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  1. 2.5mm Allen key for M3 screws
    • 2.5mm Allen key for M3 screws

    • 2mm Allen key for nut alignment

  2. For MK2.5 there is a redesigned RAMBo cover case and door. In the following steps we will remove the older parts completely. Proceed with caution, as you might break the cables. MAKE SURE you won't mix old and new parts!!! Their design is sometimes similar. Using 2.5mm Allen key, remove the M3x10 screw together with the upper hinge.
    • For MK2.5 there is a redesigned RAMBo cover case and door. In the following steps we will remove the older parts completely. Proceed with caution, as you might break the cables.

    • MAKE SURE you won't mix old and new parts!!! Their design is sometimes similar.

    • Using 2.5mm Allen key, remove the M3x10 screw together with the upper hinge.

    • Remove to the RAMBO cover door.

    • Using 2.5mm Allen key, remove the M3x10 screw together with the lower hinge.

  3. Release upper two M3x10 screws holding the RAMBo board together with the RAMBo cover. Release lower two M3x10 screws holding the RAMBo board together with the RAMBo cover.
    • Release upper two M3x10 screws holding the RAMBo board together with the RAMBo cover.

    • Release lower two M3x10 screws holding the RAMBo board together with the RAMBo cover.

  4. Slightly release two M3x10 screws holding the RAMBo cover on the frame. DO NOT unscrew them completely!!! Carefully slide the RAMBo cover from the frame. Plugged cables won't allow you more than few centimetres. Separate the cover from the RAMBo board.
    • Slightly release two M3x10 screws holding the RAMBo cover on the frame. DO NOT unscrew them completely!!!

    • Carefully slide the RAMBo cover from the frame. Plugged cables won't allow you more than few centimetres.

    • Separate the cover from the RAMBo board.

  5. In order to match the wrapping style of the printer, an extra textile sleeve is included for the X-axis motor cable. You can remove the spiral wrap and replace it with the textile sleeve, or leave the wrap in place. It is up to you, this step is optional ;) For the following step, please prepare: Textile sleeve 6 x 300 mm (1x)
    • In order to match the wrapping style of the printer, an extra textile sleeve is included for the X-axis motor cable. You can remove the spiral wrap and replace it with the textile sleeve, or leave the wrap in place. It is up to you, this step is optional ;)

    • For the following step, please prepare:

    • Textile sleeve 6 x 300 mm (1x)

    • Zip tie (1x)

    • Wrap the sleeve around the X-axis motor and endstop cable. The sleeve is shorter, than both cables.

    • Secure the sleeve using a zip tie, you have to tighten the zip tie firmly and it is only a temporary fix until the Einsy case is assembled, but you can leave the zip tie in place afterwards.

    • Note the rest of this chapter was photographed with the spiral wrap, but the assembly procedures are the same for the textile sleeve.

  6. For the following steps, please prepare:
    • For the following steps, please prepare:

    • RAMBo-cover-base (1x)

    • M3n nut (4x)

    • M3x10 screw (4x)

  7. Insert four M3n nuts in nut traps. Slide RAMBo inside the base and tighten it with four M3x10 screws.
    • Insert four M3n nuts in nut traps.

    • Slide RAMBo inside the base and tighten it with four M3x10 screws.

    • Tighten the screws carefully, you can damage the board.

    • Use the needle nose pliers to help with positioning the screws.

  8. Push the spiral wrap in the slot and leave some slack of the cable along the board (don't stretch the cable). See the slots on the printed part, which will be used for the M3x10 screws (those are already on the frame).
    • Push the spiral wrap in the slot and leave some slack of the cable along the board (don't stretch the cable).

    • See the slots on the printed part, which will be used for the M3x10 screws (those are already on the frame).

    • Slide the RAMBo-cover-base on the prepared M3x10 screws and align it with the edge of the Z-axis frame.

    • Using 2.5mm Allen key tighten both screws.

  9. For the following steps, please prepare:
    • For the following steps, please prepare:

    • RAMBo-cover-door (1x)

    • RAMBo-cover-hinge-top (1x)

    • RAMBo-cover-hinge-bottom (1x)

    • M3nS nut (1x)

    • M3x10 screw (2x)

  10. Insert M3nS nut all the way in. You can use the small screw driver to push it down if needed. Check the proper alignment with the Allen key.
    • Insert M3nS nut all the way in. You can use the small screw driver to push it down if needed.

