Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

Locke357

macrumors newbie
Original poster
Oct 23, 2008
5
0
The computer boots, I hear the startup tone, but the display stays black. On occasion the display turns on for a brief amount of time, I was able to run First Aid in disk utility (nothing), and even erased the HDD and reinstalled MacOS. But before long the display went black again and hasn't turned on since. The caps lock light can turn on and off on the keyboard, but not the num lock.

I've had this computer for 10 years now and the only issue I've ever dealt with was replacing the HDD with a replacement when it died.

I know this model has a GPU with known issues (AMD Radeon HD 6970M 2gb GDDR5), and I'm still peeved I missed the recall. From the searching I've done it seems like it may indeed be the issue, I just want to be sure so I don't blow $130 on getting a replacement GPU.

Specs:

iMac 27-Inch "Core i7" 3.4 (Mid-2011)
MD063LL/A - iMac12,2 - A1312

3.4 GHz i7-2600 Quad Core
12 GB 1333 MHz DDR3 SDRAM
1 TB HDD
AMD Radeon HD 6970M 2gb GDDR5

I am the proud owner of this computer, I've nicknamed it "The Beast," and while I've since moved on to game on a PC I built, I use this computer for streaming and light gaming for my kids. I'm not ready to say goodbye yet so please help me diagnose the problem. Thanks!



If it is indeed the GPU, wdyt about these to replace it with?

K2100M
https://www.ebay.ca/itm/175395520130

K1100M
https://www.ebay.ca/itm/154448606238
 

Nguyen Duc Hieu

macrumors 68030
Jul 5, 2020
2,929
969
Ho Chi Minh City, Vietnam

Locke357

macrumors newbie
Original poster
Oct 23, 2008
5
0
1. It is indeed the GPU, or the LCD backligkt power board.
2. I wouldn't want any of those. Search for K3100m or K4100m, a little increase in price but better performance and more "Mac native" feelings. Choose those that have been flashed with Mac compatible vBIOS.
Something more like this? https://www.ebay.ca/itm/385075606827

How would I troubleshoot if it was the LCD backlight instead? Thanks
 

Nguyen Duc Hieu

macrumors 68030
Jul 5, 2020
2,929
969
Ho Chi Minh City, Vietnam
Something more like this? https://www.ebay.ca/itm/385075606827

How would I troubleshoot if it was the LCD backlight instead? Thanks

Yeah, that kind of thing.

I've read somewhere that you can use a powerful light source pointing toward the LCD panel, if only the backlight is bad, you will be able to see a part of the login screen.

I simply assemble the LCD panel to another working iMac, to check the quality as well.
 
Last edited:
  • Like
Reactions: appltech

farscaper

macrumors newbie
Mar 22, 2023
18
2
Yeah, that kind of thing.

I've read somewhere that you can use a powerful light source pointing toward the LCD panel, if only the backlight is bad, you will be able to see a part of the login screen.

I simply assemble the LCD panel to another working iMac, to check the quality as well.
Hello did you ever figure out why the LCD is randomly turning off?

Here is my experience with that

Post in thread '2011 iMac Graphics Card Upgrade' https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/post-32065871
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.