Upgrading My iMac27 (11,3)

Aug 28, 2011
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Southeast Alabama
Your Mac's Specs
iMac 27 (11,3), 32GB RAM, 480GB SSD, 2 TB HD, Logitech Mac KB, Trackpad, 2 USB ext HDD (8 tb)
I began to have almost intolerable slowdowns in the past 6 months on my 3+ year old iMac27. Then it took a induced jolt via the phone line Christmas Eve that began to cause erratic behavior and closed down my Ethernet port. I could access Disk Utility with CMD-R but it froze and did nothing. It was time for action. I was out-of-extended-warranty, and realized I could upgrade some internal components. After talking with Tech Help at Other World Computing, I decided to add a new SSD + HDD to my iMac. Then do a clean install of OSX Yosemite 10.10.1 and start over.

I ordered an 120GB SSD (6G model) and a 2 TB WD Black HDD, along with the DIY install kits from OWC. I watched the install videos multiple times until I was sure I knew what I would see inside the iMac.

I decided to install the new HDD first, then the SDD. Again I watched the two install videos (HDD, SDD) and made a checklist of each item to do. With a little trepidation, I began opening the iMac. Not hard to do, but tedious. One problem was the magnets in the LCD screen---it was difficult to get the Torx T10 screws out with the included tweezers and driver. (small right angle hemostats or forceps would have been much better suited for this). But when removed the screen came out as I methodically disconnected the four cables from the screen to the motherboard. I did find that the box worked great for holding the glass front and the screen safely. When the screen is removed, I took pictures of the MB and cables along the top edge for reinstallation and reference.

Replacing the HDD was not difficult. I was pleased to see that Apple engineers shock mounted the HDD in special rubber crommets. The new 2 TB drive was exactly the same size as the old, and fit easily. I did not connect the cables because next it was time to install the SSD.

OWC figured out that their SSDs would fit to the right of the HDD behind the MB heatsink frame, and be held in place by supersticky double sided foam tape. (This was not difficult to do, but the data/power connectors need to at the top to connect properly.)

So I then approached undoing the screws holding the MB in place, disconnecting a couple more cables (all plug into the MB), so that I could pull the MB up and out along the upper edge and reach the SATA port on the upper back side of the MB. This was the difficult part, due to lack of visibility and my fat fingers, but with the help of my spouse, I got it connected. Routing the SATA cable up to the SSD was easy, but connecting the power splitters was more tricky (OWC, you should definitely pay to develop SMALL connectors such as you furnished to the HDD splitter). With some thought and ingenuity, the power cables and data cables were configured to fit in the limited space.

Then careful reassembly of the MB and cables, following the checklists in reverse, resulted in restoration of a correct assembly. (I used my phone to photograph the before appearance of the MB and cables to use as a reference). Then reinstall of the screen was done. Take my word for this. Lie the iMac down on its back to do the reinstallation of the screws on each side of the screen...the magnets make this a difficult job. You can magnetize the screwdrivers using the magnets by stroking them with the screwdriver heads...This helps. At last, you can clean the screen and the glass with the included lint-free cloth.

When I plugged the iMac in, and inserted the USB install drive into the USB port, I was rewarded with the Yosemite install menu. From that point on, it was a piece of cake.
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