Broke the ribbon cable trying to install

machine: Plain vanilla k40.

Board: M2Nano - ribbon cable variety.

Firmware: I’m using whatever it came with

Problem/ Question: While replacing the M2Nano with ny new Laserboard the ribbon cable partialy broke. It looks irreparable. I need to get a replacement ribbon cable asap. Anyone know where I can get one?

I have had no luck in locating a replacement ribbon cable for the one I broke. In reading some of the past posts related to the ribbon cable type M2Nano replacement with the C3D Laserboard, I conclude it is possible to completely replace the ribbon cable by installing some new mechanical endstop switches, an external stepper motor driver for the X-axis, and associated wiring. This is probably the most expedient way to get my machine working again. Is there a guide available for parts to order and in accomplishing this conversion?

I have had no luck finding a replacement ribbon cable. However, you should be able to cut the cable a little shorter (past the tear) and scrape the insulation off the leads with a hobby knife. It’s tedious, but it will work. You might also need to build up the exposed terminals with a little solder in order to make a good connection. Just don’t overheat the cable. it melts fairly easily.

If you don’t want to mess with the ribbon cable or don’t have luck with that method, you shouldn’t need to replace the limit switches and can definitely just run wires to everything. You’ll need four 24ga wires and 4-pin JST plug and socket to drive the motor, and depending on the style of endstops in your machine, four or six more wires and some clever soldering (I rehabbed a K40 that had an unsalvageable, burned up ribbon cable and ended up rewiring the whole damned thing). You’ll have to look up a pinout for the ribbon connector and solder the wires to the back of it. The hardest, most tedious part about it for me was - surprisingly - twisting the wires together to make pretty, snag-free bundles.

This connector pack will be useful when wiring your endstops. I forget what exactly it ships with - might have one side of the JST connector too:

Thanks loathar, this is music to my ears. I’ve been kicking myself for being so stupid as to break an irreplaceable cable and take myself out of the game.
I ordered the connector pack you referenced. Should be helpful.
I had earlier ordered the external stepper motor cable 4-pack along with an external stepper driver under the misapprehension I needed that to drive my X-axis stepper. I have since read that the stock K40 steppers can be driven directly from the Laserboard, but at least I can use one of the stepper motor cables to wire up my X-stepper.
BIG help my friend.

You will almost certainly not be able to source a replacement ribbon cable in the needed length, as it seems you have discovered.

You are probably best off replacing the ribbon entirely and substituting in mechanical limit switches instead of the optos currently in your machine.

…Yes. These switches are the best type to use:

No. The external stepper driver and our signal wires for it will not help you. You will need to extend the 4 wires from the X motor, and deal with that wiring yourself.


Again, there should be absolutely no need for this.

You may find the resources here helpful:

If you like, I can cancel your existing orders and you can place a new one for probably just a few of those switches and a connector pack to be safe. Let me know.

Thanks for your prompt answer Ray.

As I examine the C3D Laserboard, I see what appear to be redundant 4-conductor connections for the X- and Y Axis stepper motors in the form of plugs and screw terminals. So I presume this is why you say there is no need for the pre-wired stepper motor cable I thought I needed to substitute for the X-stepper leads that formerly were carried on the ribbon cable. I agree.

I have two separate orders extant at the moment, one (Order #24889) was for the stepper driver, 4X external stepper driver cables, and 2 mechanical limit switches. Please do cancel this one if possible, and I will re-order the limit switches alone.

A second order (order # 24906) was for the connector pack, which I believe is still required.

I cancelled the one order as you requested.

This simply does not exist (from us), please try to understand again. The cable pack that we sell for the external driver is different.

You need to run wires for the motor to the board, and you can put them to the screw terminals on the board.

The switches will plug directly into the board, as long as the 1 meter cables are long enough.

View the basic pinout diagram we have here:

Thank you for following up an cancelling the one order so quickly.

Yes, thanks, I did later notice that the connection points for external stepper drivers were different from the actual stepper motor socket connections after making that comment. I was planning to use the provided screw terminal connections for direct connection of stepper motors, this seems relatively straightforward.

I am now trying to understand the easiest way to replace the optical end stop sensors with the mechanical switches. I did see one blog where a mount was produced with a 3D printer. I do not have a 3D printer. I wonder if there is a more conventional way to affix them after removing optical sensors.

Also, I presume access to swap the end stop switches will require removal and replacement of the gantry, which I also need to research. If you know of a method depicted somewhere on the web and what to avoid here it would be helpful. (I think I will probably replace the exhaust vent with one with a better profile for a modified bed while the gantry is removed).

Loather, your suggestion for stripping the insulation off the end of the ribbon cable is working at least temporarily. I cut the bad end off and used a little sanding drum on a craft tool to grind the insulation down until the bare strips mostly showed about the same distance from the end as the original one. It holds and makes contact in the socket, although kind of precariously given the shorter length and not much slack to play with. At least it’ll do until I can replace the FFC altogether.


use of the dremel to do this is clever. adding that one to my toolbox for the next time i encounter similar problems.

1 Like

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.