iMac 27" Black Screen?

Well they replaced the entire LCD screen as well as back light board and of course the new logic board.....BUT

because of the "genius" mistake....

the cost was .....well.....not costly....at all

All I can say is this

replace the backlight board AND the LCD is the only way

See if your machine was part of the recall for defective LG made displays.....

If not.....well, "maybe" the people at the Apple store can "good will" replace/low cost

mine is working fine now....

Sol I hope it lasts for another 5 years....by then a new iMac will cost $4000.00, have 18K video display

project as a hologram in space in front of your face and have a AI Siri that can read your brainwaves before you say (and you won't never have to type anymore) and get your answer for you

Hi,

First time I have posted! But have a 27" imac mid 2010 and two weeks ago it started to experience the black screen if the setting was above 3 or 4 on brightness. External monitor worked fine so I'm thinking maybe not a hardware issue, After reading many different threads, I upgraded to 10.11.6 called apple and I think we did this - open system preferences go to display, turn the brightness the whole way up, then go to color, and calibrate, and save the setting. It worked for me! 24 hours in and like new. Good Luck

I've had this problem as well. I just got it to stop though. Here's what seems to have worked for me:

It was either A. Switching to a wired keyboard or B. Blowing compressed air through the vent covers to better increase air flow to computer.

To do the second one, you can just peel off the black glass screen (it's apparently only attached by magnets. Peel from top) and shoot the compressed air down through the ventilation holes.I don't know which fixed it, but now I'm at full brightness with no shutdown, when I previously could only run with ZERO brightness. Hope this helps someone else.

As you can see from earlier posts the black screen problem has been with me for 4 years now.I have tried every suggestion on this site and others.

Now for the spanner in the works!!!Up until last week my 2010 iMac has not black screened for almost 6 months,i have had the brightness on full,medium and low and it has been fine.I have not cleaned it out or changed anything.Then last week it decided to black screen and after several cmd option eject presses it eventually came back on and stayed on for about 2 minutes.Since last week it has worked for a couple of days on nearly max brightness,i have used my Ps4 via remote play so i can use the Mac's screen to play my Ps4,watched loads of youtube videos,edited photos and general other things.Then all of a sudden the black screen returns.

I'm glad people are finding their own solutions for this annoying problem and please keep posting to let myself and others know about any changes.

Steve

As you can see from earlier posts the black screen problem has been with me for 4 years now.I have tried every suggestion on this site and others.

Now for the spanner in the works!!!Up until last week my 2010 iMac has not black screened for almost 6 months,i have had the brightness on full,medium and low and it has been fine.I have not cleaned it out or changed anything.Then last week it decided to black screen and after several cmd option eject presses it eventually came back on and stayed on for about 2 minutes.

Since last week it has worked for a couple of days on nearly max brightness,i have used my Ps4 via remote play so i can use the Mac's screen to play my Ps4,watched loads of youtube videos,edited photos and general other things.Then all of a sudden the black screen returns.

I'm glad people are finding their own solutions for this annoying problem and please keep posting to let myself and others know about any changes.

Steve

I've had the intermittent black screen problem for a few years now on a mid 2010 iMac. This past May it got so bad that I could bring it to Apple for the tech to see it happen. I ended up with a new backlight board which seemed to solve the problem until last week. Again the screen would go black unless the brightness was set all the way down.

Brought it back to Apple again and the tech concluded that the LCD display would need to replaced but that I would have to find an independent repair shop because it was too old for Apple to fix. Found a shop that would do the repair with only a 30 warranty for $500. That was unacceptable so now my only choice was to replace this piece of junk.

Then a few days later the display started working reliably again but only at full brightness or minimum brightness. Any setting in between and it instantly goes black.

This is just crazy and infuriating. I don't think that Apple's techs have a clue as to whats going on with this problem.

I just started having this issue on my late 2009 27inch iMac. I run a crippled version of 10.7.5, some quartz related kexts removed because of a dodgy ATI Radeon 4850 video card. I came across this blog and tried a few of the keyboard related solutions, but none worked. I saw one post about loose connections on the monitor that looked useful, so I removed the screen, unscrewed and pulled the lcd monitor out a bit. Everything inside was filthy with dust, so I pulled it off completely, vacuumed and air sprayed everything. I noticed the video card heat sink was particularly bad. Put it all back, checked every connection, screwed everything back up and put the screen back. So far so good, its been about 4 hours with the screen on about 70% brightness. The temp hasn't been above 40C, usually about 47C on 50% brightness. I always have to nurse this pos along, a new one would cost about AUD$2,700 and I can't really justify that. Maybe when it finally dies I'll go for a Mac mini and a Acer 28" 4k monitor or something.

OK, the screen finally got to the point where it would only stay on for a couple of hours with the brightness at zero. I'm able to use UltraVNC to get into it from a PC even when it goes black, but I can't really go on using it like that. I now have a shiney new Philips 272P4QPJKEB/75 monitor connected as a primary mirror (mini Display Port to Display Port) and am getting the full 2560x1440@60Hz. I think I can go like this for some time now, waiting too see if there is a new Mac mini in October 2016. The late 2009 27 inch iMac is a lost cause.

Change the keyboard to a wired one. I don't know why but it actually works!! I have a Late 2009 27-inch IMac. No more having to lower the screens brightness so the screen can stay on. : )

In posession of an iMac 27" (mid 2011), facing the black screen challenge since aprox 2 years now. Did all of the suggestions except rewiring inside, replacing the screen or replacing keyboard. Since the black screen happens on both MacOS and Bootcamp/Windows, this indicates it is not a software problem. Reinstalled OS anyway 2x since which did not bring relief.

Will try new keyboard. Also... anyone tried plugging in an external monitor. Did this happen to anyone with an external monitor too? That would indicate whether the problem lies in Apple's display or potentially something on the graphic card.

Hi Mark I have tried the external monitor from my 2010 iMac,the Mac still black screens, however the external monitor stays on and works fine.

Hi Steve, thanks. So this supports the hypothesis of me & Steve's issue lying in the areas of

1- the display

2- the dedicated part of the graphic card that sends the video output to the internal display

3- the cables between graphic card and internal display

Keyboard & power seems unlikely as they would tend to affect both your internal and external display.

At least - for the most frustrated users, an external monitor may bring relief to the black screen problem.

That said, as long-time user and lover of Apple products, I start questioning the company for not providing out-of-guarantee support on this kind of broad quality issue, while making $8.3million net profit per hour. Shame.

My last fix was not a permanent one (May 4, 2016 9:57 AM, Page 9). I know how to force screen flickering and thus make the monitor work for a couple of hours, but it is not a solution. At first it would work for a week, but in the end sometimes even less than a minute.

However, I have found something else. Since I couldn't afford a new iMac, I went for a Windows desktop (yes, I know, shush). I moved lots of my files to my new desktop and backup, and deleted them of my Mac. I went from 120 GB free space to 600 GB. And here it comes; since I have done that (2 months ago), the **** iMac has not gone black screen once...

The idea was to hook up my iMac to my new monitor, as it is performance wise a very good computer. But since it is up and running like it used to be, I had to extend my desk. I refuse to trow away (or sell) my good old iMac.

So my guess is that the black screen is being caused by several faults. De HDD is probably demanding more power when it is nearly full, the PSU can't handle that, so it turns of something that won't hurt hardware or software, so it turns to the backlight.

This may not help everyone (or anyone else at all), but it did for me. We're talking 2 months now, at full brightness. But it might be worth a try to delete some stuff of the internal HDD (Backup First ⚠)