iphone 7 that does not want to boot.

Hey guys. Sorry, I need your advice.
I have an iphone 7 that does not want to boot.
Have tried another dock and battery.
The iphone charges 0.41A.

PP_VDD_MAIN = 3V8
PP3V0_TRISTAR_ANT_PROX = 3V
PP5V0_USB_RVP = 5V
PP_VDD_BOOST = 3V9

I have already replaced the chestnut U3703
PP5V1_TOUCH_VDDH = 0V
PP5V7_LCM_AVDDH = 0V
PP5V7_MESON_AVDDH = 0V
PN5V7_LCM_MESON_AVDDN = 0V
PP6V0_LCM_BOOST = 0V

I removed the chestnut and tested the lines, i have no short to ground.
PMU_TO_AOP_TRISTAR_ACTIVE_READY (reset) =1V8
LCM_TO_CHESTNUT_PWR_EN =0V (with connected screen)
With an iPhone 6, I know that this line (LCM_TO_CHESTNUT_PWR_EN) with the lock screen should also be 1V8.
Does the iPhone 7 also have 1V8 on this line with connected screen?

Have someone an idea what the next step would be?
Thx