I just got the 4X version of the smoothie board and I have everything working except the Extruder driver. All the other drivers output enough power to turn the motors. The M3 or Delta port doesn't seem to change its current when I change it in the config file. If I give the motor a little help I know its trying to spin in the right direction but it is really weak.
Try another motor on that driver, and check your connector carefully. What you describe can happen if only 3 out of 4 wires are actually getting to the driver.
Still nothing. I have tried every motor I have and they all don't work on the M3 (extruder) port. If I only plug in the AA wires it does the same thing as if they were all plugged in. If I only plug in the BB wires I get absolutely no response. These motors work fine on all the other ports but everything plugged into this one just "ticks" and goes back and forth a little bit
Which shop did you buy the board from ?
I got it from Robotseed.
Stephane got me my new board without any hassle. It came in today and after a little set up and steps per mm calibration it is working flawlessly. I think the original board I got had its Delta capacitor soldered on a little crooked. The new one is on straight and everything is perfect. Loving this way better than the 4 ramps boards I went through previously.