iMac screen goes black

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Level 1

36 points

iMac screen goes black

Short story shorter: my iMac's screen goes black.

Ever since upgrading to Yosemite about six months ago I have been having system issues. Particularly vexing has been the crashing out of nowhere with pattern of actions on my part. I finally decided a couple weeks ago to do a clean reinstall. That went as smoothly as one might hope and I even decided not to install Chrome as it always seemed to muck up the works plus I've seen plenty of comments regarding its poor performance on Macs.

so for about a week following that things were cool even tho I didn't realize the performance improvement I'd hoped for with the clean reinstall. However the worst thing is that the screen goes black out of nowhere. It's not going to sleep. It happens when I'm in the middle of doing things. I first noticed the phenomenon when I was listening to music on Spotify. The screen went black but the music played on. I could still hear hard drive noises. Clearly things were going on behind the scenes but the video portion of the proceedings was out.

I have since been able to wake it up by waiting about two minutes, briefly pushing the startup button and then tapping a keyboard key. Needless to say that's an absurd workaround. I zapped the pram pram countless times; same with repairing permissions. I reset the SMC. The screen just keeps going dark on me.

A friend who might know of such things suggested at one point it might be the graphics card going bad. This machine is 5 years old so I suppose SOMEthing's going to give eventually.

Any thoughts?

BTW it's a Late 2009 27" 2.8 GHz Core i7; 16 GB memory; ATI Radeon HD 4850 512 MB; running OS 10.10.3

iMac, OS X Yosemite (10.10.3)

Posted on May 3, 2015 8:12 PM

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Answer 1

Marc-Hel

Level 1

0 points

Aug 12, 2015 3:21 PM in response to Brunettin

My problems started a year ago. Screen turned black every once and a while and it got worse upto every 3 seconds.

The computer got slower and slower and would not even startup anymore. It's an iMac 2009, jeez not that old.

They put a new HD in it, which crashed after one week so a new one was installed, for free.

Now a year later same thing is happening, another HD,....yeeey why not?

When i got home i wanted to start it up,....nothing,...no sound, no lights, no nothing,...back to repair shop again.

That took a few days, and a new power converter,...but when it came back i reinstalled my backup and YES,...it worked!!! ,...for 4 days.

We're back to a failing backlight that turns of every 2 hours at best or every 3 minutes, or secs.

That's where it all started, that **** black screen,...Computer works fine, music even video if you shine a torch on the screen.

Tried pretty much every thing, PRAM, SAFE-Boot, SMC, reinstalling Yosemite,...etc,...i better saved my money for another

computer instead of having it repaired.

Always been a great MAC fan,...but reading that many "black screen" problems on the internet without Apple taking care of it?

Terrible,

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