Z axis not moving up. RAMBO

Just started trying to wrap my head about how to wire this all up. I have a RAMBO board, LCD and the Z 84oz steppers wired up. I’m trying to raise and lower the gantry but its only moving down. When I flip the whole assembly upside down the motors will move in both directions but doesn’t seem to want to lift the weight of the gantry even without the weight of the router. I can rotate the lead screws with two fingers pretty easily when power is both off and on. I’ve also bored and cleaned up the hole for the lead screw nut in case warped parts is causing any binding.

Is there any settings or firmware things I need to worry about? I noticed the LCD looks like its set up for 3d printing. I’m all new to this kind of stuff, I’ve got mechanical aptitude, but wires scare me.

These are the steppers I’ve purchased:

Any way of testing them? If one goes bad will it affect the other?

By build is 28" X travel.

What firmware, and how did you wire the steppers? Did you buy anything from here, if so what, and if not you need to give a lot more details.


Pictures of your build will help, people have been assembling things backwards.

There could be a couple other culprits causing the issue, but id like to go through and see if its anything easy before I go and cut out new flat parts or reprint pieces.

Got the board, power supply, lcd, wires all from you. splashscreen says bugfix 2.0

After a little more investigating, both motors are fine, and mechanics are fine. If I unplug 1 motor (with power off) then the connected stepper lifts up the gantry perfectly. If I unplug the other stepper, the other side works just fine.

Have you tried to wire the steppers in series instead of parallel? Running them in parallel means roughly half the current goes to each stepper, reducing their torque. In a series winding configuration, both steppers get the full current. See Ryan’s wiring page for more info.

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Does the gantry fall on it’s own when there’s no power?

I thought Ryan’s wires were series. If you have it wired in parellel, then the current setting on the Rambo isn’t high enough for two motors. Series is better, just a bit more complicated.

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Yup, series.

Why the new end caps?

Wired in series now and works great. I had ordered the dual endstops wiring kit to be used at some point in the future. Ill be explaining the new endcaps in a build thread once I get this all up and making a mess. Thanks for everyones help figuring this out.