Macbook Pro 8,2 GPU reflow/repair - Page 1
Forum section: electronics / repair

author: John B
author_rank: Frequent Contributor
timestamp: August 17, 2023, 02:35:01 am
content: I've got a ~2011 MBP with symptoms of the dying GPU that these laptops are known for. I've stripped out the logic board and I think the last chance of getting this working for a little while longer is to reflow the GPU. I realise the chance of success, even temporarily, is quite low. However it's almost e-waste at this point so it's worth a shot.I don't have an automated oven or anything like that, so I'll have to do a manual reflow with my SMD hot air station. Does anyone have tips on a nominal temperature profile for this sort of thing? Perhaps keeping the board on a heated plate at >100degrees or so to keep the board hot during reflow etc? Looks like no-clean flux paste should flow underneath the BGA package fine as well.

author: philwong5176
author_rank: Unknown
timestamp: August 17, 2023, 02:44:29 am
content: Please watch this alternate solution (bypassing the AMD GPU):

author: John B
author_rank: Frequent Contributor
timestamp: August 17, 2023, 02:53:18 am
content: Thanks, I was running linux on the laptop so I can't really follow those instructions, however I did something similar in that I was booting the kernel with the flags radeon.modeset=0 which should be doing roughly the same thing.However I've had major issues with the graphics going haywire even at the initial boot. So I'm wondering if the GPU can cause issues even when the OS isn't loading drivers and theoretically not using the GPU.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: August 17, 2023, 03:38:32 am
content: I have done a few GPU bypasses using the CMIzapper Tiresias modules, along with videos showing it, this is likely what you will want to do.Forget trying to fix the GPU, they are junk, just disable it and move on using the CPU internal GPU.https://youtu.be/Wc-EEZ3hfMEhttps://youtu.be/PPUyJ_gNIRQhttps://youtu.be/j9m3Fz0tfokhttps://youtu.be/gcZopc2j6i4

author: philwong5176
author_rank: Unknown
timestamp: August 17, 2023, 06:04:50 am
content: the other way to disable the GPU is to re-program the MacBook's gMux IC:https://doslabelectronics.com/Demux

author: kripton2035
author_rank: Super Contributor
timestamp: August 17, 2023, 06:52:08 am
content: soldering this addon really workshttps://www.cmizapper.com/products/tiresias-gpukiller.htmlI've done tens of them with permanent success (still working today even if I switched to apple silicon)reflowing doesnt last more than a few months.

author: Koray
author_rank: Regular Contributor
timestamp: August 17, 2023, 10:50:54 am
content: Wow. Cmizapper sounds great.

author: John B
author_rank: Frequent Contributor
timestamp: August 17, 2023, 10:21:28 pm
content: Yeah sounds like the CMIzapper might be the way to go. Knowing my luck a whole bunch of components will drop off the other side when I reflow it.I would like to get a bit more use out of it since I just put an SSD in it, damn you sunk cost fallacy.

author: wraper
author_rank: Unknown
timestamp: August 17, 2023, 10:55:52 pm
content: Several Macbook models of that timeframe had a bad polymer capacitor causing GPU problem. Frying GPU is not a real repair and doing so outright without investigating a root cause can irreparably destroy a board with a minor issue somewhere else. If you want to apply heat, heat the GPU die by hot air for like 20 seconds. If it does not help, either it's not a GPU chip issue or it's dead enough that reflow would unlikely to help anyway. Not to say that without a bottom preheating, you have zero chance actually melting solder under the GPU by just applying hot air on top anyway.

author: kripton2035
author_rank: Super Contributor
timestamp: August 18, 2023, 06:21:09 am
content: these macbooks with the bad C9560 where for the 2009-2010 models. the 2011 doesn't have this problem (but it is worse as the whole gpu chip is bad)

author: John B
author_rank: Frequent Contributor
timestamp: August 18, 2023, 08:26:47 am
content: I placed an order for one of the Tiresias modules this morning. I wont touch the board with the hot air station, it will probably do more damage than good at this rate and the laptop is otherwise in good condition. It's all stripped down so I'll give the board a clean and reapply thermal paste to the CPU (which had all dried out and had spotty contact as it is)

