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You are here: MacNN Forums > Hardware - Troubleshooting and Discussion > Mac Desktops > iMac turns Dark

iMac turns Dark
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Harvey
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Jun 28, 2014, 12:38 PM
 
I have a 2007 iMac with a new power pac and HD which unfortunately has a total black display as of yesterday. I have tried a PRAM at restart with no change. Through firewire I am able to access the HD and have begun to migrate files onto my MacBook Pro. If I knew precisely what was causing the blackout I would try to repair it with the help of YouTube and Fix-it. It sound like it might be an expensive undertaking. Apple policy at my local genius bar was that they won't touch it due to it's age and were nice enough to give me a list of repair shops that would. Any and all ideas are appreciated. I am close to recycling it at my local apple store but would rather pass it down to someone who may find it useful. It has been replaced with a new iMac
Harvey
PS-anyone know of diagnostics I can run from my MacBook Pro while in Firewire mode?
     
Mike Wuerthele
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Jun 28, 2014, 01:11 PM
 
Without looking at it, my first guess is a GPU problem. Yeah, Apple has put that model on the list of obsolete machines, so Apple stores won't be much help.

Either way, a LCD failure, or GPU problem, the fix is more expensive than the value of the machine.
     
reader50
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Jun 28, 2014, 01:39 PM
 
Boot it up with the black display. Hold a flashlight near the LCD, see if the screen images are present. If they are, the backlight has died. This is the most likely answer.

If the flashlight doesn't reveal any screen patterns, then it's probably a GPU problem. Though a damaged cable or connector is possible, especially if the iMac has been opened previously.

Replacing a backlight shouldn't cost a ton. Also, you can work around a backlight or cable issue by using an external monitor in mirror mode.
     
Mike Wuerthele
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Jun 28, 2014, 01:44 PM
 
I'm nearly certain the backlight in the LCD in those models is integral to the panel, and not an independent bulb like in 1995-2003.
     
reader50
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Jun 28, 2014, 02:09 PM
 
Even a screen replacement isn't as big a deal as it once was. LCD prices have fallen, and ebay will have salvaged panels for even less.
     
P
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Jun 28, 2014, 02:11 PM
 
I thought so too, but figured I'd check. Turn out that the real integration happened only in 2009 as the LED backlights came - that model appears to have a replaceable backlight still:

https://www.ifixit.com/Guide/Removin...+assembly/5865

That replacement looks hairy, though.
The new Mac Pro has up to 30 MB of cache inside the processor itself. That's more than the HD in my first Mac. Somehow I'm still running out of space.
     
Mike Wuerthele
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Jun 28, 2014, 02:32 PM
 
Originally Posted by P View Post
I thought so too, but figured I'd check. Turn out that the real integration happened only in 2009 as the LED backlights came - that model appears to have a replaceable backlight still:

https://www.ifixit.com/Guide/Removin...+assembly/5865

That replacement looks hairy, though.
Nasty. The backlight replacement on a clamshell was easier than that!
     
Waragainstsleep
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Jun 28, 2014, 03:52 PM
 
Does it get external video?

Who replaced the HD and power? Maybe a loose connection.
I have plenty of more important things to do, if only I could bring myself to do them....
     
akent35
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Jun 28, 2014, 03:56 PM
 
Originally Posted by Waragainstsleep View Post
Does it get external video?

Who replaced the HD and power? Maybe a loose connection.
The loose connection idea is a likely culprit, as apparently (an assumption on my part) everything was fine prior to the HD and power replacement.
     
Harvey  (op)
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Jun 29, 2014, 08:35 AM
 
Thank YOU all very much. Great ideas and much to ponder. I replaced the HD 18 months ago and Apple replace the power supply 12 months ago.

Just wondering: Is it best to reinstall Adobe CS5 or is migrating the same.
     
Waragainstsleep
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Jun 29, 2014, 09:37 AM
 
Creative Suite is an odd one. It should migrate OK but every now and then it doesn't. Try migrate first, you can always install it after if you need to.
I have plenty of more important things to do, if only I could bring myself to do them....
     
donaldkepler
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Jul 1, 2014, 05:41 AM
 
Although the first method is zapping the PRAM by following the below mentioned steps:

Find the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
Step 1: Turn on the computer.

Step 2: Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.

Step 3: Hold the keys down until the computer restarts and you hear the start-up sound for the second time.

Step 4: Release the keys.
     
Mike Wuerthele
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Jul 1, 2014, 09:10 AM
 
Originally Posted by donaldkepler View Post
Although the first method is zapping the PRAM by following the below mentioned steps:
OP mentioned that was tried. Good info, though.
     
   
 
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