Released on September 19, 2014, this 4.7" screen iPhone is the smaller version of the iPhone 6 Plus.

4035 Questions View all

No audio on speaker [board level repair]

Hi! So I have this iphone 6 that came in for tristar replacement (typical symptoms, died after being used on a car charger), after tristar I had to replace PMIC because it had an internal short on the 1V2_SDRAM line (I found it dicking around the rear cam FPC) Everything was working fine at this point. The day after I gave it back the client tells me he can't play whatsapp voice messages but before he was making phone calls and it was ok so I know audio worked before.

Now with the phone back in my hands, mics work, earpiece works, and headphones work, but whenever it tries to play audio through the loudspeaker it freezes for a few seconds, nothing happens and then it gives you back control (like it tries to access the speaker but it can't so the cpu locks up until it times out)

Long story long, what I have ruled out is:

-Parts (obviously), charge port flex, loudspeaker, housing shorting smth, etc.

-Software, fresh installed ios 11

-Audio codec IC, first reflowed, then reballed, then replaced it, nothing changed

-Power lines to the Audio IC, every line is fine

-Speaker Amp IC, reflowed then replaced, also power lines to this chip are fine

-CPU to speaker amp IC enable signal, can't remember the exact net name, but it is present when I try to play some audio through the speaker.

This is definetely a rabbit hole, and I've been dicking around with it for a whole week and not much progress.

-Also compared to a known-good board every diode mode measurement I felt was relevant, nothing came suspicious

Has anybody seen anything similar or can point out somewhere I may have overlooked? At this point I'm out of ideas really

If you read till this point: thanks in advance!!

Answered! View the answer I have this problem too

Is this a good question?

Score 0

Comments:

what about u1601 ?

by

Add a comment
Mac RAM Kits
Speed up your Mac. Max out its memory.
Mac RAM Kits
Get more memory out of your Mac.

1 Answer

Chosen Solution

Rabbit hole for sure...you've done a lot already and I don't know if my suggestions will be of any help or not but here goes.

  • First, I wold double check my previous work to insure there are no obvious issues (you probably already did this multiple times :>)
  • The Speaker Amp has a built-in Boost Converter (see the top left-hand corner of the schematic). Although you tried replacing the IC, I would check all of the components in the circuit, particularly the coil (L1604) and the P_L19_VBOOST caps. One or more of those components may be out of spec. An LCR meter is the perfect diagnostic too for this.
  • You said you checked the voltage rails but just to confirm, did you test P1V8_VA_L19_L67?
  • I would also check the communications lines (I2C / I2S) to see if there are any shorts.
  • I would check the CODEC_BI_TRISTAR_MIKEYBUS rails as they connect the Codec to Tristar and you did work on Tristar. Maybe something got dislodged or damaged.
  • Finally, I would check FL1895/1866 as well as DZ1813/1814.

Hopefully you will find something. However, unless you tested the speaker functionality yourself prior to repair, I wouldn't necessarily trust the owners assertion that everything was fine.

Was this answer helpful?

Score 1

Comments:

Ok so the client asked me to return it as is, so this was a no fix. Too bad. I'll mark your answer as the correct one anways. Thank you very much kind sir!

by

My pleasure!

by

Add a comment

Add your answer

Rodrigo Maero will be eternally grateful.
View Statistics:

Past 24 Hours: 8

Past 7 Days: 42

Past 30 Days: 127

All Time: 263