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]

Thank you for the update. I have reported this issue internally, and will keep you updated. It seems to be related to the VIO_REF pin on header P20, which will disconnect the Interface MCU if it is shorted. We are investigating this issue and will keep you updated. Please confirm the following for us:

• Are both DKs reacting the same way? That is, does both MCUs power off if you get close to the power select switch SW9?
• Does the nRF chip continue running when the MCU is turned off or not? That is, does the LED1 keep blinking while the MCU is powered off by your presence?
• Can you try to put a (plastic) cover over the VIO_REF pin on P20 and see if you still short the board when getting close to SW9?

Best regards,

Simon

[vishal.roy]

• Are both DKs reacting the same way? That is, does both MCUs power off if you get close to the power select switch SW9?
  • Both were behaving the same way but now not able to reproduce the issue on one of them.The other board still exhibits this behavior.The board which has this issue if i leave it ON for about 5 min it will start working normally after it tries by itself to boot up.Cant say is stable can go OFF any time.
• Does the nRF chip continue running when the MCU is turned off or not? That is, does the LED1 keep blinking while the MCU is powered off by your presence?
  • When the system goes down everything switches OFF.
• Can you try to put a (plastic) cover over the VIO_REF pin on P20 and see if you still short the board when getting close to SW9?
  • Tried this will attach  a video , no improvement.

[vishal.roy]