PPK2 bricked?

[Sebi]

I just got a PPK2.
I was able to use it perfectly with Power Profiler. Great tool!
Today I wanted to learn more about nRF Connect other applications.
(Actually I was looking for a software that could replace iOS nRF Connect to perform DFU upgrades from my PC).

So I launched the Bluetooth Low Energy software, the first in the software list.
I wanted to start a scan but the icon was grayed (at first I thought the scan would rely on my PC bluetooth adapter).
I noticed I could select the PPK2 in the device list so I selected it (it is indeed made with a nRF53840).
The Bluetooth Low Energy software asked me if I wanted to flash my PPK2.
The flash process started.

After a few seconds, I got an error message in the log and the PPK2 LED stopped flashing.
I tried to launch Power Profiler again but the PPK2 had disappeared from the device list (there was no device shown anymore).

I rebooted. I retried.
Under Windows Device Manager the only difference when plugging the PPK2 is that "USB Root Hub (USB3.0)" appears in the list.
The PPK2 LED is still off.

Can you help me fix my PPK2 not working anymore?

[Sebi]

I did follow that process.
During a short moment I thought I fixed the problem as the red LED started flashing after switching the board ON and realising GND from TP34. After I followed the rest of the instructions:

Open the PPK app, and select the device which is now just a serial number, e.g  

When selecting it, the user will be prompted to program the application and it should now be working again. 

But when I started the power app, I noticed there was still no device to select from.
I checked with Windows Device Manager and no particular device appears when the red LED starts blinking: always only USB Root Hub (USB3.0) in the device list, PPK2 being ON or OFF.

I am afraid my board is not only bricked but broken too...
What additional tests can I do to try to fix it?
Is there a warranty coverage to replace the board?

[Stian Røed Hafskjold]

Can you try to go through the process again, and use a different USB cable, also connect the PPK2 directly to the computer, not through a USB hub. If already connected directly to the computer, try to use another USB port, possibly one which is not USB 3.0. Or maybe try another computer. Let me know how it goes. Are you using a Mac or PC?

[Sebi]

Thanks to your encouragements Stian, I kind of did all what you asked:

At first, I checked that my USB ports were not damaged plugging a USB key in all the ports.
I changed my cable, my USB C to old-standard USB adapter, my port and... my computer (kind of).
Actually I was under Windows 10 under Bootcamp on a MacBook Pro so I booted on Mac OS X.
I was looking for a linux lsusb equivalent and found the system_profiler SPUSBDataType Mac OS X command. After connecting my PPK2 in bootloader mode, this command yielded:

Open DFU Bootloader:
    Product ID: 0x521f
    Vendor ID: 0x1915 (Nordic Semiconductor ASA)
    Version: 1.00
    Serial Number: E1A796966364
    Speed: Up to 12 Mb/s
    Manufacturer: Nordic Semiconductor
    Location ID: 0x14100000 / 2
    Current Available (mA): 500
    Current Required (mA): 100
    Extra Operating Current (mA): 0

So I felt reassured about my PPK2 not being fried.
Thus I decided to install nRF Connect on Mac OS X and started the power application.
I could then successfully select the unknown device shown in the list and reprogram it with the adhoc firmware.
I switched to Windows 10 and it was working still!

I a nutshell: my PPK2 is working again!
I don't know why I was not able to find and reprogram the PPK2 under Windows 10, but still, it is working now.

I will do a set of current measurements to see if I observe some glitches, but I doubt it.

Thank you.

[Sebi]

Dear Stian, my problems with the PPK2 are not over...

I didn't do anything more in the meantime I thought it was fixed.
But this morning when I wanted to do some measurements I plugged my PPK2 in my computer but it is not recognized anymore.

I tried under Windows and Mac OS X, in every one of the 4 USB C ports, using 2 different USB C to USB 2 adapters, using 2 different USB cables...

The LED is flashing green in a slow dimming pattern when I plug the PPK2 (meaning the power app firmware is running correctly?) or turns on red if I set the PPK2 in DFU mode.

My computer sees the the USB C to USB 2 adapter when I plug it in, but no PPK2 afterwards when  I plug it in using the adapter. The PPK2 LED starts flashing though. If I connect a different USB device (e.g. a bluetooth adapter) instead, this other device is been discovered though.

Thus I believe my PPK2 has a hardware failure that makes it not reachable now and then.

Can you help?