Hello,

Thank you for your reply.

The thunderbolt firmware was been updated 2 mouths before the breakdown​. This previous owner didn't perform the firmware update...
I tried to flash with CH341, not better.

With my voltmeter, I ckecked VCC on the Winbond chip (U15), it's various voltage between 4V and 0V by loop.

I can manage to replace this chip....

Hello all,

I tried to repair my T480 motherboard.
The PC can not power off at all.

I tried the USB-C meter on both ports : it's loop on/off. I think I can not negotiate the 10-20V voltage.
I tested with an USB "classic" 5V charger with to USB-C : the USB-C meter displays 5,080 V, 0,02 A with some pics to 2,5 A

The USB-C meter was being tested on other USB-C device, it's works fine.

Thank you in advance for your help.

[B]LINK to Schematic[/B] -> [URL="https://www.badcaps.net/forum/troubleshooting-har...