As I said in the title there is some issue with my z axis steppers. They will make a humming sound and vibrate a little but won't actually spin. I'm fairly sure this is an issue with the firmware (but I might be totally wrong) since they turn when the wires are switched with the ones for the Y axis and swapping the driver board for a spare had no impact on them. Any help would be appreciated. I am using RAMPs 1.4 and marlin firmware.
Try connecting Y-motor to your Z ports. If Y-motor will behave like Z-motors, then there's problem with your Z ports, be it hardware or software. I'm not a RAMPS user, but have heard that there is voltage regulator for every motor port. Sounds like your motors may be underpowered.
Let's tick off the factors you have already checked for.
It isn't the driver board, because the Z driver board drives the Y motors. It could be the Z motor itself (or the cable), which you could test by plugging the Z motor into the Y driver board. If only one of the two motor coils were being energized, it would cause vibration but generate no motion.
@ZuOverture suggests it could be the drive current setting on the motor driver board. Possible, especially if the Z motor requires more current.
It is also possible that the output pin from the Arduino Mega board may be bad, or not connecting well.
To investigate, find the step and direction inputs to the stepper driver board. Use a voltmeter, logic probe, or oscilloscope to verify the signal levels. If the signals don't jiggle when moving the motor, then follow the wires and check at each point along the way.
You could also plug in a replacement Arduino, which you have programmed with the firmware, and check if that works.
If the Arduino pin is bad, you can keep it in your junk box for future projects.
Looking at the firmware angle, one would check the speed and acceleration settings for the Z axis. When in doubt, try slower speed and lower acceleration. Z-axis performance doesn't make much difference in the printing speed.
Hello it's seems to be the voltage regutaltor on the steppers drivers for the nema motors. Check to adjust the voltage with a multimeter connecting the red pin from the multimeter on the voltage regulator on the driver and the black pin on the GND pin on the ramps 12v connector.
Also make sure that you have connected the jumpers to setup the microstep resolution:
Full step,Half step,Quarter step,Eighth step,Sixteenth step