How to replace the Hotend flat cable (BCN3D Sigma)


Hex head screwdriver
Allen Key 2mm
Allen Key 2.5mm


The flat cables connected to the print heads are in constant movement and with time it is possible that they need replacement because of the wear damage. If you have checked the cables and found that they are damaged, this article will help you replace them:


1. Raise the printing surface to the top (Utilities/Maintenance/Move printing Platform)

Move printing platform

2. Turn off and unplug the printer.

sigma-turn-off-1 sigma-turn-off-2
3. Remove the center and side cover corresponding to the side of the cable you need to change.

screw-iconx6 M3 8mm

screw-iconx2 M3.2 9.5mm



Note: If you have the R16 | R17 version you will have to remove the lower bowden of the extrusion motor, to do this: unscrew the screws with a 2mm allen key and remove the bowden with the printed part.




4. Disconnect the flat cable from the mainboard, it will be the widest flat cable and on the mainboard, it will be identified as H0 for the left side or H1 for the right side

flat cable mainboard disconnect

5. Remove the connection cover and disconnect the flat cable screw-iconx2 M3 8mm


6. Remove the curved flat cable holder nut-iconx2 M3

Curve flat cable holder

7. Remove the ribbon cable from the printer, it is best to pull it from the upper area of ​​the printer.


8. Insert the new cable through the bowden exit and bring it to the bottom.

Note: When you insert the flat cable, the silver part should face the bottom of the printer and this cable should be behind the other cables. If you have trouble inserting the cable, you can remove the bowden exit. In case it breaks you can get the model to print here:

Printed parts (BCN3D Sigmax)

Bowden entry R

9. Secure the flat cable by inserting it into the studs.

flat cable stud tachuela

10. Connect each end of the cable to the extruder board and the mainboard.



It is extremely important once the change is made, to check that all the flat cables are correctly connected, during the process they are very likely to come loose from their position, this article has more information on how to do it: How to check the flat cable connections (BCN3D Sigma)

Forum community 

If you have any more questions, check out our forum community for more information about models and materials.


It's important to keep your printer in good shape to make the most out of it. In this chart you can find a list of the extruder maintenance procedures and how frequently these should be done. Maintenance Plan


bcn3d-recycle Take your e-waste to a certified recycler. Check how we do it in BCN3D.


Parts   Buy these parts
flat cable Flat cable Left Hotend - sigma FFC H0 SKU 11901
flat cable Flat cable Right Hotend - sigma FFC H1 SKU 11902


check flat cable eng check mainboard fuse eng


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