Laptop screen is black but touch screen is working.

Hi @mangomonte ,

Check if you can see any images on the laptop screen when you shine at torch at an angle close to the screen. They will be very faint if they are there so trying this in a darkened room may help to see them

If there are images then no backlights may be due to a signal voltage not being received on the dispoff# lead on the eDP cable connector (see pin 5 on eDP connector image below).

You could always check if there is power on the +LEDVDD inputs (see pins 1 &2). Backlight power is always supplied to the LCD panel and it is turned on and off in the LCD panel by a signal voltage on the dispoff# lead.

If the LED power is there and if the dispoff# lead has a signal voltage (3.3V DC?) you may have to check the eDP cable connection on the LCD panel.

Here’s the hardware maintenance manual for the laptop. Go to p.48 to view the necessary pre-requisite steps to remove the LCD unit, so that you can check the cable connection.

Also maybe check the sensor board connection in the lid. The sensor board signals (see pin 26) when the lid is closed and this causes the backlights to be turned off. (see p.59 in the manual).

(click on image to enlarge).

Hopefully this is of some help.