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xkam1x

Cancelled
Original poster
Dec 15, 2014
69
251
Back in June 2012 when I gazed upon the newly released MacBook Pro with Retina display, I know that it was the machine I wanted to purchase. It ticked all the boxes; had good battery life, great screen, CPU, GPU and all I wanted back then. Sadly the demand was rather strong and I waited for 2 month patiently, checking if it was in stock daily without any luck.

In September 2012 I walked in to a Comet store in Oxford, and decided to try my luck and asked to see if the manager could let me have the display model since my old Toshiba laptop was running at a snails pace. To my surprise she agreed and I bought one with 10% student discount and a free leather case which costs £99. A great deal.

Things were looking great but in June 2013, I was editing a photo and the image had a white shade going through it (thought it must have been lint on the lens), did some colour correction and exported it. It turns out that the white shade was actually an artefact in the display. Took the computer to my local Western Computers store to get it fixed and week later I could collect it. Brought it back, turned it on and now I had full red display, sometimes it would switch to green and interesting patterns. Took it back and another week later It was fixed for free.

Fast forward to February 2016 and I am getting kernel Panics and the cause, bad GPU. Since the model had extended warranty repair scheme for this very issue, they replaced the logic board for free and things were good.

Fast forward to March 2017 MacBook display's coating is pealing off. Took it to store and they replaced the display for free. All good.

Fast forward to September 2017(exactly 5 years and 1 day from date of purchase) GPU is dead once again and getting artefacts on screen (I do CAD design and rendering in Fusion 360 + some games). Took it to apple store and they asked for £600 for a logic board repair. I thought this laptop had a good run and declined repair and stated looking for a new machine.

2016 rMBP 15 and 2017 rMBP 15 were priced very aggressively £3300 and I could not justify purchasing them at that cost when compared to Dell XPS 15 and others. So I decided to wait.

I am finding it rather difficult just limiting my usage to Intel HD4000 GPU, so I have deciding to fix the logic board myself. Looked a bit deeper into the issue and sourced the laptop Schematic and board view files. After a couple of days of looking and making sense of documents, I found that all the power rails are working well, namely GPU VCORE and GDDR5 VCORE.

The usual fault in this model was overheating logic board which caused the GPU VCORE buck converter contacts to come loose but this was different. I suspected the GPU silicone itself as NVIDIA had issues like this before (PS3 YLOD and XBOX RROD) which I cannot replace.

Digging further GPU silicone was clear but now my guess was GPU GDDR5 frame buffer. As pure GPU memory tests were failing. This laptop has 1GB VRAM total from Hynix chip H5GQ2H24AFR four of them small enough for me to replace (I think).

Looked around for replacement chips but couldn't find any. Then I looked around for next best thing and decided to purchase 4x H5GC4H24MFR from a Chinese seller which are probably stolen since you can not buy them as an individual. The difference being, the new chip has twice the capacity and runs on 1.35v instead of 1.5v. Bigger capacity should be fine and apple already runs the GDDR5 frame buffer on 1.35v (measured and schematic) so voltage should also be fine.

In the next week or 2 I will make an attempt to replace the chips and see what happens.

Stay tuned to fined out if this MacBook lives or dies!!
 

TonyK

macrumors 65816
May 24, 2009
1,032
148
More resourceful than I would be under the same conditions. Very interested to see how this all plays out.
 

xkam1x

Cancelled
Original poster
Dec 15, 2014
69
251
These are the video memory chips I plan on replacing. They have cost me about £17 all inclusive from china.
 

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xkam1x

Cancelled
Original poster
Dec 15, 2014
69
251
Over the Christmas holidays I managed to replace the VRAM chips in the laptop but unfortunately it did not fix the issue.

Details:
I removed the logic board from the laptop and discovered that it had glue holding the VRAM's in place, tried to remove it with sharp blade but no go. Then used some hot air but what ever that glue material was did not budge. I was trying to be extra careful the glue was also over some 0201 SMD parts which I was sure if nudged, their contacts will break.

At the end I heated the glue with hot air and removed the parts which meant some of the SMD parts got removed aswell. (but I didn't notice that at first as I was busy cleaning the residue)

So then I attached the new* VRAM modules and realised that some components were missing. I ordered the missing components from mouser and they took a week to arrive.

After I added the missing components, the laptop would power on but no display/backlight. Looking around the schematic couldn't find anything but then I looked at the schematic of 820-3787-a which had basically the same GPU and VRAM and use the config straps from its schematic. Finally there was display and apple logo. Then I put the laptop together and called it a day.

Trying to boot into OS and realised that the display now has more artefacts than before and would freeze before OS could load. Looking around for the fix, I managed to update gpu policy in NVRAM and os finally loaded on integrated gpu.

Looking at system information, I get 512MB VRAM where it should be 2GB.
And switching to Nvidia GPU, I got the same artefacts as before.

This all indicated that the source of my artefacts was in-fact the GPU Core NOT the GPU VRAM and the GPU VRAM I used is also not what it should be.

