retrolefty:
Does the board work if just plugged into USB with no other external power or other things attached to it?If not you must have damaged the board somehow when you applied the external +5vdc to the 5V pin. If you have a multimeter you might try measuring the voltage at the 5V pin to see what it reads when just attached to to the USB.
Lefty
Hey,
yes, the board works when I connect it just to USB cable, but the computer doesn't read it.
I tested my board as you said and the results are:
The 5V output gives me 4.3V which is OK.
The 7805 of the Arduino gives me the same Voltage, on the middle leg I get 4.3V and on the left leg I get 3.8V.