compare the guiding of the extruder main cable. Note the curve of the cable guide. Compare the guiding of the X motor cable. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 111: Step 37 Reward Yourself
Here it is! Compare your build with the picture. Everything is right? Congratulations! You have successfully assembled the Z-axis with some other small things. So, let's continue with the next chapter: 5. Nextruder assembly Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 112: Nextruder Assembly
5. Nextruder assembly Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 113: Step 1 Tools Necessary For This Chapter
For the following steps, please prepare: Nextruder heatsink (1x) Hall filament sensor (1x) Prusa ball holder (1x) Magnet 3x3x3 mm (1x) Spring 3x9 mm (1x) smaller one Steel ball 4 mm (1x) M2.5x6rT screw (1x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 114: Step 3 Assembling The Filament Sensor
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. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 115: Step 5 Nextruder Idler Assembly: Parts Preparation
Both bearings must be able to rotate without significant resistance. From the same side, push the tubular spacer into the assembly. The "bottom" of the tubular spacer must be flushed with the bottom part of the Idler assembly. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 116: Step 7 Assembling The Extruder: Parts Preparation I
PG-ring (1x) The list continues in the next step... STEP 8 Assembling the extruder: parts preparation II. Extruder motor (1x) M3x25 screw (3x) Spacer 5x10x0.1 mm (1x) Socket set screw M3x25 (1x) Lubricant (1x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 117: Step 9 Assembling The Extruder
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. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 118: Step 11 - Assembling The Pg-Ring
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. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 119: Step 13 Checking The Pg-Assembly
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. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 120: Step 15 Covering The Planetary Gear
For the following steps, please prepare: Idler-nut (1x) Idler-swivel (2x) M3x30 screw (2x) M3x20rT screw (2x) M3nN nut (2x) Spring 15x5 (2x) Spacer 6x3.1x8 (1x) In some older packages this part is called "Spacer 5.5 mm". Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 121: Step 17 Assembling The Idler-Swivel
Secure both parts together by inserting the M3x20rT screw from the same side, like the first screw. Secure the screw with M3nN nut. Do not overtighten the nut. It must be possible to move with the Idler-swivel on the Idler-nut. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 122: Step 19 Mounting The Idler-Swivel Assembly
STEP 20 Attaching the extruder: parts preparation For the following steps, please prepare: Thumb screw (2x) M3x10 screw (3x) M3x4T grub screw (1x) NTC thermistor 90 mm (1x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 123: Step 21 Assembling The Heatsink
There is a cutout in the plastic part. Guide the thermistor cable through this cutout. DO NOT PINCH ANY OF THE CABLES! 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. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 124: Step 23 Connecting The Ntc Thermistor
Guide the NTC thermistor through the cable channel in the X-carriage up to the LoveBoard slot. STEP 24 Assembling the hotend fan: parts preparation For the following steps, please prepare: Hotend fan (1x) M3x18 screw (2x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 125: Step 25 Assembling The Hotend Fan
Guide the fan cable between the thumb screws under the cable channel up and connect it to the lower slot on the LoveBoard. STEP 26 Inserting the hotend assembly: parts preparation For the following steps, please prepare: Hotend assembly (1x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 126: Step 27 Inserting The Hotend Assembly
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. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 127: Step 29 Assembling The Fan-Door: Parts Preparation
Keep a small gap between both parts. Turn (close) the fan around and attach it to the fan-door by using two M3x6 screws. Pull the fan cable very gently to reduce the slack as much as possible. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 128: Step 31 Assembling The Fan-Door
Be careful that the magnets do not stick together, it will be difficult to separate them. Mark the sides that are attracted to each other with a permanent marker. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 129: Step 33 Assembling The Fan-Door
