iPhone 7 System Stuck with Voice Memo Can not Work
Malfunction Phenomenon
iPhone 7 system stuck, when clicking on an APP icon, the APP responds slowly. Voice memo can not work with the red icon on the interface is grayed out, also there is no sound when playing the ringtone.
Trouble Shooting
Ringtone can’t work with voice memos function abnormal, which means the audio circuit is abnormal. Audio IC U3101 related to this issue.
Then we remove Audio IC and measure the diode value of the U3101 bonding pad. We found the diode value on pad C12 was “OL”, which indicated that the relevant line was disconnected. According to the circuit diagram, we know that pad C12 is connected with pad BV65 on the CPU via R1103.
We tried to jump a wire to connect pad C12 and R1103, and put back the Audio IC get the motherboard and display assembly, press the power button, and test again, all function back to normal, problem resolved.