https://devzone.nordicsemi.com/f/nordic-q-a/49431/pca10056-nrf52840-dk-defective-during-useHi, it now happened to me for the second time that an nRF52840 DK broke during debugging. I had it connected to an external controller via the Pin header: VTG, SWDIO, SWDCLK, GND, GND DETECT (the header with all pins next to each other). Suddenlyen-USTelligent Community 13Mon, 08 Jul 2019 11:59:37 GMThttps://devzone.nordicsemi.com/thread/197116?ContentTypeID=1Mon, 08 Jul 2019 11:59:37 GMT137ad170-7792-4731-bb38-c0d22fbe4515:900f1413-9366-41b6-8c47-96bf82e1c528Kenneth<p>Hi,</p> <p>We have had very little problems with these boards in general, so it may seems as if they are damaged somehow here (ESD or EOS). What power supply was used as external source? Maybe it would be better to feed VDD to the external board from the DK? There is always the option to get a pure debugger/programmer from SEGGER if you are working on your own prototype and you have experienced this issue already a few times.</p> <p>Best regards,<br />Kenneth</p><div style="clear:both;"></div>