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iMac 27 won't boot - gray screen issue

A

ami-

macrumors newbie
Original poster
Apr 21, 2015
9
0
Hi,
I have iMac 27 Mid 2011.
After pressing the power button, I can hear the startup chime, then apple logo shows up, then animation "ring" and then everything is gone and iMac stuck on grey screen.
You can watch the movie with this issue here.
Here is what I did:
1. SMC reset
2. PRAM reset
3. Safe boot - it ends on black screen, sometimes on grey and sometimes on blue. Here are the movies movie1, movie2
4. Hardware test - no fault found:
34q8i6f.jpg

5. Boot from install disk - the movie here
6. Recovery option acts the same as safe boot (3).
7. Boot on another Mac - I removed the hard drive from my iMac and attach it to other iMac using a USB adapter. The system starts perfectly! I made disk check and permission check using the disk utility - no faults.

Still no luck with my iMac :(

Can anybody help mi with that?
 
ami- said:
Hi,
I have iMac 27 Mid 2011.
After pressing the power button, I can hear the startup chime, then apple logo shows up, then animation "ring" and then everything is gone and iMac stuck on grey screen.
...
1. SMC reset
2. PRAM reset
3. Safe boot - it ends on black screen, sometimes on grey and sometimes on blue.
4. Hardware test - no fault found:
5. Boot from install disk - the movie
6. Recovery option acts the same as safe boot (3).
7. Boot on another Mac - I removed the hard drive from my iMac and attach it to other iMac using a USB adapter. The system starts perfectly! I made disk check and permission check using the disk utility - no faults.

Can anybody help mi with that?
Click to expand...

A couple of steps that I would try:
Can you boot into Single User mode? (Restart, holding Command-S)
You should see text scrolling down, ending with a command line. You can try fsck-fy
Then "exit"
If you still get nowhere, try a "verbose" boot, which is restarting with Command-V.
You will see mostly the same text scrolling as Single User mode, but should continue to boot. The text will show the various services as they load, and may stop at some point, where your boot stops. The text when it stops may be important.

You appear to be trying to boot to a Yosemite installer, and your Boot chooser screen shows that your Recovery system is Mountain Lion. Does your hard drive boot (if it was working) to Mountain Lion?
Have you tried booting to the original system installer DVD? That should be Snow Leopard, probably 10.6.6 or 10.6.7. If you have Apple's commercial installer for Snow Leopard, that won't work - you have to boot with the DVD that originally came in the box with your iMac when new.
Finally, your videos don't show a very long wait time (please don't post a video about this :D ), but does anything appear on the screen if you give it more time? 30 minutes should be long enough to determine that nothing else is going to happen
 
Hi,
thank you for quick response.
DeltaMac said:
Can you boot into Single User mode? (Restart, holding Command-S)
You should see text scrolling down, ending with a command line. You can try fsck-fy
Then "exit"
Click to expand...
Yes, I can. The fsck -fy result is:
"** The volume Macintosh HD appears to be OK.
*****The volume was modified *****"
DeltaMac said:
If you still get nowhere, try a "verbose" boot, which is restarting with Command-V.
You will see mostly the same text scrolling as Single User mode, but should continue to boot. The text will show the various services as they load, and may stop at some point, where your boot stops. The text when it stops may be important.
Click to expand...
Here is the movie with verbose boot.
DeltaMac said:
You appear to be trying to boot to a Yosemite installer, and your Boot chooser screen shows that your Recovery system is Mountain Lion. Does your hard drive boot (if it was working) to Mountain Lion?
Have you tried booting to the original system installer DVD? That should be Snow Leopard, probably 10.6.6 or 10.6.7. If you have Apple's commercial installer for Snow Leopard, that won't work - you have to boot with the DVD that originally came in the box with your iMac when new.
Click to expand...
Yes, the hard drive boot to Mountain Lion.
The Yosemite installer is an USB stick - I prepared it on other working iMac special for testing. I can't find the original DVD.

