Tutorial: iPhone 5S Audio Part Repair

Received an iPhone 5S with audio part problem from one of our customers, there are many different situations if the audio part get damage, how to fast test and repair it? Let's find answers from this article!

As we know, the audio part is made of iPhone audio IC -U21 and ringtone amplification IC-U22.

1. If there is no sound on iPhone 5S, first we need to check whether every power on the U21 circuit is normal. If there is an abnormal voltage, we need to deal with it first; if all the voltages are working properly, then reinstall or replace U21.

2. If the receiver has no sound (normal call mode), replace the receiver and flexible cable, check the channel of the receiver, check the short connection of FL51 and FL 51, and reinstall or replace the audio U21.

3. If the other side can't hear your invoice during normal calling, replace the iPhone tail plug flex cable, check the microphone channel, check short connection FL49, check if C222 and C333 are dropped or replaced, re-install or replace audio U21. Furthermore, after make the phone call, please use Fluke 15B+ Digital Multimeter to measure the power supply on microscope to check whether there is a 3V, if not, we can solder a jump wire from the iPhone Nand flash power supply PP3V0_NAND to FL49

4. If both the receiver and the transmitter have no sound， test the recording to see if it's normal，and whether the receiver has the sound （receiver mode）. If the receiver and the microphone channel are not detected by the recording, check the short connection FL49, FL51 and FL52, check if C222 and C333 are dropped or replaced. Re-install or replace U21.

5. If the recording is normal, but there is no sound on the phone call, this situation is usually caused by CPU virtual welding, re-install iPhone baseband CPU.

6. If the voice is normal, there is no sound in the speaker mode, check the iPhone speaker, replace the light sensor bend cable, check the speaker receiver channel, check the short connection FL48, check whether the C55 and C61 are discarded or replaced, reinstall or replace the audio U21.

7. The loudspeaker does not have any sound and ringtone, check whether the C335 has a voltage of about 4V, check short circuit connection L4, check short circuit connection FL6 and FL9.

Tips: you can check iPhone schematic diagram on WUXINJI Dongle.

If you have any other questions about professional cell phone repair, please check on www.vipfixphone.com