[Resolved] Dead Core after power cycle

Hi All,

During rebuild of my prototype I need to shut power down and up. After this the Core doesn’t wake up !
Nothing changed on the power supply (5.6V DC on VIN).
Now I’m measuring 5,25 Vdc on the 3.3 V pin.
Does this mean that the all Core is dead ? Nothing burns.
Could it still be used without the power regulator and power with a 3.3 V power supply ?


If that’s true, I would suspect it’s dead. You can try to apply +3.3V on the 3V3 pin and GND, but it has to be exactly 3.3V. You could also try two AA batteries on this 3V3 input briefly.

Maybe something happened during the rebuild that got wired incorrectly?

Thanks for your suggest. I will try it out. Power regulator should not be disconnected before ?

When you say power regulator, I’m assuming you mean the on board LDO that regulates the +3.3V. You don’t necessarily have to remove this (at least not on a functioning Core). You should definitely remove the USB power and also and external power sources connected to the VIN pin. If the on board LDO is damaged, you may have to remove it (for example if it’s output is shorted to ground).

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Thank you for your suggestion again. I tryed it yesterday and the result was positive. I connected two AA batteries on the 3V3 pin and the Core comes on live again. Then I connect the same batteries on the VIN pin and same result.
I guess my problem sits on the board not in the Core himself.
Again thank you for your support.