Nucleo-H755ZI-Q not detected by usb

[JOKH]

Hi there

I bought two Nucleo-H755ZI-Q (NUH755ZIQ$AT3) boards.
Non of them show up as USB devices on either of my computers.

I have tried connecting through the IDE 1.13.1; STLinkUpgrade  3.12.3 and the newest cubeprogrammer. neither can find the device.

I suspected driver issue and reinstalled the en.stsw-link009 driver
Still no luck; also the devices are not shown as "unknown" there is no reaction at all from the PC when i plug and unplug the device.

The MCU is running the preprogrammed program that switches between LD1,2 and 3 when user button is pressed. but except from that; nothing is working.
They also do not show up as 

[Issamos]

Hello @JOKH 

Can you try to connect under reset using Cube Programmer.

Best regards.

II

[TDK]

Are you using the CN1 USB connector?

Perhaps try a different USB cable, could be using a power-only cable.

[JOKH]

I did use the CN1 but the two cables I tried were apparently power-only cables.
I guess third time really is the charm.

Thank you for your response.