iMac Intel 21.5" EMC 2428 CPU Replacement

Replace the CPU in your iMac Intel 21.5" EMC 2428.

Use this guide to upgrade your CPU.

Sections
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Edit Step 1 Access Door  ¶ 

  • Lay your iMac face-down on a soft, clean surface as shown.

  • Be sure there isn't any dirt or debris on your work surface, as it may scratch the glass panel on the front of your iMac. We recommend placing a towel between the iMac and the work surface.

  • Loosen the three Phillips screws securing the access door to the bottom edge of your iMac.

  • All three screws will remain captive in the access door.

  • Remove the access door.

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Edit Step 2 RAM  ¶ 

  • Gently slide the black plastic RAM pull tab out from the RAM slot.

  • Pull the black plastic tab away from the bottom edge of the iMac to eject the module(s) on that side of the RAM bay.

  • This may require a bit of force.

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Edit Step 3  ¶ 

  • Slide the old RAM module(s) out of their slots in the RAM bay and set them aside.

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Edit Step 4  ¶ 

  • Repeat the process in the previous steps to remove the RAM module(s) from the other side of the RAM bay.

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Edit Step 5  ¶ 

  • When installing new RAM modules, it is important to orient them correctly.

  • Be sure the small notch cut into each RAM module (shown in the first picture) mates with the protrusion in each RAM slot (shown in the second picture).

  • Your iMac has four RAM slots. Be sure to slide each RAM module into its slot horizontally. This will prevent getting the modules stuck between two of the adjacent slots.

  • Once you have oriented the new RAM modules correctly, gently slide them completely into the iMac and use your thumbs to firmly seat them in their sockets.

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Edit Step 6 Glass Panel  ¶ 

  • Before beginning, unplug your iMac and lay it on a soft surface as shown.

  • Stick a suction cup near each of the two top corners of the glass panel.

  • To attach the suction cups we sell, first position the suction cup with the movable handle parallel to the face of the glass panel. While lightly holding the suction cup against the glass, raise the movable handle until it is parallel with the other handle.

  • If your suction cups refuse to stick, try cleaning both the glass panel and the suction cup with a mild solvent.

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Edit Step 7  ¶ 

  • Gently lift the glass panel perpendicular to the face of the LCD enough to clear the steel mounting pins attached along the underside of the top edge of the glass panel.

  • Pull the glass panel away from the lower edge of the iMac and carefully set it aside.

  • During reinstallation, be sure to meticulously clean the inside of the glass panel and the face of the LCD as any dust or fingerprints trapped inside will be annoyingly visible when the machine is turned on.

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Edit Step 8 Display  ¶ 

  • Remove the eight 8 mm T10 Torx screws securing the display to the outer case.

  • The last two pictures are detail shots of each side of the display.

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Edit Step 9  ¶ 

  • Slightly lift the top edge of the display out of the outer case.

  • Do not lift it too much. There are several cables attaching the display to the logic board.

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Edit Step 10  ¶ 

  • Pull the vertical sync cable connector out of its socket on the LED driver board near the top left corner of your iMac.

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Edit Step 11  ¶ 

  • Rotate the display out of the outer case enough to disconnect the LED backlight power cable from the LED driver board.

  • Disconnect the LED backlight power cable by depressing the locking mechanism while pulling the connector away from its socket (toward the bottom edge of the iMac).

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Edit Step 12  ¶ 

  • Grab the plastic pull tab secured to the display data cable lock and rotate it towards upwards.

  • Pull the display data cable straight out of its socket on the logic board.

  • Do not lift up on the display data cable, as its socket is very fragile. Pull the cable parallel to the face of the logic board.

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Edit Step 13  ¶ 

  • Disconnect the LCD thermal sensor cable connector from its socket on the logic board.

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Edit Step 14  ¶ 

  • Carefully pull the display toward the top edge of your iMac and lift it out of the outer case, minding any cables that may get caught.

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Edit Step 15 Optical Drive  ¶ 

  • From here, the repair will be easier if you flip the computer around so the base is facing you.

  • Remove the following four screws:

    • One 9.3 mm T10 Torx screw with a large head

    • Three 9.3 mm T10 Torx screws with a normal sized head

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Edit Step 16  ¶ 

  • Pull the optical drive thermal sensor connector straight up from its socket on the logic board. Pull parallel to the board.

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Edit Step 17  ¶ 

  • Lift the inner edge of the optical drive and maneuver its connector past the GPU frame attached to the logic board.

  • Carefully pull the optical drive off its mounting pins on the right side of the outer case to gain clearance for disconnecting the optical drive cable.

