Geeetech

I recently purchased a GEEETECH 3D Printer Pro B and was able to get it built successfully, but when I tried printing the extruder motor would not push the filament through. I was able to track the issue back to the stepper motor driver by moving it to the x-axis slot. When testing it on the x-axis the motor it would only move in one direction and just twitch in the other. After doing a little searching online I was to find a link to another thread
(viewtopic.php?f=17&t=17038) stating that it might be the voltage settings of the stepper driver. I tried turning the potentiometer to adjust the voltage, but it would only switch to 0 volts or 4.6 volts. I was not able to adjust it down to .8 volts like the other drivers. So I am thinking that I received a bad stepper driver, unless you can think of another fix for the issue.

The stepper motor driver my board came with is the A4988. See attached image.

If you don't home the printer after you start it, all the axes will regard the original coordinates as the home position and will only go in one direction.

I did home the printer when trying this. After homing I was not able to move the x-axis to the right it would only move the the left when I tell it to move left after manually moving the motor to the middle. I tried moving the x-axis through both the computer interface and the printer's interface. If I leave the potentiometer set to 4.6 volts everything works as expected and the motor moves in both directions, but it runs louder than the rest. I am assuming it is not good for the stepper motor to be running at 4.6 volts.

the voltage should be 0.8-1.2 V.if the voltage is much more than the value,the motor's temperature will be high.

Ok, I just wanted to verify that. I think I received a faulty stepper motor driver then, because even turning the potentiometer a 1/16 turn in either direction drops the voltage down to 0 or 4.6 there is no middle ground. I cannot get it set to 0.8-1.2 V.

So did you try swapping a driver for your X motor to take a look?
Maybe the one of X was broken.

Yes, originally the extruder motor was the one having the issue. I swapped the that stepper motor driver with the one for the x-axis and then x-axis had the same issue and the extruder motor was fine. It would only move in one direction, I think this was because the driver wasn't supplying enough power because of the bad potentiometer. I tried adjusting it but I cannot get it set to .8 -1.2v volts.

If that is the case,i guess you can ask your seller to send another one?