2011 iMac 27" 6970M 2GB graphics/display issues

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2011 iMac 27" 6970M 2GB graphics/display issues

Hi,

A few days ago, I woke my 27” 2011 iMac from sleep and it was just a white screen with 5 thick red vertical lines, the lines went away after almost a minute and then it was just a blank white screen. I did the following:

Restarted it
Reset PVRAM – Option + Command + P + R
Reset SMC – Shutdown, unplug power cable, wait 30 seconds, plug back in, wait 5 seconds and turn back on
Enter recovery mode
Run disk utility
Run safe mode – text appeared on startup, though lines over screen etc – nothing changed
Held option key and chose the startup disk – this failed before though did work a few times, but I don’t believe it worked because I did it this way.
Ran Apple hardware test in extended mode. Found no issues. I’ve read to run it multiple times before assuming everything is fine.

It seemed to work fine the next day though I’m worried this could happen again as a few times it was perfectly fine and then the desktop would just go all over the screen. After searching online I noticed there was a replacement program for the AMD 6970M in 2011 iMacs. I believe this could be over though at the time of writing?

About 6 months after getting my iMac I installed a 120GB OWC SSD myself and everything has been fine until this issue. I recall a few times over the life of the iMac, it has few times not even powered on when pressing the button. I would remove power cord, wait, plug back in and that would fix it. This has only happened say 3-4 times over 4 years.

If the GPU is faulty, what are my options? I’d like to think just because I was not aware of the replacement program, wouldn’t mean I simply miss out?

Has anyone else heard of these symptoms I’ve mentioned above.

Thanks, any help would be appreciated!!

iMac (27-inch Mid 2011), OS X Yosemite (10.10.3)

Posted on Apr 26, 2015 5:28 PM

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Roofman

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Dec 1, 2015 11:24 PM in response to zztopgtb

I had the same problem.

I took my machine down to the local repair shop and they searched the internet for a solution and told me that I needed a new screen. ( I could have done that!)

I asked them to guarantee that was the problem, at £600 it needed to be right.

So they carried on investigating and dismantled the imac finding a huge build up of dust inside.

They cleared out all of the dust and tested the components again, everything worked fine.

So it appeared to be an overheating issue caused by a build up of dust inside the casing.

The overheating caused a OS corruption, all in all with the data recovery it cost me £150.

Had the mac back for a week so far and all good.

Please feel free to message me in the future to make sure it hasn't malfunctioned again!

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