  • Allow the optical drive to hang down as you de-route the optical drive thermal sensor connector from behind the GPU heat sink.

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Edit Step 18  ¶ 

  • Disconnect the optical drive cable by pulling its connector away from the optical drive.

  • Remove the optical drive from the iMac.

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Edit Step 19 Optical Drive Fan  ¶ 

  • Remove the single 13 mm T10 Torx screw securing the optical drive fan to the outer case.

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Edit Step 20  ¶ 

  • Pull the optical drive fan off the pins attached to the outer case.

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Edit Step 21  ¶ 

  • Pull the optical drive fan connector away from its socket on the logic board.

  • Remove the optical drive fan from the iMac.

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Edit Step 22 Logic Board  ¶ 

  • In the proceeding steps, you will disconnect the following cables:

    • SD Board

    • Left/Right Speaker and Microphone

    • Audio Port

    • Wi-Fi Antenna

    • Right Temperature Sensor, Bluetooth/Ambient Light Sensor/Camera/Left Temperature, and Hard Drive Fan

    • CPU Fan/Ambient Temperature and Power Button

    • IR Sensor

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Edit Step 23  ¶ 

  • Pull the SD board cable out of its socket on the logic board.

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Edit Step 24  ¶ 

  • Disconnect the microphone, left speaker, and right speaker cables by pulling their connectors toward the right side of the iMac.

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Edit Step 25  ¶ 

  • Use the flat end of a spudger to pry all three AirPort antenna connectors up from their sockets on the AirPort board.

  • During reinstallation, connect the cable with no stripes to the socket marked CH0, the cable with one stripe to CH1, and the cable with two stripes to CH2.

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Edit Step 26  ¶ 

  • Pull the hard drive fan connector toward the top edge of the iMac to disconnect it from its socket on the logic board.

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Edit Step 27  ¶ 

  • Use your thumbnails on both sides of the Bluetooth/ambient light sensor/camera/left temperature connector to push it toward the top edge of the iMac and out of its socket on the logic board.

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Edit Step 28  ¶ 

  • Use your thumbnails to push the right temperature sensor connector toward the top edge of the iMac and out of its socket.

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Edit Step 29  ¶ 

  • Pull the CPU fan/ambient temperature sensor connector toward the bottom left edge of the iMac and out of its socket on the logic board.

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Edit Step 30  ¶ 

  • Pull the power button connector toward the bottom left corner of the iMac to disconnect it from its socket on the logic board.

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Edit Step 31  ¶ 

  • Use your thumbs to push the IR sensor connector toward the top edge of the iMac and out of its socket on the logic board.

  • Pull the IR sensor board up from behind the front face of the outer case.

  • Remove the IR sensor and set it aside.

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Edit Step 32  ¶ 

  • Pull the audio port cable connector toward the left side of the iMac to disconnect it from the logic board.

  • Do not pull the cable toward yourself (away from the front face of the logic board) as you disconnect it.

  • Peel the audio port cable off the front face of the logic board and let it hang down as shown in the second picture.

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Edit Step 33  ¶ 

  • Remove the following seven screws:

    • Two 7 mm T10 torx screws

    • One 30 mm T10 Torx screw

    • Two 25 mm T10 Torx screws

    • Two 21 mm T10 Torx screws

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Edit Step 34  ¶ 

  • Remove the following four screws:

    • One 9.3 mm T10 coarse-threaded screw

    • One 25 mm T10 coarse-threaded screw

    • Two 22 mm fine-threaded screws

  • Pull the upper right and lower left corners of the power supply away from the rear case to dislodge the mounting posts attached to the power supply's corners.

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Edit Step 35  ¶ 

  • Carefully lift the power supply out of the outer case and rotate it to expose the cable lock as shown, minding the DC-out and AC-in cables still attaching it to the iMac.

  • Disconnect the DC-out cable by depressing the locking mechanism on the connector while you pull the connector away from its socket on the power supply.

  • Once the locking mechanism has cleared the socket, pull the DC-in connector away from the power supply.

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Edit Step 36  ¶ 

  • Disconnect the AC-In cable by depressing the locking mechanism while pulling the connector away from its socket.

  • Remove the power supply from the outer case.

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Edit Step 37  ¶ 

  • Remove the plastic wall that is installed directly to the right of the LED driver board.

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Edit Step 38  ¶ 

  • Slightly pull the logic board away from the back of the outer case, then lift it upward to clear the lower front face of the outer case.