Attach the fan-door hinge into 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! Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 130: Step 35 Connecting The Extruder Cables
Connect the filament sensor cable to the lower slot on the right side of the LoveBoard. STEP 36 Connecting the print fan Connect the print fan cable to the middle slot on the left side of the Loveboard. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 131: Step 37 Loveboard: Wiring Check
Close the extruder idler to the extruder Close the idler-swivel and lock it over the extruder idler assembly STEP 38 Covering the LoveBoard: parts preparation For the following steps, please prepare: LoveBoard-cover (1x) LoveBoard-cover-right (1x) M3x10 screw (1x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 132: Step 39 Covering The Loveboard
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. Be careful not to pinch any cables. Ensure that the two plastic covers fit together perfectly. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 133: Step 41 Tensioning The X-Axis Belt
For the optimal performance, the belt must be a bit harder to press with your fingers. Move the extruder all the way to the X-end-idler and try the belt tension in the middle of the X-axis. When you achieve optimal tension, please tighten the screws again. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 134: Step 42 Belt Tension Check
If the belt is stretched properly, you should feel a resistance and the extruder won't move at all. If the belt is too loose, it will deform (create a "wave") and jump over the teeth on the pulley. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 135: Step 44 Haribo Time
But don't do that now. STEP 45 The extruder is assembled That was tough. But we made it! Let's go the next chapter: 6. xLCD assembly Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 136: Xlcd Assembly
6. xLCD assembly Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 137: Step 1 Tools Necessary For This Chapter
For the following steps, please prepare: xLCD (1x) Remove the protective film from the xLCD screen. xLCD-cover (1x) xLCD-support-right (1x) xLCD-support-left (1x) xReflector sticker set (1x) The list continues in the next step... Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 138: Step 3 Xlcd Assembly: Parts Preparation (Part 2)
This is because we have used the identical steps and photos from the MK4 assembly instructions. STEP 4 xLCD assembly: inserting the square nuts Insert two M3nS nuts into the xLCD-support-left and xLCD- support-right. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 139: Step 5 Installing The Xreflector Sticker
Note the recess for the xLCD-support-right in the xLCD-cover. The support must perfectly fit into the recess. Make sure the hook on the xLCD-support-right holds onto the xLCD now. Otherwise, you won't be able to attach it later. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 140: Step 7 Installing The Pe Faston
Maintain the position and secure the PE Faston with the M3x8 screw. STEP 8 Assembling the xLCD-support-left Attach the xLCD-support-left on the xLCD board and align it with two holes in the board. Secure both parts together with two M3x8 screws. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 141: Step 9 Xlcd Cables: Parts Preparation
Make sure the xLCD cable is connected in the same orientation as seen in the picture. Otherwise, your display won't work Take the end of the PE cable with square connector. Slide the connector onto the PE Faston all the way down. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 142: Step 11 - Attaching The Knob
Attach the xLCD assembly onto the front plate. The screws should fit into the corresponding openings in the xLCD assembly. Guide the xLCD and PE cables under the front plate to the frame. Tighten up all four screws. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 143: Step 13 Guiding The Xlcd Cable
Select the appropriate instructions for your PSU before proceeding: Black PSU - go to Connecting the PSU (Black PSU): parts preparation follow the instructions. Silver PSU - go to PE cable (Silver PSU): parts preparation and follow the instructions. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 144: Step 15 Connecting The Psu (Black Psu): Parts Preparation
Secure the cable by re-using the screw together with the washer. Note the correct orientation of the PE cable connector. Guide the PE cable so that it does not interfere with the threaded column under the PE connector. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 145: Step 17 Power Cables Info (Black Psu)
The red cable (positive) may have a black stripe on it. Similarly, the black cable (negative) can have a red stripe on it. Do not connect any cables yet, wait until you have prompted. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 146: Step 18 Connecting The Psu (Black Psu)
