'08 24" iMac has black spots at the top of the screen

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Level 1

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'08 24" iMac has black spots at the top of the screen

I've got an issue with my 2008 24" iMac with 2.8GHz Core 2 Duo processor, 6GB 800MHz DDR2 RAM and ATI Radeon 2600 Pro 256MB video card. When turning on the iMac you will notice the black spots and lines at the top of the white screen at startup. They are still visible once El Cap loads.

What would be my first troubleshooting steps for figuring out whether it's the lcd, the backlight or the video card? Or could it be something else?

I was going to hook it up to another monitor or screen to see if the black spots appeared on the 2nd monitor. Would cable do I need if I'm trying to do that with a 2008 iMac to a 2011 iMac or 2011 MacBook Pro? https://support.apple.com/en-us/HT204592

Thank you for your help

MacBook Pro, Mac OS X (10.7)

Posted on May 2, 2017 12:24 PM

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Answer 1

Top-ranking reply

den.thed

Level 10

82,540 points

May 2, 2017 1:35 PM in response to Mauiloving

Apple sold Mini DVI to DVI and Mini DVI to VGA adapters back in those days for running dual monitors.

You can still find them and other third party adapters at amazon and other on-line retailers. You may also fine that some Mini DVI to HDMI adapter will also work, although I never personally tried any of them.

https://www.amazon.com/Mini-DVI-DVI-Adapter-Cable-PowerBook/dp/B001G8DTN0

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Answer 2

Mauiloving Author

Level 1

9 points

May 2, 2017 1:20 PM in response to den.thed

Thank you for the reply again, den.thed!

If it is dust in the panel or if the panel is burnt, THEN I should be able to find out by connecting to another Monitor. Do I need to hook my 2008 iMac up to another 2008?

There isn't a thunderbolt cable hookup on the '08 models and nothing listed here for anything older than 2009- https://support.apple.com/en-us/HT204592

Is there still a way to hookup the '08 iMac to another monitor? I really want to know for certain what the issue is.

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Answer 3

rkaufmann87

Level 10

144,102 points

May 2, 2017 1:23 PM in response to Mauiloving

Mauiloving wrote:

https://support.apple.com/en-us/HT204592

Is there still a way to hookup the '08 iMac to another monitor? I really want to know for certain what the issue is.

Mini DVI port adapter to DVI or VGA.

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Answer 4

rkaufmann87

Level 10

144,102 points

May 2, 2017 12:30 PM in response to Mauiloving

The best method is to take it to your local Apple Authorized Service Provider. However considering it's age I wouldn't spend any money on it. It's 10+ years old and is way overdue for a refresh. That being said please look over:

https://www.lifewire.com/troubleshooting-mac-display-problems-4121097

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Answer 5

Mauiloving Author

Level 1

9 points

May 2, 2017 12:49 PM in response to den.thed

Hey, Den.Thed! Thanks for the reply, but it's not dust between the display glass panel and cover. I don't have a local AASP, I am actually the local uncertified repair store. So, I'm very interested in actually figuring out the issue. I've seen a few machines like this over the years, and I'd like to find out what happens when this occurs.

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Answer 6

Mauiloving Author

Level 1

9 points

May 2, 2017 12:52 PM in response to den.thed

I have previously taken the panel off and cleaned it thoroughly, replaced the hard drive, cleaned out the dust from every corner of this thing.

I think it's either the video card, or backlight or the LCD itself. I'd like to troubleshoot by hooking it up to another monitor, that should tell us something.

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Answer 7

rkaufmann87

Level 10

144,102 points

May 2, 2017 1:02 PM in response to Mauiloving

Mauiloving wrote:

I have previously taken the panel off and cleaned it thoroughly, replaced the hard drive, cleaned out the dust from every corner of this thing.

I think it's either the video card, or backlight or the LCD itself. I'd like to troubleshoot by hooking it up to another monitor, that should tell us something.

True, that will rule out all but the GPU.

BTW, there is no reason to throw insults at someone that is attempting to assist you. You may not like what you hear however the advice has proven to work.

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