Stepper Motor Unresponsive in E01 Port; Unsure as to how to switch

Hey there! Running a Taz 4/Kittaz with stock standard equipment. except for a few cosmetic modifications. my extruder motor stopped responding a little while ago. Assuming it dead, I replaced it. Still nothing. When swapped from the E01 port to the Z Axis port on the Rambo board, it works fine, leading me to believe it’s an issue with he connection port on the board or the firmware.

I noticed I have a spare board port for an extruder, E0, but I’m not sure how I’d go about swapping the extruder to it. Plugging it into said port gets no response. Otherwise, the machine responds as expected.

Anyone have some insight as to how to fix this issue? I haven’t got the scratch to replace the Rambo board at the moment.

Did you build this machine, or did you buy it assembled from someone? The reason I ask is that the stepper with the default firmware should have been attached to E0 already. The only reason to move a single extruder over to E1 is if the E0 motor control stepper driver chip has failed. Otherwise it’s a bit of work for no good reason. Having even one of them fail by now would be pretty rare, but not unheard of. Having both fail would point to either inadequate cooling (machine in an enclosure without the control box vented, failed fan, wrong fan firmware, etc.) or possibly inadequate grounding of the rambo board. If it was moved and adjusted in firmware, it may be due to the other extruder port having already failed.

To switch to using E1 if it isn’t already enabled in firmware does require some firmware surgery. Cura can probably do it automatically. if not, it’s going to be in the Configuration.h file for the printer, or you can just flash back to the stock Taz 4 firmware (or the Taz 5 firmware if the machine has been upgraded to a hexagon nozzle) Here are the Kittaz instructions on where everything should have ended up.

It would require more effort to switch the harness over to E1 than it would to just set it up using E0 if nothing was wrong.

If it turns out it is melty, you can source an inexpensive used board from

If you want a brand new one, ordering directly from ultimachine is the least expensive option. You can also source them directly from Lulzbot.

If the extruder motor is the only part not working, it’s not likely to be the fuses unfortunately.

Sorry, I got my numbers backwards; yes, it’s switching to E01, not E0. And it looks like this is going to require some surgery then.

So just to be clear; Do you know exactly what to edit to change the Harness from E0 to E01? Because I’m currently trying to reset firmware (Didn’t work) And I have no clue what exactly I need to edit to change it.