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Released in July 2018, the 15" MacBook Pro, model A1990, features a 15.4 inch LED-Backlight display with True Tone technology, TouchID, and up to 6 Core i9 Processor.

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No backlight or image

So i got this Macbook from my brother. Macbook Pro A1990 15 Inch. I got neither backlight or image on the screen.

No history of liquid spills or anything. It's fully functional on external monitor - and the webcam works.. But i doesn't seem like the internal display is even detected.

I've tried using a known working LCD panel and still no image. I guess it must be a logicboard/cable thing.

When i try booting into recovery-mode, i sometimes get working backlight on the LCD. But nothing else.

Also tried with a fresh installation of OSX. Still noting. It's a bit weird i think.

I see no indications of shorts or anything after visual inspection with a microscope.

I also get the correct voltages on pins 43/44 and 45/46 in the J8500 display connector.

Any ideas? Thank you

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I would inspect the logic board and the T-CON board connectors and the short eDP cable. I’m suspecting corrosion or bent contact.

If you don’t see anything check the Hall sensor units on the back side of the logic board. On the left & right sides you’ll find two elevated segments which press the sensors to the back side of the case, one or both may be bad.

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Thank you for answering @danj !

I just tested the board again, and i actually get 0V on Pin 43 (PPVOUT_S0_LCDBKLT). With and without the LCD connected.

I just got a new eDP cable and it didn't fix the issue unfortunately. I see no signs of corrosion.

I've used the display panel on a friends MacBook, and the panel was working fine. For that reason, I don't think the T-CON board is the problem. Do you think a defect Hall sensor could lead to the display not being recognized at all?

I'm guessing that somewhere on the logic board, the PPVOUT_S0_LCDBKLT voltage is not being created correctly. I just can't find the problem.

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@Asmus Johansen - it could be the Buck converter logic which creates the backlight power or the Hall sensor logic both are one the main logic board. At this point you’ll need to just trace out the logic to discover what has failed. Do you have access to the full schematics and boardviews? You’ll need them.

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