I keep breaking my board!!

Hi, I'm now moving on to my 3rd Arduino and though some of you guys might know what I could be doing wrong. My first board was a Mega2560. I had it about 3 weeks and it stopped working. I powered it off USB and was using it to power a small motor with a L293d chip. In the end up the output pin going to the motor was only reading 0.03 volts. All the output pins were doing this. If I took the load off the pin it would read 5Volts but as soon as I connected anything, even an LED it would drop to 0.03 volts again. I then got another mega2560 board and only had it a little while and the same thing happened again. Next I got an Uno R3 so I could replace the chip if this happend again. I had it a week this time and once again it stopped and when I replaced the 328p-pu chip there was no difference so I assume the chip has not blown! Is it possible it could be the voltage regulator or am I doing something very obvious wrong? :) Thanks for your help!

Can you post your wiring?

Paul, If you haven't been using resistors with the LEDs , or tried to connect the motor directly to the Arduino pin, then yes you probably have messed up something. There are lots of tutorials on the web for doing these kind of projects and the reasons behind the resistors and transistors used to drive things from seperate power supplies. Mostly it boils down to not drawing over the specified 40mA from any one pin, or 200mA combined from all. There are ways to bypass the voltage regulator to test the AT328, but you run the risk of letting ALL the magic smoke out if you don't know what your doing, and I'm not about to be your accomplice in that. This part of the forum will answer lots of questions about running high power stuff. http://arduino.cc/forum/index.php/board,9.0.html TomJ