DeltaMac said:
Finally, your videos don't show a very long wait time (please don't post a video about this :D ), but does anything appear on the screen if you give it more time? 30 minutes should be long enough to determine that nothing else is going to happen
Click to expand...
Please do not worry, I do not put here 30 minutes of a gray screen video :)
Yes, I was waiting about an hour. My iMac was warm and constantly displays grey screen. Nothing else.
 
You said that your hardware test passed. Did you try both the standard test, and the extended test?
Do you have an SSD installed - OR - have you changed the internal configuration, such as removing or changing the DVD drive?

You SHOULD be able to boot to the Yosemite USB installer, assuming that it is prepared properly.
Have you tested that by booting to the USB installer on a different Mac?
If that doesn't actually boot another Mac, then you need to redo your USB installer.
If you know the USB is good, then _disconnect_ your iMac's internal hard drive.
Try booting to the USB installer with NO hard drive installed.

Obviously, you won't be able to install - but you just want to get booted to SOMETHING, just to know how that feels :D
 
My answers:
Yes, both hardware tests are passed with "no fault" result.
No, I don't have SSD installed. The configuration is original.
Yes, I have tested Yosemite USB on another iMac - it works fine.
I'll remove hard drive and try to boot from USB tomorrow. I'll let you know.
 
The grey screen CAN be a memory issue. Try reseating the RAM sticks.

Try disconnecting your DVD drive (this is probably not likely, but something to rule out... )

I don't think that the video card can be the issue, as you can boot to the hardware test.
 
RAM modules reseated without improvement. There are two modules. It's not work on single module too. Tomorrow I'll disconect the DVD drive.
 
Also, while you are inside the iMac, remove the battery (the coin battery on the logic board) for a minimum of one minute. That will fully reset the logic board.

Make sure that nothing else is connected to your iMac, other than the power cord, keyboard and mouse.
 
After bios reset (battery removal) is it required to make some initial settings (like in PC's)?
 
Apple doesn't use a BIOS.
There's nothing special that you have to do after a full hardware reset.
There's just the usual settings that would be lost with a battery replacement, such as time and date, boot volume selection, that type of thing.
 
DeltaMac said:
Also, while you are inside the iMac, remove the battery (the coin battery on the logic board) for a minimum of one minute. That will fully reset the logic board.

Make sure that nothing else is connected to your iMac, other than the power cord, keyboard and mouse.
Click to expand...

Still no luck.

SirYossi said:
the mid 2011 27" and some 21" imacs are having known graphics card issues

https://www.macrumors.com/2013/08/1...eplacement-program-for-mid-2011-27-inch-imac/

if you rule out hard drive and boot issues then it is graphics card issue.

I have a 21" mid 2011 2.7 ghz model and it shipped with OS X.7 Lion so not all these iMacs came with an install DVD with 10.6 mine did not.
Click to expand...

My iMac contain serial number with the last four characters of DHJQ so it is affected.

Unfortunately it is one year too late for replacement without cost. :(
 
ami- said:
...
My iMac contain serial number with the last four characters of DHJQ so it is affected.

Unfortunately it is one year too late for replacement without cost. :(
Click to expand...

Keep in mind that Apple sometimes will extend a repair to folks that are already out of warranty, or past the end of a repair program. It would be on a case-by-case basis. Even thought your unit is older, your model was still being sold less than 3 years ago, so the program itself is likely still active, and may even have a time extension. That information is not always made public.
It might be worth your time to actually call AppleCare, and get their final answer to your situation.
 
DeltaMac said:
Keep in mind that Apple sometimes will extend a repair to folks that are already out of warranty, or past the end of a repair program. It would be on a case-by-case basis. Even thought your unit is older, your model was still being sold less than 3 years ago, so the program itself is likely still active, and may even have a time extension. That information is not always made public.
It might be worth your time to actually call AppleCare, and get their final answer to your situation.
Click to expand...

Thank you for your advice and for the time you have consecrated for me.
 
Hi,
My iMac just came from repair.
It was repaired in the Graphic Card Replacement Program with no cost. :)

Thank you for all advices.
 
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