Problem with ULN2003AN

Hi.

I am having an issue with the ULN2003AN driving a stepper motor. The motor in question is this:

http://www.ebay.co.uk/itm/NMB-Linear-Actuator-2-phase-4-wire-Stepper-Motor-5V-9V-6V-small-motor-For-DIY-/361162808335?pt=LH_DefaultDomain_3&hash=item5416fb1c0f

I have used the wiring diagram and code similar to that in:

http://www.geeetech.com/wiki/index.php/Stepper_Motor_5V_4-Phase_5-Wire_%26_ULN2003_Driver_Board_for_Arduino

I originally connected the motor to pins 9-12 of the arduino. I know I shouldn't do this but was only temporarily, but it worked. The actuator went up and down.

Now I want to use the ULN2003AN to drive the motor but nothing happens. I am powering it using the 5V from the arduino to pin 9.

I measured with a scope the output from the arduino pins and the pulses are about 5.3V but pins 13-16 on the ULN2003AN are only 1.12V.

How can I get greater output on these pins?

Thanks,

Mark.

GND, A+,B+,A-,B-.

Turns out it is actually a 4-wire bipolar stepper. The 5th wire is just an old fashioned GND chassis wire. Got it working using a H-Bridge.