Issues with iMac screen

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Level 1

12 points

Issues with iMac screen

Hello everyone! My name is Oswaldo, I am new to this forum, and I hope to find some help here.

So, I have an iMac A1224 (8,1/early 2008) which is having issues with the screen since a week ago. Everytime I press the power button it boots like this:

And after a few minutes it just goes white, nothing else. But if I press the option button to select the hard drive it stays like this:

I already opened it and I see no loose cables or anything. So, what could it be? Should I replace the screen or something else?

iMac

Posted on Jul 7, 2018 11:36 AM

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Answer 1

Top-ranking reply

iCare

Level 4

2,490 points

Jul 9, 2018 9:56 AM in response to ojquirozr

I suspect that you are having an issue with the graphics processing unit based on the pattern being displayed. One easy way to help determine whether the issue is caused by the LCD or the GPU is to take a screenshot and email it to a computer with a working display. If you see the same issue in the screenshot when viewed on a different computer then the issue is probably with the GPU. If the image looks fine on another computer then the issue is probably with the LCD or less likely, the cable.

Good luck. I hope you are able to find a solution.

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Answer 2

macjack

Level 10

111,242 points

Jul 7, 2018 11:53 AM in response to ojquirozr

Try running Apple Hardware Test (You may need to run it from the discs that shipped with your Mac):

How to use Apple Hardware Test on your Mac - Apple Support

Try an NVRAM reset:

How to reset NVRAM or PRAM on your Mac - Apple Support

Try an SMC reset:

https://support.apple.com/en-us/HT201295

Try starting up in Safe Mode:

Use safe mode to isolate issues with your Mac - Apple Support

If it still doesn't work boot into Recovery and Reinstall Mac OS.

About macOS Recovery - Apple Support

If none of that works make bring it to an Apple Authorized Service Provider for an evaluation.

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Answer 3

ojquirozr Author

Level 1

12 points

Jul 20, 2018 6:43 AM in response to ojquirozr

Well, I changed the LCD screen and it had the exact same problem. So I decided to change the GPU, i finally did so with this guide

https://www.ifixit.com/Guide/iMac+Intel+20-Inch+EMC+2133+and+2210+Video+Card+Rep lacement/1014?revisionid=HEAD

And now it works just fine, everything is ok. I don't know why the screenshot was fine if the problem was the GPU.

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Answer 4

ojquirozr Author

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12 points

Jul 12, 2018 7:41 PM in response to ojquirozr

Hello everyone!

Well... I found another iMac which is the same model as mine and decided I could replace the LCD screen to check if it was the screen before buying it. I installed the second LCD screen and it shows the exact same problem. I don't know what else could it be!

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Answer 5

macjack

Level 10

111,242 points

Jul 8, 2018 10:35 AM in response to ojquirozr

Yes, I agree with Old Toad. It's probably not worth putting money into.

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Answer 6

ojquirozr Author

Level 1

12 points

Jul 7, 2018 1:23 PM in response to macjack

Ok, now it boots fine, but the screen still has the same problem:

I don't think this has to be with software, I think it is hardware related. And I can't send it to any Apple Authorized Service Provider 'cause there isn't one in my state.

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Answer 7

iCare

Level 4

2,490 points

Jul 10, 2018 6:52 PM in response to macjack

Yes, screenshots are a handy tool for troubleshooting. The display is simply relaying the information it is being sent. When you take a screenshot you are simply capturing the contents of the video RAM that is supporting the GPU. If the VRAM is bad, or the GPU is sending corrupted image data to the VRAM then that corrupted information will be captured in the screenshot. After many years helping family and friends with their issues I've found it much easier and safer to isolate the issue using simple methods like this before tearing into the hardware.

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Answer 8

ojquirozr Author

Level 1

12 points

Jul 10, 2018 6:54 PM in response to iCare

Thank you very much iCare, I took a screenshot and it looks fine on my windows computer, so the GPU is working just fine. I still don't know if the issue lies on the LCD screen or the flex cable, so I'll try the flex cable first since it is much cheaper.

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Answer 9

Old Toad

Level 10

215,346 points

Jul 11, 2018 9:09 AM in response to iCare

iCare:

I made a User Tip of this topic and, in particular, your contribution to the topic. I felt it was worth while to document for others to have access to.

It's located here: Issues with iMac screen

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Answer 10

macjack

Level 10

111,242 points

Jul 7, 2018 1:36 PM in response to ojquirozr

Are you just seeing issues with the screen on boot up and the display works as expected after that?

You can check here for an Apple Authorized Service Provider near you:

Apple - Find Locations

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Answer 11

ojquirozr Author

Level 1

12 points

Jul 8, 2018 10:12 AM in response to macjack

No, the screen is always like the picture I posted.

And no, there are no Apple Authorized Service Providers near me, I live in Venezuela.

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Answer 12

ojquirozr Author

Level 1

12 points

Jul 9, 2018 5:23 AM in response to macjack

Buying a new one is not an option for me right now. I wonder if just replacing the LCD Flex Cable would solve the issue or I should replace the whole LCD screen.

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