IMac screen dimming problem

Can someone please tell how to fix this? I believe it may be a hardware issue, but when I reload the iMac, it goes away. When I put my HDD image back, the problem starts up again.
Note: this is networked iMac (it is bound to a AD domain). This only happens after the iMac has been sitting idle for enough time to log out.
Here a video of the problem:
http://www.youtube.com/watch?v=gpNCKdP5wo0
Thanks!!

Hello,
The 2012 macs (and later apparently) not waking normally from sleep after hours being in sleep. (noted here ...
http://www.xlr8yourmac.com/archives/feb13/022813.html#2012macswontwake
"Why 2012 iMac/2012 Mac Mini won't Wake After Hours of Sleep (Hibernates/Powers Off)")
The sleepimage file still reappears even if never slept. Delete it (hibernate off, etc) - within minutes its back.
Anote on that here - http://www.xlr8yourmac.com/feedback/Chameleon_SSD_Optimizer.html
About iMac sleep, but...
http://forums.macrumors.com/showthread.php?t=1529750
https://discussions.apple.com/message/22336226#22336226
Daniel Leary 2008
Re: Mac Mini wake up issues
Okay this workd for me, I typed into Terminal:
     sudo pmset autopoweroff 0
     sudo pmset standby 0
then verified that the changes were made with
     sudo pmset -g
and so far so good!

Similar Messages

IMac screen dims itself automatically; all attempted fixes fail; how can normal brightness be restored?

Machine and OS:
2007 white plastic iMac with 20" screen and 2 GHz Intel Core Duo, running OSX 10.6.8.
The problem:
The screen dims itself for no known reason. It is especially noticeable when waking from sleep: for the first second or two after waking up, the screen is at normal brightness -- but then after a second the computer seems to "remember" some setting or command, and the screen unquestionably dims itself to be about 20% or 25% darker.
Because the screen for a brief moment after waking is at full brightness, that proves to me that there is nothing physically "broken" about the display that prevents it from illuminating fully; it could be at full brightness if it "wanted to," but some kind of software or firmware glitch is telling it to be dimmer.
The fixes I have attempted so far -- ALL of which have FAILED (so please don't recommend them again):
- Reset the NVRAM or PRAM by holding down Command-option-P-R upon startup. For some reason this technique doesn't cause the second chime, so it doesn't appear to be zapping the NVRAM or PRAM or whatever, and consequently has no effect on the dimness, which persists unchanged after restarting.
- Reset the NVRAM using the terminal command ' sudo nvram boot-args=”-p -r” ', as recommended on this page: https://discussions.apple.com/thread/2172681?start=0&tstart=0. I can't tell if this really did reset the NVRAM (it doesn't cause a second chime upon restart), so I'll just have to assume that it "worked" -- but except for one instance, it had no effect on the screen dimness. (That one instance went like this: after issuing the Terminal command and restarting, the screen did go back to full brightness -- but only until the first sleep. After waking from that sleep, the screen once again dimmed itself as before. And no, I have not been able to repeat this momentary "success"; on all subsequent attempts following the exact same steps, no brightness has ever returned at all since.)
- Reset the System Management Controller (SMC) as recommended on this page: http://support.apple.com/kb/HT3964 . Basically this just entailed shutting down the computer waiting a few seconds, then unplugging it, waiting a few more seconds, then plugging it back in, then waiting a few more seconds, and then finally starting it up again. Result? No change: screen still dims itself.
- Pressed the "brighter" and "dimmer" keys on the keyboard; those do make the brightness go up and down, but the top brightness setting is much dimmer than it should be (and used to be). All the way to brightest setting = still noticeably dimmer than normal.
- Used the "brightness" slider in the System Preferences > Displays > Display window. That also does indeed adjust the brightness up and down, but as with the keyboard brightness keys, the highest setting is still too dim.
- Readjusted the "Calibration" in the System Preferences > Displays, which had no noticeable effect; even when going into Expert mode and adjusting every little aspect of the screen display's default settings. Those all seem to be about color balance anyway, not about brightness. I now have three different new calibration settings, and clicking back and forth between them and the default setting makes no real significant difference. Whatever setting I choose, it is still dimmer than it should be, even though in all my attempts at calibration I tried to make it brighter.
- Tried going to System Preferences > Universal Access > Seeing and adjusting the "Enhance Contrast" slider and trying out "Black on White" vs. "use Greyscale"; none of that helped, and did not seem to be relevant to the problem.
- Tried going to System Preferences > Energy Saver, and clicking the "Automatically reduce the brightness of the display before display sleep" check box on (and then closing the preference pane) and then off again (following the advice at http://support.apple.com/kb/TS2309?viewlocale=en_US) -- but it had absolutely no effect whatsoever on the brightness level.
Final note: The keyboard and mouse are both Apple products and work perfectly, and the machine has no other performance issues. Just the dimming, which started a few weeks ago inexplicably and without warning.
I can't imagine what is causing this problem, and I've absolutely run out of ideas about how to fix it. One thought I had was that maybe the screen is dimming itself due to detected ambient illumination, but I'm not sure 2007 iMacs even have that feature, and also the screen remains dim whether the room is dark or bright. Maybe there is an ambient light detector somewhere that is malfunctioning?
Help! How can I solve this? The screen is not so dim as to be unusable, but it's annoying enough that I'll have to get a replacement machine if this is not fixed eventually.

