My first experience with Arduino ended in a tragedy. I bought a Leonardo from ebay and upon arrival, attached it to my laptop. Programmed a simple blink demo with the onboard LED. It started working. Then detached it from USB and plugged in a 9v adapter. The board started smoking and it doesn't work anymore. I measured the voltage of the adapter and it reads 9.7v. So, what is the reason of this tragedy?


I think that the smoke was from a component close to the processor. Right now, when I attach a 9v battery to the board, both the ON LED and the L LED remains on. The processor also warm.

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    I hate to sound like a prick but if you bought a knock-off then it could be absolutely anything. – Ignacio Vazquez-Abrams Dec 3 '14 at 5:16
  • Well, it looks like a legitimate made-in-italy one! How can I detect if it is fake or not? – Mohsen Dec 3 '14 at 5:19
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    If you bought it on eBay then it's a knock-off. They are very, very good at making exact copies. Except where it counts, as you've discovered. – Ignacio Vazquez-Abrams Dec 3 '14 at 5:21
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    Did you check the polarity of the adapter? If it's reversed the diode (SMT version of a 1N400x) will overheat. – Spehro Pefhany Dec 3 '14 at 5:23
  • I checked the polarity of the adapter and it seems OK. When I attach the COM cable of the multimeter to the inner contact of the adapter, it shows +9.7v. Does it confirm that the polarity if OK? – Helium Dec 3 '14 at 5:38

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