Check all the connections again! The red wire is in the first slot and black in the third. Make sure that cables are tightened properly. Otherwise, there is a risk of a damage to the printer and its surroundings! Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 147: Step 19 Connecting The Power Panic (Black Psu)
Start tightening the zip tie so it is snug and holds the wires on both sides. Be careful not to over-tighten the zip tie as it could damage the wires. Cut off the remaining part of the zip tie very carefully. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 148: Step 21 Guiding The Power Cable Bundle (Black Psu)
Leave it free for now. Guide the PE cable from the xLCD through the cutout in the frame and include it in the cable bundle. Secure the cable bundle with the zip tie. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 149: Step 23 Y Motor Cable Adapter (Black Psu): Parts Preparation
Connect the Y motor cable to the second slot from the left on the top of the xBuddy. STEP 25 Connecting the PSU cable (Black PSU): parts preparation For the following steps, please prepare: Power terminal screw 6-32 (4x) M3x6 screw (1x) M3w washer (1x) Zip tie (3x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 150: Step 26 Connecting The Psu Cables (Black Psu): Pe Cable
Verify the correct placement of the cables comparing it to the picture. This is crucial! Incorrect wiring may cause damage to your printer! The following instructions are for the silver PSU. Go to Securing the PSU cables Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 151: Step 28 Psu - Pe Cable (Silver Psu): Parts Preparation
Zip tie (5x) STEP 29 Inserting M3nEs nut (Silver PSU) From the inner PSU side of the short extrusion, insert the M3nEs nut between two cable clips. The exact position of the nut doesn't matter. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 152: Step 30 Guiding The Pe Cable (Silver Psu)
Attach the joint of cables to the M3nEs nut in the extrusion profile and secure it by fully tightening the M3x6 screw. The free extended PE cable must be in the left position and lead freely outside the printer. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 153: Step 32 Connecting The Extended Pe Cable (Silver Psu)
Start tightening the zip tie so it is snug and holds the wires on both sides. Be careful not to over-tighten the zip tie as it could damage the wires. Cut off the remaining part of the zip tie very carefully. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 154: Step 34 Guiding The Power Cable Bundle (Silver Psu)
Leave it free for now. Guide the PE cable from the xLCD through the cutout in the frame and include it in the cable bundle. Secure the cable bundle with the zip tie. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 155: Step 36 Power Panic Extended Cable (Silver Psu): Parts Preparation
However, specific instructions will be provided if there are differences for the silver PSU. Pre-screw three 3/32 PT screws into the terminals on the xBuddy board. Do not tighten the screws completely, 3-5 turns will be sufficient. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 156: Step 38 Y Motor Cable Adapter (Silver Psu): Parts Preparation
Connect the X motor cable to the first slot from the left on the top of the xBuddy. Connect the Y motor cable to the second slot from the left on the top of the xBuddy. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 157: Step 40 Connecting The Pe Cable (Silver Psu)
Secure all power cable connectors with the terminal screws. Tighten the screws firmly. Verify the correct placement of the cables comparing it to the picture. This is crucial! Incorrect wiring may cause damage to your printer! Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 158: Step 42 Connecting The Power Panic Cable (Silver Psu)
Secure all cable paths with the zip tie to the cable clip. See the detail showing how to push a zip tie through the cable clip. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 159: Step 44 Guiding The Z Motor Left Cable
Arrange the xLCD cable like in the picture. The xLCD must covering the cable bundle. Tighten the cable bundle with the first two zip ties in the bottom of the xBuddy box. Do not overtighten the zip ties! Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 160: Step 46 Connecting The Extruder Main Cable
It was almost like rocket science, but you did it! Take six gummy bears. Did you know that some gummy bear manufacturers offer sugar-free versions of the candy, which are sweetened with artificial sweeteners like maltitol or stevia. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 161: Step 48 Almost There
