Basic problem with Arduino motor shield

Got an Arduino Motor Shield Kit from Amazon (, soldered it up, plugged it in and voila...nothing. THe LED lights up, but won't turn a 3V DC motor. Where do I start? The solder joints all look OK.

There is no documentation on this thing, there were lots of extra parts, so god knows what is wrong.

I followed these instructions from Amazon (, even though the instructions did not look exactly like my board, some parts were different, etc. My board, for example, has three ICs, (74HC00N, 74HC32N and SN754410) whereas the instructions only reference two ICs. What a mess. Can anyone suggest where to look for the problem?

When I probe the "motor output pins" for a motor B when executing the following code, I don't see anything that makes sense, just a few hundred mV, and indeed the motor does not respond when attached to these pins.

int dirbpin = 12; // Direction pin for motor B is Digital 12 int speedbpin = 9; // Speed pin for motor B is Digital 9 (PWM) int speed = 200; int dir = 0;

void setup() { pinMode(dirbpin, OUTPUT); Serial.begin(9600); }

void loop() { digitalWrite(dirbpin, dir); // set direction analogWrite(speedbpin, speed); // set speed (PWM) dir = ((dir == 0) ? 1 : 0); // change direction Serial.println ("Changing direction"); delay(3000); // 1 seconds }

Thanks for any advice.

"THe LED lights up, but won’t turn a 3V DC motor. Where do I start?

From the Freeduino site:

"The motor driver can support 3.6V to 36V motors (1A). But the shield is designed to take Vin from the Arduino / Freeduino power supply, before the 5V voltage regulator. You cannot supply Arduino / Freeduino with 36V without burning the voltage regulator.

“If you need to use a motor rated < 7V or > 14V, you will need to modify the shield.”

What’s your “V_in”, anyway?

I have a 12V DC supply going to the Arduino power jack, and USB to the computer.

Can anyone help with this?

I have looked at a few things, the dir signal voltage is getting to the motor shield, and shows up across the correct resistor. Is in possible the ICs are bad? Does that ever happen?

There does not seem to be very much that can go wrong on this shield, so I'm not sure how to proceed. Can anyone suggest a source for the ICs, or does it make more sense to just get another motor shield? But I'd hate to then have TWO non-working shields...

But nothing over a few mV arrives at the motor B output pins.