Imac display won't power up or stay on when it does

imac display won't power up or stay on when it does

Have you checked the Energy Saver settings? System Preferences / Energy Saver.
If the settings are what you want, you can try this. Change them to anything at all then change them back to what you want. The restart the computer and reset the PRAM.
Shut down your Mac.
Locate the following keys on the keyboard: Command (⌘), Option, P, and R. You will need to hold these keys down simultaneously in step 4.
Turn on the computer.
Press and hold the Command-Option-P-R keys before the gray screen appears.
Hold the keys down until the computer restarts and you hear the startup sound for the second time.
Release the keys.

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IMac G4 won't power on

Hi,
I have an iMac G4 1.25Ghz that I have dissemble to upgrade the hd and now it won't power on. It just start and does nothing, no chime but you can hear the fan spinning. Could it be something I forgot to do when I open it? The first time I when to boot up the dvd it froze and after that nothing works except the fan spinning.
Thanks
ChicoSmile

Hmm, hard drive seems not to be the problem. Have you checked all cable connections inside?

My iphone won't power down and stays on all the time. I have rebooted but it still wont power down. any solutions?

My iphone stays on all the time and won't power down. I have tried rebooting but it still won't power down. any suggestions?

i mean that after i use my phone it won't go to a black screen after a few minutes...i guess maybe its called to 'sleep' but the screen stays bright...the light doesnt dim.

23 inch hd display won't power up

After not using my G5 dual 2.7 for 3 weeks, i powered it up and the display remained black. the only hint that something was getting to the display was two quick blinks and a pause that repeated on the inrared on the mouse....keyboard was dead too. the screen turned on once after several restarts but remained blank after restarting again. i plugged into my powerbook with the same symptom. i have a 20 inch display that fired up fine on the tower so i ruled out the video card ( or so i speculate). what i discovered was by unplugging the power from the display to the power supply and plugging it back in , the screen came to life and stayed on until i shut down again. i duplicated this on the powerbook also. anyone hear of this? wouldn't think the power supply would have an affect but obviosly it does. I have a radeon 9650 in the computer.....any thoughts?

sorry i posted this question in the incorrect forum

IMac DV won't power up

My iMac DV 400 won't power up. When I press the power button, the light comes on for a second or so, and I can faintly hear the drive start to spin up but then before the computer is able to check any other hardware, before it makes the standard "bong" sound, it just shuts off. I can hear it make a faint clicking sound just before it shuts off. Sounds like a switch is opening. If I press the power button again, nothing happens. I have to unplug the computer and plug it back in to try to power up again, but it just does the same thing.
The computer is plugged directly into the wall (not through a ups or any other device). I tried with a different power cord, but no impact.
Any ideas for what to do to correct this problem?

I have heard reports suggesting that a problematic PMMU can cause the logic board battery to run down in a matter of days. At least, I recall an Apple Knowledgebase article about Power Mac G4's that said a crashed PMMU, if left in that state, drains battery in 4-6 days. I don't know if this applies to the iMac, but logic board batteries are cheap and worth a try.
If you have already updated the firmware for OS X, then there is no need to do it again. The current firmware updater is the one that's posted to Apple's site. It has not changed since 2001.
You can try the usual things that people try when machines don't power on: reseat RAM, swap out RAM, remove and reinstall the logic board, blow on it, whack it, dust it (not with a vacuum -- with canned air), check connections, check fuses on the analog board, disconnect all drives, replace the drive with a test one to see if the drive is the problem, etc.
If these are not the problem, you can repeat some steps (to see if it is an intermittant fault). Otherwise, you will need to download the appropriate service manual from this page:
http://www.whoopis.com/computer_repair/
Detailed therein is the way in which you can test (using a voltmeter, and with extreme care) whether the analog board/the power supply are good. Conducting this test will require you to have the machine powered on and will put you inches away from 26kV of voltage used to drive the CRT (at the back of the tube and on some of the components). Personally, I have never done this because I consider it too risky. If you are experienced with electronics, go ahead, otherwise I'd wait until someone else on the forum take a look at this and suggest things that I might have missed.
Based on what you said though -- clicking sounds, and power off shortly after powering up, I am guessing an internal short somewhere is causing a safety mechanism to trip out and power down your computer, esp. when it will ignore the power button. Check for a loose screw (pick it up and jiggle it, do you hear a loose part?) Check for things that might be causing a short. If you don't see anything obvious then it might be a component failure (specifically, a capacitor, a chip, or the flyback transformer we talked about earlier) that is causing the shorts. Tracing component-level faults in an iMac is beyond my technical expertise.
The iMac I picked up curbside has a screw loose. So far I haven't been able to find it, but it isn't causing any shorts, so I just left it.

