PCA10056 Not working

[vishal.roy]

Just bought 2 nrf52840 DK's both stopped working

Observation

• Was able to program and run SDK examples.
• Above working setup not disturbed,so all cables are in order verified that
• The current problem i have:
  1. when I connect the DK to PC the device is not shown in device manager initially.After awhile it pops up
  2. When I try to flash it fails and LEDs switch of and come back up.
  3. The board had the blinky example code.So if from Step 1 I toggle IF Boot/Reset switch I can see the UART logs in terminal.
  4. Very weird observation is there is buzzing sound coming from the board.Can i do something to fix this issue.
  5. When I go near the switch usb/VDD/Lipo selection the entire board switches off and comes back up as a move my hand.Attached video.The buzzing sound can be heard in video
•  

[Simonr]

Hi

We were able to recreate the issue to the point that the device powers off if you physically touch the VIO_REF pin on P20, but we have not seen any resets when touching SW9 in any of our DK versions, so that is likely specific to that one board. It seems to be too weak from a design point, and we are looking into what the best way to resolve this for future revisions are.

Best regards,

Simon