Does an external display also act in a similar manner as the internal one?
Some earlier Intel-based iMacs had graphic processor card issues; not sure what
the symptoms of the majority of them were, but some had odd patterns, others
went black, and some would range from OK to totally unusable. Among others.
So there is a chance the graphic processor may be going out; or just the circuitry
that controls the backlight. An inverter may be weak or other circuit to the display
could be wearing out.
http://www.apple.com/retail/geniusbar/
If you have access to an Apple Store with Genius bar, they can perform some kinds
of diagnostic tests there even though the computer is out-of-warranty; that may be
of help to narrow down the cause of the symptoms you've noticed. They may not be
able to repair it, however, at an Apple Store; as it is rather old by today's standard.
An Apple Authorized Service Provider could do repairs and testing on older models
the Apple Store's Genius and other may not be set up to handle due to vintage.
Find an Apple Authorized Service Provider
Visit an Apple Retail Store
There is a country locator page to help find either of the above in regions outside
of the US & Canada, not sure how the above links would work; and it appears my
bookmarks to the country locator page may not be accessible now to post here.
You may be able to get an idea about what kinds of parts support the display
function by name by looking into an iFixit.com repair guide for your iMac series.
Hopefully the parts supporting the display are the reason it is dimming down, as
a graphic processor failure likely would exhibit other behaviors than just dimming.
PS: I see you've added content to your thread after I'd started working on this
& the answer likely is a hardware repair; professional testing is worth the time
and you seem to have at least one other thread on the same topic....
Good luck & happy computing!
edited 2x

Screening Dimming Problem

Hi everyone,
I find the "automatic dim display before sleep" to be very annoying. So naturally, I go into Energy Saver, and disable it. Ok, all is well, until I connect an external monitor/TV. Then even with or without the monitor connected AND the dimming check-box still deselected, my PowerBook's display defaults back to it's Auto-Dim setting. Argh, how can I fix this? Has anyone run into this problem?
I've tried the Terminal "pmset" option of changing the halfdim setting to 0 instead of 1, which is the same has using the Energy Saver option. Even after plugging and unplugging the ext. monitor, the screen dimmed after a while, and I verified in Terminal (pmset -g), that the value of halfdim was indeed still 0.
Thanks,
William
12" PowerBook G4/1.5GHz/SuperDrive/80GB/1.25GB RAM Mac OS X (10.4.7) 4G 20GB iPod, OWC Mercury Elite Pro 500GB FW HD, OWC Portable 80GB FW HD

Hi William, have you tried creating a test user and testing the behavior in the fresh account? If it behaves in the new user then delete ~/Library/Preferences/com.apple.systempreferences.plist then log out and back in or restart.
-mj
[email protected]
Message was edited by: macjack

IMac screen sharing problem

I have an iMac and a MacBook Pro both running Mavericks. I can screen share my MacBook's screen and see it on my iMac with no issues. But I get an error message when I try to screen share my iMac screen and see it on my MacBook's screen. I've tried turning off both firewalls. Setting are the same on both computers. Also, file sharing works perfectly on both computers.
This has been frustrating as I only really want to see my iMac screen from my MacBook Pro.

Hi,
As a Starting point go to iChat Menu > Preferences > Video Section and change the Bandwidth Drop down to 500kbps
Do this at both ends.
10:36 PM Friday; October 28, 2011
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
 G4/1GhzDual MDD (Leopard 10.5.8)
 MacBookPro 2Gb( 10.6.8)
 Mac OS X (10.6.8),
"Limit the Logs to the Bits above Binary Images."  No, Seriously

New 24" iMac Screen Brightness Problem

My new 24" iMac's screen is much brighter on the left side than on the right. What should I do? Surely this is not normal for an iMac. Did I get a defective screen? Please help! Thanks in advance!