Thunderbolt display won't power up at all

Hi I recently purchased a new 2.5ghz i5 mac mini and a thunderbolt display and when i plugged it all in the display wont power up all. Tried the hdmi connection on my hdtv and it worked fine. Tried a display port to hdmi adapter in the thunderbolt port to my hdtv and that worked fine. updated the mini to the latest software, checked all the cables, reset the pram still can't get it to power up. Am i missing something? There is no power button on the display that i can see, from what i understand it is supposed to come on when the mac powers up. For all the people that own a working thunderbolt display when going does it make any kind of noise or anything that you can tell that it is going, apart from a picture being on the screen. Because mine is seems to be dead doesnt make a sound, screen is blank. So far its a worthless piece of junk & i'm 3hrs away from the nearest apple store to get a replacement or get it fixed. Really starting to wonder about purchasing anything apple, just have one problem after another, first it was the apple wireless keyboard not pairing with lion os now this. Any help appreciated

I suppose the TB cable could have gone bad. If you get a another TB cable and plug it in from your MBP to the TB port of the display and see what happens. If it powers up and all ports work then it means the built in cable is bad. If nothing happens means the TBD is dead and will require repair.

IMac Second Display won't power down

I've added an LG 20" widescreen as a second display for my 20" Intel iMac (white). When the iMac sleeps or powers down, the LG display goes blank but not black, power button remains on and a "check signal cable" message displays.
A second problem is that I've been trying to get the two displays to look the same, color-wise. The color match option under displays>color gets it close, but that option has disappeared from the list of choices. Before, I could choose from the LG color settings as well as several generic choices (Color match, Adobe RGB, etc.) Those other choices have gone away. The calibrate option is still there. I just upgraded to Leopard. Did that have anything to do with it or was it just a coincidence?

Have you checked the Energy Saver settings? System Preferences / Energy Saver.
If the settings are what you want, you can try this. Change them to anything at all then change them back to what you want. The restart the computer and reset the PRAM.
Shut down your Mac.
Locate the following keys on the keyboard: Command (⌘), Option, P, and R. You will need to hold these keys down simultaneously in step 4.
Turn on the computer.
Press and hold the Command-Option-P-R keys before the gray screen appears.
Hold the keys down until the computer restarts and you hear the startup sound for the second time.
Release the keys.

IMac display won't stay asleep while encoding with iDVD

My iMac's display refuses to stay in sleep mode while I am encoding a project in iDVD. (Note that I'm referring to sleeping the display, not the entire computer.) I encode large projects overnight, and I am concerned about possible burn-in, the annoyance of the unwanted light when I'm trying to sleep, and the waste of energy. A search of the archives reveals a long history of the same problem which unfortunately has remained unsolved.
I have tried the following with no success:
1. Ruled out accidental mouse/keyboard strokes as the problem
2. Used Hot Corners to initiate sleep (wakes back up after 5 seconds)
3. Setting the sleep display timer to 1 minute in the Energy Saving settings
4. 3rd party app and widget "Sleep Display" (only works for 10.4 Tiger apparently)
Does anyone have any new ideas about this bug/problem? Does it only affect iMacs?
Thanks

rfarwell5 wrote:
there is no activity besides the encoding that is waking up the monitor. I
How can you be sure? It may be some system operation that's doing it.
This may also prevent the display from sleeping, but the next time you're doing this you might launch Activity Monitor and order the process list by CPU. Then when the display wakes up, note what processes (besides the DVD encoding software) are using non-trivial amounts of CPU time.

IMac display won't wake up

I recently replaced the HD on my iMac Graphite 600mhz G3 and all was well until the other day it wouldn't wake up from sleep ... the light on the on/off button was not pulsing so the HD wasn't asleep. Now the display will not wake up whenever it goes to sleep and I have to restart with the power button every time. Also when I plug my iPod in it crashes from time to time and I get the message to 'restart by pressing on/off switch for 5 seconds' message. Is there a firmware update I need? I zeroed the new drive from the Panther install disc. Or is it something else. Please help!

If your Mac happily goes to sleep but won't wake up--Hold down the power switch to force-reboot your machine and get it running again.
Don't worry-your Mac isn't narcoleptic. Its Open Firmware system or NVRAM (nonvolatile RAM) is likely corrupt, and your Mac can't remember how to wake up.
Restart your Mac and immediately hold down the Command-Option-O-F key combo until you see a somewhat intimidating command-line display that ends with the Open Fimware prompt. Type the following lines:
reset-nvram
press Return on keyboard
set-defaults
press Return
reset-all
press Return
Your Mac will reboot. Once it's running, put it back to sleep to test. If the problem recurs your Energy Saver preferences may be the culprit. Delete the com.apple.PowerManagement.plist file (go to Finder/Hard drive/Library/Preferences/SystemConfiguration)--don't worry, your Mac will regenerate a new one--and then restart to see if that rights the wrong.
Still did'nt work? Might be time to call AppleCare or see an Apple Genius or a technician.
Cheers!
DALE

New iMac display won't sleep?

