It's been a while since I worked on this board, but I believe I had occasional backlight with this board previously but the LDVS connector was damaged... I replaced it and I have double, triple checked solder and connector inside but this board acts like it doesn't see the display. I also tried another compatible display with working backlight/image and same.
0V on PPVOUT S0 LCDbklt and over 1V diode red to ground WITH display connected
0V on PP5VR3v3_SW_LCD
0V on PPVOUT S0 LCDbklt and over 1V diode red to ground WITH display connected
0V on PP5VR3v3_SW_LCD