DK Boards Not Working

[DataMate]

I have 2 DK boards neither of which is working.

The first is a PCA10040 V1.2.1.  When I plug it into my Window 10 computer with a data cable, Windows says it's an unrecognized device.  I tried uninstalling the driver in Windows Device Manager but that did not fix the problem.  The green LED is flickering.  No matter which computer or USB port I try to plug into, it always behaves the same way.  If I hold the IF BOOT/RESET button down when I slide the power switch to on, the green LED will start blinking, but there is still no USB connection.

The second is a PCA10056 2.0.2.  When I plug in to either USB port on the board and switch the power on, nothing happens, even while holding IF BOOT/RESET down.  No LED's are lit.  If I measure between the 5V and GND pads on the back of the board with a voltmeter I get 5V.  I tried switching between VDD and USB for the nRF power source, but it didn't make a difference either.

Is there a way to restore both of these boards so that I can use them again.  They were both working at one time.  I was using them for power profiling.

Thanks,

Alec

[DataMate]

For the PCA10040, I was able to get the BOOTLOADER drive to appear and follow step 4 at   My nRF52/nRF51 DK kit doesn't work. dragging and dropping the bin file from https://www.nordicsemi.com/Products/Development-hardware/nrf52840-dk/download#infotabs but after powering off and powering back on I still don't see the mass storage drive appear, though the unrecognized device error message doesn't pop up any more.  Just LEDs 1, 2, 3, and 4 are faintly lit. 

For PCA10056, I can see JLink Device in nRF Connect for Desktop Programmer when I plug my JLink probe into the DEBUG IN connector on the board.  Is there a zip file I can drop in to restore functionality so that the board enters mass storage mode when I plug it into the USB port on my PC without the JLink probe connected?

[DataMate]

After I held the BOOT/RESET button on the PCA10040 board, then slid the Power switch to the ON position, I was able to copy j-link-ob-sam3u128-v2-nordicsemi-170724.bin at https://www.nordicsemi.com/Products/Development-hardware/nrf52-dk/download#infotabs to the BOOTLOADER drive that appeared, then after powering the board off and back on, I was able to see the JLINK drive.  However, no matter what hex file I drop onto the drive, for example, the one in nrf52dkfw110.zip at that URL, a FAIL folder appears on the JLINK drive containing the text "Error while connecting to CPU". 

When I try to use nrfjprog -f nrf52 --recover --log at the Windows command line, I get

[error]: [SeggerBackend] - JLinkARM.dll reported "-1", "An unknown error.". 

When I use JLink Commander v7.66a from the PC, I get the following:

SEGGER J-Link Commander V7.66a (Compiled May 19 2022 15:14:46)
DLL version V7.66a, compiled May 19 2022 15:13:27

Connecting to J-Link via USB...O.K.
Firmware: J-Link OB-SAM3U128-V2-NordicSemi compiled Jan 20 2022 16:43:31
Hardware version: V1.00
S/N: 682910671
License(s): RDI, FlashBP, FlashDL, JFlash, GDB
USB speed mode: High speed (480 MBit/s)
VTref=3.300V

Type "connect" to establish a target connection, '?' for help
J-Link>connect
Please specify device / core. <Default>: NRF52
Type '?' for selection dialog
Device>
Please specify target interface:
J) JTAG (Default)
S) SWD
T) cJTAG
TIF>
Device position in JTAG chain (IRPre,DRPre) <Default>: -1,-1 => Auto-detect
JTAGConf>
Specify target interface speed [kHz]. <Default>: 4000 kHz
Speed>
Device "NRF52" selected.

Connecting to target via JTAG
InitTarget() start
InitTarget() end
TotalIRLen = ?, IRPrint = 0x..000000000000000000000000
Failed to identify target. Resetting via Reset pin and trying again.
InitTarget() start
InitTarget() end
TotalIRLen = ?, IRPrint = 0x..000000000000000000000000
InitTarget() start
InitTarget() end
TotalIRLen = ?, IRPrint = 0x..000000000000000000000000
Failed to identify target. Resetting via Reset pin and trying again.
InitTarget() start
InitTarget() end
TotalIRLen = ?, IRPrint = 0x..000000000000000000000000
Cannot connect to target.
J-Link>

What else do I need to try to restore drag 'n drop capability to this board?

Thanks.