Z-Axis Only Makes Noise

Hey everyone,
As I've been getting my printer set up I've run into a problem with my z axis. When I engage them using printrun the steppers make a noise but dont move at all. I tried changing the mm/min and all this did was change the pitch of the noise the steppers make. Both steppers do this. When I hit the .1 move button it just makes a sharp noise and jolts. The jolting does not move the axis though. If i press the 1cm move button it jolts and then hums for a longer time, then after humming for a short time the steppers will make a very high pitch noise that will not go away unless I press the "motors off" command. I know that my threads are easy enough to move for the steppers because I have tried them by hand and it was smooth. Does anyone know what the right mm/min should be b/c I've been going off of 400 to test but have tried many others as well.

Thanks a lot

What's the DEFAULT_MAX_FEEDRATE in Marlin? I found I had to change the defaut from 5 to 1 to stop Z-axis chatter.
Also have you set the pot on the stepper driver?

Steve

Thanks for the response, I just changed the default feed rate and am doing some testing....OK I updated the Marlin and I'm still getting noise with no movement. What is the pot of the driver?
thanks

UPDATE I was doing some more testing and I set the mm/min on Printrun to 1 and it worked! but it took a super long time to go down 1cm haha, I bumped it up to 5 and thats a nice speed... For some reason though it won't go down further than a certain point and I'm not sure why. It is not anywhere near the bottom but I think the machine thinks it hit its max.

Quote
erikn
UPDATE I was doing some more testing and I set the mm/min on Printrun to 1 and it worked! but it took a super long time to go down 1cm haha, I bumped it up to 5 and thats a nice speed... For some reason though it won't go down further than a certain point and I'm not sure why. It is not anywhere near the bottom but I think the machine thinks it hit its max.

If you don't have your end stop setup the axis won't know the limit of it's travel.

Steve

I have my endstop set up at the bottom of the printer but the z won't even go anywhere near it. It goes up as much as I tell it to but when I want it to go down it will always stop at the same spot. When I tried sending the homing command it just made a very high pitch noise for a long time and did not move at all. I looked at the settings in printrun for printer hight and it was at 10cm which is very short so I raised it to 230mm but that still did nothing.