Macbook 820-2915 (A1286) White Screen after apple logo

[senakahks]

Dear All,

I have a problem which results white screen while loading with apple logo. Found in internet that it is a failure of C9560 which needed for PP1V5_GPU_REG.

I checked the voltage of PP1V5_GPU_REG and it is 1.36V
Removed C9560 and capacity is 250 uF.

Original values should be

PP1V5_GPU_REG: 1.36V
C9560: 220uF

Even after removing C9560 the voltage of PP1V5_GPU_REG is 1.36.

Any idea to go ahead?

[piernov]

Re: Macbook 820-2915 (A1286) White Screen after apple logo

Dead GPU as always on 820-2915.
C9560 is only on 820-2850.

[tata123]

Re: Macbook 820-2915 (A1286) White Screen after apple logo

GPU of course, or if you have luck NVRAM (VIDEO RAM)!!

you can also have luck and its the Video RAM, check if the Chip gets extrem hot...

as piernov say, the C9560 is only on older models 2010...

[lordhex]

Hey guys I seem to be having the same issue as OP. I realize this is a three-year-old thread, but maybe one of you will answer.
MacbookPro A1286 with logic board 820-2915-B.

Mac powers up, chimes, Apple logo, shows progress bar up to 60-70% then goes white/grey screen then fans are running at full speed.
Took it apart and the GPU area is extremely hot.

I did find the C9560 on the other side of the board (after I took it completely apart) but I don't know how to power it up now since it has no connectors attached to it.
Should I solder a wire on the capacitor, put the board back in, connect all the flex cables then measure the voltage on PP1V5_GPU_REG/ C9650? .
How do you guys do it?

Also, I see Piernov said above, "dead GPU as always". Can my GPU be dead even though it boots up, shows an Apple logo, and progress bar?

Please help.

Many thanks in advance
Merry Christmas and A Happy New Year!

EDIT: After watching some more videos of Louis Rossman, I put in the RAM, and both fans then attached the 85W power.
Both fans spin, slow, and measured voltage on C9650 - 1.348V

[ACS-Repair]

Sorry this is a bit delayed...
Yes, it is a GPU fault. The transition you see is where it switches from internal to dedicated GPU.
It is possible to bypass the dedicated GPU a couple of different ways. Dosdude1 has a procedure that although lengthy, it does give you back the use of the computer. I have done several of these with success.
Do a search for him where he will outline the process on his website.

[piernov]

The transition you see is where it switches from internal to dedicated GPU.

By default it starts from the dedicated GPU, here it's more likely that it's the dGPU driver getting loaded that causes the machine to crash.

[ACS-Repair]

Thanks piernov, I may be wrong about the startup order, but in either case, my experience is that this condition is indicative of a dedicated GPU hardware failure, common on this model. This can be brought back temporarilly by a GPU reflow or by using the dosdude1 patch process.
Hopefully, this will help lordhex or anyone in this position to get their MBP back with limited operation. I've done several of these with the dosdude1 procedure and it has worked well.
Another test is to boot with Linux and see if computer completes the startup. I have 2 logic boards now 820-00165 and 820-00138 that have this exact condition but load Linux fully. You're definitely right about the GPU driver not loading properly in this condition.

[lordhex]

Sorry this is a bit delayed...
Yes, it is a GPU fault. The transition you see is where it switches from internal to dedicated GPU.
It is possible to bypass the dedicated GPU a couple of different ways. Dosdude1 has a procedure that although lengthy, it does give you back the use of the computer. I have done several of these with success.
Do a search for him where he will outline the process on his website.

Thank you for taking the time to explain. I did find his procedure here -- https://doslabelectronics.com/Demux.html -- ordered the programmer from Aliexpress, arriving in couple of weeks. Will try to flash the DeMUX with his software. I realize its a very old computer, but I cannot bring myself to throw it in the trash. I think I've seen some YouTube videos how to install Catalina, Mojave something past High Sierra.

I did try to reflow the GPU (I have a hot air station), got it to move, didn't reball it as I dont have the stencils. Still the same issue.

Many thanks,
Happy New Year 2024

[lordhex]

By default it starts from the dedicated GPU, here it's more likely that it's the dGPU driver getting loaded that causes the machine to crash.

Thanks Piernov for taking the time to answer.

Happy New Year 2024