Failed Crown-test

ORDER #4018

I have completed the assembly of MPCNC and plan to use it as a router.
However, on the crown-test, some problems started.
“Repetier” with pleasure lifts the Z-axis upwards to any given values.
Down he does not always lower it. Approximately 80% of the commands for moving the Z axis down are simply ignored.
When we try to draw a crown, we see devilry.
The axes move chaotically.
It seems that the X axis periodically thinks that it is the Y axis.
The Z axis for some reason only moves upwards. Moreover, it moves with every turn higher and higher.
The problem is repeated on the versions ReptierHost 1.6 - 2.0 - 2.1
WinXP, Arduino 1.85, Marlin 1.1x

You only bought a mini rambo, what else is plugged in and how are your steppers wired? Are you using my gcode or did you make your own?

Thank you for the quick response.)


Exactly. MiniRambo.

Plugged? Steppers only. Serial wired. Nothing else.

Im using my own Gcode. I use the code ELTSCAM generated exactly according to your recommendations.

Use my gcode so you can eliminate the biggest possible source of error.

Of course. I’ll try your gcode.

But, what do you say about ignoring the comand “down” on the Z axis?
The system shows this even without any gcode.
This is normal?

Too fast of commands, binding, loose wire. Usually the gcode when going that direction.

I tried your code.
The problem persisted.
Therefore, it’s not about the code.

It seems to me that the problem in mini-Rambo.
How to make a full reset of the board to re-fill the Marlin?

Can you move the Z axis all the way up and down very easily with your fingers just twisting the coupler?

I really doubt re-flashing the board will change anything, I also strongly feel you should try everything before you do that. Can you put up some pictures of your build and wiring. maybe what size steppers you bought, what voltage you set the drivers to? All that is much more likely to be the issue. If you just work with me here we will go in order of common issues. A video of the problem will also help.

Are you using a leadscrew or a Allthread?

Have you seen the troubleshooting questions at the sticky post on the top of this forum?

Here is a photo of the assembly.
I can send you additional photos of settings and videos of devilry to email or in any other way.

Upd: I sent more files to your e-mail.

So the red flag I am actually seeing here is I am fairly certain you do not have my firmware. Your repetier host says your extruder is at 11.6C. That is not correct for either what I receive the boards with or what I ship them with so somehow you have something else on there.

If you move each axis 50mm, does it move exactly 50mm?

“He’s alive!” (с)

It’s a delight.

Many thanks.


Houston Ryan, I have a problem ©

I`m watching a new devilry in athe execution of the G-code.

This is some kind of failure of the algorithm.

I drill 6 holes with a distance 20.5 cm

In fact, it turns out that the mpcnc drills first 19.7cm, then 20.5 cm. Then again 19.7 and again 20.5

Take a look please:


Draw a large square and see if it has equal diagonals.


Diagonals are not the same.

They need to be. If you have the dual firmware you need to calibrate, if not you need to measure your rollers before you start.

Dual firmware?

“Repetier-Host 2.13” and “Estlcam 11.02” its all.

Will I need some more calibration software? Which one?


Can you upload a picture of your machine please.

Dual endstops you mean?

I dont have them.

I catch quadrature by printed devices.