Arduino UNO board looks like without soul.

Hello everyone,

I have been using several months my Arduino UNO Board without problems. However since a few weeks ago it doesn’t work alone. I mean if I connect it to the computer I can upload sketchs and the program is executing properly but if I unplug it from the computer and I power it as normal the program never starts. The “L” Led blinks twice very quickly, keeps off for a short time and blinks again… it looks like without soul. Like whether it wouldn’t have enough energy to work without computer, like is dying, I don’t really know.
I have tried burning the bootloader again but no positive results.

Please, any ideas. Likely I will have to buy a new ATMega328 chip.

Thanks a lot.

You should measure what voltage you have on the shield 5V pin when being powered externally as it sounds like a hardware problem with the board. Also what are using to power the board and what voltage and current rating does that source have?

Lefty

That is odd. We see that same compaint here from time to time. I have never had a '328 lose its programming while keeping the bootloader, which yours appears to have done (the quick flashes is indication bootloader running).

I am using a 5VDC supply power of 1A. It is a good one (I mean it isn't a chinese mobile phone charger). Even if I plug arduino to the computer after having unplugged it, the problem still so that I need to upload the sketch again. I have checked how much voltage arduino receives and of course it is 5V. A hardware problem? What kind of problem are you talking about? Perhaps... I have worked a lot with this board.

I don't really understand what happen. This situation drives me mad. The bootloader is certainly ok but what happen with the sketch?

albuino: I am using a 5VDC supply power of 1A. It is a good one (I mean it isn't a chinese mobile phone charger). Even if I plug arduino to the computer after having unplugged it, the problem still so that I need to upload the sketch again. I have checked how much voltage arduino receives and of course it is 5V. A hardware problem? What kind of problem are you talking about? Perhaps... I have worked a lot with this board.

By hardware I meant something effecting board voltage when being powered by external source only Vs being powered by USB. You do know that the Arduino official stance is that the 5V pin is for outputting 5 volt current, not to power the board and while many do it there can be problems due to having USB and external power wired together when you power via 5V pin. Not saying it's your problem however.

You sound like you have burned the bootloader at times, are you sure you are using a procedure that is correctly handling the lock bit fuse?

Lefty

retrolefty: You sound like you have burned the bootloader at times, are you sure you are using a procedure that is correctly handling the lock bit fuse?

I have always burnt the bootloader by Arduino as ISP according to the official procedure at arduino playground. I have 2 ATMega328 chips, both giving the same problems. I put one of them into the Arduino board and load the ArduinoISP and WITHOUT unplugging it from the computer, I do the differents conexion to the another chip on breadboard and burn the bootloader.

I am using Arduino 1.0 and my Arduino UNO board is the rev.2.

A 5V power supply won't work if you are powering it from the DC-jack

To power it from 5V - connect directly to 5V pin.

The voltage on the DC-jack or Vin-pin needs to be between 7V & 13V to work.

//Per.

It seems to be a problem with the R2 board. Had the same thing myself.

http://arduino.cc/forum/index.php/topic,134129.msg1009019.html#msg1009019