First, we press the iPhone power button, the Apple logo appears normally, and then the iPhone 6S Plus restarts automatically. We tried several time, the problem was the same, the iPhone 6SP kept restarting after the Apple logo appeared.
This iPhone 6S Plus has been repaired before due to overheating problem, the iPhone CPU overheated after dropping, and the iPhone screen has been replaced. After repairing, the iPhone functions are normal, but when the iPhone in standby mode, it keeps restarting. The iPhone 6S Plus only can be turned on by pressing the CPU, and the iPhone CPU is overheating.
There are several reasons can cause the iPhone restarting problem, one is the iPhone baseband power supply condition problem, the second is the iPhone Nand flash, the third is the iPhone CPU chip, and the fourth is the iPhone battery.
Connect the iPhone 6SP to the computer, and then use iTunes to restore it, it reports an unknown error 40, seems it's the iPhone Nand flash circuit problem.
Disassemble the iPhone 6SP, remove the iPhone screen, disconnect the iPhone battery, and then take out the iPhone motherboard.
Use digital multimeter to measure the circuit around the iPhone Nand flash, the data measured is normal. Nest use hot air gun and BGA graver blade to remove the iPhone Nand flash, and then use ZT-X multimeter to measure the resistance value for the solder pad.
Use hot air gun and CPU removal graver to pry the iPhone CPU, we found the solder pad missing some pins, which are connected to C0703 and C0707 capacitors.
Assemble the iPhone 6S Plus, press the power button, the Apple logo appears normally, and then it gets into the IOS system properly.
So, these are some of the tips to fix iPhone Keeps Restarting issue. If we have missed any of the great ways to solve the issue, please let us know in the comments below.