    • Check the proper alignment with the Allen key.

  11. Take the RAMBo-cover-hinge-bottom and push M3x10 screw through. Note there is a cutout for the screw's head in the printed part.
    • Take the RAMBo-cover-hinge-bottom and push M3x10 screw through.

    • Note there is a cutout for the screw's head in the printed part.

    • Place the hinge on the frame and tighten the screw. The hinge must be facing upwards.

  12. Place the RAMBo-cover-door on the lower hinge. Take the RAMBo-cover-hinge-top and push M3x10 screw through. Assemble the RAMBo-cover-hinge-top in the door and mount it to the frame.
    • Place the RAMBo-cover-door on the lower hinge.

    • Take the RAMBo-cover-hinge-top and push M3x10 screw through.

    • Assemble the RAMBo-cover-hinge-top in the door and mount it to the frame.

  13. Cable bundles are held in place by cable clips, which HAVE DIFFERENT SIZES of the inner cutout. Please ensure you are using the CORRECT CLIP for each cable bundle! RAMBo-heatbed-cable-clip is used for a smaller cable bundle, therefore its opening is smaller.
    • Cable bundles are held in place by cable clips, which HAVE DIFFERENT SIZES of the inner cutout. Please ensure you are using the CORRECT CLIP for each cable bundle!

    • RAMBo-heatbed-cable-clip is used for a smaller cable bundle, therefore its opening is smaller.

    • RAMBo-extruder-cable-clip is used for a bigger (thicker) cable bundle, therefore its opening is bigger.

  14. For the following steps please prepare: Rambo-heatbed-cable-clip (1x)
    • For the following steps please prepare:

    • Rambo-heatbed-cable-clip (1x)

    • M3x10 screw (2x)

    • M3n nut (2x)

    • Press the cable bundle from the heatbed in the hole on RAMBo-cover-base. Make sure the textile sleeve is partly inside the cover.

  15. Insert both M3n nuts in the traps on the RAMBo-cover-base, see the picture. Make sure the nuts are all the way in. Take the Rambo-heatbed-cable-clip and press it against the heatbed cable bundle. Using M3x10 screws fix the clip in place, tighten both screws equally.
    • Insert both M3n nuts in the traps on the RAMBo-cover-base, see the picture. Make sure the nuts are all the way in.

    • Take the Rambo-heatbed-cable-clip and press it against the heatbed cable bundle.

    • Using M3x10 screws fix the clip in place, tighten both screws equally.

    • If you can't reach the nuts, use temporarily longer screws, from the spare bag.

  16. Connect the cables from the heatbed to the RAMBo board:
    • Connect the cables from the heatbed to the RAMBo board:

    • Heatbed thermistor

    • Heatbed heater

    • Thermistor cable can be also in white color and missing the green label. It's polarity doesn't matter, it can be plugged both ways.

  17. For the following steps please prepare: Rambo-extruder-cable-clip (1x)
    • For the following steps please prepare:

    • Rambo-extruder-cable-clip (1x)

    • M3x10 screw (2x)

    • M3n nut (2x)

    • P.I.N.D.A. probe v-cable (1x)

    • Left hotend fan v-cable (1x)

  18. Original Prusa i3 MK2.5 upgrade brings several improvements from the MK3, however, there are not enough pins on the on RAMBo 13a(10a) board's connectors. Using v-cables we will split one cable into two connectors. Take v-cable for the PINDA V2 probe and connect it to the PINDA probe cable from the Extruder.
    • Original Prusa i3 MK2.5 upgrade brings several improvements from the MK3, however, there are not enough pins on the on RAMBo 13a(10a) board's connectors. Using v-cables we will split one cable into two connectors.

    • Take v-cable for the PINDA V2 probe and connect it to the PINDA probe cable from the Extruder.

    • Take v-cable for the Left hotend fan and connect it to the Left hotend fan cable from the Extruder.

    • Quick check: PINDA probe is using 4 wires, therefore, you need to connect v-cable with 3+1 wires.

