iPhone 8 Plus turns on with black screen. Run boot current measurement and we can confirm that the phone is turning on with no display. After analyzing with the maintenance drawing, our initial judgment is that the fault is related to backlight circuit. The cause of iPhone 8 won't turn on problem is confirmed as resistor damage after further measurement, so we can fix the iPhone 8 black screen issue by replacing with a new resistor. Let's check the tutorial video to find out the details.