Issues with stepper motor and cnc shield

Other Hardware Motors, Mechanics, Power and CNC
1

I will try to explain this well.
My son and I are trying to do a project that involves a nano, a cnc shield with the $4988 drivers, and a couple steppers. The problem is, the motors and shield with driver breakouts are from aliexpress and I cannot find a good datasheet on either. AND it appears there are some typos in what they did have.

Essentially our main issue is that we cannot figure out the A1, A2, B1, B2 wiring. We can get it to jitter a little but it is not moving reliably. I installed GRBL and flashes the Hex to the nano controlling this, but it mostly makes the "falling bomb" noise.

the links to the two things we are troubleshooting are:
https://www.aliexpress.us/item/3256806887945088.html?spm=a2g0o.order_list.order_list_main.35.d09218028Pjp65&gatewayAdapt=glo2usa#nav-description
and
https://www.aliexpress.us/item/3256806552557516.html?spm=a2g0o.order_list.order_list_main.17.d09218028Pjp65&gatewayAdapt=glo2usa#nav-specification

I am seeing that if this is a "Chinese knockoff" I might have to fix the traces because the thing is pulling the jumpers to ground not HIGH. BUT I am not trying to enable microsteps yet, just get it to move correctly without the noise.

TLDR.
I bought some cheap stuff off of aliexpress that did not come with thorough documentation and the documentation that was available seems erroneous. Getting these things wired correctly is my main priority right now.

Thank you.

2

Pololu supplies this wiring diagram for the A4988:

600×361 54.1 KB

If you have a DMM, you can test that whatever coils you are hooking to 2B&2A or 1A&1B have continuity. Some of the other drivers use different names, but it is one coil on one pair at one end of the 4 pins, and the other coil on the other end of the 4 pins.

I think these folks might be the designer of the shield:

https://wiki.keyestudio.com/Ks0096_keyestudio_CNC_Kit_/_CNC_Shield_V4.0_%2B_Nano_3.0%2B3pcs_a4988_Driver_/_GRBL_Compatible#Connection_Diagram

3

I did not know it was possible to test continuity for each coil...I never thought of that. That helps a lot.
I just smoked a NANO. Not sure how, I had it connected to my PC without anything else connected and it smoked. Very strange. Glad I have a dozen more.
It is pretty bad quality.

Also yes they were the OG designers of these shields but someone ripped them off and got a few things wrong...apparently. I did the modifications of removing the traces from GND and jumping them over to 5V which enabled my ability to mod the microsteps. Making progress...slowly.

Thanks.

4

Just swap over A1 and A2 and it should move.

By the way this is an international forum so be aware that "spazz" is considered a very offensive word in the UK and other places as well.

I am aware that many Americans do not find it offensive but even major corporations have been guilty of ignoring this fact, only to have to retract and apologist for using the term.

5

I had no idea. I modified my original post. Apologies.

6

Thanks for being sensitive to these matters.

7

UPDATE:
I have it moving. It jitters at the beginning and end of each motion. I have corrected the mistakes by modding and jumping the traces to the way the original designers intended pulling my 9 jumpers to 5V instead of GND. This is a clone board apparently. SO the jittering is very odd, and so isn't the unreliable direction. It will go the right direction several times, then next command it will go backwards...very very strange.

I do thank those that are responding. I love this community...so very helpful.

8

This sounds like the direction pin is floating, that is not connected to anything.

9

I can confirm it is connected to D2 and the step is D5. Just as the GRBL wants. I did a continuity check on it...I will check to see if I can figure out how to see if it is flipping tomorrow...

10

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