author: John B
author_rank: Frequent Contributor
timestamp: September 03, 2023, 03:01:01 am
content: The CMIzapper turned up a few days ago, installed it straight away and having been running the laptop for a while to see if there's any issues. So far so good.The GPU was definitely causing issues even at the boot stage as the GRUB bootloader wouldn't even show up running the AMD GPU, now GRUB shows up at boot.The previous workaround in software disabling the GPU by telling linux to not load any AMD drivers was clearly not enough, as the system was recognising the system and the GPU was causing the whole system to freeze randomly. As you can see now the GPU isn't even detected by the system. Also, battery life has drastically increased, the GPU must have been absolutely chewing power (less than 1 hour battery life before).Keyboard and backlight dimming still work, not sure if the mod is needed for linux, but I did it anyways. The display doesn't auto dim down anymore after ~5mins, though I'm not sure if that's hardware or software based, as all the keyboard brightness controls work as intended.So far a pretty successful revamp of this laptop.

author: amyk
author_rank: Super Contributor
timestamp: September 04, 2023, 06:00:07 am
content: Only downside is a bit reduced graphics performance, but Intel iGPU from that era is quite fast for productivity applications and even some casual gaming, and as you have now experienced, uses far less power.

author: jfiresto
author_rank: Frequent Contributor
timestamp: September 04, 2023, 07:20:54 am
content: Quote from: amyk on September 04, 2023, 06:00:07 amDoes the module support a second/external display?

author: John B
author_rank: Frequent Contributor
timestamp: September 04, 2023, 09:47:34 am
content: Looks like no luck on that front. The laptop only has a thunderbolt port, no dedicated HDMI. I tried a thunderbolt to DVI and thunderbolt to HDMI adapter. While plasma detects both as a separate screen being connected, neither outputs a signal.In fact thinking back a few years, the external display adapters may have been the first symptoms that something was turning faulty, but had no idea about the GPU faults at the time.

author: John B
author_rank: Frequent Contributor
timestamp: September 04, 2023, 10:31:29 am
content: Also before I forget my notes, the CMIzapper is basically just a preprogrammed PIC18F25K40 piggybacked onto one of the chips on the motherboard, no resistors or even bypass caps

author: cruff
author_rank: Regular Contributor
timestamp: September 04, 2023, 12:38:38 pm
content: Quote from: John B on September 04, 2023, 09:47:34 amThe GPU may be the device that generates the pixel streams for the thunderbolt connected displays, unless you attach an external GPU via thunderbolt.

author: John B
author_rank: Frequent Contributor
timestamp: September 04, 2023, 09:04:09 pm
content: I can't find the exact block diagram, but I think most of the macbooks of that era have the internal display connected through a mux which allows either the iGPU or dGPU to be used, while only the dGPU is connected to the thunderbolt controller. So yeah I was expecting a fail.

author: John B
author_rank: Frequent Contributor
timestamp: September 20, 2023, 06:02:19 am
content: Well unfortunately the success seems to have been rather short lived. It decided to die in it's sleep. As far as I can tell the screen stopped working, there's no display at all and the apple logo doesn't light up. It still chimes at boot but the screen stays black (doesn't even turn the usual apple blue-grey), I don't think there's any operating system activity afterwards. Bugger.

author: John B
author_rank: Frequent Contributor
timestamp: September 22, 2023, 12:38:41 am
content: I'm probably shouting into the void at this point, but I think the CMIZapper itself has failed. By shining a light on the screen I can see that the LCD elements still work and is still receiving a signal. Protip, you can also shine a light through the apple logo on the back of the screen, but you'll only see the middle part of the screen.- It will still start the computer to the boot menu by pressing the option key.- Trying to boot the computer normally results in the screen finally reaching a folder with a question mark icon. SSD not detected?- The backlight is entirely controlled by the CMIZapper, so that explains the lack of screen lighting or key lighting, but no idea about the SSD.

author: amyk
author_rank: Super Contributor
timestamp: September 22, 2023, 02:31:58 am
content: Schematic is easily found for this model, you can try to hardwire the backlight to get around that problem. This model is old enough that it's closer to a regular PC, it has a standard SATA drive interface and can boot from USB too, so try doing that.