Almost there! Wasn't as hard, right? You are almost there! Just compare the xLCD assembly and the cable management to the pictures. Let's go the next chapter: 7. Y- carriage & Heatbed assembly Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 162: Y-Carriage & Heatbed Assembly
7. Y-carriage & Heatbed assembly Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 163: Step 1 Tools Necessary For This Chapter
7. Y-carriage & Heatbed assembly STEP 1 Tools necessary for this chapter For this chapter, please prepare: 1.5mm Allen key 2.0 mm Allen key 2.5mm Allen key Torx T8/10 key Needle-nose pliers Phillips screwdriver PH2 Universal wrench Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 164: Step 2 Heatbed Cable Assembly: Parts Preparation
The one on the left with "GND" sign must be connected to the BLACK WIRE. Take both Heatbed cables. Note the label on each cable. For the following steps, prepare the ends of the cables without the label. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 165: Step 4 Heatbed Cable Assembly (Part 2)
Press them gently, but leave a gap between them. Now, tighten both screws firmly using the Allen key and the wrench. Maintain the position of the connectors while tightening. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 166: Step 6 Covering The Heatbed Cables: Parts Preparation
M3x10 screw (3x) M3n nut (3x) Textile sleeve 5x350 (1x) STEP 7 Assembling the heatbed-cable-cover-bottom Insert three M3n nuts into the shaped openings in the heatbed- cable-cover-bottom. Use the screw pulling technique. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 167: Step 8 Assembling The Heatbed-Cable-Cover: Nylon Filament
Assembling the heatbed-cable-cover-bottom Slide the cable-cover-bottom under the heatbed cable connectors (M3nN nuts). See the correct orientation in the picture. Secure the cover with the M3x10 screw from the top. Tighten the screw firmly. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 168: Step 10 Assembling The Heatbed-Cable-Cover-Top
Make sure there is no big gap between both covers. STEP 11 Wrapping the textile sleeve Finish wrapping the cable bundle in the textile sleeve. And twist the sleeve, not the cables. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 169: Step 12 Y-Carriage Variations
(old). STEP 13 Y-carriage (old): parts preparation LM8UU bearing (3x) Y-carriage (1x) Bearing clip (3x) Rubber bearing pad 31x16x0.5 mm (3x) M3x12 screw (6x) Plastic bearing pad 31x16x1 mm (3x) M3nN nut (6x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 170: Step 14 Y-Carriage (Old): Parts Preparation (Lubricating)
It is necessary to lubricate all 4 rows of balls inside the bearing. Open the lubricant and pierce the hole in the tube with the tip in the cap. Screw the tube into the applicator. Carefully slide the entire bearing onto the applicator. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 171: Step 16 Lubricating The Bearing (Old)
Insert the plastic bearing pad on the screws. Repeat the same for the remaining two bearing clips. The order of the pads is crucial. Check the order on all three bearing clips. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 172: Step 18 Installing The Bearing On The Y-Carriage (Old)
We will tighten the screws firmly later on. Using the 2.5mm Allen key and the universal wrench, slightly tighten the M3nN nuts. Do not tighten it completely, just secure the bearing orientation and position. We will completely tighten it later. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 173: Step 20 Installing The Bearings On The Y-Carriage (Old)
Do not tighten it completely, just secure the bearing orientation and position. We will completely tighten it later. STEP 21 Y-axis: smooth rods holders (old) For the following steps, please prepare: Y-rod-holder (4x) M3x10 screw (12x) M3nS nut (12x) Smooth rod 8x330 (2x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 174: Step 22 Inserting Smooth Rods Into Y-Carriage (Old)
After the final tightening, the movement of the smooth rods must be gentle. If the smooth rod moves stiffly, loosen the screws and repeat the procedure. Now, please go to step Preparing Y-rod-holder. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 175: Step 23 Y-Carriage: Parts Preparation (New)
Prusa lubricant applicator (1x) Prusa lubricant (1x) for LM8UU bearings Several paper towels to wipe oil and grease from the bearing surface. Each bearing must be lubricated before mounting on the printer. Follow these instructions carefully. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 176: Step 25 Lubricating The Bearing (New)
