iMac 27" display sleep problem

Question

iMac 27" display sleep problem

Hi I have a iMac 27" running YOSEMITE 10.10.2 which has been told never to sleep under energy saver settings and Screen saver has been set to "Never" however every now and again the screen goes to sleep, or goes "dead". I have an external monitor I can connect which when it happened initially I was not using but I plugged in to find out if it was a screen or graphics card issue. when connected I had a picture even though the main screen was blank.

I then used "CMD" "F1" to mirror the main screen and was able to shut down the computer and then start up again and the main screen came back to life. This then happened again, so I called the Apple support desk and they had me remove ALL cables to the iMac including the power cable and hold the power button for 10 to 15 seconds to de-power something inside the computer, then connect the power and the keyboard only and reboot resetting the NVRAM by starting up with the "OPTION", "CMD", "R", & "P" keys depressed and wait till the startup bong occurred twice.

This appeared to fix it for 1 to 2 weeks when the problem came back as suggested, by Apple Support, I took it to the Apple store and they ran tests on it for 3 to 5 days and it did not do it so I collected it and it ran fine for another 2 weeks. Last week I upgraded the memory to 12GB (was 4GB) and when I booted it did not recognise the additional memory so I reset the NVRAM as detailed above and it recognised the memory however 2 days later the screen went to sleep again.

I made another trip to the Apple store and the Genius replicated the problem and we jointly thought it might be worth trying the backlight board which he did not have in stock so it is on order and I brought the computer home. However the genius suggested leaving the external screen connected all the time in extended mode to see what happened when/if the main screen went to sleep next.

When I got home I started the computer up and the Fans were whizzing away at full speed and I suspect as the power button is sticky for some reason it was depressed when I connected the power cord. After tracking down this problem, and resolution, I reset the NVRAM again and the problem with the fans and the screen appeared to disappear again. I then for 3 days made the computer work itself continuously when I was near it (I am using my Macbook Pro till I get to the bottom of the problem) and the problem did not manifest itself. Last night I left the iMAC playing a film that would finish at about 2 am this morning and this morning I came to the iMac with the main screen blank again but the external monitor was still up and running mouse travelled into it and back to main screen (which I could not see of course). When I used "CMD", "F1" to mirror the Screens the main screen woke up so I did not have to restart in order to get the main screen back this time.

I have just come off the phone with Apple Support and they are not sure if it is a hardware or software "glitch" and are supporting me! They are recommending I take the machine back to the Store with the further information but after discussion with the support Representative I have decided to remove the software as an Issue first. I plan to take out the 1TB drive and install a brand new 3 TB drive and install YOSEMITE direct from my YOSEMITE USB drive this should remove Software as any form of contributor to the problem. Alternatively I will install the original Snow Leopard and upgrade to Yosemite without installing anything else and reinstall all my Application programs fresh.

I would like any other constructive suggestions, please and will post further as I get further into resolving the issue

iMac (27-inch Mid 2010), OS X Yosemite (10.10.2)

Posted on Mar 1, 2015 4:56 AM

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Answer 1

Mar 3, 2015 4:08 AM in response to Duncan Stuart Elliott Parker

Further information:

Last night I decided to put the iMac 27" to sleep overnight and also put to sleep the Macbook Pro (Mid 2012) and the 21.5" iMac from 2010 (so the iMac is the same model series). So I chose apple symbol sleep on all three devices.

This morning I came to all three devices and the 21.5" iMac and the macBook both woke up by typing the right arrow on the keyboard. (In the case of the Macbook Pro a keyboard connected to a Thunderbolt Display) however the iMac 27" would not wake up so I had to hold the power switch to force a reboot which when it rebooted the operating system told me that the USB had not been ejected properly which is what I would expect from a forced reboot.

This is more and more looking like a firmware problem.

21.5 " iMac Boot ROM Version IM112.0057.B01 SMC Version (system) 1.64f5

27" iMac Boot ROM Version IM112.0057.B01 SMC Version (system) 1.59f2 (I suspect this might make a difference but have yet to check it out)

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Answer 2

Mar 3, 2015 5:37 AM in response to Duncan Stuart Elliott Parker

For information I have spoken to a gentleman called John at Apple Support and the PrincesHay store and when I go and pick up the 24” cinema display soon I am going to spend time down there reinstalling Yosemite from Scratch on a fresh 3TB Seagate Barracuda disk that I will install just before I go down there. Then if that still has the problem after the Snow Leopard disks arrive should the problem still exist I will try another hard disk with Snow Leopard and see if the problem still persists if it does then it has to be hardware related but I think it is worth trying each of the steps identified.

According to the store the firmware comes packaged with the operating system so they are suggesting a nice clean both download and install on a fresh disk. In conversation with Rob, he also suggested that Joe and my decision to look at a Backlight board could still be relevant as switching to mirror would involve a backlight and AVI refresh so could be a good indication "if" we are looking at hardware, It could of course also be the LCD screen.

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Answer 3

Mar 4, 2015 5:24 PM in response to Duncan Stuart Elliott Parker

Thanks for sharing your experience with us. Looking forward to hearing from you on your new findings using a different HD. Hope you could find the cause of the problem and the solution of it so we could learn hpw to solve our similar problem as well.

Oh, my Mac OS X on my iMac is 10.10.2.

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Answer 4

Mar 5, 2015 5:52 AM in response to Duncan Stuart Elliott Parker

Currently at the Apple Store PrincesHay in Exeter new disk installed Last night and a clean install from the stores 10.10.2 rebuild image straight onto the clean disk. Downloading all the applications fresh so no import from Time Machine. I will copy my personal data files etc across direct from the removed disk. So from here on there is nothing that has come from an pre-existing software version, including firmware. The BootROM and SMC are installed fresh when the operating system is installed apparently with the latest version that is supported for that particular machine.

I Will update either if the problem continues or on a weekly basis until I think it is cured if the problem does not re-occur.

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Answer 5

Apr 17, 2015 4:02 PM in response to Duncan Stuart Elliott Parker

My machine was getting worse, i.e. the screen turning black even before the machine finishing starting-up process. So I took it to a local Apple authorized repair shop. They found out the problem is a faulty Display LCD Panel. If I would like to replace it, it would cost Can.$780 (parts and labour, the labour is only about $60). So I decided NOT to repair it since I could get a brand new 21" iMac for Can.$1299 + Taxes. Then I realized that I might have a solution, i.e. how about I attach an external Monitor to the machine, would it work? I asked the technician at the repair shop, his answer is affirmative. So I picked up my machine (paying $56 for the repair work) and bought a 27" Acer LED Monitor ($280) and brought them home. After I set it up, the machine came to live and I am in business.

I just would like to share this experience with those who have similar problem.

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