Analysis & Solved: iPhone 5S Audio No Sound Error

The iPhone 5S audio has no sound error, what's going on? how to solved it? Actually, the iPhone 5S no sound is a common issue, after check iPhone schematic diagram on WUXINJI Dongle, we know that the iPhone 6S audio part is made up of iPhone audio IC-U21 and ringtone amplification IC-U22. After analysis it, we can solve it.

If your voice can't be heard （normal call mode), 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.

If there is no any voice on iPhone 5S, first we need to check each power supply on U21 circuit whether they are normal. If there is a voltage is abnormal, we need to handle it first; if all voltage works normally, then re-install or replace the U21.

If the receiver has no sound （normal call mode）, replace the receiver and flex cable, check the channel of the receiver, check short connection for FL51 and FL 51, re-install or replace audio U21.

Speaker no sound and no ringtone, check if C335 has a voltage of about 4V, check short connection L4, check short connection FL6 and FL9.

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 iPhone audio IC U21.

If the sound is normal when in phone call, but there is no sound in speaker mode, check iPhone speaker, replace light sensor flex cable, check speaker receiver channel, check short connection FL48, check if C55 and C61 are dropped or replaced, re-install or replace audio U21.

If the recording is normal, but there is no sound on the phone call, this situation is usually caused by CPU virtual welding, use QUICK 861DW hot air rework station to weld the CPU , and then re-install iPhone baseband CPU.