Weird Grey Screen And Can't Get Start Up

G

guapagirl

Registered
Hi there,

I have an iMac (7 I think, it's the aluminium one) running Mavericks. When I went to turn it on today I got this on the screen. Ignore the moire stuff, it's the small pixel type things that run over the screen. I have tried the following:
Resetting the NVRAM
Resetting the SMC
Doing a safe boot

I have no idea where the original disk is. I fear it might have been thrown out accidentally.

Any other suggestions?

Thanks

Liz

ETA: when I do any of the above, it shuts down again when the progress bar gets to the end.
 

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This looks like either you have a hard drive failing or a video card malfunction. To test the hard drive follow the single user method in the blog post Your Mac Doesn't startup ... to see if you can fix the hard drive or not (then it will need to be replaced).
 
Thanks Satcomer, helpful as ever! :)

I'll try the Verbose mode as it looks a bit less mess-up-able than single mode.
 
I have the last line:
** Repairing volume

When it says the volume is repaired, do I type in "sudo nvram boot-args=" or "reboot"?

Black screens with white text fill me with horror that I'll do something wrong and eff the whole thing up!
 
ok, in single user mode it says

"incorrect number of thread records (4, 30733)
checking
repairing volume
rechecking volume
checking journaled HFS Plus volume. the volumes name is Mackintosh HD"

over and over and now finally it says the "volume could not be repaired after 3 attempts."

If I can find or get the original disk would that help?

If not, is there any chance of recovering anything from the HD?

If I get a new HD, what kind should i go for and how do I get OS back on? I do have a back up made a couple of months ago but assume I'd need to have the disk formatted?

Thanks :)
 
Well IMHO don't use Segate drives. Try to use externals to move your iTunes, pictures to an external and replace your hard drive with an SSD! This will give new life to your Mac!
 
If you're looking for a drive I'd recommend Hitachi. There new line is very fast. I've got a 2.5" 500GB in one of my systems and it's a lot faster. If it uses a 3.5" drive look for the newer models that use AF format because that's the fast family. I believe Western Digital has similar speed HDDs but I've never used them. You could of course also consider an SSD. Be careful and check the specs because there are still a lot of the unsold earlier types of drives out there and they often have very similar model numbers. The new lines all have big buffers (like 32M or more) and at least a 7200RPM spin speed.

Regarding drive problems I've found the set of articles in the following link useful:

http://scsc-online.com/DriveProblems.html

That's part of a set of other links describing a lot of different types of problems, but I think it's probably safe to guess that the drive is your problem.
 
Well I found the start up disk, but when I start up by holding down the C key, after the spinning icon, I get a dark grey screen saying I need to restart my computer. Except I can only shut it down completely, not restart it.

Booting with the option key down (found somewhere on the net) revealed a recovery disk, but hitting that doesn't seem to do anything any more than hitting the install icon. I just get the grey screen, apple logo and a non-spinning progress icon.

I'm guessing there is no chance of recovering any unbacked up data by using the back-ups on the external HD?
 
Sure you can try to get un-backed up data - if you have a bootable backup on your external HD.
How long did you wait to see if the recovery system will boot?
The other method to boot to the recovery system is to restart while holding Command-R.
Try waiting it out to see if it will eventually boot. 20 or 25 minutes should be long enough to give up on the drive.
If you don't get anywhere with that, the recovery system is a separate partition from your normal booting partition, and that's more evidence that the drive has gone south.
 
Ok, well I got a new hard drive. A WD black and tried with the original installation disk and got this: same old lines as before. Is it not the hard drive then?

I'm also attempting to make an install drive of Yosemite, but it's taking forever.

IMG_20150731_213739.jpg
 
Have you tried reseating the RAM sticks? Try swapping them between the slots. The install takes a very firm push to seat the sticks properly.

But, it really appears to be a video problem. You do have a replaceable graphics card in a 24-inch iMac, but it's a bear to change out. You have to remove the logic board completely, as the graphics card is mounted on the back side of the logic board. (And, you have to buy a replacement card somewhere. They are not always available, and will get worse as time goes on. It might be a grand moment to think about purchasing a replacement Mac. :D )
 
say it ain't so! Sadly a replacement is out of my reach financially at the moment :( Especially after forking out a couple of hundred quid trying to get it fixed already.

I suppose it is good news in a way in that the original hard drive is actually ok though?
 
It could be something on the built in video card!

Since this is an older iMac have you taken to local repair shop to have them clear it the dust out? Also some users have report over the years the video cards processors cover gel gets older and ause the video card to over heat. You might would have the local tech re-artic sliver the video card too.
 
heh, I sucked the dust out last night. I was quite shocked by how much there was.

I'm calling up the local mac techs on monday to see if they can do anything. Having looked online at possibilities of diy video card replacement, it looks like a no go for me to do, even if I can source one.
 
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