Hi, new iMac 24", 10.5.7, set screen saver at 5 minutes, and display to sleep at 10 minutes. Screen saver works, but it will not sleep. I've changed the setting, and rebooted, still no luck.
I tried everything from suggestions, with no help. I found that if I turn off "screen sharing" in system preferences, it will sleep the display for whatever minutes I set. I have to leave "screen sharing" on because I have flat screen tv hooked up to watch video files on, and I use iPhone app to control screen, to hit play and pause, etc. It is set up with a password, and only my iPhone is used when I am watching something. Why should screen sharing stop display from sleeping? I've left screen sharing on since I got this, so I can remotely log in with "back to my mac" from the road, and it never stopped the display from sleeping before? I shouldn't have to turn off screen sharing just to sleep the display? Am I missing something?

This is for a Mac that won't sleep.
Here is KB article HT1776 with their tips.
Mine follow;
USB devices and hubs often cause Macs to not sleep or wake quickly from sleep (notably HP printers and scanners, HP all in ones, and Cannon scanners). Disconnect all USB except for keyboard and mouse and try. If it sleeps, add one back at a time testing after each one to find the culprit.
If you've set your Mac to receive faxes, it may not be able to sleep. It might also have a damaged preferences file.
If you use your Mac for faxing, open System Preferences. click Print & Fax, click the Faxing tab, and uncheck the Receive Faxes On This Computer box.If that doesn't work or you've never faxed on your Mac, go to Finder/Hard Drive /Library/Preferences/SystemConfiguration and delete the com.apple.PowerManagement.plist and com..apple.AutoWake.plist files (if your Mac asks, type your admin. password).
If the latter file isn't present in the folder, go to user name(probably your name)/Library/Preferences, delete the com.apple.systemuiserver.plist file, and reboot your Mac.
Hope this helps!
P.S. One member here reported this (Michael Gleason);
"I have had this problem with my IMac G5. It is surprisingly irritating. LaCie's Silverkeeper backup software was the cause. By default it gave itself permission to wake up the computer to check if a backup was needed. Do you have this or a similar program installed which has scheduled activities including wake-up permissions as an option?"
Dave Hamilton provided this link, xlr8yourmac.com, to a member, which addresses failure of deep sleep with some users that updated and added new FireWire and USB card.
Also, here is Apple KB article TA2469 about PCI cards and sleep.
tomhorvat adds this; After few days of messing around I found out that I had desktop background (wallpaper) set to change every 1 minute.
After unchecking "Change picture..." in system preferences (under Desktop/Screen saver), my powerbook went to sleep all by itself.
Tristan Currier noticed this; "I have a Canon printer(shared) and my imac would not sleep. I opened up printer/fax in system prefs and noticed it said the printer was in use when it was off. Opened up the printer queue and noticed about 7 pending documents. Deleted them all and now it sleeps.
Check the printer queue!"
Allan Jones says "sometimes there is Network activity: launch System Preferences > Energy Saver > "Options" tab and uncheck "Wake for Ethernet network administrator access."
Good Luck!  DALE

IMac Intermittently Won't power on...bad heat sensor maybe?

So, I have a mid-2011 iMac 21.5" that I am having some apparent power issues with.
Note : About 8-10 months ago, I had the screen replaced under AppleCare due to a discoloration that started in the upper left corner of the LCD. I am not sure if this has any relevance, but wanted it included.
A couple months before this, I was experiencing an issue where the Mac would shut down on its own, hard, and then wouldn't turn back on. No bios post, no chime, no CD-rom noise, no nothing. I thought something was fried, and became very worried. I unplugged it for several days, and setup a Genius bar appointment. Before going, I decided to plug it in and try one more time. To my surprise, it worked and booted as if nothing at all was wrong. It ran for several days, and then did the same exact same thing. Turned off, wouldn't turn back on, left it unplugged for several hours, came back, worked fine. It continued this process for about a week or so off and on, as I troubleshot, but then eventually just stopped occurring and worked great.
Then a few weeks later the LCD went bad as described above, so I had it replaced. All was still fine after getting it back. We moved to a new home, and didn't have any issues for about 6 months or so, until the last 2 weeks, when the issue has started again, and is much more frequent. At this point, if I plug the iMac in, it will last for only about an hour at most, then will not turn back on until I leave the power cord unplugged for a couple of hours. I am testing it currently with varying amounts of time having the power cord unplugged. For example, incident occurred and I unplugged for 30 minutes. I then tried to plug in and turn on, and was greeted with the CD-Rom sound, and about half a chime, then it died. Almost like it is "charging" something inside that isn't holding power maybe...? I have entertained the thought that maybe the heat sensor either is going bad, or maybe it is getting hot inside, causing it to turn off, although I must say, the outside of the casing of the iMac is literally cool to the touch. For the past 6 months, the computer has been stored and used in a half-finished basement room, that at times can get to as low as 55-60 degrees fahrenheit, again not sure if that has any relevance.
I have tried resetting the SMC obviously by leaving it unplugged for so long, and I have tried resetting the PRAM/NVRAM by holding COMMAND+OPTION+P+R until the computer reboots, but this has had no effect on the machine and this issue.
I assume that since it won't even post to the Bios or chime, that this is likely not a hard disk issue? My biggest fear would be logic board of course.
My next step in troubleshooting is going to be to leave it unplugged for the next few hours, then hopefully get it to boot, install a temp monitoring program like iStatMenus or iStatPro and monitor to see if it is reporting a steep temperature increase, and go from there. If it is reporting a high hard disk temp, then I can try booting from an external hard disk and see if that has any different effect.
Anyone else have experience with this? If the temperature isn't actually high, but just reporting high, then I assume I will need to replace the Ambient Temperature Sensor, which looks fairly involved based on the iFixit article, would possibly look at having Genius Bar perform. Is there a way to disable the temp sensor temporarily to see if this is possibly the cause of the issue? I assume not, since if used incorrectly, you could seriously damage your machine.
Thank you everyone,

