Step 4: Upgrade the Interior RAM
The iMac’s internal RAM slot requires a PC133 SDRAM 168-pin SO-DIMM. To upgrade the RAM in this slot, pull apart the ejector tabs on the side of the RAM currently in the slot and lift out the RAM. Line up the notch in the new RAM with the key in the RAM slot. Insert the new RAM in the slot, and press down until the ejector tabs snap into place.
Step 5: Remove the Drive Carrier Assembly
In the upper portion of the iMac’s base is a large silver box. This is the drive carrier assembly—a bracket that holds both the optical drive and hard drive in place. Before removing it, rotate the iMac’s base so the Apple logo faces up.
Remove the two Torx-10 screws that hold the EMI shield in place (K) . A strip of copper tape attaches the EMI shield to the optical drive (L) . Peel this tape away from the optical drive, set it aside, and then gently pull off the EMI shield.
Remove the drive carrier assembly’s four Torx-10 screws (M) . Grip the assembly in both hands and firmly pull up and out. There are power cables attached to the assembly, so don’t pull so hard that you risk stressing these cables. Once the assembly is clear of the base, turn it to the right.
A white cable clip is attached to the top of the carrier assembly just above the optical drive. The video and AirPort antenna cables are routed through the clip. Press down on the cable clip to open it, and pull the cables away from the clip so the carrier assembly is no longer tethered to the iMac.
Detach the power cable that’s connected to the hard drive (N) . Pull gently but firmly on the connector , not the cable. (Pulling on the cable may damage it.)
Step 6: Remove the Hard Drive
The hard drive is covered by a white wrapper that’s sticky on one side. You must peel it away to access the screws that attach the hard drive to the carrier assembly. Carefully remove the wrapper (O) , and stick a couple of its corners to the outside of the iMac’s base to keep it from sticking to itself.
Detach the data cable from the hard drive and remove the four Torx-10 screws—two on each side of the assembly—that hold the hard drive in place P. Slip the drive out of the assembly and replace it (15-inch flat-panel iMacs use Ultra ATA/66 7,200-rpm hard drives by default).