iMac 27" Black Screen?

Hmmm - not invoking screen saver sounds like a funny way to have to solve the issue. Anyway my son turned off the hotspot you go to ti put a iMac to sleep. that worked. However there must be a USB angle - becsuse I connected my camera to download phots and is messed up agin until I restarted mr iMac. OK since. The othr thing of note is that the keyboard would not even recognise Caps lock - does that mean the keyboeards power is being switched off ( I have USB connected keyboard).?

Ive tried everything i could. go for the genius, replace the graphic chip,change the key board,lower the brightness (it helped,for a while),reinstall whole system ,4 times. Now,u wanna me to change my monitor,which is the only reason that i brought the 27"iMac for the first place.

I thought it just me got unlucky, but when i ask help from my friend and search the solutions on internet, i find it wasn't just me and I'm sure as **** that even the latest imac running now in my university have the same black out issue.

Ive been using iPad ,iPhone and iPod it worked fine (for the most of time) and did brought me lots of fun and convenient. But iMac, tell you what,the computer I've been using mostly for 2 years is the cheap notebook i got 4 years ago.(i got this iMac 2 years ago).

Apple build up the expectation through all these fancy little tools but when it comes to the real problem, the silence is really broken the users heart and this is not the apple i once knew.

So,i gonna abandon this god **** iMac and tell all my friend to never make the same mistake i made.

Ps:Im sure as **** that the black out problem is not caused by softwares, and once it happened that means your iMac just fked, no matter what you do it just beyond help(well,unless you change the monitor but it just unbearable for graphic designer) , the only way to prolong your usage of your iMac is to watch out the temperature, the high temperature caused either by running the program or direct sunlight will melt your iMac.

Pss:In that case,the best environment for your iMac is the basement,where all the useless garages are.

I bought a new iMac 27" in Jun of 2011 and in 2013 the screen started going black. I brought it in for repair, the replaced the graphics card it went black shortly after I returned home, brought it in again, they replaced the backlight and a few other things, shortly after I returned home it went black again. I kept fiddling with it, bought a fan program that makes your fan run as fast as you wish etc., nothing worked. When I turned if off and on and off and on and off and on I sometime would get it to stay on for enough time for me to finish my work, what a headache. I brought it back and laid into them, I was really ******. They took it in and called me about 10 days later ready for me to take it home. I did but was as skeptical as could be. Guess what, been using it steady for 10 days and no black screen. What did they do? The simply went into the computer and unplugged all the switches and wires and replugged them again. Evidently sometimes these things are put together too fast and employees are a little sloppy putting them together. They say that they found one connection loose. It's worked perfectly since then. Hope this helps.

I had the same problem with black screen on my 27" iMac. Had graphics card replaced, backlight replaced, shut off hot corners, installed a fan accelerator program, all to no avail. Brought it in for repair again, they called about 10 days later and said it was ready. picked it up skeptical as could be. Good news, it hasn't gone black screen since. What did they do? Replaced nothing. They went in and unplugged all the switches and replugged them again. Found one that was loose (they say). I had the black screen problem for over a year. Would go black, I'd shut it down, turn it on, turn it off, turn it on etc., until it would stay on for a few minutes etc. I've used it steady since and no black screen. Hope it works for you. 🙂

I have the same problem and thought it was something to do with the Power Saving ,Screen Saver ,Sleep ,Hard Drive idle use .

Now after reading some blogs I think it might be related to a loose connection ,as I connect an old USB powered hub and think that maybe the source of a loose connection or static surge from one of the USBs or the Power adapter itself .

I'l wait for the Shut Down notice again and then try without the added USB Hub .

Mine has worked properly and NO BLACK SCREEN since I brought it in and they went into the machine and unplugged and replugged all switches and wiring. I had black screen for over a year. I tried everything, and brought it in for repair and they replaced a lot of things. The last time I brought it in they just went into the machine, unplugged everything and replugged all the wiring and switches in again. Has worked perfectly since then, and that was over three week ago. Will keep posting to let everyone know, but I am certain that they found the problem, and it was only a loose switch or wire in the machine.

I have been having this problem for the last months, sometimes I just want to throw out the window my 27 inch IMAC!!!!

I have called apple support in Stockholm (Sweden) but they told me since my computer has 2,5 years old I will have to pay for the repair.

I took my computer to the local apple store and they started replacing components and when they replaced the display things seemed to work with NO BLACK screen anymore. The problem is that they wanted about 600 Euros + keep my current display!!!!.

I didn´t accept to have to pay that amount specially since I´m not 100% confident that the problem comes from the display alone.

My only solution is to lower the brightness to the absolute minimum, I can barely see the screen but it stays on.

Sometimes I can pull up my brightness for a couple of minutes.

BUT I always have to shut down the machine with the display brightness to the absolute minimum or else next time I restart my computer , he will turn black wile he is still starting and I won´t be able to login even. (And before logging in the trick ctr+alt+ eject won´t work).

I´m very very very disappointed with apple and their silence on this issue.

It´s obvious that this is an engineering issue

Regards

Ana

I am in Italy and that makes problem even worse, as local technicians usually opt for the most expensive option and as I do not know is it a hardware or a software glitch, it would be unwise to leave them an iMac because I could end up with a mass of replaced parts and unresolved problem. Anyway, I keep my fans running, use ctrl+shift+eject button combination to awake display (I usually lower brightnes to minimum, start up fans and then increase brightness to max).

