2009 iMac i7 27" clean install from USB won´t boot White screen

[Metallsau]

hi,

-my 2009 iMac stopped working. Beachballl Only.
- i could secure my data through Windows Safe Mode (only thing that worked)
- Put in a new 1tb SSD, as i thought maybe the HDD is broken. (HFS journaled GUID)
- bootable Yosemite and El Capitan USB Stick clean install (erased and Formated the SSD with Disk Utility)
- takes forever reboots like 2-3 times whilst installing and then
- Stuck on whitescreen.

- Restarting the mac, the installation kinda worked because there is now
not only the bootable usb drive but Mac and Mac recovery.
- opened Disk utility and Checked the MAC installation no ... harms

anyways it won´t boot.

maybe there is a hardware defect?

broken RAM like it can install but not boot OSX properly?
(i ordered 8GB to test in a few days)

Power Supply, GPU and CPU should be safe otherwise the Mac couldn´t
produce a picture, or do anything even in Windows Safe mode with the old HDD installed, right?

HELP guys i am very desperate.


Thanks

 

[ElCani]

Does the OS install off the USB? I had problems with a 2007 iMac when I upgraded it to an SSD (wouldn't boot off the USB installer so I couldn't install the OS) and in the end the only way I got it to work was to install the OS on to the SSD via a caddy and another Mac, then put the SSD into the iMac. Worked fine ever since.

 

[Metallsau]

Update:

the installation worked, as the Mac partition and Recovery pops up after the
clean install on the new SSD with Bootable USB Stick.

it will stuck on the Boot (whitescreen) UNLESS i am taking it into
Safe Mode, then it turns on Yosemite so i guess the install was complete.

i googled a bit and it seems the AMD Radeon 4850 512mb i have could be the problem.
i need to take it out bake it and it should be good to go for the next months even years.




@ElCani i only have a 2009 Macbook, i think i cold not install OSX that way.
did you have the exact same iMac to do what you did? i thought otherwise the installation
wouldn´t work due to other hardware

 

[nambuccaheadsau]

Also what did you use to make the thumb drives bootable - DiskMakerX? Each version is OS independent.

 

[ElCani]

Update:

the installation worked, as the Mac partition and Recovery pops up after the
clean install on the new SSD with Bootable USB Stick.

it will stuck on the Boot (whitescreen) UNLESS i am taking it into
Safe Mode, then it turns on Yosemite so i guess the install was complete.

i googled a bit and it seems the AMD Radeon 4850 512mb i have could be the problem.
i need to take it out bake it and it should be good to go for the next months even years.




@ElCani i only have a 2009 Macbook, i think i cold not install OSX that way.
did you have the exact same iMac to do what you did? i thought otherwise the installation
wouldn´t work due to other hardware

Nope, it wasn’t the same Mac. Here’s the thread I started when I had the problem.

Replaced HDD with SSD on 2007 iMac, now won't boot past white screen (with cursor)

Hi. I have just replaced the HDD on a 2007 iMac with a Kingston 240GB SSD. I followed the iFixit guide and everything appeared to go smoothly. However when I try to boot the Mac into start-up mode (holding down the Option key) it get's stuck on a white screen with a movable cursor. All other...

forums.macrumors.com

 

[Metallsau]

Also what did you use to make the thumb drives bootable - DiskMakerX? Each version is OS independent.

i used the Terminal Code given by the official Apple site.

i found the Problem.

the GPU failed and caused my iMAc to stop at the Bootlogo.
So the OSX installation from the Bootable USB stick worked although it took forever.

once i could enter the OS in Safe mode (hold Shift) i knew the OS installed properly.

so i knew it was defective Hardware and i startet googling towards this.
and found out you could bake the GPU at 200° Celsius for 10 minutes.
Which basically melts the old broken Solder, causing the problem, to a new working
state.

started the mac back up with the new SSD installed and it runs like hell.