iMac only gives grey screen

[raymueller]

I only got a blue screen on iMac with OS10.6.8. In safe mode I did permissions repair with Disk Utility & in single user mode I did the fsck & mount -uw commands. I don't have separate start up disc. Still problems. Now get a grey screen with scattered tiny black rectangles. Any ideas?

 

[chscag]

Which iMac do you have, year and model? And, you should get a start up disk from Apple in order to do some testing. Snow Leopard 10.6 is only $19.99 from Apple. Give them a call and order the disk or order on line here.

 

[harryb2448]

No startup disc no diagnostics alas. As suggested buy one today.

 

[raymueller]

Thanks. I have ordered a start up disk. I have a 2011 iMac model iMac11,2, Inel core i3, 3.06 GHz, 4 GB RAM.

 

[chscag]

That particular model iMac (I owned one) had a lot of problems with the hard drive that Apple used. It's a proprietary hard drive made by Seagate and has a high failure rate. Mine failed and Apple replaced it for free with a Western Digital model. However, it's hard to tell from your symptoms whether it could be the hard drive or a problem with the graphics.

 

[johnodd4]

it sounds like a faulty logic board

 

[raymueller]

Thanks for the replies and info. I received Snow Leopard 10.6 and loaded the disk in safe mode. Then tried restarting holding down the C key but no luck. Get grey Apple logo and continue to get faint stripes in background. More ideas?

 

[chscag]

Can you start up in safe mode at all? And is there any warranty left on your 2011 iMac? I'm beginning to think the problem may be with the GPU which on that model is soldered to the logic board.

 

[raymueller]

Yes, I can start up in safe mode, and used it to back up our data. I don't know if any of this iMac is still under warranty.

Thanks.

 

[dtravis7]

With the Snow Leopard DVD in the drive, power on, just as you hear the chime hold and keep down the OPTION key. See if the OSX DVD shows up in that boot menu. If so select that and the arrow and see if the DVD then boots. If so do you still get the squares on the screen?

 

[raymueller]

Thanks. Did this and the OSX DVD did show up. I selected it, and heard a bit of sounds from it, but then nothing. Just the grey Apple logo and faint stripes the the background.

 

[ron4mac]

Turn off the computer, remove and re-insert the ram stick(s). Power up and see if there is any change (maybe try the DVD again).

[edit: only do this if you have some experience with this sort of thing]

 

[raymueller]

Thanks. I gave this a try. First time after doing it, the desktop came up using internal drive as usual! But then computer froze after trying to use it with some software (Skype). Tried it again, and with the DVD as startup, and re-inserted the 2 ram sticks into the other slots, and desktop has not come up again. Just get either small rectangles or the apple logo, always with faint stripes the the background.

Other ideas?

 

[ron4mac]

My guess here would be that either one of your ram sticks is faulty or there is a logic board problem. You could try booting the SL dvd with just one or the other ram sticks installed. You may be able to determine if one is bad.

 

[raymueller]

Tried booting with each ram stick individually, both with internal drive and with the DVD. Sorry to report that the results are the same as before. No desktop appears.

 

[johnodd4]

it's because you can't do that the 2011 iMac needs both sticks in order to boot

 

[raymueller]

If the problem is the logic board, then what?

Is their other troubleshooting I can do?

Any suggestions as to next steps are welcome.

Thanks.

 

[ron4mac]

My bad (so unlike me) ... johnodd4 is likely correct that it needs both slots populated.

Is it worth $55 for you to find out if it is just the memory?
Memory up to 32GB for Apple iMac 2011 Thunderbolt equipped models

 

[raymueller]

Yes, if there's a decent chance the problem is the memory. (BTW, I see now my iMac is 2010, not 2011).

When I boot in safe mode and go to About This Mac/More Info/Hardware/Memory, I see the 2GB DDDR3 memory cards with a line "Status: OK". Could they still be the problem?

Thanks again,
Ray

 

[chscag]

I don't think your problem is with the memory modules. It's rare for modules to fail after they've been in use for awhile. Not impossible but like I said, rare. It's beginning to look like you might have a logic board defect. Since you say you have a 2010 model instead of the 2011 you originally told us, that might change things somewhat.

I believe the graphics chipset in your model iMac is on a daughter card plugged into the logic board. That means if it is defective, it can be changed out. My advice at this point in time is to take your iMac to an Apple store and let the genius bar run diagnostics on it. If you take it to an Apple store there will be no charge for the diagnostics. If you use an authorized Apple service repair center they will charge for the diagnostics.