In that way I can work for hours. I'll wait for Yosemite to see if the problem persist. My guess is that it is not software, as I tried to run DiskWarrior from the boot USB disc and the display remained black. It could be some loose switch...Anyway, I am monitoring PSU primary and running fans via iStat pro. All the test I did with various tools are negative (DiskWarrior, TechTool Pro, Drive Genius, Disk Utility).

Hi Guys,i too have had the same problem for nearly 2 years with my mid 2010 Imac.

When this first started i did the same as everyone else,googled it hour after hour with no working results,i have my xbox 360 connected to my Imac via display-port-HDMI video converter,i also get Black screen when my console that is up and running,once again that can work for weeks and then black screen appears

i can sometimes run my Mac for weeks and weeks and then it just starts,i have taken the Mac apart and cleaned it of dust,several times now,tried All the OSX'S from S/L including Yosemite.

I usually have to have my brightness set to 4 marks,any higher and it black screens,it black screened a few weeks ago and out of total frustration once i got the screen back on i turned the brightness up 1 dash over half and the screen stayed on!!!

It worked for several weeks and has decided to play up yesterday,messed around for 3 hours this afternoon watching it black screen and also losing signal for my xbox360,tried several different Brightness settings to no avail.As i type this it has stayed on for 20 minutes now on Brightness mark 3,which is way too dark for me.

Over the past 2 years i have tried everything,i can use my Mac no problem for weeks and that includes my Xbox 360,then all of a sudden it black screens and the nightmare starts again.I know the problem is not with my Games console as it works on other screens including another 27" Mac.

I have emailed apple and basically been told to take it Genius bar which is 2 hours away from me,i bought my mac second hand so have no warranty

I have a friend who has the exact same problem with the black screen on his 2012 Imac,i agree its deffo an engineering issue

really sick of this problem on a £1000 computer

Steve

use option+command+ eject then click your mouse. this usually helps but i'm at the point where it takes more than 5 tries to keep it on that i restart the computer. I've been having this problem for months now others have speculated its a million things but nothing helps. it goes away for awhile or happens less even gets to the point where the before mentioned sleep shortcut works on the first try but personally its gotten worse as of late. My guess its an apple error in the making of the imacs because all gens have it.

I noticed that after display went black, my external speakers also reduce the intensity and loudness. So, I have to hit ctr+alt+ eject and then turn the volume up. Anyway, it's been a quite a while that this issue hasn't happened again (black screen). I am running fans in default mode via iStat menus. Fingers crossed.

My 27" iMac got to the stage where the screen was permanently black except for a few seconds on startup and when waking from sleep, though the computer worked fine and I managed to limp along by setting my second monitor as the main monitor. It was bugging me as that was far from ideal. Then I came across this post and tried switching the bluetooth keyboard off - so far the iMac screen is working perfectly again. I happened to have a very old (and very long) apple usb kb hanging around, so I'm using that with no problems so far. I've been maintaining my own macs pretty competently since 1995 but I'd never have guessed this one without reading here, so thanks very much! 🙂

I found a fix.

I am running Yosemite and my iMac started to have this problem after I tried a bluetooth keyboard. It still had the problem even after I switched to a USB keyboard. Now after I turned off all three options in the Blue tooth advanced menu, it never goes blank screen again. These options are:

[] Open Bluetooth Setup Assistant at startup if no keyboard is detected

[] Open Bluetooth Setup Assistant at startup if no mouse of trackpad is detected

[] Allow Bluetooth devices to wake this computer

I thought the wireless keyboard fixed the issue and it did for the longest time, but that was only about a week. I just tried your suggestion and that isn't working for me either. I even switched the iMac's bluetooth off completely, using a usb mouse and kb, still black screened. That suggests to me it's not a bluetooth problem.

So far (on mid 2010 iMac with 12GB RAM) I have tried:

Switching all bluetooth off.

Unplugging all external devices including my 2nd monitor, a dell 24" and running the mac on its own - even without internet connection.

Resetting PRAM and SMC.

Verifying and repairing permissions.

verifying HD, no faults found, it is a relatively new one as part of the replacement program.

Scanning for baddies with ClamXav.

Checking for any firmware updates.

The problem began under Mavericks and has persisted in exactly the same way on upgrading to Yosemite, suggesting either a hardware problem or a software bug that hasn't been squished.

One constant is that my 2nd monitor, 24" dell which is much older than the iMac never blacks out, thankfully. At least I can still work, albeit in a more cramped and degraded way.

A 4 year old computer should still have years of life, especially when you pay a premium.

This is fun! 🙂

In 20 years as a mac user I've never had one give up, that's why I've always been a rock solid mac user. Perhaps times and standards are changing - or perhaps statistically speaking, it was simply bound to happen at some point!

Grateful for the continued suggestions though.

This is what i tried on my 2010 intel i5 imac

remove dust (one day good)

unplug and plug all the cables from the monitor including the small backlight cables in the corner (one day good)

set the sleep-mode to "never" (no effect)

set the brightness to 4 blocks (seems to occur less)

set the brightness to 6 blocks (seems to occur more)

PRAM reset (no effect)

SMC reset (longer problem-free intervals after reset)

set the brightness to 80 % yesterday (didn't occur since)

turn off the bluetooth an hour ago (didn't occur since)

i have a wired keyboard and mouse.

it occurred in cold and hot conditions.

it occurred several times while browsing and playing minecraft.

it didn't occur once in screensaver mode.

When it happens it happens several times in a short time.

it occurred once in mavericks the day before i upgraded to yosemite.

After the upgrade to yosemite it went a lot worse.

it occurred while running ubuntu from a USB stick.

I hope this helps, if everyone analyse the conditions in with it happens maybe we could one day find a real cause.

It drives me mad,