Open Hardware
Assembly Instructions

Note:
This replacement bed harness cable is compatible with LulzBot Mini 3D printers with a serial number range up to: KT-PR0035NA-07126 and KT-PR0035EU-6703.

WARNING:

At Aleph Objects, Inc. we respect your freedom to modify your LulzBot 3D printer. Any modifications or attempted repairs that cause damage are not covered under the Warranty.

Questions? Contact Technical Support by emailing Support@LulzBot.com, or by calling +1-970-377-1111.

3A
Remove filament if desired or place the filament reel off to the side. Turn off the 3D printer

3B
Unplug power cable

3C
Unplug USB cable

Note: Carefully unwrap the following wires only to help minimize loose wiring.

5A
Locate the Y-axis Min end stop connector. This red and black wire pair has a three-wire connector and is secured with a locking tab. Press in on the locking tab and disconnect the Y-axis Min end stop wiring. Image Labeled 1

5B
The Y-axis Max end stop is next to the previous connector. This double black wire pair has a three-wire connector and is secured with a locking tab. Press in on the locking tab and disconnect the Y-axis Max end stop wiring. Image Labeled 2

5C
Locate the print bed thermistor connector. Identify the two pin yellow wire pair with locking tab. Press the locking tab in and disconnect by print bed thermistor wiring. Image Labeled 3

5D
Locate the print bed heater connector. Identify the large-diameter purple wire pair. Disconnect the print bed heater wiring by lifting straight up and away from the Mini-Rambo. Image Labeled 4

5E
Locate the case fan connector. Unplug the red and black wire pair. Image Labeled 5

5F
Locate the Z-axis ground connector. Unplug the red and black wire pair by pressing in the locking tab and disconnect the Z-axis ground wiring.

Note: Take care not to damage the crimp terminals.

7A
Gently disconnect Y-axis Min end stop wire by pulling away from the switch using needle nose pliers.

7B
Gently disconnect Y-axis Max end stop wire by pulling away from the switch using needle nose pliers.

7C
Disconnect the smaller two wire pair heated bed thermistor connector while pressing on the locking tab.

7D
Use the flush cutters or scissors to cut the small zip tie securing the larger two wire pair heated bed power connector. Cut the small zip tie securing the cable chain. Throw away the zip ties.

7E
Disconnect the larger two wire pair heated bed power connector by pulling them apart.

7F
Unscrew the Z-axis ground wire, using either a hex driver, wrench, or needle nose pliers. Place the screw or nut in a secure location.

Tips:

• Reminder: the dental pick is sharp.
• Place each removed connector on a sheet of paper marked with the connector identifier.
• Once removed, bind the wire pair together using as little tape as possible and mark them with the connector identifier.

9A
Remove the pins from the three pin Y-axis Min end stop connector with the red and black wire pair. Use the dental pick or other sharp pointed instrument to gently push down on the locking catch for each metal pin through the small square opening closest to the end.

Note: Only use the small square opening nearest the wiring if the locking tab catches it. Slide out the two pins.

9B
Remove the pins from the three pin Y-axis Max end stop connector with the black and black wire pair. Gently push down on the locking tab for the two pins and slide out the two pins.

9C
Remove the pins from the two pin heated bed thermistor connector with the yellow and yellow wire pair. Gently push down on the locking tab for the two pins and slide out the two pins.

9D
Remove only the black wire pin from the two pin Z-axis Min end stop connector with the red and black wire pair. The connector will not need to be pulled through the cable chain.

9E
Use the 2 mm flat screwdriver to free the large purple and purple wire pair from the two pin heated bed power screw terminal connector.

11A
Move the print surface all the way to the back of the Y-axis.

11B
Continue gently guiding the wire bundle through the cable chain. Use a finger to block gaps in the cable chain and to help allow the bundle to pass through.

11C
Gently pull the wire bundle through, leaving room at the bed end of the wiring bundle, similar to the attached picture.

11D
Route the taped wire bundle end through the wire pass-through in the frame.

11E
Remove the tape covering the pins once the bundle is through

11F
Place the split round wire wrap back on the new bed cable harness with the end of the round wire wrap inside of the pass-through.

Tips:

• Place the right wire pair into the correct connector.
• Remember: the pick is sharp.
• Use the dental pick or other sharp pointed instrument to gently and slightly lift up on the locking catch for each metal pin. Do not exceed an angle higher than 30 degrees.

13A
Insert the pins with the red and black wire pair into the three pin Y-axis Min end stop connector. Slide the pins in until the pin catch is visible in the small square opening closest to the connector end.

13B
Insert the pins with the black and black wire pair into the three pin Y-axis Max end stop connector . Slide the pins in until the pin locks in place.

13C
Insert the pins with the yellow and yellow wire pair into the two pin heated bed thermistor connector. Slide the pins in until the pin locks in place.

13D
Insert the sole black wire pin into the two pin Z-axis Min end stop connector. Slide the pin in until locked in place.

13E
Insert the large purple and purple wire pair into the two pin heated bed power screw terminal connector. Use the 2 mm flat screwdriver to attach the connector to the pins.

15A
Slide the electronics enclosure back in place, taking care to keep all wiring away from the case fan blades.

15B
Use the 2 mm hex key or driver to install the six screws securing the electronics enclosure to the 3D printer frame-- three in the front and three in the rear of the electronics enclosure.

Verify the functionality of the printer prior to your first test print.

Prior to moving any axis:

• In Cura LulzBot Edition, in the control window, send the M119 command to view current end stop status. Each end stop should report open when each axis is in the middle of the travel range.
• Move the X- and Y-axis to both the min and max travel range until the end stop click can be heard. Send the M119 command again. Each end stop should report triggered when clicked, or when pressed.
• Home each axis through the control interface.

Prior to heating the hot end or heated bed:

• In Cura LulzBot Edition, in the control window, check the hot end and heated bed temperature. If a 0 or zero is displayed the heated bed thermistor is not connected properly.
• When connected properly the heated bed should display an ambient temperature of 10°C - 30°C.

Start a test print and carefully observe the auto bed leveling sequence.

During the auto bed leveling sequence the nozzle should lightly touch down on each metal corner of the bed.

If you encounter issues please contact Technical Support by emailing Support@LulzBot.com, or by calling +1-970-377-1111.