nRF52840 DK not powering on

[Vishnu Pradeep]

This is our 4th nRF52840 DK this year that got damaged this way. After using it for 1 to 2 months the DK does not work power up normally. Then we can only use the board with external  USB connected to J3 and power select switch set to USB. Even with this mode, the LEDs lights up with very less intensity. We could program and debug external board for a maximum of 1 month this way and then suddenly it doesn't turn on. We haven't faced any similar issue with nrf52832DK. 

We tried to change the USB cables, tried to power up with external battery. Nothing is working at the moment. Dev kit is not detecting in PC at all to load the boot loader or firmware image. Device not showing in device manager as well. Please help,this hardware issue is really annoying.

Thanks,

Vishnu Pradeep

[Vishnu Pradeep]

Hi Jonathan,

From where can I get that? 
I can see only 400236 0364RUBR on top side and SS-3 94V-0 1420 E229342 on the back. 

Edit: Yeah on the cover it is written as 2.0.1 2020.20

Thanks,

Vishnu 

[Vishnu Pradeep]

Shorted the SB39 switch and got it working, 
I've tried shorting SB34 switch first, but didn't work.
Any thoughts on the possible issues?

Will try with other non working DKs. 

[JONATHAN LL]

Hi Vishnu,


The behavior seems odd, when powering the device from J3 connector if the switch SW9 is in VDD position(center) then the LED's should not be faded in power, compared to when connecting and powering through J2 connector. If the SW9 is put in to USB then the lade is faded when powering over J3 connector. 

The J3 connector can not be used to program/debug. 




Do you have both SB34 and 39 shorted or only one of them ?
What additional hardware are you connecting to the DK's and how do you normally power them. 

Regards,
Jonahtan