Mbed OS not work on nRF52840-DK

[UriC]

I received  nRF52840-DK from Mouser :

Sales Order No: Web Order No: Order Date:

242789421 14270760 29-May-18

I started to use it and some problems exist:

 

1. I placed power selector to "USB" and connected USB cable but board is not powered.

It's work only when I select "external power source" and  connected USB cable. I don't know what need select when I connect  "external power source" or "lithium battery"

 

2. I got it for use with Mbed OS.  I used online compiler with simplest "mbed-os-example-blinky"

After success compilation I placed bin file to JLINK drive but after reboot led is not blinked :(

I opened settings of board : https://os.mbed.com/platforms/Nordic-nRF52-DK/

and see that it's not same board I received.

Please help to make it work.

[UriC]

If you look at start of discuss I started with nRF52DK as platform and always power cycle the board.

ARMbed found bug in last version of mbed 5.9.2 When I swapped to 5.9.1 led is worked.