stepper problem

[Guevara]

Hi there !

I am new to Arduino. Recently a scavanged 3 bipolar motors from 3 old printers. They are 4 wire so i think they are bipolar motors. I build a driver using only 2 inputs for Arduino according to this circuit:
http://www.arduino.cc/en/Reference/StepperBipolarCircuit. I changed L293 with L298 and transistors with a NAND gate. In ISIS simulation everything worked fine. I hooked the input 1 to pin2 and input 2 to pin3 to the arduino board, and i configured those pins as outputs.Then I wrote the code for this sequence: http://www.tigoe.net/pcomp/code/circuits/motors/stepper-motors

Step
wire 1 wire 2
1 low high
2 high high
3 high low
4 low low
After I started the board the motor does 3 steps clockwise and after that it returns to the start position.
Do you have any idea what is going worng? Any help would be appriciated.
Thanks in advance!

[system]

Going forward three small steps and then taking a big three-step jump back all at once is very unusual. Are you sure it's going exactly back to the start?

Do you have any load on the motor? What are you using for a motor power supply? Any chance you can sketch out your wiring (your text description is better than nothing but a diagram would be better).

--
The Rugged Motor Driver: two H-bridges, more power than an L298, fully protected

[Guevara]

Thak you all!

I have only modifyed a bit the circuit with 2 wires with l293.

I said 2 wires to control the motor but there are 4 combinations.

Yes i have measured corectly the motor coils they have 10 OHM res. and the power supply of the motor is 5V
in picture on l298n first pin is IN 1 sorry for mistake.