Stepper doesn't turn

Hi,

So I've managed to put my first Prusa together. I'm at the point where I'm wiring the elctronics.

I have a sanguinololu and 5 x 42BYGH0425 steppers. When I try to make a motor move it makes the noise you would expect from it but it doesn't turn. It just steps back and forward a tiny bit.

I've fiddled around with the stepping junpers on the sanguinololu but that makes no difference.

With the power switched on there is holding torque and I have checked that I have the correct wires/ pair on the steppers.

Any hints and or help would be apreciated.

regards
Andy

Looks like your carriages have too much friction or your stepper drivers deliver not enough current. I'd start with the belts off, just the bare motor connected. Then turn the trimpot on the Pololu all to the left. Send a slow, long movement command to the controller, for example G1 X50 F10. Then turn the trimpot slowly to the right until motors start to rotate. This done for each axis, you can be sure your electronics works properly.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

Ouch, a broken stepper AND a broken stepstick, Murphy strikes (again).

How much did you turn the pot? We have a test program running that plays the imperial march from Star Wars. When we upload the sprinter firmware, we can't seem to operate the motors. There is power going to them, since there's resistance when we try to turn by hand, but when we send a signal from the software... nothing!
Perhaps the pots need to be readjusted for the new firmware?

Did you ever find a solution? I have the same problem. Here's a video of what happens: [www.youtube.com] . I've tried everything, triple-checked the wiring, swapped out motors, swapped firmware, controller, everything. Any ideas would be appreciated. Thanks.

@ Dorphaus

I have looked at the video. Two things spring to mind.

1) Incorrectly adjusted current (You have probably already tried this)

2) One motor coil wiring is inverted and they are fighting against each other. When you checked the wiring, did you just check the connections only or check which way around the coils are. Disconnect pin 1 and 2 and check with a multimeter. You should get continuity. If thats OK try switching 1 and 2 to over see if that works. Dont depend on the colour coding as this can vary across motor brands

Edited 1 time(s). Last edit at 02/15/2012 05:01PM by martinprice2004.

Thanks for the suggestions, I played around with it some more today. Unfortunately I didn't make any progress, the stepper is still acting the same way. I had adjusted the current before, but I did try switching the wires for each coil around (swapping coil A wire 1 to the other coil A pin, swapping coil A wire 2 to the original coil A pin, repeating for coil B ). I thought it didn't matter which coil A wire went to which coil A pin (and same for coil B ), but maybe I'm wrong. It didn't make any difference in my setup.

I also tried a brand new different model motor in place of my original motors that were the same model and I got the same results, proving that the problem isn't with the motors I'm using. I must have something hooked up incorrectly or there is something wrong with a component of my system.

Any further advice is greatly appreciated. Thanks a lot.

Edited 1 time(s). Last edit at 02/18/2012 09:18PM by Dorphaus.

@Dorphaus

Did you ever get it to work? I've watched your YouTube video and all of my stepper drivers are doing the same thing. I've tried asking on #reprap, but no one knew what to do.

Im having the exact same problem, Ive tried everything i can think of! any help would be greatly appreciated!

The video looks like the wrong wiring sequence to the motor, or only one coil being driven (bad connection or faulty driver).

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[www.hydraraptor.blogspot.com]

I've solved it. Originally I wired up my RAMPS 1.4 according to this diagram. It turns out that some NEMAs are to be wired differently. I had to skip the middle 2 and wire up to 1,2,5 and 6.