iMac Video Card Replacement

Question

Level 1

7 points

iMac Video Card Replacement

Hello Apple Community,

I've got a late 2009 27" iMac with ATI Radeon HD 4850 video card. It's showing vertical lines on the screen at startup and won't even boot into OS X anymore. When I did get into Yosemite via safe mode the lines were still there and flickering and wacky behavior made it hard to see anything. Any advice on where to get a replacement video card, or test to run to find out FOR SURE if it is a video card issue? Everything else works fine, so not willing to part with it yet. Would be open to third-party hardware if Apple doesn't still sell the 4850. Just want a workable solution.

Thanks so much!

iMac, OS X Yosemite (10.10.3), 27", Late-2009 Model

Posted on Jul 21, 2016 8:22 PM

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Answer 1

babowa

Level 9

78,574 points

Jul 21, 2016 8:32 PM in response to jaywalkin

Well, the first step would be an appointment at your nearest Genius Bar - they have testing equipment and should be able to tell you if it is. You can then decide what to do. You can also check ifixit.com for your model and graphics card including instructions on how to replace it.

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Answer 2

Jul 22, 2016 3:59 AM in response to jaywalkin

You can try running Apple Hardware test (Using Apple Hardware Test - Apple Support)

as a start. This could determine if just graphics card or more may be at issue.

May determine if a trip to an Apple Store or an AASP may be warranted vs. a new

computer. Reason is, if there is an issue with the display itself, the cost of replacing

it will be very expensive.

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Answer 3

jaywalkin Author

Level 1

7 points

Jul 24, 2016 12:19 PM in response to woodmeister50

Thanks for the advice. Unfortunately, my iMac wouldn't even run that, I've tried more than 5 times with no luck...Mac just goes to gray screen and halts, no diagnostic screens, nothing.

I've been told that that's pretty typical for a bad GPU, and I've been able to get into El Capitan using the "safe mode", and the flickering and lines are really bad, so yeah, pretty certain that it's a GPU issue at this point. Just wish the replacement options were cheaper!

Thanks again!

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Answer 4

jaywalkin Author

Level 1

7 points

Jul 24, 2016 12:21 PM in response to babowa

Thanks for the help, will attempt to diagnose at a local mac 3rd party repair shop, since I have no local Apple stores and they're cheaper than apple support anyways.

I have looked at ifixit.com, that's a great resource for sure!

Thanks again for the help,

Jaywalkin

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