Chosen Solution
I just scored a 27"EMC for free, because it apparently has intermittent display issues. Also the p,o. did take out the HDD, instead of just transferring the data. Further I have no keyboard with it. Given that it is a gift horse I did not question the wisdom to take out the HDD, but just asked to be told what make and model it was, so I can replace it based on that info, as your most excellent site advises. Still awaiting the answer, WD or Toshiba I was hoping to boot up from an external drive before I get a new HDD, but have no keyboard either, to hold down my control button. So I guess, first, I need to know what is the appropriate keyboard for me to find, and is the boot-up from a time-machine external drive the same as in a MBP : press control after chime. And would this process work with a bluetooth keyboard…? I did a start up test, without the missing HDD and so far I am getting chime, fans surprisingly noisy going and just black screen. Any good advice is appreciated, to get this big boy to come back to life….
A standard Windows PC USB keyboard & mouse will work here. Hopefully you have one kicking around to borrow. For now when you power the system up shine a flashlight at a sharp angle towards the middle of the screen. What you want to look for is the faint image of a folder with a blinking question mark. If you do see it your issue is the backlight circuit. If you can you could also try plugging in an external display it should show you the blinking question mark. If you can’t see any image then you could have deeper issues. I would first make sure the system is viable before going too deep here. Update (04/12/2016) You’ll need to follow this IFIXIT guide to replace the HD: iMac Intel 27" EMC 2390 Hard Drive Replacement As to what HD to use you can use a standard 3.5" SATA II (3.0 Gb/s) drive but you’ll need this adapter: OWC Complete Hard Drive Upgrade Kit including tools for all iMac 2009-2010 Models. As you’ll need to replace the needed thermal sensor the custom HD’s Apple had. The next issue is creating a bootable drive. Here you’ll need to find a friend with a Mac to download from the App Store the OS installer. Then prep up a USB thumb drive (16 GB or larger) running Disk Utility to format the drive with a GUID partition map and create a journaled file system partition. Then run the installer program you downloaded to install the OS on to the drive. Once done copy over to the thumb drive the OS installer so you can repeat the process on the new drive once you boot up using this USB thumb drive.
