How to Solve The iPhone 6S Receiver no sound problems?

The iPhone 6S receiver has no voice when it is in calling, we can’t hear the voice from another side, we can hear from each other when we turn on speaker on iPhone.

According to our repair experience, the iPhone receiver no sound, but the iPhone speaker can hear the voice, this problem is usually caused by iPhone receiver, receiver flex cable, receiver circuit or iPhone audio IC problems.

First we need to test the iPhone 6S. Power on iPhone 6S, go to Settings->Sounds & Haptics to test the ringtone, the ringtone voice tested is normal. Make a phone call to someone else, the receiver has no sound, but the speaker is normal.

Now, replace the receiver and flex cable, and then test the iPhone 6S, but the failure still exist.

Use digital multimeter to measure the diode data of receiver signal 1 pin and 3 pin that on the connector J3100, the data measured are normal.

After excluding the cause of the peripheral components，we start to check U3500. Take out the iPhone motherboard, we found the U3500 has been replaced before by other repair man,  the several filter capacitors around it has been removed, and there is a power supply IC of NFC also has been removed.

Now, we need to fix iPhone receiver failure, directly replace the iPhone audio IC U3500. After replacement, connect iPhone 6S to the DC power supply, the trigger current jumps from 0 to 80mA, it’s been circulating like this.

The replacement IC has been soldered well, the iPhone CPU didn’t been blown by QUICK 861DW hot air rework station. Remove the iPhone audio IC, now the current is back to normal, so we confirmed that it’s the problem of the iPhone audio IC. Replace it with new iPhone audio IC, and then install the iPhone.