MSI GE70 MS-17571 VER.1.1 LCD backlight is not working

Hello; I installed the wrong LVDS cable. LVDS 19V line short circuit. There is no 19V line. There is no LVDS 19V on the MS-17571 motherboard. I couldn't find where this 19V comes from. Which circuits should I check? Thank you. What can I do.

Please post a clear photo of an LVDS on-board connector (J29 or J30, depending on your config) with approx. 2cm surrounding area.

Measure the voltage to ground on the jumper marked with yellow arrow (with both battery and power supply connected and laptop powered off).

Lack of this voltage means the laptop is completely dead, is that correct?

Hello;
There is no voltage in the area marked with the yellow arrow. However, the PC's HDMI and VGA port outputs are working normally and displaying an image. There is a faint image on the LCD screen, but the backlight is not on. I cannot find where the 19v is coming from to pins 17-18-19(marked with the yellow arrow) in the J29 socket.
Thanks.

Try to power the computer on without battery connected (only power supply). Does the computer start up normally with picture present on HDMI?

It works with or without the battery via the PC's HDMI output.
It also works with just the power supply. Only the LSD panel backlight doesn't turn on.

The via marked in yellow is most likely damaged, or the copper trace inside the PCB is damaged.
Open (cut) the jumper as marked in yellow and solder a 2A fuse (package 0603) to the place of this jumper. Then solder the jumper wire as marked in green.
There is no fuse on this board originally, but I recommend one for a better level of protection. The fuse voltage rating must be at least 25Vdc.