NRF52840 DK Board not working

[Rahul Chavda]

I have an NRF52840 DK (3.0.2) board, but it is not working. The USB port is not detected. When I power it through USB, the debug LED (LED5) turns on and then off. On the SoC side,

LEDs 1, 2, 3, and 4 are dimly lit. Please help and provide a proper solution.

[JONATHAN LL]

Was this a brand new DK ?

Did it work at some point that you are aware of?

Have you tested different USB cables? 

VEXT should be in OFF position. 


It also looks like this DK has been modified with extra pins on the sides, make sure that there is no shorts VDD and GND or 5V or GND or any of the GPIO pins.  

Regards,
Jonathan

[Rahul Chavda]

I also tried changing the USB cable, but it is still not working.

I checked by turning off the VEXT pin, but it didn't work either.

I have checked the 5V and GND, and they are fine. I also checked the nearby pins where I connected external components, and there are no shorts anywhere.

[JONATHAN LL]

Thanks for the info, 

Can you try and connect an extra USB cable to the nRF52 USB port? 

Where the arrow indicates. So both USB connectors on the DK is connected to the computer. 

Regards,
Jonathan

[Rahul Chavda]

"We also tried this, but it did not work. Only the SoC is working."

[JONATHAN LL]

Can you measure the voltage on TP35, it is the VDD supply line for the debugger chip. 
SB37 also has access to the debugger VDD. 
https://docs.nordicsemi.com/bundle/ug_nrf52840_dk/page/UG/dk/solder_bridge.html You can se description here, but it can be shorted to bypass the power switch. 



Regards,
Jonathan

[Rahul Chavda]

We measured the voltage at TP35, and it is 3.014V. We have also soldered SB37, but our debugger is still not working.

Please let us know how to proceed.

[JONATHAN LL]

Thanks for the info. 

It seems that the debugger MCU is getting the voltage it needs, so it is likely not completely broken. But there is either an issue with the data lines\USB interface here somewhere in the circuit. 

Rahul Chavda said:

We have also soldered SB37,

I did not intend for you to solder the SB here, only that it was available as a test point. Sorry for the ambiguity here. 


It would be interesting for us to do som failure analysis here, can you contact your nordic RSM?  They can help arrange shipping and a replacement DK. 

Regards,
Jonathan

[Rahul Chavda]

can you Provide me nordic RSM?

what is next step to forward with board ? 

[JONATHAN LL]

You can contact : [email protected] 

You can still use this DK but only with an external debugger, so its a bit up to you. It would be nice if you could send the unit to us so that we can debug. 

You will have to send the device to us and we will issue a replacement DK once we get the DK or have proof its on the way. 

Regards,
Jonathan

[Rahul Chavda]

We  will sent the board, but we will not pay any costs. Can you arrange the shipment and all other expenses? We will not pay any additional costs.

[JONATHAN LL]

I will see what I can do. We have had a few customers not send the HW back to us when we sendt new to them so there has been some change in policy here, but I will try and set up something. 

Regards,
Jonathan

[Rahul Chavda]

what is next step to forward board