iMac Mid 2011

[Riallio]

Hi there.

I have recently acquired a iMac (27-inch, Mid 2011) from my father in law. "if you can fix it, you can keep it".

I'm not as knowledgeable with Mac OS than I am with Windows machines, I mean I have a MacBook but Ive never had to fix it.

Anyway..

Theres a weird issue, I just get a Grey screen after booting.

I have tried placing a brand new (unformatted and formatted) SSD into the Mac, I have tried the original HDD (Seagate 1TB). And it just does the same. Command R does nothing, it doesn't boot into the Recovery. It basically shows the Apple logo, shows the loading bar and then either reboots or goes to Grey screen and hangs there for hours and hours if left on.

I have also tried Internet Recovery, it asks for Wireless details, accepts them and then stays on Internet Recovery with the spinning globe. Again for hours if not switched off.

I have tried downloading Mojave and High Sierra on the mac, and then creating a recovery boot disk on my MacBook using the official Apple command they ask you to put in terminal. USB creates fine, I then hold Alt and it does show in the Boot Menu, again just a grey screen after the loading bar finishes.

I have also tried Single User mode, on the Original HDD (that has Mac installed). Which does seem to load fine, but unsure what to do here.

I have also tried "Safe Mode" to no success.

Has anyone had this before? I have read other forums saying that its an issue with the GPU, but as it POSTS and shows graphical elements on screen, Im unsure this is the issue.

Rob.

 

[mdgm]

Have you tried running Diagnostics (press and hold D as the computer starts up)?

Perhaps the memory (RAM) could have come loose or failed? You could try reseating the RAM and if that still doesn't work perhaps see if it will boot with just one RAM stick installed. That's an easy thing to check before resorting to replacing the graphics card.

An advantage of replacing the graphics card with one of the suggested ones from the Graphics Card upgrade thread is that you can then use OpenCore to run a newer Mac OS than Mac OS 10.13 High Sierra.

 

[Riallio]

Hi there

Thanks for the quick reply.

Yes I have tried numerous RAM modules in both slots and on their own.

I have tried holding D and Alt D to enter diagnostics, but it seems to load the Internet Recovery?

Ill take a look at a new GPU, but doubt the thing is worth the time and money - if its not the GPU.

 

[Nguyen Duc Hieu]

Hi there

Thanks for the quick reply.

Yes I have tried numerous RAM modules in both slots and on their own.

I have tried holding D and Alt D to enter diagnostics, but it seems to load the Internet Recovery?

Ill take a look at a new GPU, but doubt the thing is worth the time and money - if its not the GPU.

I bought (unluckily I don't have a father-in-law with a half-dead GPU) my iMac late 2009 with a half dead HD4850m. The symptom was just like yours.
I got it baked at a laptop repair shop, but it didn't help resolve the issue.
I bought a quadro K1100m (ripped off from a Dell laptop, as the seller said) to replace the half-dead HD4850m.
It needs Vbios reflash, some tweaking in the EFI, but eventually it displayed.

And I now have a working iMac.

Check your local shops for laptop graphic cards, if you can buy one cheaply, it will be a fun fix for you.

 

[passatgt]

Most likely a dead GPU. Your best option is to check out this thread: https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/