Motors just vibrating and not moving in one direction

Hello all,

Im currently putting together a Prusa i3 and have hit a road block. The motors (all of them X, Y, Zs, and Extruder) will not step in one direction. They move back and forth erratically. I have adjusted the trimpots on the drivers in different positions from completely counter-clockwise to over half-way. Turning them up just causes more vibration and noise.

I got the Arduino 2560 and Ramps 1.4 (all 3 jumpers for micro-stepping on each driver slot) with A4988 stepper drivers in place. The thermistors read correctly and the heatbed heats ups just fine. I have currently running Sprinter firmware(I have tried Marlin and Teapot also with the same results). I'm using a Xbox 360 PS (203w).

I have also flipped the wires around for the motors (NEMA 17) but no change. I finally tested with a motor just sitting by itself and the shaft just steps back and forth.

Here are the drivers I purchased (http://www.ebay.com/itm/140967386673?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649).

Any advice on how to troubleshoot this issue would be great.

Thanks

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Prusa i3
Greg Wade v5 Extruder
Jhead hotend
Ramps 1.4 using Marlin

Tried to run motors with no load at all?

Looked at this? :
[reprap.org]

Itek,

Yes I pulled the extruder motor off and put it my workbench by itself and it hold it up to the Y driver and then the E0 driver. I got same results, just steps back and forth..

Thanks for the link about the stepper drivers. I'm going to contact the person I bought them from to verify the sensing resistors ohms. Also I will test one of them.

Looks like I made a rookie mistake... I bought stepstick drivers instead of pololu...so I looks like that is the problem...

So the difference in ohms on the sense resistors is likely causing the issue. Could I change them out from the 0.2ohm to 0.5ohm or Im better off just buy the pololu drivers and selling the stepstick?

Your problem is likely firmware or wiring related. I've used stepsticks for years, no problems what so ever.

PROBLEM SOLVED!

Solution: Wiring diagram that I was looking at for my motors was incorrect and the wires came shipped that way too. The 4 wires were crossed... I corrected the wiring and all is good!

Thanks for everyone's input on this issue.