This machine can still be fixed, it needs new GPU die and GPU VRAM. BUT sourcing the original/working parts is a big issue. Another big issue is sourcing the documentation on the memory chips and Nvidia chips without them I would not know how to configure the straps properly.

I am now thinking to purchase old desktop GPU with same memory and gpu and use that in the laptop.

Further research is needed, also I think I might purchase BGA machine to replace the GPU processor.
 

maerz001

macrumors 68030
Nov 2, 2010
2,528
2,434
A desktop GPU in a mbp? How should that connect or work?

Why don't u just buy an old logic board or broken mbp and swap the board?
 
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xkam1x

Cancelled
Original poster
Dec 15, 2014
69
251
A desktop GPU in a mbp? How should that connect or work?

Desktop GPU and laptop GPU have mostly the same components (GPU core and VRAM). They differ in their configuration. Let me explain how.

Let’s consider the latest GTX1000 series graphics cards. NVidia designed only one GPU chip to begin with. Let’s call it pascal chip. That pascal chip went through manufacturing and they got their first batch of 500 pascal chips.

One thing you have to believe that no two chips are alike, they have many small differences which add up. From their 500 batch they tested and found that 100 chips worked perfectly with grade A.
200 of the remaining had a fault where they would cause data corruption when operated at designed specification caused by manufacturing errors, but worked fine when slightly under clocked, they got grade B.
100 had a bad memory controller which meant it could not address the designed memory, grade C.
90 of them would shutdown if a certain power level is reached, grade D.
Rest 10 just fail to operate, grade E.

At this point NVidia sits and decides that grade A chips would be used for their Titan series.

Grade B would be called GTX1080.

Grade C would be called GTX1070.

Grade D would would be used in a laptop in low power.

and finally Grade E gets recycled (but in reality it makes its way to AliExpress, eBay etc as “New and Original” but in fact this grade is not worth using).

Although this explaination is a bit vague, it is accurate in principle. This is also where intel i7, i5, i3 and their sub-models come from.

And the way companies set pascal chip to be a GTX1070 or GTX1080 in a computer is either by VBIOS, VBootRom, or config straps. Also the same for VRAM.

This way if I can source the same GPU core from a desktop GPU as the one Apple used, it will work fine since it was designed the same. It will not work like a desktop GPU since all the configuration in MBP would under clock and/or under volt the GPU because it expects a GPU core with lower grade. It only means that the GPU is more stable. There maybe a way to change the config straps to allow the GPU to work faster but Apple only designed the power supply and thermal dissipation for the low graded GPU so it really makes no sense to change those straps.

One benefit I would get by doing this is unlikely hood of the GPU failure in the future since it is far more we’ll manufactured.

Why don't u just buy an old logic board or broken mbp and swap the board?

My laptop logo board is 820-3332-A and majority of these had graphic issues since they all used NVidia core N13P-GT-xxxx made around late 2011 and early 2012. Which means if I get the same board, it will most likely have the GPU from the same era which will cause the same fault. Therefore I am not considering this as an option.

NVidia did however change the manufacturing process in 2013 for the same N13P-GT-xxxx this time the same design did not experience the same issues. Apple used this new chip in late 2013 mid 2014 retinas which are going well.

The only solution I can thing of now is source the updated NVidia core chip and use that in the logic board.

Just for reference, I have had 2 logic boards die because of this fault (replaced by Apple) and not willing to risk a third.
 

Samuelsan2001

macrumors 604
Oct 24, 2013
7,729
2,153
Desktop GPU and laptop GPU have mostly the same components (GPU core and VRAM). They differ in their configuration. Let me explain how.

Let’s consider the latest GTX1000 series graphics cards. NVidia designed only one GPU chip to begin with. Let’s call it pascal chip. That pascal chip went through manufacturing and they got their first batch of 500 pascal chips.

One thing you have to believe that no two chips are alike, they have many small differences which add up. From their 500 batch they tested and found that 100 chips worked perfectly with grade A.
200 of the remaining had a fault where they would cause data corruption when operated at designed specification caused by manufacturing errors, but worked fine when slightly under clocked, they got grade B.
100 had a bad memory controller which meant it could not address the designed memory, grade C.
90 of them would shutdown if a certain power level is reached, grade D.
Rest 10 just fail to operate, grade E.

At this point NVidia sits and decides that grade A chips would be used for their Titan series.

Grade B would be called GTX1080.

Grade C would be called GTX1070.

Grade D would would be used in a laptop in low power.

and finally Grade E gets recycled (but in reality it makes its way to AliExpress, eBay etc as “New and Original” but in fact this grade is not worth using).

Although this explaination is a bit vague, it is accurate in principle. This is also where intel i7, i5, i3 and their sub-models come from.

And the way companies set pascal chip to be a GTX1070 or GTX1080 in a computer is either by VBIOS, VBootRom, or config straps. Also the same for VRAM.

