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Laser engraver A4988 driver problem!


Hello, I started a project to a laser engraver and I chose as the driver “A4988” because I can use with Arduino shield grbl code. I was already in possession of two stepper motors a NEMA 17 “103H5210-4240” and a NEMA 23 “103H7123-0140” both engines are from 1A per phase and a minimum of 24v power. Unfortunately, connecting all, drivers fail to move the engines, powering the shield with a power supply of 24V and 4A. What am I doing wrong ?
Thank you all
sorry for the bad English


Have you installed the 100µF capacitor across VMOT and GND as shown in the minimal wiring diagram in the “Using the driver” section of the A4988 product page? If not, it is possible that you damaged the A4988 with an LC voltage spike since you are using a 24V power supply.

Also, have you set the current limit for the A4988 to the 1A rating of your stepper motor? If not, you should set it per the instructions and video in the “Current limiting” section of the A4988 product page.

If neither of those things help, can you post some pictures of your setup that show all of your connections?



ok, I get it, so it should work! however, I use one shield Arduino Arduino Nano CNC v4 and grbl code, but then setting the current limit to the maximum I can not make these two stepper! the shield is this …
what’s wrong? I have to set the maximum or minimum?


Since I am not familiar with your shield, it would be difficult to help you troubleshoot your problem while the A4988 stepper motor driver carrier is installed in the shield.

I recommend connecting the A4988 according to the “Minimal wiring diagram for connecting a microcontroller to an A4988 stepper motor driver carrier” in the “Using the driver” section of the A4988 product page, and setting the current limit using the instruction from the current limiting video on the same product page. You should then be able to test the A4988 carrier to make sure it is functioning properly. Once those have been done if you are still having a problem you please post pictures.



Good morning, I also tried to make the connection without using the shield as the minimum wiring diagram, I have “played” with the potentiometer the turning driver while the engine was working but nothing engines do not go!





Thank you for adding those pictures. It is clear from them that you do not have our A4988 carrier. I recommend contacting the manufacturer of those boards to see what they recommend since there might be differences in how to set the current limit of their carrier (as well as other things).

By the way, “playing with” the potentiometer is probably not a good way to go about setting the current limit , and might lead to damaging the board or stepper motor.



I’m sorry, so this is not your A4988 drivers?
it seems to me that the pinout is identical!


maybe there seems because I applied a heat sink???


I am very sure that the A4988 driver in your picture is not ours (many companies make divers with the same form factor and pinout of our carriers). Your heat sink was not a factor in identifying the driver. The silkscreen and component placement on your driver is not the same as our carriers.



it’s true you’re absolutely right, I compared the images and is not the same drive, however, but the pinout is the same, to what I have to set the vref for engines that I have?

it is right that I connect to GND and then the potentiometer? but how should I measure?


The pinout might be the same, but the components and values for the components could be different, so the process and formulas for setting the current limit could be different. As I said in my last post, you should contact the manufacturer to get further instructions.