iMac screen shutting off frequently

[freshnet]

My iMac has just started having this problem. The screen will shut off about 10 minutes after rebooting. The system is still on because I can still access the drives from my laptop, but nothing will reactivate the screen.

As far as I'm aware this problem doesn't coincide with any change I made to the system, definitely no new software or hardware. I thought for a while it might be related to display mirroring, so I turned that off, but no luck. Anyone have any thoughts? If I have to take it to a retailer and get it repaired I will, but I'm not even sure what they would do with it at this point. Any help would be much appreciated.

 

[freshnet]

A couple of extra things I've tried. I tried resetting the PRAM and SMAC, no change. However this does seem to be tied to the graphics card somehow. I left the computer on for 20 minutes without doing anything and it worked fine, but then as soon as I played a video, the screen shut off again. Could the graphics card be faulty?

 

[MacOG728893]

A couple of extra things I've tried. I tried resetting the PRAM and SMAC, no change. However this does seem to be tied to the graphics card somehow. I left the computer on for 20 minutes without doing anything and it worked fine, but then as soon as I played a video, the screen shut off again. Could the graphics card be faulty?

Could it be faulty? Sure. Best way to test that is with an external monitor. If it exhibits the same behavior on that external monitor, then it is safe to say the GPU is faulty. However, if the external monitor stays on while the iMacs LCD is blank, then it's probably the LCD screen, video cable or a combination of the two.

 

[freshnet]

I hooked up the external monitor as an extension of the display and it also shut down. Is the GPU even something that can be fixed?

 

[jlehman]

You'll have to take it to an Apple Store or Authorized Repair Center. I work for a college in their IT Department and was the Mac Admin (now network specialist). We had a 2010 27" that did the same thing. Luckily it was under Apple Care warranty and they replaced the Logic Board at no cost at the Authorized Repair Center. Unfortunately It happened again right after the warranty expired and its sitting on a shelf for parts.

If it's not under warranty i would talk to Apple and see what they say. If they are going to charge alot to bring it to a store or ship it to them then see if there is a Authorized Repair Center nearby and see if they can take a look at it cheaper. Probably needs the logic board replaced.