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?
Is this a good question?