iMac 2010 GPU in 2011

[Faloude]

I have an iMac 21.5" EMC 2428 A1311 (mid-2011) here that tends to crash with square artifacts on screen and discoloration so I’ve decided to replace the GPU.
After a lengthy repair, I’m left with a powering iMac, beautiful chime but no visual on LCD nor on external screen.

The GPU I’ve installed is, apparently, from a 2010 model and has partnumber 109-b80357-00. It looked visually different too and didn't have the AMD logo on it although the connector was exactly the same. Should it work on my 2011 iMac?

 

[rc3105]

Sounds like the new card is dead. Have you screenshared in to see if the card is detected in system report?

 

[Faloude]

Hi! Sorry what do you mean "screenshared in"? There is no video signal output on iMac LCD nor external monitor through mini displayport

 

[rc3105]

MacOS has network screen sharing. Log in from another mac/pc to remote view & control the mac even if the video card doesn't work or isn't installed.

When macs run headless (without a video card) MacOS allocates a virtual screen that's aprox 1200x1200. Connecting to that virtual screen lets you run system report, diagnostics or whatever.

 

[Juicy Box]

Have you tried baking the original GPU? I fixed the 2GB AMD Radeon HD 6970 GPU in a 27" Mid 2011 iMac by baking it in the oven.

As for compatible GPUs, IIRC, any GPU that came with the Mid 2011 iMac can be swappable plug and play. Other GPUs can work, but it takes some Hackintosh work to make it happen.

Apple's support page lists these two GPU as options for the 21" Mid 2011:
AMD Radeon HD 6750
AMD Radeon HD 6770

Based off of the serial number of your "new" GPU it is the:
AMD Radeon HD 4670

So, I think it isn't a plug and play option, but you might be able to get it to work.

My suggestion: Try to do the oven bake of the old GPU, it might fix it and is a better GPU anyways.

If you don't want to or it doesn't work, do some searches for Late 2009-Mid 2011 GPU swaps, I am sure you will find an answer on how to get it to work.

 

[Faloude]

First off let me say I did not expect the answers here to be better than on iFixit but it is, thank you.

MacOS has network screen sharing. Log in from another mac/pc to remote view & control the mac even if the video card doesn't work or isn't installed.

I did some research on this and it looks like "Screen sharing" has to be turned on in system preferences on the host iMac which it is not and would require me a video output to turn it on, ugh.

Have you tried baking the original GPU? I fixed the 2GB AMD Radeon HD 6970 GPU in a 27" Mid 2011 iMac by baking it in the oven.

Any tips on this? Temperature and timeframe?

 

[rc3105]

A basic HighSierra install will fit on a 32gig sd card. You could use another mac to install MacOS & config screen sharing on the card, then unplug the hd and boot the dead video card machine from sd.

It won't boot quickly but it'll let you see if the mac motherboard is recognizing the video card.


If you set startup disk to the sd card then you can plug the hd back in and retrieve files from it.

 

[arkieboy72472]

if you have a 4670, it will work with a 27" 2011 running Catalina with a patch. just make sure and boot into the bootable USB after everything is done, select the model, and purposely select the legacy graphics card patch, it is a crap card but it works. I know because I am using it right now.

 

[Faloude]

if you have a 4670, it will work with a 27" 2011 running Catalina with a patch. just make sure and boot into the bootable USB after everything is done, select the model, and purposely select the legacy graphics card patch, it is a crap card but it works. I know because I am using it right now.

That's awesome. Let me ask you, before the patch, did you get zero video output? Audible chime but on a black screen? Also no video output or any video detection on external monitor? That's what I'm getting so I'm wondering if the replacement card is faulty..

Also I tried to bake the original card. After loading screen everything turns red now so it looks like it's worse off than before lol.

 

[arkieboy72472]

That's awesome. Let me ask you, before the patch, did you get zero video output? Audible chime but on a black screen? Also no video output or any video detection on external monitor? That's what I'm getting so I'm wondering if the replacement card is faulty..

Also I tried to bake the original card. After loading screen everything turns red now so it looks like it's worse off than before lol.

Before that patch it worked but the graphics card was seen as something completely different.
Video was choppy at times. Eventually I was tired of it so I rebooted from the USB and patched everything but this time added legacy patch. After that it worked just fine and showed up as the right model. To bake, obviously clean it off very good with air then a little alcohol >90%. 10 minutes @ 200C. It has to be elevated from baking sheet with aluminum foil balls.

Prior to and after the patch it worked and booted fine.
I figured it out because a 2010 21.5" with a 4000 series will run Catalina, and the default patches are different slightly. So, i tried it in a 27". Of course I had to swap heat sinks and repaste everything. I still have the old card, but it is only good for High Sierra. Also, if you swap out the main drive for a SSD and use macs fan control to up the idle temp, you may never have another graphics issue. more room for the fans and less heat equals happy card!

 

[Faloude]

Well if your Radeon 4670 GPU worked in your 2011 iMac (although choppy), that means mine is simply faulty. I'm returning it to seller today.

 

[arkieboy72472]

Mine worked after install. It was choppy until the legacy patch and then it was normal. And i mean choppy in the sense that when you dragged a window you had ghosting and sometimes colors on videos were off. That same card on a 2010 with the patch installed also worked fine. With it being a 256mb card it is obviously the worst catalina card you can run that works.