I’ve almost finished my MPCNC build, but am having an issue with the stepper motors.
I’ve wired the steppers in series, but if I try and move the x or y axis, one stepper moves in one direction, the other moves in the opposite direction.
I’m sure I can’t be the first person to experience this, but I couldn’t see an obvious answer to what wires need to be swapped around to get them moving in the same direction.
I’ve gone down the DIY route, so everything is soldered and covered in heatshrink tubing and braid now. 99% sure I’ve got the cabling as per the diagram, can anyone suggest what I should try next?
You’ll need to reverse the connections to one of the motors. Unfortunately, that sounds like you’ll need to redo the heatshrink tubing and undo the soldered connection.
If one of the steppers is going the wrong way, flip it’s plug over to reverse it. If they are both going the wrong way, flip them at the board (is series wired of course).
Hmm, I might have more of an issue with the stepper motors / mini rambo board. I can’t seem to get the z-axis to move without some serious juddering. Checked the wiring, tried multiple combinations, different ports, but all seem to produce the same result.
Have you tried the z stepper motor connected to either the X or Y stepper drivers to confirm the motor works the way it is supposed to? If it’s the motor, then you should only have to replace it. If it is the driver, then you may have an option to swap the z-axis to the 4th stepper driver on the board; this will require some firmware changes, though.
Yes, I did try using another port on the board (x,y,extruder). Not tried every combination, but it all seemed to produce the same result. Also tried another stepper motor. Not sure if it’s something I’m doing wrong with the cabling.
As BT pointed out there are ways around a bad driver if that is actually the issue but you need to verify all your steppers first. If you are wiring them yourself you need to remember to always power down completely before connecting or disconnecting any stepper wires. The mini is protected, you should not have been able to kill a driver unless something went terribly wrong.
Thanks Ryan. I’ve ordered another stepper motor to try and narrow down the issue. Just wondering if there is anything in the firmware that could cause this behaviour?
It’s an import from China. I’ve tried reflashing the board a few times (mostly to get the LCD screen working). Didn’t seem to make a difference to the steppers though. I’m using the ‘Marlin-MPCNC_MRambo_T8_16T_LCD.zip’ firmware, I assume this is the correct one?
There have been a ton of questions about those it seems they must have swapped out some components. You can look at the components themselves and see if the numbers match up, at least for the bigger chips.
I have never handled or used one so I can’t be sure, but with all the questions something is not as it should be. Just like the ramps, they are great boards (genuine) the imports typically can not even handle an LCD anymore and some have extremely old usb chips.
Not sure if that would cause the issue I’m having though, or even if it was I don’t have the equipment or skills to swap out SMD components that small!
Will stick with the RAMPS for now and see if I can get a refund on the mini rambo (unlikely I know)
Is that a photo of the genuine board? The revisions on that are correct, the imports can change all sorts of things, it sounds like the digi pots (it it has them) are not correct.
