Products & Services

iPhone 6 Plus low voice in speaker

After the replacement of speaker or charging port flex cable of iPhone 6 plus, the output sound of speaker is still low and hard to hear even the volume up is turned to the high value. We may consider the issue is from the audio speaker Amplifing IC U1601 or Boost Voltage Circuit around.

The replacement of IC U1601 is strict forward. Sometimes issue is still remained and boost voltage circuit around is considered to be failed.

In order to raise the voltage of pp_batt_vcc, 4.2V input of IC U1601, to SPKAMP_TO_SPEAKER_OUT_CONN_P, 6.3V output of IC U1601, a combination of components: IC U1601, C1632, L1604, C1603, C1648, C1642 form a boost voltage circuit so that the speaker has enough power to voice out loud. It includes three steps 1) convert DC-AC, 2) voltage up AC-AC and finally 3) convert AC-DC. Check theroy for step 2 here.

Coil L1604 and capcitor C1648 are most power consuming components in the boost voltage circuit and are easy to damage. So that why they are shielded to increase heat penetrating. Removing the shield, testing them one by one, replacing if burnt will fix the issue.















Disclaimer: The content of this page is for reference only. You take your own risk to perform any test or repair on your device. We are not responsible to any damage or lose due to any false statement in this page.
Source of all circuit diagram are from Apple's schematic. iPad, iPhone, iPod, Macbook are trademarks of Apple company.