Replacing Endstops/Limit Switches

These instructions apply to the Ultimaker 2 series printers. For instructions on replacing the endstops for the Ultimaker 3 series printers, please see here. The term end-stop and limit switch may be used interchangeably in this article. You can skip ahead to the instructions for the endstop you need:

• X-Stop (blue cable, triggered by hot end at left)
• Y-Stop (red cable, triggered by hot end at rear)
• Z-Stop (black cable, triggered by bed at bottom)

 
Replacing the X-Stop

1. Remove the left corner cable cover, which is held in place by 2 screws. One screw is located on the left panel, and one is located on the back panel, designated on the screw diagram. Remove the cover with the bed lowered. For the Ultimaker 2 Go, the cable cover is held in place as a push fit, so there are no screws. Pull the cable cover forward and out away from the left and back panels.
2. Raise the bed and lay the printer on its back or side. This will not damage the standard feeder. To prevent damage to the panel, you may want to place down a clean piece of cardboard or a towel first.
3. Undo the two screws that hold the electronics cover on. These screws go down through the bottom panel. You will need to hold the corresponding lock nuts with pliers or a nut driver. Remove the cover. 
4. Locate the port on the electronics board labeled “X-stop”. It is on the left side of the board. The wires are blue. Unplug the x-stop. 
5. Using a pair of pliers, carefully bend the silver trigger bar of the new x-stop. Press the bar to the black block. Grip the trigger bar with the pliers where it sits against the edge of the block and bend. Thread the new x-stop down through the bottom panel from the inside and plug it in at this time.
6. Unscrew the two screws holding the x-stop to the top panel. Remove the old x-stop.
7. Position the new x-stop in place and screw it in. The wire should come up from the bottom panel and sit between the y-motor and the back panel. It should not loop around any rods or belts. The silver trigger bar should be on the right with the opening toward you. Use two of the 12mm (larger) screws to secure it in place.           
8. Position the black ferrite core to the left of the electronics board. 
   Make sure the flat cable and red/black LED cord are in the cut outs at the top left of the cover. There is an opening on the bottom right for the x-motor wire, z-motor wire, and z-stop wire.
   
   Screw the cover in place using the remaining two 12mm screws (larger).
9. With the bed lowered, replace the corner cover. Use the two 8mm screws to secure it to the panels. 
10. Manually move the hot end all the way to the left of the printer. Watch and listen for the black sliding block to trigger the x-stop. The trigger bar is bent too far if it goes completely behind the sliding block without triggering. The trigger bar is not bent far enough if the fan hits the left panel at the point of triggering.
    

 
Replacing the Y-Stop

1. Unscrew the left corner cable cover. One screw is located on the left panel, and one is located on the back panel. Remove the cover with the bed lowered.
2. Raise the bed and lay the printer on its back. This will not damage the standard feeder. To prevent damage to the panel, you may want to place down a clean piece of cardboard or a towel first.
3. Undo the two screws that hold the electronics cover on. These screws go down through the bottom panel. You will need to hold the corresponding lock nuts with pliers or a nut driver. Remove the cover.
4. Locate the port on the electronics board labeled “Y-stop”. It is on the left side of the board. The wires are red. Unplug the y-stop. Thread the new y-stop down through the bottom panel from the inside and plug it in at this time.   
5. Unscrew the two screws holding the y-stop to the left panel. Remove the old y-stop. It may be glued to the side panel. As you are removing a defective part, it does not matter if you break the wire or insulation.
6. Position the new y-stop in place and screw it in. The wire should come up from the bottom panel and sit between the y-motor and the back panel. It should not loop around any rods or belts. The silver trigger bar should be toward the front of the machine with the opening up. Use two of the 12mm (larger) screws to secure it in place.
7. There is a notch in the panel where the y-stop cord should rest. This recess keeps the cord from shredding on the belts. Carefully superglue the cord in the recess (do not get glue on the pulleys, motor, or belts). If you have difficulty applying glue to this area, you can secure the wire at another point as long it is safely away from the moving parts of the axis.
8. Position the black ferrite core to the left of the electronics board. 
   Make sure the flat cable and red/black LED cord are in the cut outs at the top left of the cover. There is an opening on the bottom right for the x-motor wire, z-motor wire, and z-stop wire.
   Screw the cover in place using the two remaining 12mm screws.
9. With the bed lowered, replace the corner cover. Use the two 8mm screws.
10. Manually move the hot end all the way to the back of the printer. Listen for the crossbar that runs through the hot end to trigger the endstop. 

 
Replacing the Z-Stop

1. Unscrew the two screws holding the z-stop to the panel using the 2mm allen key (middle size) that came in your accessory bag. The z-stop screws are located at the bottom of the back panel.
2. Raise the bed and lay the printer on its back. This will not damage the standard feeder. To prevent damage to the panel, you may want to place down a clean piece of cardboard or a towel first.
3. Undo the two screws that hold the electronics cover on. These screws go down through the bottom panel. You will need to hold the corresponding lock nuts with pliers or a nut driver. Remove the cover. 
4. Locate the port on the electronics board labeled “Z-stop”. It is on the left side of board. The wires are black. Unplug the z-stop. Plug the new z-stop in at this time.
5. Undo the four screws that hold the z-motor on. These screws come down through the bottom panel. Carefully pull the motor away from the panel. This will move the entire bed assembly. You only need to move the motor enough to access the recess in the panel behind it.
6. The old z-stop should be completely free now. Remove it, and maneuver the new z-stop so the cord sits in the recess.
7. Replace the z-motor and tighten the screws. Use the four 10mm screws (the smaller ones). Be careful not to pinch the wires between the motor block and the panel. If the wires are completely in the recess, they will remain in tact. 
8. Orient the z-stop so the silver trigger bar is angled with the highest point on the right. Screw it in place.
   
9. Position the black ferrite core to the left of the electronics board. 
   Make sure the flat cable and red/black LED cord are in the cut outs at the top left of the cover. There is an opening on the bottom right for the x-motor wire, z-motor wire, and z-stop wire.
    
   Screw the cover in place.