Macbook Pro A1990 820-01814-A - no webcam, no True Tone, no keyboard backlight

[abadcap]

Hi there,

after I replaced the topcase of the Mac, there is no webcam, no True Tone, no keyboard backlight working and also in the display settings there is missing the option for automatic display brightness. When I run the Apple Hardware Test, there is no issue found.

I would highly appreciate any kind of hint.

Thank you.

[mon2]

Re: Macbook Pro A1990 820-01814-A - no webcam, no True Tone, no keyboard backlight

These all sound to be smbus / I2C linked.

Carefully measure the voltage to ground of the SCL and SDA pins. Post the voltage measurements.

[abadcap]

Re: Macbook Pro A1990 820-01814-A - no webcam, no True Tone, no keyboard backlight

Thank you, mon2.

I'll take a look into it. Do you know what might have caused the issue?

[mon2]

Re: Macbook Pro A1990 820-01814-A - no webcam, no True Tone, no keyboard backlight

No, fault could be anything.

Also review the voltage of IPD_LID_OPEN. The above symptoms could be due to the logic board believing the lid is closed. This signal is on the trackpad connector.

As an idea, remove the trackpad cable and use an external mouse -> does the webcam function ? There is a MUX that is enabled / disabled for the webcam signals. Be sure the webcam is not disabled via software.

Apply a PRAM reset.

[abadcap]

Re: Macbook Pro A1990 820-01814-A - no webcam, no True Tone, no keyboard backlight

I disconnected the trackpad cable; the keyboard does not work now, the fans are on high speed. The webcam still does not work.

Anyway, thank you so much.

[mon2]

Re: Macbook Pro A1990 820-01814-A - no webcam, no True Tone, no keyboard backlight

Yes, fan will be high speed since the sensors are in the trackpad. Ok to attach the trackpad again.

Review the voltage of IPD_LID_OPEN to ground on the logic board.

[spidertnt]

Re: Macbook Pro A1990 820-01814-A - no webcam, no True Tone, no keyboard backlight

I doubt anything is wrong ....but suspect a mismatch of components between 2018 and 2019 models.

MBA offers the same symptom's if you try to use a 2019 screen on a 2018 model.

But i have no experience with 15" Pro so cannot say for sure.

[mon2]

Re: Macbook Pro A1990 820-01814-A - no webcam, no True Tone, no keyboard backlight

Have you asked the vendor of the topcase? Aliexpress or from a donor ?

[mon2]

Re: Macbook Pro A1990 820-01814-A - no webcam, no True Tone, no keyboard backlight

Yup, see here:

https://www.ifixit.com/Answers/View/...en+replacement

[abadcap]

Re: Macbook Pro A1990 820-01814-A - no webcam, no True Tone, no keyboard backlight

Both components (topcase + screen) are from Apple, no Aliexpress. Just the topcase might be from 2018. The board and screen are from 2019.

[mon2]

Re: Macbook Pro A1990 820-01814-A - no webcam, no True Tone, no keyboard backlight

Was it ordered directly from Apple by you or through a reseller?

If it is an Apple original, can you ask their tech on why the truetone; webcam features are now lost?

I think compatibility is a factor - not sure if you have seen the following webpage - believe it is by @Piernov.

https://logi.wiki/index.php/MacBook_..._Compatibility

(still trying to navigate through the comparisons..)

[abadcap]

Re: Macbook Pro A1990 820-01814-A - no webcam, no True Tone, no keyboard backlight

Short update: All voltage measurements are correct. The board has still the issue. I also tried another topcase, nothing changed. It is kind of a desperate situation with that board.

[samolo75]

Re: Macbook Pro A1990 820-01814-A - no webcam, no True Tone, no keyboard backlight

Its being a while from this post. I read in a different post here that if you connect a 2017 LCD into a 2018/2019 it will work but you will have exactly this symptoms, and even installing later on a 2019 LCD. And this is because the serial number is saved in the security chip and get deleted? I am sure you can find the post here. To solve it the SSD needs to be wiped and installed from scratch with the good LCD connected (this is what I read)

[walkteck]

I HAVE ALREADY DETECTED THESE SAME FAULTS IN SEVERAL EQUIPMENT AND IN ALL OF THEM IT TURNS TO BE A FAILURE OF THE "FLEX" THAT GOES FROM THE MOTHERBOARD TO THE DISPLAY

[Lisa Su]

Don't shout (writing in all-caps). Also you could have edited your previous post.