Apple A1989 no Sound

[Strolch]

I have an A1989 and it had some liquid on it. Nothing is visible on the board. Everything works! But I only have one short sound on the left speaker. When I ask Siri about the weather, there is only one sound on the left, after that there is no more sound!
Even if I restart once briefly sound then nothing more.

[bluestone]

Re: Apple A1989 no Sound

I have an A1989 and it had some liquid on it. Nothing is visible on the board. Everything works! But I only have one short sound on the left speaker. When I ask Siri about the weather, there is only one sound on the left, after that there is no more sound!
Even if I restart once briefly sound then nothing more.

You need to check areas around U6300, U6400, U6450, U6500 and U6550, these are the audio and speaker controllers, check for liquid damage or bad traces.

[Strolch]

Re: Apple A1989 no Sound

I did it looks all ok!

[mon2]

Re: Apple A1989 no Sound

Can you play music and/or Youtube videos with sound normally ?

[Strolch]

Re: Apple A1989 no Sound

Hi, I just played a youtube video and had sound on the left side! On the right I had no sound! But when I closed the page and opened it again I had no sound! The sound is always just left.

[mon2]

Re: Apple A1989 no Sound

What is the 820-xxxx number markings on your logic board? This will help to locate the proper schematic for reference.

[Strolch]

Re: Apple A1989 no Sound

850

[mon2]

Re: Apple A1989 no Sound

See attached.

Measure the voltage on both sides of R5305 & R5306. These are the local pull-up resistors for the RIGHT side of the audio amp circuit for this open-drain circuit. These resistors are required to define the soft 'high' logic level.

What are the readings for the respective,

I2C_SPKRAMP_R_SCL
I2C_SPKRAMP_R_SDA

signal lines ?

[Strolch]

Re: Apple A1989 no Sound

Hi, i have on R5305 and R5306 both sides 1,7930 Volts

[mon2]

Re: Apple A1989 no Sound

Voltage readings look fine and this implies the local pull-up resistors are pulling up the I2C lines to the 1v8 rail.

Confirm that the audio amp (U6550) is being powered - check for the 1v8 rail on the linked parts. See attached.

Any sign of liquid damage in this area ? The U6550 component is a WLCSP package (tiny BGA) which may need some TLC with flux and reflow -> tweezers to make it dance if you suspect corrosion which may be under the package.

[Strolch]

Re: Apple A1989 no Sound

Everything looks very good. And 1.79 volts are there

[Strolch]

Re: Apple A1989 no Sound

you think the U6550 is damage?

[mon2]

Re: Apple A1989 no Sound

Perhaps but confirm the voltage as per attachment for the VBAT pins. You can check this on the caps.

Then confirm that L6550 & L6551 are present on the logic board. These are acting like filters but they must mate onto the woofer connector.

Remove all power, meter in resistance mode -> check the resistance between:

L6550, pin # 1 and # 2 - should be ~0 ohms
L6551, pin # 1 and # 2 - should be ~0 ohms

then check resistance between pin # 1 -> woofer connector as per attachment.

Need to be sure that both P (Positive) and N (Negative) leads of the speaker are reaching the pin # 1 of the respective ferrite beads.

[Strolch]

Re: Apple A1989 no Sound

one question are the TAS5770LB2 and the TAS5770LB2YFR ,TAS5770LB. All the same? I want to order some

[Strolch]

Re: Apple A1989 no Sound

i will check L6550, L6551...after a bike ride ;-)