Y Right getting dragged by Y Left


During a carving project, almost 3/4th of the way, the cut wasn’t going fine. I noticed that only the Y Left stepper motor was moving. It was dragging the Y Right in the process. This was causing the cut to go bad.

I have made about 20 cuts before and it was all fine. Well, there was a difference in the dimensions in my design and the actual cut ( about 0.5mm less ) and this particular cut was to test the difference and the scale with different width and depth.

Not sure where the fault was. Earlier, when both motors were working, they would lock up as soon as I connected my laptop to the controller. Now I see that the Y-Right is not looking up. So, I swapped the Y-Right and Y-Left cables on the controller box. Now when I gently nudged the carriage the Y-Right stepper motor locks up but Y-Left is loose. Obviously, something in the controller is wrong.

I’m no expert with the controller box. Not able to figure out if something is wrong in there. I opened up the controller and I don’t see anything burnt, no burnt smell, no visual damage of any kind.

So, I’m stuck at this point. Kindly let me know how I can find out what is wrong in there.


Check and double check your wiring, all the way from the controller to the stepper. The driver could have gone bad too.

Without having the actual machine it is difficult diagnose the problem, but here are some guidelines. Link

Make certain that all ribbon cables are completely seated as well while you have the controller open. I’ve seen issues like this caused by those. The ribbons will lock in place, even though they are not fully seated.

@HaldorLonningdal: The wires are fine. If I swap the Y-Right wire with Y-Left wire, then the Left motor does not lock up. So, both stepper motors and both wires are fine. Basically, whatever is connected to the Y-Right outport on the controller is not working. That what made me believe the issue is within the controller box.

@LarryM: Thanx a for the link. Thats a lot of info there! I’ll go through them and check. I see there are videos there on calibration too! That was what I was starting to check when I hit this snag.

@AlAmantea: Thanx! I doubble checked all the connections and reconnected the ribbons but the result is same.

The fact that this started in the middle of a carve probably means some loose connection somewhere. Now I’m starting to think some electronics has gone bad.

LarryM gave some good links. Let me try them and see if that helps somehow to narrow down where the issue is. I’ll update again after that.

@JayakaraKini If there was a loose connection during a carve, the motor could have been disconnected and possibly reconnected while powered. This could cause damage to the stepper motor driver which would cause what you’re seeing. Is this the X-Controller?

@NeilFerreri1 The controller box is not from inventables. This is Arduino+Protoneer v3.51 cnc shield based controller. Hmm… I’ll see if a new set of cnc sheild gets this to work. Thanx!

Don’t those have discreet, replaceable drivers? With the power off, try swapping drivers to determine if the driver is bad.

@NeilFerreri1 Whoa! Yes they do! I swapped the drivers and noticed that wherever the bad one is plugged in, that motor does not work!! Found the bad one and I’m ordering a new one now. Thanx a ton !!!

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@NeilFerreri1 Just to update, after replacing the driver the the Y-Axis is working.

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