Wipe off excess grease on the outside of the bearing with a paper towel. Use this procedure for all three bearings. The bearings may leave excess grease on the smooth rods after their installation. Wipe off any residue with a paper towel. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 177: Step 27 Assembling The Bearing Clips (New)
Installing the bearing on the Y-carriage (new) Note the three pockets for bearings in the Y-carriage. Start with the side with the one pocket. Attach the bearing clip on the cutout. Insert the bearing into the bearing clip. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 178: Step 29 Aligning The Bearing (New)
Maintain the bearing's position and slightly tighten the screws. Just barely to maintain the position and orientation of the bearings. We will tighten the screws firmly later on. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 179: Step 31 Y-Axis (New): Smooth Rods Holders
Tighten the screws on each bearing clip. After the final tightening, the movement of the smooth rods must be gentle. If the smooth rod moves stiffly, loosen the screws and repeat the procedure. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 180: Step 33 Preparing Y-Rod-Holder
Check the correct position of the Y-rod-holders. The screw hole must be facing up and towards the center of the Y-carriage (see the picture). Repeat for the remaining Y-rod-holders. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 181: Step 35 Installing The Y-Carriage
Move the Y-carriage back and forth across the entire length of the smooth rods to align them. Then move the carriage to the front plate and tighten all screws in the front-Y- holders. Move the Y-carriage to the rear plate and tighten all screws in the back-Y-holders. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 182: Step 37 Assembling The Y Belt: Parts Preparation
(a few turns are enough). Do not tighten the screw, pull the nut all the way into the Y-belt-holder. Don't forget to remove the M3x40 screw from the part and keep it aside for later use. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 183: Step 39 Assembling The Y Belt
Guide the Y-axis belt around the Y-axis motor pulley. Make sure the belt is inside the frame, not under! Take the free end of the Y belt guiding from the pulley and push it into the groove in the Y-belt-tensioner. Secure it with the M3x10 screw. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 184: Step 41 Assembling The Y Belt Tensioner
M3x10 screw. Do not overtighten the screw. We will adjust the exact position later on. Insert the M3x40 screw into the Y-belt-tensioner and tighten it until the screw reaches the nut in the second part. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 185: Step 43 Tensioning The Y Belt
The belt tuner app was tested on multiple phones and should work across all most common phone manufacturers. However, in some rare cases it might not work as expected. Please state your brand and model in the comments below the step. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 186: Step 45 Aligning The Y Belt
Note: If you need to readjust the belt position, don't forget to check the belt tension once again. STEP 46 Installing the Expansion joints: parts preparation For the following steps, please prepare: Expansion joint (8x) M3x6r screw (8x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 187: Step 47 Preparing The Expansion Joints
Proceed the same for the rest of the expansion joints. OLD Y-CARRIAGE: On the old Y-carriage without the recesses, maintain the correct position and orientation of the expansion joint using the universal wrench while tightening. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 188: Step 49 Attaching The Heatbed: Parts Preparation
Put the heatbed on the Y-carriage and secure it by the M3x14bT. Do not fully tighten the screw yet. Insert the M3x4bT screws into the remaining holes in the heatbed. Do not fully tighten the screws yet. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 189: Step 51 Tightening The Heatbed
Last four screws (corners) Tighten the screws gently, but firmly. STEP 52 Guiding the heatbed cables: parts preparation For the following steps, please prepare: Heatbed-cable-holder (1x) M3x6 screw (2x) Power terminal screw 6/32" (2x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 190: Step 53 Guiding The Heatbed Cables
Connect the heatbed thermistor cable to the xBuddy board. STEP 54 Covering the heatbed cables Attach the heatbed-cable-holder to the xBuddy box. The cable bundle must be pointing up. Secure it by tightening both M3x6 screws firmly. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 191: Step 55 Verify All Connections Once More
