This morning I was attempting to upload a program to my Mega (2560 R3) when I got the error 'Serial port 'COM7' not found'. The 'serial port' menu is greyed out in the Arduino software. I tried it on another PC and got the same error (except it was using 'COM3'.)
When plugged in, the orange and green LED's are both on.
I'm using windows 7 on both PC's. It was working fine yesterday. Last night I was working on getting the Arduino powered with an external 12V battery, going through the DC power plug and regulator. It seemed to work fine.
Is there any way to tell if I've fried the Mega or if it's another issue? I tried the loopback test but it seems like the PC isn't even recognizing the board.
You maybe turned off your arduino manualy with the external battery.
Try this : put your arduino on your computer and try to connect and disconnect fast (with a jumper wire)the Ground and +5V pins
(Don't forget to have the PC speakers ON) you will be able to hear a Plug in and out of a USB connection.
So you will be able to Turn ON your arduino manualy again.
Don't forget [Do not] hold the Jumper wire from the GND to 5V just tuch it and get the wire away fast.
Try this, I hope will work.
Domino60:
You maybe turned off your arduino manualy with the external battery.
Try this : put your arduino on your computer and try to connect and disconnect fast (with a jumper wire)the Ground and +5V pins
(Don't forget to have the PC speakers ON) you will be able to hear a Plug in and out of a USB connection.
So you will be able to Turn ON your arduino manualy again.
Don't forget [Do not] hold the Jumper wire from the GND to 5V just tuch it and get the wire away fast.
Try this, I hope will work.
Not sure what you mean here - I haven't read anything about this and it seems like I could damage the arduino - do you have any more info about this?