Motor Shield Killing Arduino


I have just started a project where I am making a camshaft inspection rig and using arduino uno rev3’s to control the rotation (DC Motor) and a linear encoder,

When installing the Motor shield it completely kills the arduino underneath, I have found the cause of that is the IOREF Pin it seems to draw a load of current!, If we bend the Pin out and put the motor shield back on it works find but dont have any controls except for one rotation, none of the current sensing or breaking works?

It has happened twice now all 3 have been bought from RS components both are REV3!

RS Numbers:

UNO- 769-7409

MS- 758-9349

Is there some compatibility issues? or a manufacturing fault?

Batch Code is 39-18 for the motor shield.

I had found on the first motor shield that was bought the chip 74TI R5R Chip had soldier across 2 pins that came from the IOREF Pin but after separating the pins it still didnt work.

Ive tried just connecting the 12v for the motor and still kills the board!

Any advice would be grateful!

This will save time and help those who do know the answer !

How are you wiring this up

  • you need a seperate power supply for the motor. Are you saying happens before connecting a motor or after .

Need to define “killing it “ a bit better ( strangulation ? Knife wound ? Voltage collapses, smokes , etc)

Can you show your wiring diagram ?
Can you identify the motor used ?
Disconnected the Vin jumper ?
Polarity wring ?

There is some mention of problems with pre v3 UNO in pin comparability , but you say you have a V3 of both boards .

Tutorial : Power Usage | Adafruit Motor Shield | Adafruit Learning System

We have a separate 12v going into the motor controller,

Literally just putting either usb or 12v into the DC power jack straight into the arduino or putting 12v motor supply into the motor controller doesn't work the arduino lights don't come on and voltage regulator get incredibly hot within seconds!

All three boards are REV3 and colleague of mine bought an older V3 and even older generation in and the motor controller still stops it from working and over heats the arduino.

DC Motor

This happens even before the motor is connected, without the IOREF pin the controller works fine and powers the motor but with limited controls.

I followed the instruction on this website and even before doing anything the arduino started to get hot just having the 5v into via usb and no lights came on.

I checked all the polarities of the circuit which is just 12v coming in and out through a bulk head nothing else

The Vin jumper looks disconnected but when a mutlimeter is placed across it is already connected.

Something on the board is using drawing huge amounts of current, when plugged in the voltage at the 5v pin is max 1.5 volts.

Dont Worry Just ordered a H-bridge instead!