How to replace xLCD (MK4/MK3.9/MK3.5)

Relevant for:

MK4 MK3.9 MK3.5

Last updated 7 months ago

Difficulty

Moderate

Steps

Available languages

Step 1 Introduction

⬢This guide will take you through the xLCD replacement on your Original Prusa MK4, MK3.9 or MK3.5.

⬢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.

If you're using the MK4 printer, it's essential to determine which version of the xLCD your printer has, before you start. Check the next step for more details.

Step 2 MK4: xLCD versions (part 1)

This step is relevant only for the MK4 users. If you use the MK3.5 or MK3.9, please skip to the preparation step.

⬢The xLCD version can be easily recognized by the location of the grounding connection (PE / FE) on the back of the PCB:

⬢

The newer version A - the grounding point is located on the top left hole.

(version number 26, 27 and higher)

⬢

The older version B - the grounding point (marked PE) is located on the bottom right hole.

(rev. 0.12.2, 0.12.3 etc.)

⬢The version numbers are printed on the PCB.

Step 3 MK4: xLCD versions (part 2)

Note: There is no functional difference between the xLCD boards. The only difference is the position of the grounding point, the fastener layout and compatible printed parts.

⬢If your printer uses the newer version A, you can continue to replace just the xLCD board itself.

The xLCD version A is the one you can get from the eshop.

⬢If your printer uses the older version B, you have to also replace the plastic parts, together with the xLCD itself.

We recommend getting the xLCD - printed parts & fasteners package from the eshop.

The printable parts are also available on Printables.com.

Step 4 Preparation

⬢Unload filament from the printer and remove the spool holder.

⬢Power off your printer and disconnect it from the power.

Step 5 Tools necessary for this chapter

⬢For this chapter, please prepare:

⬢2.5mm ball-end Allen key

⬢T10 key (depending on the fasteners used on your version of the xLCD)

If you’re upgrading the plastic parts on your MK4 to the newer version, you might optionally also need these tools for removing the M3nS nuts:

⬢1.5mm Allen key (optional, for removing the M3nS nuts)

⬢Needle-nose pliers

Step 6 Removing the xLCD

⬢Look from above. Remove the four M3x10 screws holding the xLCD assembly in place.

⬢Disconnect the Faston connector.

Note that position of the connector might differ, depending on the xLCD version you have.

⬢Disconnect the xLCD cable.

Step 7 xLCD Disassembly (part 1)

⬢Remove the xLCD knob by pulling it up.

⬢Remove the M3x8 screws holding the xLCD-support-left part.

There might be two or three screws, depending on the xLCD version you have.

You might need to use the 2.5mm Allen key or the T10 key, depending on the fasteners used on your version.

⬢Remove the xLCD-support-left plastic part.

⬢On the Version B, there is a faston connector underneath the plastic part. Remove it.

Step 8 xLCD Disassembly (part 2)

⬢Remove the M3x8 screw in the marked location.

⬢On the version A, there is a faston connector held by the screw. Remove it.

⬢Remove the M3x8 screw holding the xLCD-support-right.

⬢Remove the xLCD together with the xLCD-support-right by lifting it up.

⬢Remove the xLCD-support-right plastic part.

Step 9 Parts preparation (part 1)

⬢For the following steps, please prepare:

⬢xLCD (1x) version A

Remove the protective film from the xLCD screen.

⬢xLCD-cover (1x) compatible with the version A.

⬢xLCD-support-left (1x) compatible with the version A

⬢xLCD-support-right (1x) compatible with the version A

⬢xReflector sticker set (1x) from the spare parts package bundled with your printer

The list continues in the next step...

Step 10 Parts preparation (part 2)

⬢M3x8 screw (4x) The ones you removed earlier, or the ones bundled to the "xLCD - printed parts & fasteners"

⬢M3nS nut (4x) Needed only, if you’re upgrading from the version B to the Version A. Use the ones from the spare parts package bundled with your printer.

⬢Faston connector 6.3x0.8 (1x) the one you removed earlier.

Step 11 xLCD assembly (Version upgrade)

This step is valid only if you’re upgrading your xLCD from the version B to the version A.

⬢Insert two M3nS nuts into the new xLCD-support-left and xLCD-support-right parts.

⬢Peel the xReflector strip off the protective layer and apply it into the marked area on the inside of the new xLCD cover.

⬢Press the xReflector sticker strip all the way towards the xLCD-cover, so that it adheres properly.

Step 12 Assembling the xLCD-support-right

⬢Place the xLCD-support-right onto the USB-connector-side of the new xLCD board. Notice there is a small hook that goes around the circuit board.

⬢Line up the hole in the plastic part with the hole in the xLCD board.

⬢Insert the xLCD with the xLCD-support-right still hooked on, into the xLCD-cover. 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 board now. Otherwise, you won't be able to attach it later.