Q: iMac 27" Black Screen?

Can't figure out how to mark it as solved

I can't figure it out either. Oh well.

I tried the keyboard thing itworked for about two days as of today my computer is caput i hadnt been using the keyboard even toke out the batteries but the screen as gone permanetly blck i turn it off turn it back on i restart it and nothing still black. Ganna go take it in soon ill let the thread know whatthe outcome is.

i was able to get the screen back by putting it to sleep and waking it up ( on the third try atleast) still have to take it in

Still running... Problem solved

Thanx you so much

I'm still problem free. I'll post again if anything changes. You're welcome. I'm glad I helped at least one person.

Hey there, I tried a different keyboard (usb from my pc) and I STILL have the same problem (screen going black), exactly the same problems Rixxi had, except none of my parts have been replaced. I'm using an smh... I've had this problem since I upgraded to Mavericks. I did not use Time Capsule (I should've), so I lost Mountain Lion. I re-installed Mavericks and still have the same issue.

Did you also remove the batteries from your Mac keyboard? If not it stays on and the computer lets more than one keyboard be connected at the same time.

I don't know what other problems are causing the same symptom. When your screen is black is the computer still on? Hitting the volume key will tell you.

I know that a new hard drive and reformating the new one didn't fix my problem. The geniuses had it in for a week, the second time, tested everything, the problem did not recur and no hardware problems were apparent. They claimed it was my software and said the computer was going to sleep. But that wasn't even right because it wasn't going to sleep, just the screen was going dark. Anyway, back home only installing files and no aps from Time Machine, within a week, same problem.

That's when it dawned on me the keyboard has a screen brightness control and they didn't test the IMac with my keyboard.

Other people in these threads had some success replacing a backlight part (look through the threads for the part name). And the people at the store suggested the video card and a connection to the motherboard or something I don't recall exactly.

That's all I got. But my computer continues problem free.

Yes, the batteries were removed and I got excited because my iMac stayed on for a full 16 hrs. Lol. When the screen goes black, the music still plays. Everything works as before, just without sight. Lately, I would hit the power button twice on the back of the iMac to get it to work. I just thought it was weird that I didn't have this problem before I upgraded to Mavericks.

They don't merge any of these threads. Search for IMac black screen and read through the threads to see what else worked for people. One person thought Maverick would fix the problem but it didn't. The one thing that is apparent is lots of people have had this problem.

ARe you saying that a new keyboard fixed the issue?  I use a USB connected keyboard, not a wireless one.  who else has had issues with wired keyboards (I gave up on th wored version cos it chewed though batteries / rechargin... etc)?

Control-shift-Eject Assume the eject is the button to eject a drive....), which is down th thread a way out didn't work my situation.

Have apple come up wiht e reliable workaround, other than replacing the keyboard. replacing a keyboard doesn't look like a long term fix to me in any case.

no the keyboard doesnt fix the problem. i still have the problem with another keyboard. The sleep shortcut (control-shift-eject) acyually does work on waking it up it just takes a couple tries

i did that and even having the keyboard disconnected withut batterie it still happened to me

Unfortunately the keyboard changed fixed the problem for a couple weeks, taking it in (jostling?) the computer fixed it for a couple weeks. Right now I feel like I'm just trying things the way one tries superstitions. But someone else had an answer that makes sense to me, but it's expensive or difficult to fix.

pbook4g5:

"...the ribbon cable between the display and the LED driver board. As I stated in my repair notes a few pages back (and now a few months ago), the only thing I could do to fix the issue was to install a new display, which had a new display cable attached to it.

I could find the main cable from the display to the logic board to replace, and that didn't fix it, but I couldn't find the cable from the backlight board to the display itself (outside of a new display) so I'm convinced its the connection with that cable.

I don't think its temperature related, I think its just a bad connection somewhere on one of those ends.

PS My replacement display (which is actually just a display pulled out of another "recycled" system, is still fully functional after almost 9 months of use."

https://discussions.apple.com/people/pbook4g5

https://discussions.apple.com/message/25054120#25054120

Mine turned out to be a software issue. Machine would boot up, could hear the hard disk. Screen stayed completely black. Went to Radio Shack to pick up an adapter, hooked up antother monitor, it worked - so - whew! - it isn't the graphics card.

Main screen had been down for two days. After hybernating - it came back to life. I had the display back. Soooo... it was a software issue. Lion has been sort of dicey with hybernation from day one... I thought about  attemting to find  and replace faulty Kext files - but who's got time to dig around and find out where the issues are. Shouldn't Apple be doing this?

I upgraded to Maverics, and bingo! No more dicey hybernation. No more black screen. Issue solved.