Water damage.

Well i went and knocked a cup of water over my arduino. Got it all cleaned off and dried. I plugged everything back in and it was running the sketch just fine. Problem is the PC can no longer communicate with it. I still get power through USB but the TX and RX LEDs stay on constantly when its plugged into USB.

As far as i can tell the chip is fine its just the USB on the board that is bad. Any chance this can be fixed?

Just plugged in a battery pack and the LEDS still stay solid. I guess the serial pins on the chip are fried. May be others but the sketch that is in it now is only using pins 2-7. Even if the chip is removed the lights stay solid. Guess its the board.

How did you dry it and how close did you look?

If this happened to me, I would probably dry it in a 200 degree F oven (warm setting, with door open), then let it cool down and check it over with my magnifying lamp and my handheld microscope, to make sure all the water was gone and that there wasn't any shorted/lifted traces or solder joints.

I would probably also try reflowing the ftdi joints; only then would I "write off" the chip, and install a header for an ftdi cable...

Good luck!


I pat it dry with a paper towel to start. I then used a can of air to help blow out any water stuck under or between components. It sat for a couple of hours before testing it. There may still be moisture in it. The chip has been removed and the board is still sitting and drying. I've already ordered a new 2009 Arduino so if i get this one back up and running that would be great.

But i'll take your suggestion and throw it into the toaster oven for a bit to be sure.

If the chip is removed are the RX and TX LEDs suppose to be on? Will the computer still register it when plugged into USB if the chip is not in it?

A 5 minute bake is all that was needed. Thanks again for the tip!

Its back up and running fine. Well now i'll have 2 arduinos to play with. :)

I then used a can of air to help blow out any water stuck under or between components

For this read "I used a can of air to blow the water into places it hadn't already got to". :D

Isopropyl alcohol may have helped.