1c. Parts preparation

Relevant for:

MK4S MK3.9S

Last updated a month ago

Difficulty

Moderate

Steps

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Step 1 Tools necessary for this chapter

⬢For this chapter, please prepare:

⬢2.5mm Allen key

Step 2 Removing the heatbed cable cover

In the upcoming steps, you will replace the old heatbed thermistor (from your previous printer model) with a new version that is compatible with MK4S, MK3.9S, and MK3.5S.

If you purchased a new heatbed with the upgrade kit — commonly for users with printers featuring 2+1 screws on the old heatbed — ensure that the new thermistor is pre-installed. You can easily verify this by checking for a white connector at the end of the thermistor cable. The presence of this connector indicates that the new thermistor is already in place and you can skip to M3nEs nuts: parts preparation

This part may vary slightly in the design of the cover, location of the screws and number of the screws.

⬢Remove the screws fixing the cable bundle.

⬢Remove the screw securing the cover. From the underside, grasp the middle M3nN nut with the pliers while loosing the screw.

⬢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.

Step 3 Removing the heatbed thermistor

⬢From the bottom side of the heatbed, peel off the yellow Kapton tape and silver aluminum tape.

⬢Remove the heatbed thermistor cable from the heatbed.

Step 4 New heatbed thermistor: parts preparation

⬢For the following steps, please prepare:

⬢MK4 Heatbed thermistor (1x)

⬢Kapton tape (1x)

⬢Aluminum tape (1x)

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.

Step 5 Preparing the heatbed and thermistor

⬢After you have removed the thermistor and the tapes, clean the entire board to remove any grease. You can leave the glue, which was under the aluminum tape.

⬢Place the thermistor on the heatbed. The tip of the thermistor must be in the circle.

If you miss this spot, the printer will read incorrect temperature values.

⬢Take the silver aluminium tape and carefully peel off the protective film.

⬢Glue the tape to the heatbed, BUT ONLY in the centre of the thermistor (inside the circle shape). We need to double-check the correct position.

⬢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.

Step 7 Fixing the thermistor in place

Now it is time to apply the final "yellow" Kapton tape. DON'T PEEL OFF the entire tape, it will curl up!!!

⬢Peel off about 1 cm (0.5 inches) strip of the Kapton tape and stick it to the heatbed, like in the picture. Ensure the tape is properly connected.

Make sure the Kapton tape does not overlap any screw holes in the heatbed.

The Kapton tape has a bigger area than the silver tape. Make sure the silver tape is overlapped from all sides.

⬢Continue with gluing the tape and stop for a second above the area with the thermistor. 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 Motor adaptation: parts preparation (MK3.9S)

In case you’re building the MK3.9S printer, please prepare:

⬢Motor cable adapter (4x)

⬢X motor (1x) you removed earlier

⬢Y motor (1x) you removed earlier

⬢Z left motor (1x) you removed earlier

⬢Z right motor (1x) you removed earlier

Step 9 Motors adaptation (MK3.9S)

This step is required only in case you will be building the MK3.9S printer.

The control board on MK3.9S uses different connectors than the MK3S+. To use motors from the MK3S+, attach adapters to the motor cables.

⬢Install the cable adapter onto the Y motor cable.

⬢Install the cable adapter onto the X motor cable.

⬢Install the cable adapters onto both the Z motor cables.

Step 10 M3nEs nuts: parts preparation

⬢For the following steps, please prepare:

⬢M3nEs nut (2x)

Step 11 Inserting the M3nEs nuts

⬢Insert the M3nEs nut into the left short extrusion (side without the PSU). Insert the side with the spring (metal plate) first.

⬢Orient the nut with the metal spring facing down.

⬢Push the entire nut inside the extrusion using your finger.

⬢Use this method for both M3nEs nuts. The exact position of the nuts doesn't matter at this time.

Step 12 Cable clips: parts preparation

⬢For the following steps, please prepare:

⬢Cable clip (6x)

Step 13 Installing the cable clips

⬢Turn the frame like in the picture and focus on the marked area

⬢Take one of the cable clips and hook the side with the clip into the inner groove of the lower longer extrusion. There is a hook on the part, see the detail.

⬢Place the other end of the clip on the underside of the extrusion.

⬢Use more force to push on the bottom side of the cable clip. It must fit into the groove and you must feel it "click" in.