Stepper motor not spinning

First and foremost:

I'm new at 3d printing, I know nothing about electricity and what not. I bought a folger tech kit prusa i3, assembled it, ran into a lot of problems, which I solved. Finally I found a problem that I can't solved. My stepper motor (one of the two on top that control z axis movement) doesn't work right. It jitters. I was told that it maybe the voltage. So I bought a multimeter (never have used one) and downloaded a page that tells you how to tune it. Problem is that It has calculations and verbage that I don't understand. I was wonder if anyone could take the time to tell me how to check the voltage on the ramps board. Tell me where to put the black cable and the red and what numbers I should get. I know it is tedious to explain things like this to someone that has no idea but I would REALLY appreciate it. Thanks again. Any info will help.

This post nicely illustrates my point that printer electronics that doesn't provide software control of stepper motor current should be consigned to history, or at least not used in kits aimed at people without an electronics background.

There are some videos on YouTube about current adjustment such as this one [www.youtube.com] - not sure if it is any good though, I haven't watched it all.

Edited 1 time(s). Last edit at 08/18/2015 04:59PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

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meeuuch
First and foremost:

I'm new at 3d printing, I know nothing about electricity and what not. I bought a folger tech kit prusa i3, assembled it, ran into a lot of problems, which I solved. Finally I found a problem that I can't solved. My stepper motor (one of the two on top that control z axis movement) doesn't work right. It jitters. I was told that it maybe the voltage. So I bought a multimeter (never have used one) and downloaded a page that tells you how to tune it. Problem is that It has calculations and verbage that I don't understand. I was wonder if anyone could take the time to tell me how to check the voltage on the ramps board. Tell me where to put the black cable and the red and what numbers I should get. I know it is tedious to explain things like this to someone that has no idea but I would REALLY appreciate it. Thanks again. Any info will help.

I am not 100% sure what your voltages should be since I did not really "tune" my stepper driver, or really need to. The way I have my drivers set is to have them about 1/4 of a turn away from being completely counter-clockwise. The way to take your readings is to contact your multimeter's red (positive) lead to the potentiometer (small silver screw) on you stepper driver, and the black (ground) lead to one of the black (ground) terminals that connects to your power supply. Be EXTREMELY careful not to let you red lead slip or touch anything on the driver other than the pot. Lots of people have blown their stepper drivers doing that.
Also, check to make sure that your stepper motor is not bad by check the continuity of you stepper motor coils. Do this by switching you multimeter to either read continuity or resistance (ohms). Contact one lead
to the outermost pin, and the other lead to the pin next to that one. Do this again for the other pair of pins. A good stepper motor will have continuity on both pairs of pins . One more thing; there is a official thread for this printer Here. If you need any help with this printer, there is alot of information, and a bunch of helpful people there that may be able to help you out ( including me )

Edited 2 time(s). Last edit at 08/18/2015 06:49PM by Mach.

Thanks for helping me out!!!! So I've been messing around with the small crews on the board and then as I was turning it the motor started turning again. But it'll turn for a bit then it locks up then it starts again. No matter where I turned the screw it did this. Do you think it is the motor or do you still think its the board? I tried doing what you said for checking the motor but I was not sure as to what side I'm checking and where the ground goes. In other words do I check the cable connected to the board or the cables that connect to the motor?