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Introdução

Use this guide to replace the power supply in your 21.5" Retina 4K Display 2019 iMac.

Some images in this guide use an older iMac, which has minor visual differences. These differences do not affect the repair procedure.

This guide requires you to handle a power supply that contains large capacitors. Unplug the iMac and hold the power button down for at least 10 seconds to help discharge the capacitors. Handle the board by the edges and do not touch surface components.

    • With the hinge free to move, the iMac will be unbalanced and hard to work on. Place an iMac service wedge, in the stand to stabilize the iMac.

    • If you are using the iFixit cardboard service wedge, follow these assembly directions to put it together.

    • Before beginning any work on your iMac: Unplug the computer and press and hold the power button for ten seconds to discharge the power supply's capacitors.

    • Be very careful not to touch the capacitor leads or any exposed solder joints on the back of the power supply. Only handle the board by the edges.

  1. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement, Insert the opening tool: passo 2, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement, Insert the opening tool: passo 2, imagem 2 %32
    • Starting on the left side of the display, near the power button, insert the iMac Opening Tool into the gap between the glass panel and the rear enclosure.

    • The hub on the iMac Opening Tool will keep you from pushing the wheel in too far. If using a different tool, insert no more than 3/8" into the display. Otherwise, you risk severing antenna cables and causing serious damage.

  2. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement, Slice through the display adhesive: passo 3, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement, Slice through the display adhesive: passo 3, imagem 2 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement, Slice through the display adhesive: passo 3, imagem 3 %32
    • Use the tool like a pizza cutter—roll it along the gap, cutting the foam adhesive in between the frame and display.

    • Be sure to always push with the cutting wheel forward. If you pull, the wheel might get pulled out of the handle.

    • Run the tool up along the left side of the display.

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    • Continue running the tool up around the top left corner.

  4. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 5, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 5, imagem 2 %32
    • Cut the adhesive along the top left of the display.

  5. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 6, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 6, imagem 2 %32
    • Continue along the top of the display.

    • You may want to run the tool back and forth a few times to ensure you completely cut through the adhesive.

  6. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 7, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 7, imagem 2 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 7, imagem 3 %32
    • Push the tool around the top right corner of the display.

  7. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 8, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 8, imagem 2 %32
    • Push the tool down along the right side of the display.

  8. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 9, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 9, imagem 2 %32
    • Finish pushing the opening tool to the bottom of the right side of the display.

    • At this point, you'll want to run the tool back around the entire display, to ensure you cut as much adhesive as possible.

  9. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 10, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 10, imagem 2 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 10, imagem 3 %32
    • While the opening tool cut most of the adhesive, the display will still be slightly adhered to the case. A plastic card will be necessary to free up the last of this adhesive.

    • Set the iMac face-up on a table.

    • Starting from the top right corner of the iMac, wedge a plastic card between the display and frame.

    • Be careful not to insert the plastic card more than 3/8", or you may damage internal components.

  10. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 11, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 11, imagem 2 %32
    • Gently twist the plastic card sideways to create a gap between the display and frame.

    • Move slowly and be careful not to stress the display glass too much—you only need to make a gap of about 1/4".

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    • Slide the card toward the center of the display to cut any of the remaining adhesive along the top right corner of the iMac.

    • Be sure to stop before the iSight camera, or you may damage it.

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    • Wedge the plastic card into the top right corner once again, and leave it there to prevent the adhesive from resticking.

  13. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 14, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 14, imagem 2 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 14, imagem 3 %32
    • Insert a second plastic card into the gap between the display and frame near the top left corner of the iMac.

  14. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 15, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 15, imagem 2 %32
    • Gently twist the card upward, slightly increasing the space between the display and frame.

    • As with the other side, twist slowly to allow the adhesive time to separate, and be careful not to over-stress the display glass.

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    • Slide the plastic card toward the center.

    • Stop sliding just before the iSight camera to avoid damaging the camera.

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    • Wedge the plastic card back into the top left corner.

  17. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 18, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 18, imagem 2 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 18, imagem 3 %32
    • With both plastic cards inserted as shown near the corners, gently twist the cards sideways to increase the gap between display and case.

    • If there are any sections that seem to stick and won't separate, stop twisting and use one of the cards to cut the remaining adhesive.

    • Begin to lift the top of the display up from the frame.

    • Only lift the display a few inches—the display data and power cables are still connected to the logic board.

  18. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement, Display Assembly Cables: passo 19, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement, Display Assembly Cables: passo 19, imagem 2 %32
    • Lift the display up enough to have easy access to the connector, but not so much that you stretch the cables and stress their connections (about 8").