I got a 24" iMac from Amazon and noticed the screen gradient after a few hours of use. Then I also noticed a stuck pixel in the middle of the screen. I was very bummed and after reading through forums I realized that this seems to be a common problem. I was getting prepared for 3 "geniuses" gathering around my iMac telling me that they can't see anything wrong with it and then me trying to sell it on ebay with a $500 loss.
But things turned out quite different for me.
I took the iMac to one of our 5! Apple Stores here in Houston and explained the gradient and the stuck pixel to the Genius. He turned the computer on, looked at it for about five seconds and says "yep", turns it off and starts typing away on his MacBook. Five minutes later I asked him what he was doing and he goes: "Oh, I'm replacing it." Me: "the screen?" Him:" No, the whole thing!"
I was overjoyed, I almost couldn't believe it.
They brought out a brand new box and I asked him if they would let me transfer my files. They agreed and handed me a FW cable. I checked the new iMac for any screen issues and it looked perfect. So I started the setup and let it do its thing. I decided to go get something eat with my daughter while the iMacs were transferring files. Got back an hour later and it was done. The new iMac started up in my user account and everything. But then I noticed a black dot that almost looked like a dead pixel but it appeared to be right behind the glass and not on the screen itself. I asked another genius (the first one had left) if he could remove the glass and try to clean it. Sure enough he went to get the suction cups and popped off the glass. The black dust speck was visible and easily removed. The glass got re-installed and I packed the new iMac back into the box.
I expressed my feeling of satisfaction and headed home.
At home I thoroughly inspected the screen again and it appears to be nearly perfect.
I'm very happy now. Apple sells their products for a premium and I my case I received premium customer service. Way to go!

24" iMac Screen Dim Humming

I have recently noticed that when my iMac's screen auto dims, a faint humming noise comes from within the iMac. Is this normal?

I have heard of this happening but I do not know how normal it actually it because mine does not do it. I would do a little forum searching because I know the topic has been discussed here before.
George

Mavericks screen dim problem

Every time my macbook starts dimming the screen, to then turn it off after a couple of seconds, if I move the mouse in that time interval (dim screen before it’s off), then I get a black screen and I have to restart to make it work again. I have had this problem several times with Mavericks, is there any way to solve it?
When I turn the macbook back on I get this message “Your computer was shut down because of a problem ….”

Hello marwandese,
Thank you for the details of the issue you are experiencing with your MacBook Air display.
I found an article with steps to troubleshoot issues with displays. This article is for internal and external displays, so you can skip any steps referring to an external display. I recommend reviewing the full article, but this step specifically stands out to me for the issue you described:
Reset the system
You can reset the Mac's parameter RAM and SMC.
You can find the full article here:
Apple computers: Troubleshooting issues with video on internal or external displays
http://support.apple.com/kb/ht1573
If the issue persists after following the steps in that article, I recommend following the steps in the following article:
OS X: When your computer spontaneously restarts or displays "Your computer restarted because of a problem."
http://support.apple.com/kb/TS4636
Thank you for posting in the Apple Support Communities.
Best,
Sheila M.

IMac screen dims immediately after logon

Have a weird problem with a 1-2 year old iMac. It's running Leopard, and as soon as anyone logs into it, the screen immediately jumps to it's lowest setting. This forces every user to open apple-->system preferences-->display to move the brightness setting back up to full. It doesn't matter who logs in, with their network account. How can we remove this behavior?

See if a PRAM reset helps.

IMac screen chessboard problem

Hi, I've got the old imac white from around 2008 and until now it was brilliant. But...yesterday a problem occured, after the initial aoole logo and the bluescreen this appears:
When I start the computer with the shift button the screen is ok. When in safe mode only the mouse pointer is affected- it has horizontal gray lines around it.
Any ideas?

Hello PalmerMac,
Yours is one of many such reports. Sadly because you are now out of both warranty and Apple Care (should you have had it), the cost of clearing it up will fall upon you.
Whatever else you may hear, unless you are truly competent, do not buy a glass screen and try to fit it yourself. Have the job done properly by an Apple retail store, or a premium re-seller.
Here is a link to a typical report ... Greyish Smudge marks behind the glass...: Apple Support Communities ...
Just look at the number of posts ... 940 and counting.

