New Primo. Hard movement, steppers just grind

New build.
23.5 conduit, PLA prints.
All parts are either from V1 or obtained from V1 links.
Rambo 1.4

Everything seems square. Diagonals measure up right, and measuring from trucks to corners all match. I only have xyz steppers connected to board, no endstops or anything else.
Confirmed steppers are moving in correct direction. Movement is fine if I give core some help in moving, but other than that steppers can’t seem to move trucks.
Before installing core and belts, movement was super easy. After core, little more difficult. Belts, much harder to move.
I’ve now taken apart and rebuilt 3x thinking I had bolts to tight, bearing stuck, something.
Any help is greatly appreciated.

Sounds like a stepper wiring issue. Could also be that barrel connector from the power supply, most of us just cut it off and wires the power supply directly to the board.

The grinding noise is typically the stepper skipping steps, though you could also get a grinding noise if the grub screws in the pulleys are not tight and the shaft spins. The noise coming from lost steps sounds ugly but is nondestructive.

Make sure you have the belts routed correctly in the trucks, and make sure the belts are not too tight. They should be just tight enough that they make a low thrum when plucked. Also check your grub screws.

Make sure your firmware matches your build. For example, if you have the serial/series firmware and are doing a dual endstop version, one of the steppers on each axis will be unpowered and being dragged by the second stepper. Though if you’ve “Confirmed steppers are moving in correct direction,” this should not be an issue.

Is it the same at all positions, or does it get worse closer to any corner or rail?

Thank you all for the help.

Removed the barrel connector and wired power supply directly.
Checked stepper wires, I’m using series, all wired tightly and correctly. I’m using the wires from V1, I didn’t make them myself.
Took one end of belts off, ran steppers. Both pairs turned as expected, so this should rule out having the wrong firmware on the Rambo, as if it was wrong firmware only one stepper would turn, if I have it correct in my head.
Checked pulleys. I had loctited when installing, and they are still tight and none were loose.
Happens no matter where, not just in one specific area.

I did loosen up belts and this helped Y axis to where it’s probably fine now.
Tried same on X, starting with extremely loose and tightening slowly. Could not find a sweet spot to where they worked without me giving them a little help.
Here’s a video, should help, also shows belt tension.
Thanks again!

Those are not my steppers. Did you get 0.9 degree ones or super high amperage? Maybe they are wired differently and the pairs are in the other positions?

Those belts look much tighter than mine.

I use the same motors, I think. Steppersonline, P/N 17HS19-2004S1

With the power off, I can move the gantry around quite easily. there is a little bit of resistance to movement from friction, but not a lot.

I did get the steppers from amazon, but they were the ones from your link. Specs seem to match ones in your shop.

I know ease of movement is relative, but I wouldn’t say mine moves easily with power off. It’s much more than just friction.
I’m going to try loosening them even more, and seeing if disconnecting steppers from board makes any movement difference as well.

Thanks all!

I get the strong feeling they are not wired the same for some reason.

Is that a genuine Rambo purchased here? If not they do have the stepper ports wired wrong.

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I’d suggest going back to basics and ensuring you’ve got the coils in the steppers properly identified. Measure resistance to find a coil, or short wires until the motor gets hard to move. Colors of wire can’t be trusted - I’ve had them change between different batches from the same supplier.

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Purchased the rambo directly from you. It’s running default firmware that came on it, 510S

Steppers are listed as
Black A+ Green A-
Red B+ Blue B-

Just checked one stepper with a meter and the pairs checked out.
I have X and Y wired the same, using wiring sets from V1 shop.
I have not verified wires on V1 harness are correct because I just assume they would be.
Harness connection to rambo is blue-red-green-black, with blue going to first pin

Steppers connections on left:

Loosened up belts to where they were to loose for the pulleys to grab them, then tightened a bit at a time till pulleys could grab. Still just grinds unless I help by gently pushing the gantry.

How about your z axis is it working correctly?

I ask because that would bypass many of the questions about the build friction and wiring order and also determine if the drivers are being powered properly.

Yep Z works fine. Granted I don’t have a tool mounted yet so not a lot of load on it, but it operates flawlessly.

Y axis mostly works, a bit of chattering and missed steps, but way better than X.

None of this makes sense.

We need to step back. Take the belts off plug the steppers in directly. If they work and have pretty good torque it is something with the series wires. If they do not, it is the steppers or the board.

Test every stepper and each X Y Z socket.

Be sure to unplug the power before moving the plugs.

Wait a minute

Yeah try that.

I just verified the pairs and the ends of the series wires that you showed. Can you show me the female end of them just to be sure.

The other thing to try is find “inititialize eeprom” in your LCD. Run that. That will make sure no setting got messed with.

The sounds are either bad wiring or trying to move way too fast. That is not what skipped steps sounds like.

That really sounds like an electrical issue to the steppers. Like one of the connector ends has a bad crimp or something.