I will keep this as small as possible and I am a total beginner. My audrino uno lights up with a green led and yellow led blinks 3times when inserted into my PC running 32bit windows 7 and shows port 5. I bought an l293d motor sheild along with it. As soon as i attach both the motor sheild and arduino uno, the audrino leds goes off and completely dims, and no led lights up in the motor sheild too and port 5 option vanishes from pc.
But when I connect an external source to the motor sheild via a 5v supply, the led of motor sheild lights up but audrino leds stays off.
As soon as I detach the motor sheild from top of audrino uno, audrino lights up again and port 5 is shown.
Possible reasons of fault and in which one??
