Here is an iPhone 7 that was damaged by water, now this iPhone 7 is failed to boot, after checking, we found it’s the problem of the iPhone audio IC. We are going to troubleshoot it in hardware aspect.
Disassemble the iPhone 7. Use screwdrivers to remove the screw next to the iPhone lightning port, and then heat iPhone 7 screen for a while by CPB screen sepatator, final we open the iPhone display screen smoothly.
Connect the iPhone motherboard to the DC power supply,the iPhone leaks 900mA and not turning on.
Take out the iPhone motherboard, and oberve it under the Trinocular Stereo Microscope, we found the capacitor C2307 was broken, the two of the iPhone audio amplification ICS under it have been corroded.
Remove the capacitor C2307, and then clean it up, connect the iPhone motherboard to the DC power again to test, the data tested is 100mA, and the iPhone can be turned on smoothly.
After the iPhone is turned on, test the functions on iPhone, there is no vibration and no voice.
Remove the both iPhone audio amplification IC, and then the diode data tested of the U3402 A2 pin is 30, but the normal data is more than 300.
After check iPhone schematic diagram via WUXINJI Dongle, we know that there only M2800 is connected to the A2 pin. Now, we confirmed that it’s the problem of the M2800.
Remove the M2800, and install the new one. After replacement, the data of the U3402 A2 pin tested by digital multimeter is normal. Now replace the new 2 iPhone big audio IC, no leakage.
Finally, assemble the iPhone, and turn it on to test, all functions tested are normal, the iPhone 7 backs to normal work.