Arduino UNO Failed Loopback Test. Now What?

So I was able to determine my UNO has a problem. Originally I was just getting the error "resp=0x00" when I tried to upload. So I tried the loopback test. FAILED. The power on light works and I can see it in hardware manager. When I tried the loopback test in hyperterminal the RX light flashed at every keystroke. In serial monitor the RX light flashes once when I hit the send command. I get nothing back from either terminal application.

Is it at this point that the board is declared defective? Or is there a fix from here? Brand new UNO that has never accepted an upload.

I'd double check the jumper across the tx and rx pins to ensure it is placed correctly.

Double, triple, quad checked connections. I do not belive the data is reaching the processor. It's getting through the usb At8u2 but not to the mega328. This is just my opinion.

Dirtleg: Double, triple, quad checked connections. I do not belive the data is reaching the processor. It's getting through the usb At8u2 but not to the mega328. This is just my opinion.

The loop back test should only be checking the usb At8u2 and not the mega328. Is the UNO seen as a com port when plugged into the pc? You might try reinstalling the UNO serial driver if not recognized.

Zoomkat thank you for the responses. I have verified the operation of the UNO as a com port when plugged into the computer. I have done this on 2 different computers (both running XP Prof.) and have the same problem on either machine. (please no Smart Ass microsoft/windows comments). I have tried the 0023 and 1.0 versions of the Arduino software and the different drivers available there.

Anyhow the fact that the TX light never illuminates during the Loop Back test seems to indicate a problem with the board itself. After all the TX and RX are jumpered at pins 0 and 1. Should they not both light up together?

Is it at this point that the board is declared defective?

Dirlteg did you end up declaring the board defective ? I am having the exact same problems: the L and ON Leds are continuously on as soon as I plug the board to my Mac and the TX and RX lights just never light up. The loopback test definitely failed several times. And I tried checking if it was a com port issue on 4 different computers (2 mac and 2 windows)..

Yes, this thread is almost exactly three years old - but it was left unanswered, and I had the exact same problem recently, so I'm updating it for future generations... :-)

In my case (to make a long and frustrating story short), the cause of the problem was a poor solder joint of a resistor, somewhere along the winding path from the ATmega328's TX pin to the ATmega16U2 RX pin.

i am using windows7 64 bit OS. trying to connect arduino nano v3 which has ftdi chip(FT232RL)please tell me what should show on printer and hardware section on my computer & also in device manager when I connect the arduino nano for uploading the sketch & printing....? FT232RL USB UART OR ARDUINO NANO(COM 1/2/3....)?

@ snehashis

Would you care to start your very own thread as this is so old and many aspects of the IDE and even your OS will probably bring things into the topic that the original one does not.