Macbook A1502 820-3476 No speakers?

[mrtutz]

Hello All.

Bit of a weird one that's got me stumped. I picked up a Macbook which wasn't seeing the internal SSD, I managed to repair that issue (broken trace) however the macbook speakers dont seem to work.

When you operate the volume up / down buttons the display comes up with a "no entry" sign underneath the speaker for some reason? Sound works OK using bluetooth speakers / headphones, but nothing on the inbuilt ones.

When I look in System preferences / sounds there's nothing listed as audio?

Anyone got any ideas?

Thanks in advance

[mon2]

Re: Macbook A1502 820-3476 No speakers?

Have not reviewed the schematic for this unit but are the internal speakers driven by an amplifier that is i2c bus controlled? That is SDA and SCL lines.

Check for this and that the related interface lines are connected from source to this local amp. Confirm the i2c pull up resistors are present to do their job.

Possible that the i2c master is unable to ping this i2c slave device so does not show it in the inventory of the present hardware.

[rotceh_dnih]

Re: Macbook A1502 820-3476 No speakers?

Try a SMC reset otherwise check power rails around U6201,U6410,U6420,U6430,U6440.

I've seen bypass caps on the amp ic's die and also the main cirrus ic.

[MobileXT]

Re: Macbook A1502 820-3476 No speakers?

Hello All.

Bit of a weird one that's got me stumped. I picked up a Macbook which wasn't seeing the internal SSD, I managed to repair that issue (broken trace) however the macbook speakers dont seem to work.

When you operate the volume up / down buttons the display comes up with a "no entry" sign underneath the speaker for some reason? Sound works OK using bluetooth speakers / headphones, but nothing on the inbuilt ones.

When I look in System preferences / sounds there's nothing listed as audio?

Anyone got any ideas?

Thanks in advance

Also check the FileVault make sure is turned off sometimes gives a lot of problems on some MacBooks when the FileVault is turn on.

[protocold]

sorry to revive this old thread but i have the exact problem, I dont see any audio devices under mac and i also dont see anything on the bus when I do lspci under linux (but device exist under same linux with a good board)

I checked power rails around U6201 is good. I have a bad U6410 which i have removed(i can see chips and cracks on it under microscope), do I need U6410 to exist for audio device to show up?

I have checked power rail PP5V_S0_AUDIO_AMP_L and PP5V_S0_AUDIO_AMP_R are both good.

what conditions need to be met for audio device to show up under mac preferences/linux lspci?

[protocold]

Can i possibly get some help on this please? Any pointers would be helpful. Much appreciated.

[mon2]

To the op - it is the headphone connector that needs to be reviewed/cleaned.

u6410 does not need to be present for the audio codec to be enumerated.

The audio codec operates using the HDA bus.

Inspect all signals with HDA_ prefix. Review the series resistor on the output line from the audio codec with HDA_ prefix.