Unfortunately there is no cheap way to diagnose, I don't believe Apple charges for a diagnostic however it does require you take the machine to be looked at. You can also speak to an AASP and find out what they charge for a diagnositic, however even if you are able to physically do the repair yourself you have to locate the part(s( and Apple does not sell individual parts to consumers, they only do this to AASPs. However you can look on E-Bay but then a) aren't sure the part you buy is OK and b) are not 100% sure the part you buy is the offending part(s).
In short, it's probably cheaper to have a professional diagnose the issue and fix it.
Good luck!

IMac G5 won't power up...HELP!!

So I've just moved and my iMac(purchased Nov. 04) won't turn on. I've had this problem before when I installed and Airport Extreme card a few weeks ago, but it turned on after a few hours. Now it has been a few days. At first I had everything plugged into it, I've unplugged that all except the keyboard/mouse. The surge protector is working fine and the outlet it is in is working. Any thoughts on what I can do to get it to work? Or will I have to spend Sunday at the Genious Bar? Thanks alot.
Dave
p.s. Is that what the genious bar is for, taking in broken equipment? cuz I never really understood that. I'm assuming it doesn't cost anything for me to take it to them, but if it's the power supply then of course I'll have to pay for repairs.

So I'm having the same problem. It happened once when I woke it up from sleep, the power shutdown by itself. I couln't turn it on at all. I opened the back and put it back on without doing anything else, then it turned on. After 2 days, the same thing happened. So I read about that extended warranty and brought it to a sevice provider. I am covered by that warranty and looking forward to getting it fixed. I was glad that it failed before my 2 years is up, I think this fall is my 2 years. It's been in the shop for 3 days now and I hear the bad news. They say that they couldn't duplicate the problem, so I would have to pay for the 94 dollars that they will charge me for labor. They will be observing my computer till the end of the day then I'll pick it up. I'm crossing my fingers that it fails so I don't have to pay them and that they charge Apple for it. Any suggestions on what I should do if they don't find a prblem and if it breaks again on me.

IMac A1195 won't power up

My old 17" iMac won't respond at all: no sounds, no lights, no activity of any kind. Likely the power supply is bad. But two different power supplies are available: one for A1195 with EMC number 2124, the other for all those with other EMC numbers.
How do I find the EMC number?
Thanks.

Here you go hen4ry
http://www.everymac.com/mac-identification/where-to-find-apple-emc-numbers-for-m ac-identification.html
Yours could be a 2110 or a 2124. Examine its case to determine which one - there should be a label on its bottom.
Failure to power up could be as simple a bad PRAM battery, so check that as well.

IMac display won't sleep with hot corner

I saw that this question was asked before but no answer was given. I got my iMac OS X Yosemite 10.10 brand new yesterday. I set up hot corners so that the display will go to sleep when I swipe it. However, no matter how carefully I swipe, it always comes right back on. I cannot get the display to sleep.
What am I doing wrong? Your advice would be appreciated.

You have 90 days of free telephone support with AppleCare, you can get started by clicking Contact Apple for support and service - Apple Support

30" Cinema and 24" IMac displays won't display the same color

I have a 30" Cinema Display on my Mac Pro and I am using a 24" iMac. I calibrated both monitors with Eye-one-Match3. I am using the same color profiles in Corel Painter and Photoshop and I am still getting different color values in my file. On the iMac the colors seem a bit darker and more saturated than on my Apple Cinema Display. How can that be?
Any help would be appreciated

Sounds like a video card issue.

Imac display won't power up or stay on when it does

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