Help me i'm stucked, as much as my steppers have done...

Greetings for all, and thank you forward for helping me.
I'm new for the 3D printers, and new for electronics.
I just finished my own 3D printer. I built in used stepper motors (bought from ebay, technical parametrs: 1,2A 5,16V ) and everyting works fine, except the steppers. If i send them to -direction, they don't move at all, but if i send them to +direction they make buzzig sounds, and they "want to move", but they can't.
It's not a mechanical problem. All of them is movable very easily by hand (schwitched off, of course)
I have adjust the pots on the stepper motor drivers, to 3 different value. First between 0,425V and 0,450V, because i heard that vellemann k8200 works on 0,425V.
Then i saw somewhere , that A=Vref/0,4, so i modified all of them, to ~0,48V , without any effort.
Then i just turn them up to a high value ~1,2V, but the result was the same.
I checked the wires, they are not broke, not burnt.
I have also changed one of the drivers (i have a spare stepper driver) to check if this is my problem. But it wasn't.

I had missed something out from the marlin code?
Have anybody experienced something similar?
I'm puzzled.

Thanks for all!

David

hello,

first i would try turning the speed of your motors down (the feedrate) - if they are trying to turn too quickly they will just buzz. You should be able to do this in your software (i know you can in Repetier Host).

Secondly I would double check the wiring of the motors, google will be able to help you there, you could also look here: [reprap.org].


I'd keep the Vref down at about 0.4V, you can damage your motors by turning it up too much for too long

Thank you so much T0mmm! My problem is almost solved. There were some wiriring problems.
Now the Z axis is working perfectly, but the X and Y won't. It has some movement, but only if i move it just <=1mm. If i move it 10 or 50 mm just make sounds, but not turns effectively. And in every movement, the motor vibrates a bit.
Somebody have any idea what could be wrong?
I also changed two motors (z and y) to see if the motor has problems, but unfortunately, after the change the Y motor on Z cables worked fine, but the Z motor on Y cables not.
Whats the optimal value for feedrate/acceleration/ ect. Can this cause this kind of problems?

Thanks forward, for all!

David

The issue of them moving in only one direction is an ENDSTOP issue.

You need to setup your endstops.

The firmware is only allowing you to move the motors in one direction because they are not HOMED
(the printer doesn't know where it is, and is trying to prevent you from colliding with something)

Thanks ShadowRam! I really had problems with the endstop wiring, i changed the order of wires, and the endstop is working properly.
However, its not solved all of my problems. (unfortunately) The x-y axis stepper motors won't step... But i'm working on it!

Thanks for all!

David

Have you found an answer to your problem yet? My steppers are doing the same thing and can not figure out what to do.

I've started a new topic in eletric group, i have got two answers, but i didn't have the time yet to try. Maybe on thursday.

Sounds like the steppers are wired wrong. The pairs on the steppers I'm using are red/blue and black/green. Try swapping the middle two wires and see if it starts moving. Then check the direction and swap either the first two or last two to correct it.