This way if I can source the same GPU core from a desktop GPU as the one Apple used, it will work fine since it was designed the same. It will not work like a desktop GPU since all the configuration in MBP would under clock and/or under volt the GPU because it expects a GPU core with lower grade. It only means that the GPU is more stable. There maybe a way to change the config straps to allow the GPU to work faster but Apple only designed the power supply and thermal dissipation for the low graded GPU so it really makes no sense to change those straps.

One benefit I would get by doing this is unlikely hood of the GPU failure in the future since it is far more we’ll manufactured.



My laptop logo board is 820-3332-A and majority of these had graphic issues since they all used NVidia core N13P-GT-xxxx made around late 2011 and early 2012. Which means if I get the same board, it will most likely have the GPU from the same era which will cause the same fault. Therefore I am not considering this as an option.

NVidia did however change the manufacturing process in 2013 for the same N13P-GT-xxxx this time the same design did not experience the same issues. Apple used this new chip in late 2013 mid 2014 retinas which are going well.

The only solution I can thing of now is source the updated NVidia core chip and use that in the logic board.

Just for reference, I have had 2 logic boards die because of this fault (replaced by Apple) and not willing to risk a third.

I understand all this but the time and effort you are putting into creating a machine that will just not work well and be a nightmare with every update if you can get it working at all are just not worth it I my opinion. Almost any home upgrade to any modern thin/light laptop is a fun project at best and a waste of time and effort at worst. If you just need a reliable modern machine to get on with work or even leisure then you are far better off selling for parts and buying a new computer.
 
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xkam1x

Cancelled
Original poster
Dec 15, 2014
69
251
I follow you with it all being not worth its time (if the goal is just to have a working laptop), but the real reason I am doing this is to understand these things better at the hardware level. I am a hardware engineer by profession and looking at how others have done/implemented different things is a great help when you are designing PCB's for yourself.

Also I do not just want to open-up a brand new machine, the risk is too high. This laptop is 5 years old and the majority of hardware design has not changed much (expect for inside silicone chip). Also as the computer ages, its schematics and board view file leaks which is a must if you want to know how things work. Therefore this laptop is the best think I have to do this type of work on and why I am doing it.
 

_Kiki_

macrumors 6502a
Aug 13, 2017
961
281
Desktop GPU and laptop GPU have mostly the same components (GPU core and VRAM). They differ in their configuration. Let me explain how.

Let’s consider the latest GTX1000 series graphics cards. NVidia designed only one GPU chip to begin with. Let’s call it pascal chip. That pascal chip went through manufacturing and they got their first batch of 500 pascal chips.

One thing you have to believe that no two chips are alike, they have many small differences which add up. From their 500 batch they tested and found that 100 chips worked perfectly with grade A.
200 of the remaining had a fault where they would cause data corruption when operated at designed specification caused by manufacturing errors, but worked fine when slightly under clocked, they got grade B.
100 had a bad memory controller which meant it could not address the designed memory, grade C.
90 of them would shutdown if a certain power level is reached, grade D.
Rest 10 just fail to operate, grade E.

At this point NVidia sits and decides that grade A chips would be used for their Titan series.

Grade B would be called GTX1080.

Grade C would be called GTX1070.

Grade D would would be used in a laptop in low power.

and finally Grade E gets recycled (but in reality it makes its way to AliExpress, eBay etc as “New and Original” but in fact this grade is not worth using).

Although this explaination is a bit vague, it is accurate in principle. This is also where intel i7, i5, i3 and their sub-models come from.

And the way companies set pascal chip to be a GTX1070 or GTX1080 in a computer is either by VBIOS, VBootRom, or config straps. Also the same for VRAM.

This way if I can source the same GPU core from a desktop GPU as the one Apple used, it will work fine since it was designed the same. It will not work like a desktop GPU since all the configuration in MBP would under clock and/or under volt the GPU because it expects a GPU core with lower grade. It only means that the GPU is more stable. There maybe a way to change the config straps to allow the GPU to work faster but Apple only designed the power supply and thermal dissipation for the low graded GPU so it really makes no sense to change those straps.

One benefit I would get by doing this is unlikely hood of the GPU failure in the future since it is far more we’ll manufactured.



My laptop logo board is 820-3332-A and majority of these had graphic issues since they all used NVidia core N13P-GT-xxxx made around late 2011 and early 2012. Which means if I get the same board, it will most likely have the GPU from the same era which will cause the same fault. Therefore I am not considering this as an option.

NVidia did however change the manufacturing process in 2013 for the same N13P-GT-xxxx this time the same design did not experience the same issues. Apple used this new chip in late 2013 mid 2014 retinas which are going well.

The only solution I can thing of now is source the updated NVidia core chip and use that in the logic board.

Just for reference, I have had 2 logic boards die because of this fault (replaced by Apple) and not willing to risk a third.


you can't replace old NVIDIA GPU Chip with new one from 10 series, different layout of pins, different size etc., also the problem can be with VRAM
 
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