NRF9160-DK - Doesn't power after external supply

[PierreLesc]

Hello,

I tried to power the nrf9160-DK with external supply on port P21, as suggered : 

https://infocenter.nordicsemi.com/pdf/nRF9160_DK_HW_User_Guide_v1.0.pdf

So I put a li-ion cell directly (which was charged at 4.1V) to try the asset_tracker outside.

But after 5 minutes it continuously blink LED 1 and 4.

So I unplugged the power, go back to the desk and connect the USB cable to see what's going on, and surprise, the LED 5 turns on for 1s, then go back to off.

I see the U24 heats a lot when the LED5 is ON.

If I disconnect the nRF current measurement jumper P22, the board works but I can't access to the NRF (of course), as soon as I reconnect P22, the board turns off.

I'm pretty sure I didn't do any short-circuit or reverse polarity or put more than 5V on external supply, but now I can't make the board works again.

Now, when I use external supply, I have the same result.

Do you know how I can fix that?

Thank you

[PierreLesc]

Ok, after checking everything, I use a charger li-ion during a test, and unplug the battery before the charger, this could (for sure) have sent a pic voltage on the external supply.

So I think I burnt something due to high voltage power in.

[JONATHAN LL]

PierreLesc said:

So I think I burnt something due to high voltage power in.

That's a bummer if that is the case. I can try to figure out what went wrong if you want to, there are som alterative ways to power the DK, some only powering the SiP, and not the on board MCU\Debugger chip.


https://infocenter.nordicsemi.com/topic/ug_nrf91_dk/UG/nrf91_DK/hw_power_supply.html?cp=2_0_4_3_2 

Some solder bridges can be cut\shorted to achieve different configurations. 
https://infocenter.nordicsemi.com/topic/ug_nrf91_dk/UG/nrf91_DK/solder_bridge_configuration.html?cp=2_0_4_3_16 


Regards,
Jonathan