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  1. Ensure the printer is turned off and not plugged in. Note your extruder is slightly different, but the principle of setting the height is the same. Don't place the steel sheet on the heatbed during the entire P.I.N.D.A. probe adjustment process. Wait for the Z calibration.
    • Ensure the printer is turned off and not plugged in.

    • Note your extruder is slightly different, but the principle of setting the height is the same.

    • Don't place the steel sheet on the heatbed during the entire P.I.N.D.A. probe adjustment process. Wait for the Z calibration.

    • While moving with the extruder, the X-axis motor works as a generator. You will create a small amount of electricity and the LCD might flicker. Move with the extruder reasonably slowly and in the future always use the printer's controls.

    • Move the extruder manually all the way to the left.

    • By rotating BOTH threaded rods at the same time on the Z-axis move the nozzle until you reach the heatbed. Try rotating both the rods equally!

    • Check again from a different angle the nozzle is touching slightly the heatbed. Don't bend the heatbed!

  2. Move the extruder carefully all the way to the right. Make sure that the nozzle is not scratching the surface during the movement! If it does, rise the right side of the X-axis by rotating the right Z motor slightly clockwise.
    • Move the extruder carefully all the way to the right.

    • Make sure that the nozzle is not scratching the surface during the movement! If it does, rise the right side of the X-axis by rotating the right Z motor slightly clockwise.

    • If an adjustment is needed, you can lower the nozzle height by rotating the right Z motor counter-clockwise.

  3. Move the extruder to the centre of the X-axis. Take a zip tie from the package and place it under the P.I.N.D.A. sensor. Use the middle part of the zip tie, not the tip. Release the screw holding the P.I.N.D.A. sensor and gently press it against the zip tie.
    • Move the extruder to the centre of the X-axis.

    • Take a zip tie from the package and place it under the P.I.N.D.A. sensor. Use the middle part of the zip tie, not the tip.

    • Release the screw holding the P.I.N.D.A. sensor and gently press it against the zip tie.

    • Tighten the screw on the P.I.N.D.A. holder again.

    • !!! DO NOT use glue to fix P.I.N.D.A. probe in the new type of holder with the M3 screw, you won't be able to release it again !!!

    • A correct height of the P.I.N.D.A. sensor compared to the nozzle should be similar to the last picture.

  4. IMPORTANT!!! Before you start downloading and flashing. There are two types of the firmware for the MMU2S. Make sure you can distinguish between them. EINSy/RAMBo firmware: This firmware is flashed to the board, which is inside the black RAMBo box near the heatbed. Use USB type B cable. (e.g. FW_MK3-EINSy10a.hex or FW_MK25-RAMBo13a_cz.hex)
    • IMPORTANT!!! Before you start downloading and flashing. There are two types of the firmware for the MMU2S. Make sure you can distinguish between them.

    • EINSy/RAMBo firmware: This firmware is flashed to the board, which is inside the black RAMBo box near the heatbed. Use USB type B cable. (e.g. FW_MK3-EINSy10a.hex or FW_MK25-RAMBo13a_cz.hex)

    • MMU2 board firmware: This firmware is flashed to the new board, which is inside MMU2 unit on the top of the frame. Use Micro-USB cable. (e.g. prusa3d_fw_MMU2board_1_0_5.hex)

    • Printer and MMU2S unit firmwares are both available to download as one package at prusa3d.com/drivers

    • PrusaSlicer won't let you accidentally flash incorrect firmware to each board.

  5. Firmware updater is now part of the PrusaSlicer.
    • Firmware updater is now part of the PrusaSlicer.

    • Go to prusa3d.com/drivers and select the MK3S/MK2.5S *MMU2S* printer.

    • Find the "Drivers" section and download the latest package.

    • Leave this page opened for the next step!

    • Install drivers on your Windows, macOS or Linux system.

    • Part of the driver's package is PrusaSlicer (previously Slic3r PE), which includes a tool for firmware upgrade.

  6. Go back to prusa3d.com/drivers to get the firmware for your  printer and the MMU2S unit.
    • Go back to prusa3d.com/drivers to get the firmware for your printer and the MMU2S unit.

    • Download the zip file with the firmware for the MMU2S to your computer and unzip it.

    • Note there are two types of the firmware for the MMU2S. One is for the MMU2S unit (top of the frame), the other for printer itself.

    • For the MK3S MMU2S and MK2.5S MMU2S use firmware combo 3.6.0 and 1.0.5 or latest.

    • We will flash the firmware files in the next step. Make sure you have prepared both cables and the printer is turned on.

