Stepper motor skipping with when using double coil

[jonathanbyrn]

Hi,
I am trying to power a stepper motor with a V1.2 shield and a 12V 1 amp power supply. I ran the sample code from the motor library (powered by usb) and the servos and steppers started turning, much to my delight. The problem occurred when I connected the external power supply to increase the torque. After a couple of turns it starts messing up and jittering back and forth. I looked at the other questions on this forum and nobody seems to be having problems after a period of time, either it works or it doesn't. I also tried the stepper motor test and the error seems to occur specifically when double coil is called. I am operating it at very slow speed so I don't think that is the issue. Any ideas what might be causing this?

If you want me to post a video of the problem let me know and I will upload them.

I tested it on another motor and had the same problem, I have wired it red, blue green, black, as this is how it was set up on the 3D printer. This is the stepper motor I am using:
http://www.mantech.co.za/Datasheets/Pro ... L42STH.pdf

[adafruit_support_bill]

Please post photos showing your soldering and connections to the shield.

Also post a link to the specifications for the motors you are using.

[jonathanbyrn]

I have attached an image of how my stepper is connected to the shield. Here is all the information for my stepper motor:
http://www.mantech.co.za/Datasheets/Pro ... L42STH.pdf

I have been testing it and the board is getting very hot. I think this may have something to do with the problem. has anyone experienced this before and should I try attaching some heatsinks?

[adafruit_support_bill]

That is not an Adafruit motor shield. Please contact DK Electronics for technical support for their product.

[jonathanbyrn]

I hadn't even noticed that, I thought I was buying an adafruit shield. This is probably why it is oveheating. Apologies for the inconvenience.