iPhone 8 plus. image but has no backlight.

iPhone 8 plus has image but has no backlight.

I have checked all 1.8v lines and all 5.7v lines which are present on the fpc. all backlight filters check out fine.

I replaced all 3 backlight coils, both backlight driver ics. still no backlight.

im getting very low voltage readings on both anode lines ( 3.7v ) .

my anode readings taken from a good working board im getting around 10v on one anode line and around 16v on other anode line. with screen connected.

However on this one both backlight anode lines measure (3.7v) on both anode lines with screen connected.

anyone know what would cause both anode lines to be only pushing out 3.7v instead of the normal 10- 16v?