Arduino mega + motor shield...

[system]

Hello, and sorry for my bad english...
I have arduino mega, and ladyada's motor shield v1.0(Motor Shield - Arduino motor/stepper/servo control) and i want connect 4 DC motors(TT Geared Motor with Back Shaft (180rpm 6v L Shape) - DFRobot).
Mega powered by USB or 9v jack, Shield powered by 5xAAA battery. I want test one motor, wired him to M1 terminal on motor shield. Then i run typical code for test:

<sup>#include <AFMotor.h>
AF_DCMotor motor(1);
void setup() {
Serial.begin(9600); // set up Serial library at 9600 bps
Serial.println("Motor test!");
motor.setSpeed(200); // set the speed to 200/255
}
void loop() {
Serial.print("tick");

motor.run(FORWARD); // turn it on going forward
delay(10000);
Serial.print("tock");
motor.run(BACKWARD); // the other way
delay(10000);

Serial.print("tack");
motor.run(RELEASE); // stopped
delay(1000);
}</sup>
but motor goes not work When i connect motor directly to battery module, he work.
But when motor connected to shield, he does not work, but sometimes it makes a noise. I use the voltmeter to test a voltage. On the shield's ext_pwr 8V, on the unplugged terminals 6v, but when i plug in motors - voltage drops to 0

Please help me fix this trouble...

[MarkT]

What happens to the battery voltage when you connect the motor? Perhaps they are flat?

[system]

That is strange, I kinda have the same set up.

I have the jumper removed, and when I call the motor pin I have this:

AF_DCMotor motor(1, MOTOR12_2KHZ);

Try that, them are the only two differences from what I did

[system]

MarkT:
What happens to the battery voltage when you connect the motor? Perhaps they are flat?

the battery voltage drops to 0V when i connect motor.
But, if i connect motor without motor shield, directly to battery module - it's ok.

Code:

AF_DCMotor motor(1, MOTOR12_2KHZ);

Try that, them are the only two differences from what I did

I tried it, but no effect...

May be my arduino or motor shield has broken?

[system]

Could be the L293D chip is bad. Have you tried the motor hooked up to M3 or M4?

[system]

Could be the L293D chip is bad. Have you tried the motor hooked up to M3 or M4?

Yes, of course... and i tried use new batteries, but no effect

[system]

You need to unplug the EXT_PWR jumper
Motors are using the usb cable as power source and not the battery pack.

[system]

panosip:
You need to unplug the EXT_PWR jumper
Motors are using the usb cable as power source and not the battery pack.

Hello, and thanks for your advice.
But, i already unplug the EXT_PWR jumper, he is installed on the single leg) But, no effect(

I unplug the L293D driver chip and connect directly to arduino, battery pack and motor, and use the pin 9 to enable 1, pin 4 to input 1, and pin 3 to input 2, then i run this code:

const int motor1Pin = 3; // H-bridge leg 1 (pin 2, 1A)
const int motor2Pin = 4; // H-bridge leg 2 (pin 7, 2A)
const int enablePin = 9; // H-bridge enable pin
void setup()
{ // set all the other pins you're using as outputs:
pinMode(motor1Pin, OUTPUT);
pinMode(motor2Pin, OUTPUT);
pinMode(enablePin, OUTPUT); // set enablePin high so that motor can turn on:
digitalWrite(enablePin, HIGH);
}

void loop()
{
digitalWrite(motor1Pin, LOW); // set leg 1 of the H-bridge low
digitalWrite(motor2Pin, HIGH); // set leg 2 of the H-bridge high delay(1000); // set leg 1 of the H-bridge high
digitalWrite(motor2Pin, LOW); // set leg 2 of the H-bridge low delay(1000);

}

And motor run, but very slowly((( Why? I connect battery pack red wire to Vs, and black wire to GND.
This is the photo.

Then, i connect Enable 1 to +5V from Arduino, Input 1 to +5V from Ardiono, and Input 2 to GND, and motor run fast!
What do you think, this is ardiuino' s problem? Or L293D chip is bad?