iMac (Retina 4K, 21.

5-inch, 2019)
Repair Guide

© 2019 Apple Inc. All rights reserved.

iMac (Retina 4K, 21.5-inch, 2019) Contents

Contents
3 About This Guide

Basics

4 Exploded View
7 Desktop Tools
11 Screws
13 Display Cleaning

Safety

14 Electrical Safety
15 Broken Display

Procedures

17 First Steps
18 Display
40 Embedded DisplayPort (eDP) Cable
43 Display Thermal Sensor Cable
46 Camera
49 Fan
54 Hard Drive
59 Chin Strap
62 Left Speaker
72 Power Supply
81 Logic Board
99 Right Speaker
101 Hard Drive Data and Power Cable
104 Flash Storage
108 Memory
112 Battery
114 Bluetooth and Wi-Fi Antennas
122 Stand

© 2019 Apple Inc. All rights reserved. 073-00161-A | 1

iMac (Retina 4K, 21.5-inch, 2019) Contents

125 Mechanism
128 Rear Housing

© 2019 Apple Inc. All rights reserved. 073-00161-A | 2

iMac (Retina 4K, 21.5-inch, 2019) About This Guide

About This Guide

This guide includes technical instructions for replacing genuine Apple parts in Apple computers.
All genuine Apple parts and special tools are available to Apple-certified technicians at an Apple Store or
at an Apple Authorized Service Provider as part of a repair. Find an Apple Store or an Apple Authorized
Service Provider at support.apple.com/repair.
Apple’s warranty and any Apple-branded extended service contract, including AppleCare+ and AppleCare
Protection Plan, do not cover service that is required due to the failure of parts that are neither supplied by
Apple nor genuine Apple parts; or because the product has failed due to unauthorized modification or faulty
installation, repair, or maintenance by any entity other than Apple or an Apple Authorized Service Provider.

Alerts

Failure to follow alerts may result in data loss, cost, damage to yourself or the computer, or death.

Danger Instructions for reducing risk of electric shock and electrocution.

Warning Instructions for reducing risk of personal injury.

Caution Instructions for reducing risk of data loss or computer hardware damage.

Supplemental information for successfully completing procedures;

Important
neither a Warning nor a Caution.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 3

iMac (Retina 4K, 21.5-inch, 2019) Exploded View

Exploded View

This section shows parts and part numbers for iMac (Retina 4K, 21.5-inch, 2019).

© 2019 Apple Inc. All rights reserved. 073-00161-A | 4

iMac (Retina 4K, 21.5-inch, 2019) Exploded View

1. Display Assembly
661-12564

2. Very High Bond (VHB) Adhesive Strips

076-00330

3. Fan
923-00563

4. Camera
923-01618

5. Speaker Pair (Left)

923-03080

6. Camera Cable
923-03081

7. and 8. Left and Right Hard Drive Brackets

076-00333

9. Speaker Pair (Right)

923-01617

10. Hard Drive

923-01619, 1 TB

11. Bluetooth Antenna

923-01619

12. Middle Wi-Fi Antenna

923-01620

13. Lower Wi-Fi Antenna

923-01621

14. Hard Drive Bumpers

661-12547

15. Hard Drive Cradle

076-00333

16. Hard Drive Data and Power Cable

923-01672
076-00333

17. Logic Board

661-12487, 3.6GHz quad-core Intel Core i3, Radeon Pro 555X, HDD, FCC
661-12488, 3.6GHz quad-core Intel Core i3, Radeon Pro 555X, HDD, ETSI
661-12489, 3.6GHz quad-core Intel Core i3, Radeon Pro 555X, HDD, ROW
661-12491, 3.6GHz quad-core Intel Core i3, Radeon Pro 555X, SSD, FCC
661-12492, 3.6GHz quad-core Intel Core i3, Radeon Pro 555X, SSD, ETSI
661-12493, 3.6GHz quad-core Intel Core i3, Radeon Pro 555X, SSD, ROW
661-12495, 3.0GHz 6-core Intel Core i5, Radeon Pro 560X, SSD, FCC
661-12496, 3.0GHz 6-core Intel Core i5, Radeon Pro 560X, SSD, ETSI
661-12497, 3.0GHz 6-core Intel Core i5, Radeon Pro 560X, SSD, ROW