    • Hold the display with one hand while using your other hand to unplug the display power cable.

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    • Continuing to support the display with one hand, flip up the metal retaining bracket on the display data cable.

    • Carefully pull the display data cable from its socket on the logic board.

    • Be sure to pull the display data cable connector straight out of its socket, keeping it parallel to the motherboard, to avoid damaging it.

  20. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement, Separate the display: passo 21, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement, Separate the display: passo 21, imagem 2 %32
    • Lift the display up to a near-vertical position.

    • At this point there is still a strip of adhesive along the bottom of the display that will hold the display to the frame like a hinge. You can loosen this adhesive by working the display up and down a few times.

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    • If necessary, a plastic card can be used to cut any remaining sections of the bottom adhesive strip.

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    • Lift the display up from the frame and remove it from the iMac.

    • It may be necessary to slowly lift from one side to peel against the remaining adhesive.

    • Be very careful handling the display—it's big, heavy, and made of glass.

    • After the adhesive is cut, it cannot be used to re-seal the display in place. Follow this guide to replace the adhesive strips that secure the display to the rear enclosure.

  23. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement, Remove the lower support bracket: passo 24, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement, Remove the lower support bracket: passo 24, imagem 2 %32
    • Remove the following five Phillips screws holding the lower support bracket in place:

    • Four 3.2 mm screws

    • One 1.7 mm screw

    • You may need to peel up the display adhesive lining the bottom edge of the iMac enclosure to access the screws.

  24. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 25, imagem 1 %32
    • Remove the lower support bracket (a.k.a. "chin strap") from the iMac enclosure.

  25. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement, Hard Drive Brackets: passo 26, imagem 1 %32
    • Remove the following T10 Torx screws securing the hard drive brackets to the iMac:

    • Two 21 mm screws

    • One 9 mm screw

    • One 27 mm screw

  26. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 27, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 27, imagem 2 %32
    • Remove the left and right hard drive brackets from the iMac.

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    • The next few steps bring your hands close to the exposed face of the power supply. Do not touch the face of the power supply or any of the exposed solder. Touching it risks a high voltage shock from the many large capacitors attached to the board.

    • Use the tip of a spudger to push each side of the power button cable connector and gently walk it out of its socket.

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    • Use the tip of a spudger to push each side of the power supply control cable connector and gently walk it out of its socket.

  29. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 30, imagem 1 %32
    • Remove the two 7.2 mm T8 Torx screws securing the power supply to the rear enclosure.

  30. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 31, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 31, imagem 2 %32
    • When working on the power supply, be very careful not to touch the capacitor leads or any exposed solder joints on the back of the power supply. Only handle the board by the edges.

    • Tilt the power supply forward.

  31. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 32, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 32, imagem 2 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 32, imagem 3 %32
    • Pull the power supply slightly up and out from the rear enclosure.

    • Rotate the power supply counterclockwise, lifting the right side up about an inch higher than the left.

  32. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 33, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 33, imagem 2 %32
    • Slide the power supply to the right to clear the screw posts on the rear enclosure.

  33. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 34, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 34, imagem 2 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 34, imagem 3 %32
    • Rock the power supply forward and remove it from its recess in the rear enclosure.

    • Do not try to completely remove the power supply from the iMac yet—it is still connected to the logic board.

  34. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 35, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 35, imagem 2 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 35, imagem 3 %32
    • Be very careful not to touch the capacitor leads or any exposed solder joints on the back of the power supply. Only handle the board by the edges.

    • Do not let any of the exposed solder joints come in contact with a metal surface, as that can cause a short.

    • Flip the power supply over to access the DC power cable connection behind the logic board.

    • To disconnect the cable, squeeze the release clip on the back side of the connector, behind the logic board, and pull the connector straight out.

  35. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 36, imagem 1 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 36, imagem 2 %32 iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 36, imagem 3 %32
    • You may find it helpful to set the iMac down on its back for the next couple of steps.

    • Use the flat end of a spudger to press the release clip on the side of the AC inlet cable connector inward.

    • While pressing on the release clip with the spudger, grasp the AC inlet cable, and pull the connector straight out of its socket.

  36. iMac Intel 21.5" Retina 4K Display 2019 Power Supply Replacement: passo 37, imagem 1 %32
    • Remove the power supply from the iMac.

Conclusão

Compare your new replacement part to the original part—you may need to transfer remaining components or remove adhesive backings from the new part before installing.
To reassemble your device, follow the above steps in reverse order.
Take your e-waste to an R2 or e-Stewards certified recycler.
Repair didn’t go as planned? Check out our Answers community for troubleshooting help.

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Adam O'Camb

Membro desde: 11/04/2015

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