My Prusa Mendel stepper motor is spinning really fast or doesn’t do anything. I just exchanged the stepper driver for a new one.
When i manually (pronterface) extrude 5 mm everything goes well, but when i start the print, the motor does nothing. When i turn up the current the motor starts spinning.
I have no idea what this could be. I didn’t change anything except the driver. Settings and firmware are exactly the same.
Do you by any chance have your acceleration or speed set to a ludicrously high number?
No. I never changed anything like that.
@Mano_Biletsky_Open_M So it worked fine at least once before then? What stepper driver? Did you set the microstepping?
Yes indeed. It has worked for 2 years, since i got the printer. I have a pololu type 4988 if i’m correct. I checked and that is the correct driver. Microstepping is set to 16 steps as it was before.
It makes noise too!
Your current has to be set right. Not enough and it will not move. Too much and it gets noisy.
If inturn the current down untill it makes no noise, it won’t move either.
@Mano_Biletsky_Open_M That reminds me of a motor on my CNC machine which uses POTs on a grbl shield on an arduino uno. The one motor will never move if the POT is turned down low enough to not whine. It insists that it must be allowed to sing out a specific note.
I just found the problem. I has never been a printer problem but a corrupt gcode file. I tried with another file and everything works fine.
Thank you so much for your help though…
hmmm…good luck finding out why the file was corrupt and stopping it from happening again.
@NathanielStenzel It seems to have something to do with slic3r. When i use the slicer from within pronterface, it uses the default config. When i print that, all goes well. But when i open slic3r and use my own configurations file, it says the print needs 81meters of fillament. Where it should accually be 81centimeters or 810mm. Somehow (even when i did not update pronterface or slic3r) the programm gained some issues.
I downloaded the newest version but the problem persists. Files with these ridiculous high fillament use are the ones that keep spinning my extruder at high speeds.
@Mano_Biletsky_Open_M (face palm) I had the same problem with Repetier Host and Slic3r. Repetier Host was reading one config file while Slic3r would use a different one when used directly. I do not remember if I had any manually installed Slic3r or not. I honestly gave up on Repetier Host due to a combination of that problem and the Mono crap that it used constantly choking up and dieing on my Linux box. I no longer slice anything using a slicer called by another program now. I just find it safer that way. Also, Cura does not seem to connect to my printer for whatever reason.
I found the problem. My extrusion multiplier was supposed to be at 0.98 but i guess i lost the “0.” Somewhere 
So the multiplier was set to 98 instead of 0.98.
So i guess i never had to replace my stepper driver in the first place. It was just a software setting…
@Mano_Biletsky_Open_M congrats. You now have spare parts.
Spare parts $15. A better understanding of your machine… priceless!