nRF 5340 DK does not show up when connecting to USB port

Question

Hi, 
 
 I just got a nRF 5340DK (PCA10095, 1.0.0 2021.9) which doesn't show up on my windows 10 computer. 
 When I connect it to my computer, the green Led 5 blinks rapidly in bursts of 3 or 4 or 5 (varies over time), but no COM device shows up in the device manager and no device shows up using USB Device Tree Viewer. 
 nrfjprog -i shows nothing and nRF Connect v3.7.0 Programmer v1.4.11 says no devices available. 
 I have the power source set to USB, only attached the USB cable, and turned it on 
 I haven't touched SW1 or SW6. They have an amber film over them which I haven dared to break. 
 VDD shows around 0.35V - 0.4V. Same with VDD nRF. 5V shows 5V steady. 
 When I attach a nRF52840 MDK USB Dongle to the same USB port, it shows up. I have tried two different USB cables. 
 
 Have I been unlucky with the board, or am I doing something stupid?

JonasForssell · Accepted Answer

On my board (also 5340 DK) I have the power source to VDD and nothing happens until I turn on the board with the switch in the lower corner. I attach my USB to the connector in the short end of the board (There are two connectors on my board). 
 Then it works on my Windows 10 without any more work. I use the SES with J-Link interface as installed by default by the NCS toolchain

nRF 5340 DK does not show up when connecting to USB port

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