Electronics Board (UM3/UM3X)

These instructions are for the Ultimaker 3 and Ultimaker 3 Extended printer. If you need help replacing the electronics board for the Ultimaker 2+, Ultimaker 2 Extended+, or Ultimaker 2 Go, see here


  • 2mm hex head screwdriver

1. With the bed lowered and the printer unplugged, remove the cable cover from the right hand side of the printer. It’s held in with tabs push fitted into the back, right, and bottom panels and may take some pulling and wiggling to remove.

2. Raise the build plate. Using your 2mm hex head screw driver, remove the 2 electronics board cover screws.



3. Lay the printer on it’s back and carefully remove the electronics cover. You may want to put a towel or piece of foam under the back of the printer to help keep it stable. Laying on it’s back will not harm the feeders on your printer, but do make sure the filament guide/reel holder has been removed and that the machine is unplugged before you lay it down.

4. Unplug each of the items from the connections in the electronics board. The bed heater wires in the terminal block are held in place with a push fit. You can press on the orange fitting at the side of the beige terminal block to release the bed heater wires. If this is difficult to do, you can slide the beige terminal block sideways (to the left) out of the printer and try again. The board below is fully connected. To make things easier during the reconnecting process later, you might consider labeling the white connector on the motor cables with a permanent marker. This will not damage the cables, and will make sure that there’s no possibility of accidentally switching the X/Y motor cables and feeder motor cables.

5. When you’ve disconnected the board, you can unscrew it. The screw heads are indicated in blue on the first picture. 4 plastic spacers sit between the electronics board and the bottom panel of the printer, so be careful not to lose these when you unscrew the board, as you’ll need them later.

6. Place your new board against the bottom of the printer. It can be a little tricky to get the spacers in as you screw it in. I recommend putting the 2 screws nearest the back panel first, and placing the spacers on them, then pushing the board against them and carefully screwing them in, then proceeding with the 2 screws at the top/front of the board and the spacers there. Make sure the back of the board is resting flush against the back panel; the screw holes for the electronics are slotted, and you want the board seated all the way toward the back.

7. Begin plugging in the cables. These can be plugged in in whatever order you find most convenient, until your board looks like the below photo.

  • X-Stop—blue cable

  • Y-Stop—red cable

  • Z-Stop—black cable

  • Temp 3—thick white cable from heated bed

  • Heated Bed (terminal block)—thicker white cables from heated bed; they should push right into place

  • Safety 1 and Safety 2—these are the black jumpers; they'll need to be moved from your original board to the new one

  • X-Motor—motor cable coming from X-motor on right hand side

  • Right—feeder motor cable coming from right hand side

  • Y-Motor—motor cable coming from Y-motor on left hand side

  • Left—feeder motor cable coming from left hand side

  • Z-Motor—cable coming from Z-motor; very short

  • RGBW—this is your LED strip, coming out of the front right corner of the printer, thick white wire

  • Filament Det. L—thick gray wire coming from left

  • Filament Det R—thick gray wire coming from right

  • The thickest white wire with the 10 connectors plugs in at the top of the board; this controls your printhead (the fans, the heaters, temp sensors, everything)

  • J1—the single flat cable should be plugged into the J1 connection. It’s imperative that the cable be plugged in with the red stripe towards the left, otherwise your Olimex board and main electronics will not communicate.


8. Put the electronics cover back into position, being careful not to pinch any of the wires between the bottom panel and cover, otherwise something could short out. You may want to hold the locknut in place with the tip of your finger as you screw the cover back on.

9. Stand the printer back up again and lower the bed the reinstall the cable cover. It may take a little pushing to get it back into place.

10. Plug your printer in and power it on. The power on process/start up will take a while, as your Olimex Board is going to write firmware to your new main board, letting it know what type of printer it is, etc. When it’s done, you will want to connect the printer to the internet and run the firmware update in the menu, just to make sure the most recent version is writing to the main board.

Was this article helpful?
0 out of 0 found this helpful
Have more questions? Submit a request


  • 0
    Jason Thumwood

    where does the other end of the Filament Det. L & R cable plug in its been a while since i stripped it down and have managed to rebuild but cant remember where these go 


  • 0
    Erin Oliver

    Hi, Jason! The filament detection cables do no plug in at the other end at all. Ultimaker included them as an extra connection in case the feature was able to be added later, but unfortunately it didn't end up being possible. The cables route from your electronics board behind your cable cover to your feeders, but there is nothing there for them to plug into. You can go ahead and remove the cables altogether without causing any issue with your machine.

Please sign in to leave a comment.