iFixit

The audio line-in and audio line-out ports are embedded deeply inside the front bezel. After removing their mounting screws, we removed the entire assembly from the case.

Another leftover from the previous generation, the IR board, can simply be lifted straight up and removed from the iMac's front bezel.

Several Torx T10 screws hold the logic board in place. We make short work of them.

If you want to remove the board, you have to snake it out from the rest of the iMac -- a combination of pulling up, as well as away from the casing. After a little bit of jiggling, it comes right out.

Is it just us, or does the logic board layout (with heat sinks) look a bit like the original Starship Enterprise?

In usual Apple fashion, one heat sink is reserved for the CPU, while the other oversees the GPU.

And, in usual Apple fashion, you have to void the warranty in order to get a peep at the processing power underneath.

In the RAM department, this iMac has space for four 204-pin PC3-10600 SO-DIMM chips.

With a bit of magic, the GPU heat sink detaches from the logic board, exposing the AMD GPU.

The main chips on the GPU include:

• AMD Radeon HD 6750M GPU
• Four Hynix H5GQ1H24AFR T2L 1 Gb GDDR5 SDRAM chips (totaling a cumulative 512 MB)

We'll do almost anything in the name of science.

After popping off the CPU heat sink, we can get a good look at the Core i5 processor.

Our machine is powered by a quad core 2.5 GHz Core i5-2400S CPU with 6 MB of Intel Smart Cache.

Thankfully the CPU and GPU on this machine have proper amounts of thermal paste applied, a happy depature from the gobs applied to the MacBook Pro we recently took apart.

The main chips on the logic board include:

• 2.5 GHz quad-core Intel Core i5-2400S CPU with 6 MB of Intel Smart Cache.
• Intel BD82Z68 Platform Controller Hub
• Broadcom BCM57765B0KMLG Integrated Gigabit Ethernet and Memory Card Reader Controller
• Cirrus 4206BCNZ audio controller
• SMSC USX2061 (we believe this a USB 2.0 Hub Controller Family)
• Intersil ISL6364 CRZ Single-Phase Synchronous-Buck PWM voltage regulator for GPU core power applications
• Intel L102IA84 EFL Thunderbolt port IC

Next, we can remove the Bluetooth board from the iMac.

With the help of our trusty iFixit vise (which is made of the same material as our spudgers, and is ESD-safe), we're able to desolder the shield covering the little Bluetooth board to reveal the chip goodies underneath.

At its heart lies:

• Broadcom BCM2046 Bluetooth IC
• 256 KB of SST 39VF200A CMOS Multi-Purpose Flash (MPF)

  • We found this same chip a long time ago in the first MacBook Air.

iMac 21.5" EMC 2428 Repairability Score: 7 out of 10 (10 is easiest to repair)

• The front glass panel and LCD are quite easy to remove for accessing all the hardware underneath.
• RAM, hard drive, and optical drive can be replaced with relative ease, as long as you don't mind taking out the LCD (for the drives).
• Limited use of adhesives (pretty much all the fasteners are mechanical) make disassembly pretty straightforward.
• Replacing the CPU and GPU is possible to do, but you need to remove the logic board from the computer.
• Removing the logic board is a pain, since you have to disconnect a bunch of connectors, and wiggle it out of the machine.
• Making the LCD and glass spotless when reassembling the machine is nearly impossible. (compressed air is useful when trying to remove dust from the display or glass panel)

Like being able to see the guts of your machines? Check out our iPhone 4 transparent rear panel!