You are a life saver, I had the same issue
Upon powering up the lapto the first time: black screen.
I had to:
- Disconnect the internal display connector
- Insert the HDMI dongle on Port 1 (Port 2 and 3 don’t work)
- Connect an external display
- Power On
- I got display output on the external screen
- Power Off
- Connect the internal display connector
- Disconnect external display
- Power On
Care:
- Anti tamper switch on the MOBO triggers blinking red light, it’s not a BIOS status LED
- Port 2 and 3 had no display out, I was getting disheartened that the problem was deeper
