Screen Black out after hibernation (XPS 12 9Q33)

Dear friends,

I bought a XPS 12 9Q33 model at Amazon site last summer and all's well till last week.

However, screen has been blacked out suddenly after hibernation mode.

The current situation is as following ;

- LED on power toggle button : working (white)

- Keyboard backlite : working

- System fan : working

- Screen : NOT working / I can't even see the DELL logo on starting up.

I've tried several methods after reading similar error reports on this forum.

- hardware reset with holding power toggle button for 30 seconds : not working

- hold D key or Fn key on power on : nothing happened

- push F2 or F12 on boot up : nothing happened

- flipping display in and out several time : nothing happened

- waiting for mini display cable I bought to test with an external monitor

Do you guys have any comments or suggestions to help me?

Regards,