IMac Screen Dimming

About a week ago my screen started to randomly dim and then get bright again. The auto brightness is turned off. Its very random when it does it, Im worried the screen is starting to going bad or something. I purchansed the computer new at the end of 2011. Its a 27" iMac 2.7 GHz Intel Core i5, Graphics AMD Radeon HD 6770M 512 MB. Is anyone else having this issue? All of my software is up to date.

First, some commentary:
http://news.cnet.com/8301-13579_3-57609897-37/apple-sued-over-alleged-imac-scree n-dimming-issues/
https://discussions.apple.com/message/22938701#22938701
This issue results usually from two things: the brightness settings, or the graphics card. It seems you've already accounted for the brightness settings, so you might want to investigate the latter.

IMac screen backlight problem

Hi
I have a 6 month old (late 2011) iMac 27" 2.7-i5-4MB/1TB, the screen constantly blanks with the iMac still running and the screen still with content on (can just see if I shine a torch at it).
Hot corners off - sleep set to 30 mins
I can bring the screen back if I press shift-control-eject and move/click the mouse, sometimes this lasts for 5 sec sometimes for 10 min or more.
Why is the backlight doing this, its seems there is a hardware problem that is restored (temporarily I admit) by a software action, I cant believe changing the backlight will fix this.
Does anyone have a solution or is it a case of getting it back to the mac tech's???
Thanks
Victor

Your iMac should still be under AppleCare warranty.
Sounds like intermittent backlight connection.
Bring it back to an Apple store or authorized Apple repair facility to be diagnosed and repaired.

Imac screen dims and two browser windows flicker.

Not sure how to explain this, but when I have two browser windows open, at random, they start to flicker and the whole screen gets dim.
What can I do?
Thanks

I just noticed that when it happens, the mouse pointer stays with the hand icon.
Then when I move it to a window, that window goes dim.
Can someone explain this?
Thanks

Lenovo Tab S8 50 Screen Dimming Problem

Hello,
I have noticed that the screen is adjusting brightness depending what is on screen, bright or dark image. This is much more noticable in the lower brightness setting. I think that this is somekind of power saving feature of the Intel CPU/GPU. Maybe something like android version of Display Power Saving Technology.
Yoga 2 Pro, a windows device, has the same feature/problem but on windows there is a way to solve it. (https://forums.lenovo.com/t5/Yoga-Flex-Laptops-and/Yoga-2-Pro-Auto-brightness-feature-and-how-to-dis...
What about android?
Thanks,
Christos

Well I tried with this settings and I still have the problem but I think it is less noticable.
<ThrottleNormal>100</ThrottleNormal>
<ThrottleWarning>80</ThrottleWarning>
<ThrottleAlert>60</ThrottleAlert>
<ThrottleCritical>40</ThrottleCritical>
Now I am trying with all settings at same value:
<ThrottleNormal>40</ThrottleNormal>
<ThrottleWarning>40</ThrottleWarning>
<ThrottleAlert>40</ThrottleAlert>
<ThrottleCritical>40</ThrottleCritical>
For now I think it's working but I don't know for sure. Maybe a placebo effect! You can try so we can verify!
P.S. I have no Idea if this is safe for the device and I am starting to lose hope on lenovo, I mean I had to void my warranty (by rooting) to fix this tablet's problems.

Bedside Mode screen dim problem

I have set my phone on Bedside Mode for my alarm. The screen goes dim and the red numbers remain on screen. However, after 30 seconds or more, the screen goes completely black. I has assummed that the screen would remain on, in that dimmed state all night. Is there something wrong with how I have it set up? Is this normal behaviour. I kind of wanted to be able to look over and see what time it is in the middle of the night without having to press the power button.
any thoughts?

So when this happened to me, I discovered that in order to keep the clock on, you click off the phone from the top button, then back on again, then place your finger on the top of the screen and pull down the screen like a shade. That's it.
~diffused
Z10, OS Version 10.2.1.3253
Verizon

IMac screen going dim . . .

Lately my older imac screen has been somewhat dim when waking from sleep.... only happens sometimes, seems to be normally bright at the bottom, growing dimmer the further toward the top you look .... if I restart, everything is fine again.
Hardware problem? Seems unlikely since it seems unrelated to how long the computer has been on, it's immediately fine on restart. Any ideas appreciated . . .

Some problem with my iMac. Took it back to the Apple Reseller, they 'repaired' it after 3 weeks. Got it back, still the same problem. Called them and they said is was a normal buzz which the inverter card(?) makes, like the fan and the HD.

IMac screen dimming problem

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