Press the iPhone power button, the iPhone 6S doesn’t respond. After troubleshooting the software, we started disassembling the iPhone 6S. Use Phonefix screwdriver to remove the iPhone screws next to the iPhone lightning port, place the iPhone 6S on the LCD screen separator to heat, after a while, use screen sucker to open the iPhone 6S screen.
Looking at the iPhone 6S motherboard, we found there are some repair marks on the motherboard, and the iPhone motherboard shield cover was not installed well.
Connect the iPhone motherboard to DC power supply via DC power supply cable to measure the iPhone motherboard current, after measurement, we found the iPhone 6S motherboard is short-circuited.
Log into the zxw dongle to check iPhone schematic diagram, it doesn't have many parts connected to the iPhone battery connector. First we suspected it's caused by the short-circuited Q2300.
Next we use SUGON T26 soldering station to remove the U2300 charging IC, and then measure it again, now the value measured is normal, the iPhone motherboard doesn't shorted.
Clean the solder pad, apply some solder paste, and then install a new U2300 iPhone charge IC to the motherboard.
Once done, measure the iPhone motherboard again, the data is normal.
Assemble the iPhone 6S, press the power button, the Apple logo appears normally, and the iPhone 6S is turned on successfully.
We hope that is helpful for you. If you have any questions, please feel free to contact us.