Macbook pro 15" 820-2915-B 2011 A1286 boot on but black screen

[resistor83]

Hi everyone, I have this 2011 MacBook Pro 15" model 820-2915-B which has a problem.
I turn it on, the startup sound is heard but the screen doesn't turn on, not even the backlight. The keyboard lights up after a while and the capslock works. If I press any key I can hear sounds as if the system is booting.

I thought it was a screen problem but after changing it the problem remains.

What could I do?

[dellxps15]

Re: Macbook pro 15" 820-2915-B 2011 A1286 boot on but black screen

hi do a pram reset. if the screen become wait then most likely it's gpu is gone and u need a gmux to disable it.

[resistor83]

Re: Macbook pro 15" 820-2915-B 2011 A1286 boot on but black screen

I have already tried to reset the pram and also the SMC but the screen is still off

here video: https://streamable.com/1761vz?src=player-page-share

[dellxps15]

Re: Macbook pro 15" 820-2915-B 2011 A1286 boot on but black screen

do u have image on external monitor ? connected with display port to hdmi-vga adapter?

if u have screen on external, then amd gpu is fine.

[resistor83]

Re: Macbook pro 15" 820-2915-B 2011 A1286 boot on but black screen

no video signal even with the display port adapter

[resistor83]

Re: Macbook pro 15" 820-2915-B 2011 A1286 boot on but black screen

some measurement:

PP3V3_S0 3,34V
PP3V3_SW_LCD 0V
U9000: pin 2 and 3 3,34V pin 4 and 5 0V

[mon2]

Re: Macbook pro 15" 820-2915-B 2011 A1286 boot on but black screen

As noted, likely a GPU fault.

https://www.badcaps.net/forum/showthread.php?t=74024

[dellxps15]

Re: Macbook pro 15" 820-2915-B 2011 A1286 boot on but black screen

he just need to be sure that it's not a lvds connector, lcd cable or lcd itself before doing a gmux .

once a customer told me to disable gpu, and problem was a bad lcds connector with some burned pins.

[resistor83]

Re: Macbook pro 15" 820-2915-B 2011 A1286 boot on but black screen

I have a working screen that I tried but it won't turn on so it can't be the display/cable

However, in the MacBooks that I have repaired over the years, when the video card was broken, either the operating system started with various lines on the screen or the screen was black/white but the system did not start in the worst cases. It has never happened to me that the operating system started up and the screen was completely turned off due to the video card