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New A4988 Stepper Driver Not Working

Posted by Ynothna 
New A4988 Stepper Driver Not Working
January 15, 2017 04:39AM
Hey everyone,

So I just got my first printer on Thursday, the FLSUN Prusa i3, and after putting it all together realized that the board that comes with only has one Z axis motor connection, but two Z axis motors. They supply an adapter to connect both to the single connection but it was missing from the kit. They're shipping me a replacement, but in the meantime I wanted to try and get things up and running.

I made my own adapter and it seemed to work just fine, but sometimes my Z axis was just a little bit off, messing up prints, so I'm not sure if I have a voltage fluctuation or something throwing my alignment off. I'm fairly new to electronics assembly so please excuse my lack of "know anything".

My board does have an E1 connector that I can set for Dual_Z_Stepper_Driver (which I have tested and it works). But I'm was stepper driver short of having a full set. So I found a place nearby (an hour away) that sells the A4988 stepper drivers, and I picked one up. I just tried to fire it up and nothing, the motor doesn't respond, no matter which axis I install it on. I made sure to set it to the same current as the others, all the motors and axis work with my original drivers, just not the one with the new driver plugged in.

This one is green (standard edition?) while the others are black edition. From my understanding they are interchangeable, black just handles load better. Am I wrong? Is there something I'm missing? Is there something I can do to test this driver so I know if it's faulty?

Any direction would be hugely appreciated, I was hoping to get some more calibration done tomorrow before leaving for a week but I'm at a bit of a stand still, haha. Worst case I also bought a spare Ramps 1.4 board with dual Z axis plugs, but it's very different than my current one and I have no idea how to actually assemble it...

Re: New A4988 Stepper Driver Not Working
January 15, 2017 09:36AM
With the machine off, turn the Z steppers by hand and see if one of them is noticeably stiffer to turn than the other, which can cause missing steps. If this is the case then you need to have a look at the alignment of the stiffer one with respect to motor, flexible coupling and die nut. Unless you solve it this will continue to be a problem even if you run the Z motors from seperate steppers. The Anet A8s happily operate with the two running off the same stepper driver. The Z leadscrews should be reasonably parallel to the plain guide bars, I've seen some machines where the distance between the two holes in the X axis moulded ends is incorrect.
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