  7. Open PrusaSlicer and from the menu select Configuration ->Flash Printer Firmware First, select the printer's firmware file on your harddrive (*.hex). Do not place the firmware on a network share. Connect the printer to your computer using the bundled USB Type B cable and select it from the menu. Hit Rescan if the printer is not on the list
    • Open PrusaSlicer and from the menu select Configuration ->Flash Printer Firmware

    • First, select the printer's firmware file on your harddrive (*.hex). Do not place the firmware on a network share.

    • Connect the printer to your computer using the bundled USB Type B cable and select it from the menu. Hit Rescan if the printer is not on the list

    • Hit the Flash button.

    • Wait until the process is completed. You can click on "Advanced: ..." to see the flashing process including detailed log.

    • When the flashing process is done, you will be informed.

    • Now, repeat this step, but this time connect the MicroUSB cable and select the firmware for the MMU2S unit.

    • In case of issues with flashing the firmware please visit our troubleshooting article.

  8. Before you leave PrusaSlicer, please add the MMU2S printer profiles!!! MMU2 and MMU2S G-codes aren't compatible! From the top menu select Configuration -> Configuration Wizard
    • Before you leave PrusaSlicer, please add the MMU2S printer profiles!!!

    • MMU2 and MMU2S G-codes aren't compatible!

    • From the top menu select Configuration -> Configuration Wizard

    • Look for the MMU2S options and select your printer

    • Click Next, then Finish

    • Expand the printer's menu and check if the MMU2S option is present. If not, please repeat the process again.

  9. Now, open the Handbook to check, how to organise the printer, buffer, spools and most importantly: VERY IMPORTANT:  follow the calibration procedure of the IR-sensor, see chapter 7.1 in the Handbook. Also, don't forget to run the Calibrate Z and then 1st layer calibration!
    • Now, open the Handbook to check, how to organise the printer, buffer, spools and most importantly:

    • VERY IMPORTANT: follow the calibration procedure of the IR-sensor, see chapter 7.1 in the Handbook.

    • Also, don't forget to run the Calibrate Z and then 1st layer calibration!

    • More here: 3D Printing Handbook - prusa3d.com/3dhandbookMMU2S

  10. You can start by printing some of our test objects - you can check them out here: prusa3d.com/printable-3d-models You can start by printing some of our test objects - you can check them out here: prusa3d.com/printable-3d-models You can start by printing some of our test objects - you can check them out here: prusa3d.com/printable-3d-models
  11. Did you print all the bundled multi-material models from us? Time to print your own designs!
  12. If you encounter any problems at all, don't forget you can always check out our knowledge base at http://help.prusa3d.com. We're adding new topics every day!
    • If you encounter any problems at all, don't forget you can always check out our knowledge base at http://help.prusa3d.com. We're adding new topics every day!

  13. Don't forget to join the biggest Prusa community! Download the latest models in STL or G-code tailored for your printer. Register at PrusaPrinters.org Looking for an inspiration on new projects? Check our blog with weekly updates. If you need help with the build, check out our forum with great community :-)
    • Don't forget to join the biggest Prusa community! Download the latest models in STL or G-code tailored for your printer. Register at PrusaPrinters.org

    • Looking for an inspiration on new projects? Check our blog with weekly updates.

    • If you need help with the build, check out our forum with great community :-)

    • All services share one account.

  14. That's it, the assembly is over.
    • That's it, the assembly is over.

    • Eat the remaining bunch of bears.

    • We hope, you've enjoyed the build. Don't forget to leave feedback and see you in the next one :)

Finish Line

132 other people completed this guide.

Jakub Dolezal

Member since: 02/20/2017

222 Guides authored

Team

Prusa Research Member of Prusa Research

Community

3 Members

364 Guides authored

23 Comments

Had to open up the MMU before I realised I have the tube numbering wrong. Really lacking a section on the buffer assembly to MM2, especially the tube number front and back on the buffer to MMU.

Parts could be printed have the number next to the hole.

Brendan Seight - Reply

Agreed. All the directions should be in the same place. Not some here and some in the handbook. Not very maintainable.

Jeff Gros -

Having the part number printed next to the hole is a good idea! :)

Jeff Gros -

I agree on the part numbers! Im fracked - madd so I can number them !

David -

My MMU2S does not react to the presence or absence of filaments. The carriage and idler can manually be moved to the correct position (which happens to be # 5; I only have one roll of filament, and that’s where it’s loaded), but no attempt is made to load it.

Manual feeding in/out of the filament causes no reaction from the MMU.

Anders Wallén - Reply

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