iPhone 7 handset has abnormal sound repair

iPhone 7 called earpiece to make an abnormal noise. It was found that it was caused by the damage of coder IC. The fault was repaired after replacement.

Machine model: iPhone 7
Fault phenomenon: there is abnormal sound when calling earpiece
Fault analysis: when you call earpiece, you can’t hear any sound. This phenomenon can be divided into several types: whether there is sound in earpiece when the recorded file is playing. If not, there may be something wrong with earpiece,FPC or earpiece.Second, whether there is sound in earpiece when calling. If not, there may be a problem with coder IC switching, or there is a problem with the I2S bus of Baseband communicating with CPU.
Maintenance process: the customer replaced the earpiece by himself, but he still made the same abnormal call as the former FPC. It was ruled out that Accessories was not the cause.earpiece can hear the sound normally when the recording file is playing, and there is no abnormal sound.

iPhone 7 handset has abnormal sound repair Figure 1.

When coder is sent to coder from the main CPU, the output signal is transmitted from ANT to coder.
When the recording file is played, the main CPU outputs to coder IC encoding and decoding, and coder power amplifier chip outputs to earpiece.The most likely problem is coder IC codec conversion, directly replace the coder IC.