basic stepper control

I have a six-wire stepper motor, and I'm trying to get it up and running with either the basic two-wire control setup. It buzzes, but doesn't turn.

Here's a pic of the layout:

+12v is at the lower right, Arduino is lower left, upper right is the stepper.

Stepper info:
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=238538
http://www.jameco.com/Jameco/Products/ProdDS/238538.pdf

On the stepper, I've determined that yellow and white are my common/center wires. Here's my chart to prove that:

As you might be able to tell from the circuit, I'm using Tom Igoe's stepper motor wiring, using the two-wire control method. I've wired the yellow and white to +12V, and the ULN pin 8 to ground. ULN pin 9 goes to the common wires (yel/whi) via diode, with the strip at the ULN end- HELP- is that the right end for the diode?

Based on the chart, I know that blue/red are linked through white, and black/green are linked through yellow. So I have ULN pins connected in this order, starting at pin 15 and going down: red/blue/green/black. I've tried switching the pairs: blue/red/black/green.

Finally, as far as software is concerned, I'm using the basic code straight from Tom Igoe's page. I've tried switching the two control pins (green/blue in the pic).

When the Arduino is powered, the motor buzzes, but doesn't turn. If I disconnect a servo wire (from the ULN), it'll at least rotate some of the time.

So I figure I've determined the pairings wrong, or I'm doing something else wrong. Can anyone help out? Would it help if I posted video of the stepper buzzing?

You may have the stepper motor's winding connected up in the wrong sequence. It'll only rotate properly if the sequence is correct.

Yeah, I figured the sequence is wrong, but how do I figure out the sequence? Just by guessing?

Just by guessing?

frade so. :frowning:

Did you ever get the motor working? If so, do you have the correct sequence/wiriing?

Thanks!