Top Half of Screen Dark

Question

Level 1

10 points

Top Half of Screen Dark

This has been happening for some time. I thought it was the inverter, but maybe not. When I first start up my iMac and I see the grey screen, for a split second the whole screen is evenly bright, but then the top half dims. I noticed this starting a while back when my screen would dim after inactivity and the top half would flicker and make a buzzing sound, but that issue went away. Now the top half is more dim than the lower half all the time, even as I adjust brightness - the top half dims along with the bottom half, but is always more dim than the bottom half. If I adjust brightness down from full I hear a very faint buzzing sound.

Is this a hardware issue?

This is a 2008 iMac 20"

iMac, Mac OS X (10.7.3)

Posted on Aug 1, 2012 10:17 PM

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Answer 1

Sep 1, 2017 2:27 PM in response to RG37

It is very straight forward. iFixit has a guide you can use to make it even easier to take apart

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Answer 2

RG37

Level 1

4 points

Sep 1, 2017 11:39 AM in response to Nandor690

Was this difficult? Did you have to disconnect the LCD board from the computer? I'm assuming you did.

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Answer 3

Jan 18, 2017 1:49 PM in response to alegasale

Mine was doing the same exact thing. There are 4 white plugs under the LCD on the right side. One of the plugs in the top corner on the right was partially unplugged. Pushed it back together, put the display to sleep, woke it back up and the screen Was fine again.

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Answer 4

BDAqua

Level 10

250,259 points

Aug 2, 2012 3:29 PM in response to craigmag143

Safe Boot, (holding Shift key down at bootup), is the top still dark?

Shine a flashlight at an angle & move it around at different angles to see if if you can see a dim Desktop on the dark part.

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Answer 5

craigmag143 Author

Level 1

10 points

Aug 2, 2012 8:22 PM in response to BDAqua

The subject title to my thread is misleading. The top half of my screen is not dark. It is more dim than the lower half. Upon startup when the grey screen appears, for a split second everything is evenly bright, then the top half dims slightly. I can still see the screen just fine. As I adjust the brightness, the top half parallels the brightness of the bottom half, just more dim than the bottom half. Does this make sense? This has to be a setting issue since I see even brightness for a short time in the grey screen at startup. Any ideas?

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Answer 6

BDAqua

Level 10

250,259 points

Aug 2, 2012 11:15 PM in response to craigmag143

Is the brightness equal in Safe Mode?

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Answer 7

craigmag143 Author

Level 1

10 points

Aug 6, 2012 5:05 AM in response to BDAqua

No. The brightness is still unequal in safe mode. Any ideas?

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Answer 8

roam

Level 6

13,637 points

Aug 6, 2012 5:21 AM in response to craigmag143

Perform an Apple Hardware Test. It might not find anything but it would still be woth running.

Intel-based Macs: Using Apple Hardware Test

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Answer 9

craigmag143 Author

Level 1

10 points

Aug 6, 2012 8:47 PM in response to roam

I can't get AHT to work. I'm using the lastest version of Lion. I recently reinstalled Lion from a USB drive I created before reinstalling. I tried holding down D, Option-D, and D using the USB drive. No dice.

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Answer 10

roam

Level 6

13,637 points

Aug 6, 2012 9:15 PM in response to craigmag143

I read on that link that for Lion the AHT is online, though how that works I have no idea. I am on 10.6.

Do you still have a clone of your 10.5 or 10.6 OS, because if you did you could boot into your clone and use the relevant DVD to test your hardware when booted into that same hardware environment.

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Answer 11

MrDuke

Level 1

4 points

Nov 12, 2012 7:59 PM in response to craigmag143

I have this EXACT problem. The only way I've found to cope is to sleep/wake the display repeatedly until the top half stays at its original brightness. I would like to find a less insane solution.

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