iPhone 7 Lower Loudspeaker Does Not Work

Fenomeno di malfunzionamento

iPhone 7 Lower Loudspeaker Does Not Work

If we covered the top loudspeaker, there is no sound output from the phone when we play the ringtone.

Risoluzione dei problemi

Take off the motherboard and measured the diode value on pin1 and pin3 of the charging connector J4101.

• The diode value on pin1 was 573, which was normal
• And the value of pin3 was 723, also normal

Then connect with the DC power supply and measured the voltage

• PP_VDD_MAIN on C3407
• PP1V8_VA on C3426

The voltage value on C3407 is 3.7V, and the value on C3426 was 1.777V, both voltages are normal.

Since both the diode values and voltage values are normal, then we can try to replace the chip U3402, this chip is the audio amplifier IC for the loudspeaker.

After replacing the Audio amplifier IC, test the audio function with the screen buckled.

Loudspeaker function back to normal, problem resolved.

Corso di riparazione della scheda madre dell'iPhone 7