Model A1312 / Mid 2010 / 3.2 GHz Core i3 or 2.8 & 3.6 GHz Core i5 or 2.93 GHz Core i7, ID iMac11,3

291 Questions View all

White screen & black screen flashing, HDD or GPU? Reballing?

Recently I was having problems with my iMac, after working for a while it would overheat & the screen would shut off so I'd have to save and force a shut down.

I installed TG Pro and that really helped - I could finally turn the brightness up above the lowest setting!

Now the day after it won't boot up the screen turns white after about 50% of loading. It then turns black and flashes back on & off where I briefly see the apple logo the loading bar half full and the spokes loading logo in-between the two.

Caps-Lock works when i'm white screened / flashing.

I am out of warrantee don't have Apple Care and live in the actual middle of nowhere without transport.

So far I have;

PRAM reset (Cmd+Opt+P+R),

SMC reset (unplugged power for a while & held down power button for 5 - 10 seconds),

Repaired the disks via Disk Utility (Option) but still wouldn't boot from HD or Recovery,

Tried Booting in Safe Mode (Shift) this loaded further to maybe 85% and hung on the loading screen with Spokes frozen before flashing on & off again.

Removed RAM and powered up where I hear the beeps repeating,

Tried to run an Apple Hardware Test (Option + D) over WiFi but I received the error "Apple Hardware Test Does Not Support This Machine" - I can't perform an EFI Firmware update as I don't have the disks,

Entered sIngle user mode (Cmd+S) as I read somewhere about running fsck -fy on boot disk to recover the data but I got scared and "reboot"ed

I have read a lot about the GPU on later models being faulty and have also been told it could be an issue with my startup drive? While in Disk Utility I noticed my startup drive only has 5GB free & I read that it needs around 9GB free to startup?

I am going to try to recover my data via Firewire and my MacBook Pro with Target Disk Mode (T) and potentially attempt to reball the GPU in an oven before I submit to spending nearly £500 for a new one to be sourced and fitted.

Before I do anything silly with my oven can anyone suggest anything that I've missed or that could help?



Answered! View the answer I have this problem too

Is this a good question?

Score 0
Add a comment

2 Answers

Chosen Solution

First don't put it in the oven, you have no control. Conversely, Think of trying to cook muffins with a blow torch.

To recover your hard drive data (incidentally your drive may be fine) get a universal adapter or a 3.5" external enclosure.

Universal Drive Adapter

Examine the diagnostic LEDs and tell us what you find. Finally don't get in a hurry here! Let's do the diagnostics, determine the real issue, which sounds like your GPU, get you to the right tools to do the job correctly. I do this everyday.

Here's the tool:

Universal Drive Adapter Image


Universal Drive Adapter


Was this answer helpful?

Score 3


Thanks a lot for this @mayer I think I have access to an air gun thru my neighbor and have a soldering iron here.

As for the diagnostic LEDs am I taking the screen off and looking on the logic board to see if any of the four are unlit?

Is there a way I can access the drives before hand to move some stuff over to my SSD?


I can see at least 3, the 1st is on when the power cable is in. 2nd when the power button is pressed & a third when the chime happens. I have the screen out right now so no 4th?


I have also moved around 10 - 12 GB of data off the startup drive while in Target Disk mode but I still won't boot up. Is it safe to assume it is a problem with the GPU now?


No, you will need to hook up the screen and see if the final LED lights. Personally I'd disconnect the internal hard drive and see if you can boot from a clean install on another drive. We still don't know if it is a hardware or software issue. Also to check the GPU you can hook up an external monitor after you know you have a clean boot drive.


Okay, would booting off a TM backup on external HD work or would I have to disconnect my startup disk?

I have had an external monitor plugged in and it mirrored the screen issues I was having.


Show 1 more comment

Add a comment

If you have another PC/Mac it should be easy to take out the sata drive from your Mac and install it on your other computer for backup. Problem is most likely not with the GPU, but it could be with the ram. Take the ram out and put it back in.

Was this answer helpful?

Score 0
Add a comment

Add your answer

Jackson Almond will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 3

Past 30 Days: 16

All Time: 587