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Edit Step 39  ¶ 

  • Disconnect the LCD temperature cable by pulling its connector up and out of its socket on the logic board.

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Edit Step 40  ¶ 

  • Depress the locking mechanism and carefully pull the DC-In cable out of its socket on the back of the logic board.

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Edit Step 41  ¶ 

  • Being careful not to damage the socket on the logic board, gently pull the hard drive SATA data cable straight out of its socket on the logic board.

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Edit Step 42  ¶ 

  • Pull the hard drive power cable connector out of its socket on the logic board.

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Edit Step 43  ¶ 

  • Remove the logic board from the outer case, minding any cables that may get caught.

  • When reinstalling the logic board, plug in a thunder port cable and a USB cable into the outer USB port before tightening the logic board screws to ensure proper alignment.

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Edit Step 44 CPU Heat Sink  ¶ 

  • Peel the piece of tape covering the heat sink thermal sensor cable up off the logic board.

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Edit Step 45  ¶ 

  • Lift the heat sink thermal sensor connector straight up out of its socket on the logic board.

  • Make sure to pull only on the connector and not the socket itself.

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Edit Step 46  ¶ 

  • If present, remove the "Warranty void if removed" sticker covering one hidden screw on the heat sink.

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Edit Step 47  ¶ 

  • Remove the following five screws securing the heat sink to the logic board:

    • Four 6.4 mm T8 Torx screws

    • One 4.3 mm T10 Torx screw

  • It may be necessary to hold the socket with a Phillips screwdriver on one side of the board while you unscrew the Torx screw on the other side of the board.

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Edit Step 48  ¶ 

  • Carefully lift the logic board off the heat sink.

  • If the two components appear stuck together, carefully pry them apart with the flat end of a spudger, being careful not to disturb any surface-mount components on the logic board.

  • Make sure to apply a new layer of thermal paste before reattaching the heat sink. Our thermal paste guide makes it easy.

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Edit Step 49 CPU  ¶ 

  • Carefully pull the CPU retaining bar away from the CPU socket.

  • Rotate the bar away from the logic board.

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Edit Step 50  ¶ 

  • Carefully lift the CPU straight up off its socket.

  • Be sure your new CPU is properly aligned and seated before clamping it back down. The small gold arrow on the CPU should align with the white arrow printed on the logic board near the CPU socket as seen in the second picture.

  • Make sure to apply a new layer of thermal paste before reattaching the heat sink. Our thermal paste guide makes it easy.

To reassemble your device, follow these instructions in reverse order.

For more information, check out the iMac Intel 21.5" EMC 2428 device page.

Required Tools

TR8 Torx Security Screwdriver

$5.95 · 50+ In stock

Spudger

$2.95 · 50+ In stock

Heavy-Duty Suction Cups (Pair)

$14.95 · 50+ In stock

Phillips #2 Screwdriver

$4.95 · 13 In stock

Arctic Silver Thermal Paste

$8.95 · 50+ In stock

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Comments Comments are onturn off

Before beginning unplug your iMac.

Henry Barnett, · Reply

i pulled very hard on this tab, could not get it to release?

is this common?

Arjun Govindjee, · Reply

It is far harder than I thought you have to pull REALLY hard and then there will be a little click and than you can gently pull out the RAM.

Alison Newton , · Reply

When reinstalling RAM in this machine or any iMac with upgradable RAM slots push hard to get them to go in (Apple really did make this one harder than it needed to be). If you don't push hard it won't go in and your computer won't work. (trust me on this learned the hard way)

Robert Wacker, · Reply

Change "Before beginning, unplug your iMac and lay it on a soft surface as shown." to "Lay your iMac on a soft surface as shown"

Henry Barnett, · Reply

my imac power sullye not powering

tahir, · Reply

imac 2544 2.5 core i5 i touched the motherboard to supply and it spark now it is not powering

please tell me the directions

thanks witting for answering .

tahir, · Reply

Im sorry to say, If it sparked when you touched it your motherboard s now fried. You need a new one.

Robert Wacker,

When putting the display down on the table, be careful not to kink the flat ribbon cable.

frank, · Reply

The replacement hard drive I used doesn't even appear to spin up and the Time Capsule restore process doesn't show it as available. It just stays at Searching for disks and never finds it.

JRBv3, · Reply

I had to use Disk Utility to partition the drive and then it showed fine. Rookie mistake.

JRBv3,

Mine has these cables exactly opposite what is shown here. (?)

Danno, · Reply

4+1 = 5

You say "remove 6 screws".

anne guillaume, · Reply

Thanks! Updated.

Andrew Optimus Goldberg,

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