Jerky twitchy jumpy

Hi All! I’m wrapping up my build and have some issue to iron out. First my build specs: 36" x 36" pub height table with a 26" x 26" box I made to house the ZenXY. My Y arms are 24 3/8" and as suggested the X arms are 1/8" less. Motherboard is one I took from my 3d printer - Anet A8 v1.7 running your MiniRambo firmware with my Anet board specified as the BOARD in configuration.h, 240 Watt PSU from my 3d printer as well , two new NEMA 17 steppers from and the parts were printed based on the stl’s I downloaded from the link here. All the other parts were purchased from the BOM Amazon links here on this site.


Not sure the belts are routed correctly or tensioned correctly. Is there a good diagram somewhere?

When running a pattern I downloaded from Sandify (platter set as 600 X 600) it is real jerky. I tipped the table up 45 degress and could see the x carriage jumping and bouncing around funky. Video and pics can be viewed here:

Either I goofed something up with the belts or I really screwed something up elsewhere.

Help! This was supposed to be a surprise 50th birthday present for the wife. I’m now 2 weeks late and thinking I should have bought her jewelry! :slight_smile:



There are good diagrams at

From the looks of the video, you’re skipping steps. It also looks like the gantry is lifting up a bit, so maybe things aren’t totally flat?

Can you use pronterface and just use the x and y buttons to make sure its moving the right way? Or repetier host, or the lcd.

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I don’t know much about the anet board, but you did something like this?:

Is ther current setting in the firmware with digipots like the mini rambo? You shouldnt need much for the ZXY, but if it’s not set it would skip steps.

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Ok so after some head scratching and sitting on the floor under the table I discovered the Y axis stepper wasn’t really skipping it was locking up. I swapped both new motors out with the X and Y steppers from my Anet and Viola! a running machine! I have more kinks to iron out (homing, X_MAX_POS & Y_MAX_POS etc etc) but I’m a 52 y.o. college student that needs to switch gears and get some homework done…

I did a step by step with lots of pictures for my first build. It’s here and shouldn’t be too hard to find. :slight_smile:

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