Otherwise, there is a risk of damage to the printer! STEP 56 Installing the ESP module: parts preparation For the following steps, please prepare: ESP-01S Wi-Fi module (1x) packed in black plastic packaging M3x6 screw (1x) Wifi-cover (1x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 192: Step 57 Installing The Esp Module
Cover the ESP module with the wifi-cover. Secure it with the M3x6 screw. STEP 58 Covering the xBuddy box: parts preparation For the following steps, please prepare: xBuddybox-cover (1x) M3x6 screw (4x) El-box-cover (1x) M3x10 screw (2x) Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 193: Step 59 Covering The Xbuddy Box
Secure the el-box-cover by tightening both M3x10 screws to the xBuddy box. STEP 60 Covering the xBuddy box Align the xBuddy box cover with the xBuddy box and secure it with four M3x6 screws. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 194: Step 61 Assembling The Double Spool Holder (Part 1)
(towards you). It should take about half the turn to lock the part in place. The assembly requires a very small force (torque). If you experience issues, check first the locking mechanism for obstacles. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 195: Step 63 Assembling The Filament Guide: Parts Preparation
Insert the two PTFE tubes into the marked openings. Fix the tubes in place with two M3x10 screws from the other side. Insert the third M3n nut into the opening on the side. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 196: Step 65 Filament Guide Assembly (Part 2)
STEP 66 Haribo time! Eat another five gummy bears. Did you know that the bright colors of gummy bears are achieved through the use of food coloring, which adds to their visual appeal. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 197: Step 67 That's It
7. Y-carriage & Heatbed assembly STEP 67 That's it That was tough. But you made it! Let's move to the last chapter: 8. Preflight check Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 198: Preflight Check
8. Preflight check Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 199: Step 1 Attaching The Steel Sheet
#1 cause of prints detaching from the print surface is a greasy steel sheet. IPA (Isopropyl alcohol) to degrease it if you have touched its surface before. We are using a steel sheet with a smooth surface. However, the same procedure applies to other variants. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 200: Step 2 Firmware Update (Part 1)
If the "New firmware available" screen appears, hit FLASH by pressing the rotary knob to upgrade to the latest firmware. If no such message appears, the printer is running the latest firmware already. Proceed to the next step. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 201: Step 4 Wizard - Selftest Start
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. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 202: Step 6 Wizard - Gearbox Alignment
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. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 203: Step 8 Wizard Complete
Did you know that Haribo gummy bears are one of the most important parts of the Original Prusa printers assembly instructions. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 204: Step 10 Loading A Filament
The printer is now ready to print! You can start by printing some of our test objects from the bundled USB drive. The sample objects are also available on the official Prusa Research Printables profile Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 205: Step 12 - Prusaslicer For Mk3.9
Open the PrusaSlicer app. If you’re running it for the first time, Configuration Wizard will show up. Visit the Prusa FFF tab in the Wizard, select Original Prusa MK3.9 in the 0.4mm nozzle version (the default nozzle size) and hit Finish to start using the MK3.9 printer profile.
Page 206: Step 14 Quick Guide For Your First Prints
Looking for inspiration on new projects? Check our blog for weekly updates. If you need help with the build, check out our forum with a great community :-) All Prusa services share one user account. Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 207: Manual Changelog Mk3.9 Upgrade
Manual changelog MK3.9 upgrade Original Prusa i3 MK3/MK3S/MK3S+ to MK3.9 upgrade...
Page 208: Step 1 Version History
Manual changelog MK3.9 upgrade STEP 1 Version history Versions of the MK3.9 manual: 09/2023 - Initial version 1.0...
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This manual is also suitable for:

I3 mk3s I3 mk3.9

Original Prusa i3 MK3 Manual

1 Introduction

1A. Parts Check

1B. Printer Disassembly

1C. Parts Preparation

2 Frame Assembly

3 X-Axis & X-Carriage Assembly

4 Z-Axis Assembly

5 Nextruder Assembly

6 Xlcd Assembly

7 Y-Carriage & Heatbed Assembly

Quick Links

Table of Contents

Related Manuals for Original Prusa i3 MK3

Summary of Contents for Original Prusa i3 MK3