Macbook Pro 15", 820-2915-b, logic board failure

[suiramix]

Hi there,
Typical case of AMD GPU failure... back in 2017 did a GPU reflow ( I'm aware reflowing is not a permanent fix) and worked fine with gfxCardStatus app (use the integrated video card only).
Last week, boot up normally and after not even 5min of light usage, crashed without any warning. I did try to restart same situation! So I did disconnect the battery and pressed to power button for 30sec. reconnected... PRAM and SMC reset...no luck ... now, when I plug in the magsafe (18.5V), the light remains green and not turning amber anymore...the macbook power up for 5 sec (front light is solid) fan spin at normal speed but no chime, no video and turn off by itself! I have the pdf. diagram and brd. files...where should I start? My guess is a short somewhere or a failing capacitor (nothing visible yet)...? What rails I have to check first? Thanks in advance!

[piernov]

Re: Macbook Pro 15", 820-2915-b, logic board failure

Does it turn on without battery? Those batteries failing would be nothing new.
GPU being dead is not suprising either. It can prevent it to boot (and even POST) altogether sometimes.
Permanent solution is to disable dedicated GPU with hardware GMUX bypass but you lose brightness adjustment in High Sierra and external display.
If it's the first generation board with 256MB VRAM sometimes you can still find some good GPU so it can be replaced, but it'll fail again one day or the other anyway.

[suiramix]

Re: Macbook Pro 15", 820-2915-b, logic board failure

Merci beaucoupe Pierre for your reply…I will try to power up without battery connected (for this 2011 model should work)…however this old one was showing around 70% charged before failure.
About disable dedicated GPU with hardware GMUX it looks like a complicated work...how can I disable the power for the ATI GPU VCORE ?

[underknowledge]

Re: Macbook Pro 15", 820-2915-b, logic board failure

I just try to disable the dedicated GPU with hardware GMUX bypass.
Still looking for the needed infos

So far I found this on youtube
https://www.youtube.com/watch?v=vbXb...47328829730256
and his post on macroumord (vid discription)
https://forums.macrumors.com/threads...ypass.2134019/

At the moment I try to find an Boardview and a buisness wich can solder this for me.
(stumbled across this post while looking for the 820-2915-B boardview)

[suiramix]

Re: Macbook Pro 15", 820-2915-b, logic board failure

Hi again,
So after quite some time, I managed to permanently disable the faulty AMD graphics by reprograming the IC Demux...Everything went well but recently this Macbook is turning off randomly by itself, sometimes after 1 or 10 min of not heavy usage. Even the resistor R8911 (Vcore) was removed, I guess the faulty graphic chip is still acting up. Removing the entire chip require some expensive equipment. What other components / coils can be easily removed and fix the issue ??? Thanks!