Hi,
Get ahold of jeff hes excellent about getting that board fixed. I just did the same. It was either a bad motor or a fluke chip. I sent it back and he fixed it for nothing. You really can't beat his service. Also you want to make sure you dont unplug your motors when you have power going to them. I think that will smoke something too!
About your stepper, Take a mutimeter and check the ohms. find the wires for each coil. I think your center tap wire will have a higher ohm rating.
I have a cheap multimeter i use. It has a setting that sets a squelling noise off when you make a connection with 2 wire that are from the same coil. Thats how I find the wire for the same coil. I then check the ohm reading of the wire for that coil to determen the center tap wire. Which like I said before should be higher.
I then wire my motors to half wind mode. Which give me the fastest speed and higher torque on the top end. to get half wind mode, you take the center tap wire and and another wire from the same coil and connect that to the A's do the same for the the other coil and connect that to the B's. Tape the other wires off. Hope this helped you out!
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