Max voltage before magic smoke released

[Triden]

Hello all,

Hypothetically, if someone in their haste to play with their newly arrived board grabbed the wrong power adapter and applied 12V instead of 5V, just how bad is that?  Lets say that after the mistake the board is inspected and no burn marks are detected, however no lights or serial port activity occur when 5V is applied correctly. Is there a quick way of determining if the magic smoke has been released from the SoC chip?

Thanks... 

[Daniel]

Hello Triden

You can connect the uart pins to a serial to usb converter cable, open a terminal program with 57600 baud and plug in a 5 V power adapter and if you can see the text your board has survived it. I made this mistake several times with the A20-OLinuXino-LIME and it only did not work with the 12 V, but there was no damage.

Best Regards,

Daniel

[Triden]

I tried connecting 5V, but I get no output from the serial port and no flashing of any lights.  The 1.8V and 3.3V test points show fluctuating voltage, but not steady 1.8 or 3.3.  I may have fried the U4 and U5 step down regulators.

I am going to try supplying the 1.8V, 3.3V, and 1.2V externally with a lab power supply.