iPhone 6p phone external no sound, headphones normal

Faulty model] iPhone 6p 64g

[Fault phenomenon]

Customer description said the phone external sound, insert headset normal, vibration and answer the phone are normal.

[Failure Analysis]

The boot test is indeed the same fault as described by the customer, because plugging in the headset normally represents the working condition of the phone big audio is already met. It could be a problem with the big audio chip and the audio amplifier or the I2S2 (the audio cable for the external amplifier). It could also be caused by the external pairing.

[Repair Process]

First troubleshoot the external match problem, the phone motherboard removed into our test machine rear shell assembly inside, boot test again found that the original fault. Now you can basically rule out the reasons for external distribution, the target directly aimed at the large audio IC disassembly chip, observe the pad with or without tin and drop point. All normal directly to the material board to remove a large audio IC tin mounted. And then this boot test found that the fault is still the same, now basically rule out the cause of the big audio IC. Disassemble the audio amplifier, measure the corresponding points, found 45_AP_TO_CODEC_XSP_I2S2_, and then remove the audio amplifier. BCLK (I2S2’s clock signal) is disconnected.

This point is only connected to the big audio, audio amplifier and CPU, dismantle the big audio to measure the corresponding point found resistance value is normal, directly from the big audio below to pull a first fly line to the audio amplifier to the corresponding point.

Directly mount the audio amplifier, power on the test.

Repair results]

Power on test, normal external playback, fault repair completed.