12 v dc gearhead motor-70 rpm is nt working with motor shiel

[sahilkumar]

The specifications of motor are following:
12V DC Reversible Gearhead Motors - 70rpm
This compact unit will give a massive 2.1 kg.cm of torque at 70rpm. Current draw rises to a modest 390mA.
SPECS:
• Torque: 2.1kg.cm
• Rated Voltage: 12.0V
• Operating: 4.5 - 18V max
• Current - No load: 30mA
• Current - Full load: 390mA
• Gear Ratio: 82:1
• Shaft Speed: 70rpm

I am using arduino duemilanove Atmega328 with adafruit motor shield v2 and i am controling four dc motors of above specifications
and powering the arduino duemilanove Atmega328 with computer through usb and using the same power supply for motor shield v2 through VIN jumper
i downloaded the library for motor shield v2 from this link ---------library from the Github repository (http://adafru.it/ciN)
and downloaded the sofware environment ..........Arduino IDE Arduino 1.0.5 for windows(isntaller) downloaded through this link -----http://arduino.cc/en/Main/Software
and i used the example dcmotor test to test the motor but it didnt work and selected serial port com9 and selected board arduino duemilanove w/ATmega328
and using M1 terminal for testing.
Thanks

[Franklin97355]

Have you connected the motor directly to 12v to see if it indeed does work? Do all four motors not work or only one? What are you using to power the motors?

[adafruit_support_bill]

i am controling four dc motors of above specifications
and powering the arduino duemilanove Atmega328 with computer through usb and using the same power supply for motor shield v2 through VIN jumper

You need 1560 mA at 12v to power 4 of these motors. The USB supply is only 5v @500mA. You need an external 12v supply. Be sure to remove the VIN jumper when connecting the external supply.