Hi I'm having the exact same issue found in this post:
nRF5340 DK not powering correctly over USB — only works on coin cell (dim/blink behavior).
I've only just started evaluating the board and haven't gone as far into measurements as that poster, but something is obviously not working correctly so i came to this forum to see if anyone else had the same issue recently. The operation is exactly the same as this poster and the DK version is the same.
With the switch on USB, and using J2, there is a short flash of all LEDs and then nothing. Power will work with the VDD coin cell and LEDs will very faintly illuminate with J3 and USB selected on the switch.
Have others seen this issue with the USB power not working from J3 and J2 as well or is this a batch isolated problem? I recently just ordered this board from Digikey in Canada and it arrived this tuesday (June 24, 2005).
Cheers
Tom