    • Press the cable bundle from the Extruder in the hole on RAMBo-cover-base. Make sure the spiral wrap is partly in.

    • The nylon filament stays as a part of the bundle. No need to separate it as on the older versions of the RAMBo cover.

  19. Insert both M3n nuts in the traps on the RAMBo-cover-base, see the picture. Make sure the nuts are all the way in. Take the Rambo-extruder-cable-clip and press it against the extruder cable bundle. Using M3x10 screws fix the clip in place, tighten both screws equally.
    • Insert both M3n nuts in the traps on the RAMBo-cover-base, see the picture. Make sure the nuts are all the way in.

    • Take the Rambo-extruder-cable-clip and press it against the extruder cable bundle.

    • Using M3x10 screws fix the clip in place, tighten both screws equally.

    • Read the text and pictures in the next step carefully, as you need to connect the v-cables to multiple ports!

    • This step was photographed with the spiral wrap, but the assembly procedure is the same for the textile sleeve.

  20. Following instructions are ONLY for users with Mini-RAMBo 1.0a!!! In case you board is different, please skip this step.
    • Following instructions are ONLY for users with Mini-RAMBo 1.0a!!! In case you board is different, please skip this step.

    • Applying this procedure on a different board might lead to irreversible damage!!!

    • For the following step, please prepare:

    • Filament sensor cable connector

    • Sharp tip (e.g. razor)

  21. Following instructions are ONLY for users with Mini-RAMBo 1.0a!!! In case you board is different, please skip this step. Carefully insert the tip in the slot for the blue wire and lift the black plastic safety pin. While the safety pin is up, pull the blue wire gently out.
    • Following instructions are ONLY for users with Mini-RAMBo 1.0a!!! In case you board is different, please skip this step.

    • Carefully insert the tip in the slot for the blue wire and lift the black plastic safety pin.

    • While the safety pin is up, pull the blue wire gently out.

    • Insert the blue wire in the empty slot on the right, mind the correct "rotation" of the steel pin on the wire.

    • Ensure the wire is fully inserted and proceed with the assembly.

  22. Connect the cables from the extruder to the RAMBo board: P.I.N.D.A. probe (v-cable, 4 wires)
    • Connect the cables from the extruder to the RAMBo board:

    • P.I.N.D.A. probe (v-cable, 4 wires)

    • Left hotend fan (v-cable, 3 wires)

    • Extruder motor (yellow label with "E")

    • Extruder heater

    • Extruder thermistor (yellow/green heat shrink, orientation does not matter)

    • Front print fan (red heat shrink, ensure that the red wire is closer to the extruder thermistor connector)

    • Filament sensor cable (use the lower row of pins in the connector and ensure the red wire is on the right, facing the outside of the board)

  23. M3x40 screw (1x) Close the RAMBo-cover-door.
    • M3x40 screw (1x)

    • Close the RAMBo-cover-door.

    • Make sure that no wire is pinched!

    • Tighten the M3x40 screw.

  24. Congratulations, you've just assembled the Original Prusa i3 MK2.5 3D printer!
    • Congratulations, you've just assembled the Original Prusa i3 MK2.5 3D printer!

    • You're almost there... Just finish the chapter 7. Preflight check

Finish Line

113 other people completed this guide.

Jakub Dolezal

Member since: 02/20/2017

222 Guides authored

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Prusa Research Member of Prusa Research

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364 Guides authored

7 Comments

Yahoo ! Now I know where to connect my PINDA v2 probe. Thanks

Dragos - Reply

You’re welcome ;)

Jakub Dolezal -

I redesigned the cable clips so that the nuts went into them rather than into the RAMBo Base because the nuts got stuck in the first one and damaged it and reprinting cable clips is much quicker and less material dependent than printing new RAMBo bases.

Paul Rapson - Reply

These instructions are the worst thing about Prusa printers. Are these even proof read and followed by people who are doing actual upgrades from the starting configuration as in the title of the manual?

Charles Larson - Reply

Hey Charles.

If you have any feedback, then please do not hesitate to post it here.

I’ve noticed that you’ve been following wrong guides, so perhaps that’s what caused problems during the assembly.

Filip M - Official Prusa CS -

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