Shortly after I got my first Arduino, a Leonardo, I plugged it into what I thought was a 12v dc supply. After the board failed to respond for about a minute I realized something was wrong and disconnected it then got out my multimeter. My power supply labeled 12v was putting out over 19v.
I've already replaced the board but I was wondering if it's possible to get the first one working again. Is there any chance the main chip is okay and I just need to replace some transistors or something? How would I tell? If the main chip is damaged what's involved in replacing it? Any advice for a noob is appreciated.
@ChilliTronix I just realized I didn't make it clear that the board is completely unresponsive at this point. The power and pin13 LEDs come on but otherwise nothing. My computers don't even register a connected device when I plug it in.
Is there a way I can check if the main chip is working? Maybe bypass the regulator if I connect USB power?
Do you know if you loaded a sketch to it before it got fried?
If not it should be running the blinking lights program. If it does nothing, then I suspect the micro controller (Which on the Leonardo is also the USB controller) is fried.
As such the only way to fix it is a chip level repair, which is OK if you like SMD soldering... but beyond economic repair if not.
I never changed the original sketch. This thing was brand new. So I guess this is my motivation to learn surface mount soldering which has been on my to-do list anyway. Any recommendations for where I get a new bare micro controller?
Well, try places like Sparkfun, DIgikey, Mouser and Farnell. The last 3 will certainly have the Armega32U4. I can't help on how to load a boot loader but there will be information somewhere.
Mouser seems to have the best Atmel prices, plus no sales tax. Shipping $5 to $7 usually.
Do you have an Uno that can run a bootload installer sketch?
If not, an Atmel AVR ISP MKii programmer will do all the Arduino chips you may eventually play with. It's all I use for programming.
How's the 3.3V look?
Ok so I'll order a new 5v regulator and a new atmega32u4. I'll check the 3.3v when I get home. Is there anything else I should look to replace?
I have another Leonardo but no Uno. Will that still work for burning the bootloader? If not I might have to give up as a programmer is not in my "things I don't really need" budget right now.
Hot air rework station with appropriately sized air nozzle for the chip to be removed works well also, 30 seconds of hot air and the chip can be lifted right off.
evilgeniusha:
I have another Leonardo but no Uno. Will that still work for burning the bootloader? If not I might have to give up as a programmer is not in my "things I don't really need" budget right now.
I've just been updating that bootloader sketch. Previously, although it would run on a Leonardo, it did not have the Leonardo bootloader in its repertoire.
Now it does (latest version on GitHub).
I have confirmed that it correctly programs a Leonardo (bootloader). Pay attention to the wiring diagram on Atmega bootloader programmer. It is different to the one you use to connect a Uno to a Uno, because the SPI connections are not brought out to the header pins (D11 to D13) like they are on a Uno.
