Steppers not working right help please

Ok everyone I’m still having issues.

So I have the wiring correct I think. I know this because if I plug the x wires into the y slot the steppers work as the should.

So the issue now.

When I plug x axis into the x slot the steppers work for a min or to the jog as they should.

But once siting idle they make a high pitched whining sound ( Liston carefully to the video it’s quiet )

Then they stop working altogether and just vibrate back and forth

Vid 3 x steppers working plugged into y axis slot

Vid 2 x steppers plugged into x slot

Vid 1. Hi pitched whining noise turn your volume way up

The stepper motors whining is normal. Don’t worry about that.

It looks like you have a mini Rambo.

I’m not terribly careful myself with this stuff, but I get a little nervous when I see the Rambo sitting on a table and seeing bare copper wire pieces on the same table. You might want to make that a bit cleaner and check that there are no odd wires on the bottom. The ESD bags they come in are also not good to put them on. Do you have a case for it? Or maybe just some risers for the corners?

That crunching noise is caused by skipping steps. Nothing is wearing out. It just means the motor isn’t getting enough current to overcome the resistance to motion. That should be very rare on a machine with zero load.

Does the machine move smoothly right there when the Rambo is unpowered?

Did you have both X motors wired in both tests? I am worried you have both X motors wired in parallel, instead of serial wiring. That would half the current to each motor.

What power supply are you using?

I know you said the wiring was good. And wiring problems are a PITA. But I would take a close look at them again. This skipping steps can be caused by one open or intermittent wire. At least keep in mind that it could be the problem.

I noticed the belt path is a bit bent. I don’t think that is the cause, but you can reverse the motor pulley to make it site closer to the path of the belt.

Thanks for the reply. So the whining I’m talking about only happens when the steppers are siting idle

My plan is to get it all cleaned up but just trying to get it all working right. I have a case coming just watimg for buddy to print it out.

Yes everything moves nicely when not powered on

Y and z axis works well jogs Nicely only issue I have is the x axis.

As stated above when plugged into x axis port on the board it will work for a min or 2 then all of a sudden it’ll start making that crunching / skipping noise If I plug the x axis wiring into y axis port on the board there’s no issues with x axis moving no skipping no crunching. Seems to work well

I’m running a 12v power supply right now. I have a 19v one I can use But have not got that far

I know the belt paths are off a bit just trying to get all the wiring figured out.

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Can you share some more pictures of the wiring?

This was easier then trying to show all the wiring.

Keep in mind that the wire colours change according the the harness. Will include a pic or two

First pic shows the wiring colour change.

Second pic is what I used to wire it

Third pic is how my wiring is laid out.

So after posting the last reply I realized the wiring is wrong. Here is the new way I wired it. Does this look right ???

That doesn’t look right. If you follow the path of one wire, it goes through 3 coils. I am not sure why that would work plugged into the Y port.

Your previous picture, the hand drawn one, doesn’t look right either.

If possible, I would make the wires from the steppers to the mini Rambo a straight 4 pins. All the way to the Rambo board. You can then test the motors individually. After that, make a small 6in or so harness to do the serial wiring (like the picture you posted from the docs). That will let you test the motors and the harness separately.

According to the second drawing I posted and the diagram I posted my wiring in the second drawing would be correct

I wired it according to the second drawing I posted and it works now. Although I don’t want to burn anything out.

I’m really not sure why I can’t find a diagram that pins out the colour wires that come with the steppers I have.

Because there isn’t a standard.

Easiest way is the spin trick. Jumper two wires and try to spin the stepper, if it’s a pair, you’ll feel some resistance to turning.

I can isolate each coil by testing with a multi meter

What that doesn’t do though is tell me what coil is coil 1 or 2 along with what wires go where

It doesn’t really matter which is “coil A” or “coil B” (which is probably why there’s no real color standard). To make the motor take a step, the driver sends a pulse to one coil, then the other. As long as the coils aren’t crossed, any series of pulses results in a series of steps. If the coils are cross-wired you get a stuttering, kind of buzzing half step forward which then falls back. You can get the same thing if one coil is not connected, which is what makes troubleshooting experimentally such a pain. You can reverse direction by flipping one coil’s connections and leaving the other alone. There’s really no other adjustment you do from “which wire goes where,” the rest is controlled inside the driver.

I see it as a similar situation to the wires on a brushless motor. The ones I’ve seen for R/C planes and cars have all 3 leads black, for 3 phases. You hook them up arbitrarily and test motor rotation, and if it’s right you leave it alone. If you need the motor to spin the other way, you swap any 2 connections. No color code needed.


This is what this wiring looks like to me. That doesn’t look like the same wiring as this:

Your drawing shows the coil going from 1 to 3 on the mini Rambo, not from 1 to 2.

Maybe the disconnect is that your motors aren’t wired the same way I expect. I am just trying to help. If it isn’t broken, don’t fix it.

If you have a multimeter, you can check the pins at the mini Rambo for pins 1-2 and 3-4.

So wire colour does not matter as long as I have both coils isolated.

And I assume +/- does not matter either ?

So if I hook up like this pic then it should work and not fry anything ??

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That is correct.

That is wiring in parallel. It works, but it halves the current through each motor

The motors are robust and won’t be damaged if wired wrong, they just won’t behave as desired.

The most important thing for the “not frying anything” when working out the motors is to completely power down before plugging or unplugging motors to drivers. The drivers can die silently and immediately if the motor connection is changed while they are powered on. Ask me how I know.

That is great to know thank you very much

Kevin, if it helps you at all - I had some steppers that would not function correctly in series, I ended up wiring them parallel. I didn’t manage to work out exactly why but assumed there must have been some large differences in the coils.