Screen brightness is very dim after boot and no KB backlight
I have a 2019 MBP (A1989) that often displays full brightness on boot (Apple logo) and then dims to about 50% brightness. The mac shows that it is displaying at full brightness in macos but the keyboard doesn't illuminate at all, the TB buttons for the keyboard backlight won't change anything,
The option for 'Automatically adjust brightness' Is missing in settings.
Everything else works: the webcam works, and all the wireless antenna seem to work fine. I get the sense that the ambient sensor isn't working The same issue as:
The thing that is different for me is that the screen is the original.
I'm wondering if this could be anything else but the ALS? or if there could be any software that could spoof the light sensor to 100% all the time. The only Mac display I have is annoyingly from a 2017 Mac that apparently will work but with reduced brightness as the ALS isn't compatible...
Is it new display time? Are there any cables or resistors I can check? I'm just trying to avoid paying for a new display if it's not going to fix anything!
Many thanks all!!!
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Take some black tape and cover the camera sensor as the ALS is within the same unit. See if that makes a difference.
Also did you damage the chin plate that sits just under the screen or from the other side the black plastic piece?
Thanks, I will give that a try! The device is free of physical damage inside and out however the device was returned by a user so could have always taken a bump at some point.
I have reseated cables from the board under the screen when inspecting for damage. Could it be this board specifically?
@slat - I would run the onboard diags to see if an error pops at this point.
If you have a spare display see if that works. I fear the issue is deeper in the display assembly.
Thanks, I'll have access to the device tomorrow so will perform a full diag and see what I get!
@danj Apologies for the delay. Was able to run the detailed Apple diagnostics and while no issues were found I did see that under about device - CURRENTSENSOR (ILBR) Description is: Current LCD Backlight, Value is: -1.000.
Possibly a failed sensor on logic board?
I have managed to source another Mac with working logic and display so will most likely use those parts in this top case (Other mac has swollen battery). Thanks for your help!
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