I bought a Duemilanove not too long ago (beginning of Dec.) and it worked fine for a couple of weeks. I then went on vacation and now as I try to use it, it is displaying very bizarre behaviors. The RX and TX lights are perpetually on when it is powered (and no other pins are connected), either by usb or by external power. The FTDI chip also becomes extremely hot, even when the usb cord is not connected. And when the usb cord is connected, no serial port appears in my drop down menu of the Arduino program. All the power supplies and cords are fine, as I tried them with another Diecimila board I have. Has anyone experienced this before? Is there anyway for me to fix it? Thanks a lot!
sounds like something on the board is shorted out, did you leave it plugged into a non usb power source while gone?
some capacitors have a bad habit of shorting themselves out when they die
and course check for bits of metal, or even "tin whiskers" which have a tendency of forming much quicker with lead free solder
Really just tossing out idea's here
I just looked and don't see any metal bits. I didn't leave it on over break and it wasn't used by anyone else during that time. Can things just short out for no reason?
Hello Mrduff,
Do you have a voltmeter?
- Pull out the Atmega CPU from the socket
- Measure the 5V pin vs GND
- Measure the 3V3 pin vs GND
These pin locations are printed on the Arduino board
Cheers
Joseph
What are voltages you get?
The FTDI chip also becomes extremely hot, even when the usb cord is not connected.
How is that possible? I thought the FTDI chip was powered by USB, not the Arduino....
No idea! That's why it is so concerning. Anyway, it looks like Sparkfun is going to let me exchange it so that will hopefully solve my problem.