stepper motor problem

I was using easydriver to control a stepper motor and a 9v battery. The motor specs are here in portuguese: http://www.robocore.net/modules.php?name=GR_LojaVirtual&prod=362

it is refurbished.

9v and 2A /phase

it was working fine but stopped. I started with theses values:

digitalWrite(x, HIGH); delayMicroseconds(10); //A digitalWrite(x, LOW); delayMicroseconds(300); // B

Then I tried increasing the delay, 20 microseconds for A and 3000 for B, and it worked for a while. But now the motor doesn't turn anymore. And I can turn it by hand with almost no effort, it wasn't like this before. There's almost no torque anymore.

What I'm doing wrong? Should I buy a new one?

Thanks in advance.

What are you using for the 9 volt source? 10us, way to fast!!

Also schematic please...

Not many 9V batteries can supply 200mA, let alone 2A....

That stepper is rated at 2A per phase and 2 ohm winding resistance - therefore it needs 4V, not 9V.

I suspect the 9V is the voltage for bipolar operation (two windings in series).

Dead Battery.