i have i brand new Arduino Uno.
I'am trying to connect this board to my pc, to get the serial port, but nothing happens. No USB Sound or any other action in hw devices.
I change the cable 3 times and used different pc's with windows 7 and xp, same problem.
An the bord, the power LED is on and LED 13 is burning permanent, no blinking.
Well, I can tell you that the led is working.
But it seems that the board is defect.
Is it an official Uno, or a clone from Ebay ?
Can you measure the voltages ?
If the voltages are okay, can you connect with an programmer and avrdude via the ICSP header ?
Detecting a usb device is easier in linux, do you know someone with a linux machine ? a lsusb command is all that is needed.
Its a original one.
Which voltage u mean. USB ? On USB i Have 5.02 Volt.
Over Pin 13 -> GND its around 200 mV and LED goes down in case of measure.
also a external LED (5v) doesnt work on PIN13, same effect as before, board led goes down.
The usb is handled by a seperate chip (which is actually also a microcontroller, almost the same as the main ATmega328P). It seems that both the chips are blown.