Everyone has cellphone for life or work, when your cellphone is broken, how do you fix and which tools do you need. Vipprog can provide some tools and guide for you. If you need cellphone repair tools you can try vipprogrammer.com.
IPhone 6S Plus displays nothing but it asks you to input password when connecting to computer.
Teardown iPhone and remove the motherboard. Charge it with DC power and turn it on. DC power shows power on current changes normally, but screen displays nothing. Most cases like this are caused by abnormal screen power supply.
1. First you use multimeter to measure the diode data of display screen interface, finding no short circuit or open circuit. Next measure the display power supply, as shown in below picture.
2. Then the multimeter shows the capacitor C4002 on bootstrap circuit of power supply chip U4000 is 2v voltage which is lower than 6v voltage when disconnecting display screen.
3. Finally, after checking, we find the working condition of U4000 is normal. So we think the damage is inside it. After replacing it, trouble is removed. The material object is shown in below picture.