Discovery board stm32f746 with i cannot connect anymore on the st-link port

[Argous]

Hi, I have a discovery board stm32f746 with witch i cannot connect anymore on the st-link port.. Windows does not detect anymore the st-link port .. i took out the chip put it on a smal test board and the chip it's ok is detected as st-link... but on the main board does not, i could connect an external programmer on the 4 pins for programming the st-link... but it still not detected by windows. Please help me recover the board.

[Tesla DeLorean]

Isn't the 4-pin to program the on-board ST-LINK?

Which chip did you remove?

Check the USB connector/integrity

[Argous]

The st-link chip stm32f103 !

[Argous]

i can connect on that chip with external programmer for program it but without the st-link connection i cannot flash the mainboard

[Argous]

I put the chip on this board and is detected as st-link chip ... but on mainboard does not... the usb port connector is ok, cable changed, pc changed, no matter what the st-link is not detected is like i'm not connecting the usb cable to the pc... no sound no undected hardware or st-link.

[Argous]

I forgot to tell there is a red led that flash all the time when i connect the st-link cable