© 2019 Apple Inc. All rights reserved. 073-00161-A | 5

iMac (Retina 4K, 21.5-inch, 2019) Exploded View

661-12499, 3.0GHz 6-core Intel Core i5, Radeon Pro Vega 20, SSD, FCC
661-12500, 3.0GHz 6-core Intel Core i5, Radeon Pro Vega 20, SSD, ETSI
661-12501, 3.0GHz 6-core Intel Core i5, Radeon Pro Vega 20, SSD, ROW
661-12503, 3.2GHz 6-core Intel Core i7, Radeon Pro 555X, HDD, FCC
661-12504, 3.2GHz 6-core Intel Core i7, Radeon Pro 555X, HDD, ETSI
661-12505, 3.2GHz 6-core Intel Core i7, Radeon Pro 555X, HDD, ROW
661-12507, 3.2GHz 6-core Intel Core i7, Radeon Pro 555X, SDD, FCC
661-12508, 3.2GHz 6-core Intel Core i7, Radeon Pro 555X, SSD, ETSI
661-12509, 3.2GHz 6-core Intel Core i7, Radeon Pro 555X, SSD, ROW
661-12536, 3.2GHz 6-core Intel Core i7, Radeon Pro 560X, SSD, FCC
661-12537, 3.2GHz 6-core Intel Core i7, Radeon Pro 560X, SSD, ETSI
661-12538, 3.2GHz 6-core Intel Core i7, Radeon Pro 560X, SSD, ROW
661-12540, 3.2GHz 6-core Intel Core i7, Radeon Pro Vega 20, SSD, FCC
661-12541, 3.2GHz 6-core Intel Core i7, Radeon Pro Vega 20, SSD, ETSI
661-12542, 3.2GHz 6-core Intel Core i7, Radeon Pro Vega 20, SSD, ROW

18. Power Supply

661-08259

19. Memory
661-12456, 4 GB
661-12457, 8 GB
661-12458, 16 GB

20. Memory Cover

923-03083

21. Mechanism
923-00559

22. Flash Storage

661-12548, 32 GB
661-12550, 256 GB
661-12551, 512 GB
661-12552, 1 TB

23. Chin Strap

923-01678

24. Rear Housing

923-00556

25. Stand
923-03078

Not Shown
Display Thermal Sensor Cable
Embedded DisplayPort (eDP) Cable

© 2019 Apple Inc. All rights reserved. 073-00161-A | 6

iMac (Retina 4K, 21.5-inch, 2019) Desktop Tools

Desktop Tools
Note: This chart includes tools for repairing multiple desktop computer models. You will not need to use all
of the tools listed.

923-02298 923-0735 923-01322

Access card Adjustable torque driver Antenna tool
(0.3–1.2 Ncm)
iMac Pro (2017) iMac Pro (2017)

076-1277 076-00377 076-1437

Display cleaning starter kit Display extension cable set Display refill kit

iMac Pro (2017) iMac (21.5-inch, 2017)

076-00375 076-1417 076-00374

Display refill kit Display removal wheel kit Display starter kit

iMac Pro (2017) iMac Pro (2017)

076-00330 923-0416 922-9468

Display starter kit Display support stand Electrostatic discharge
(ESD) bag
iMac (21.5-inch, 2017)

© 2019 Apple Inc. All rights reserved. 073-00161-A | 7

iMac (Retina 4K, 21.5-inch, 2019) Desktop Tools

ESD mat ESD-safe tweezers ESD wrist strap with clip or

plug

922-1731 076-00376
Isopropyl alcohol (IPA) wipes Kapton tape Logic board service tray

iMac Pro (2017)

923-02217 922-5065
Logic board stiffeners Nylon probe tool (black stick) Painters tape

iMac Pro (2017)

923-0189
Phillips #00 screwdriver Phillips PH2 bit Power supply cover

© 2019 Apple Inc. All rights reserved. 073-00161-A | 8

iMac (Retina 4K, 21.5-inch, 2019) Desktop Tools

922-8252
Ruler Safety glasses Suction cups

922-7144 076-1445
Thermal compound syringe Thermal pad kit Torx T4 screwdriver

iMac (21.5-inch, 2017)

923-00304
Torx T5 screwdriver Torx T6 screwdriver Torx T6 security bit

923-0734 923-0740
Torx T8 screwdriver Torx T8 security bit Torx T10 bit

© 2019 Apple Inc. All rights reserved. 073-00161-A | 9

iMac (Retina 4K, 21.5-inch, 2019) Desktop Tools

923-0030
Torx T10 screwdriver Torx T25 screwdriver Trilobe driver, large #1

923-01806 923-02218 923-03086

Wireless card support tool Wireless card support tool Wireless card support tool

iMac (21.5-inch, 2017) iMac Pro (2017) iMac (Retina 4K, 21.5-inch, 2019)

923-03085
Wireless card support tool

iMac (Retina 5K, 27-inch, 2019)

© 2019 Apple Inc. All rights reserved. 073-00161-A | 10

iMac (Retina 4K, 21.5-inch, 2019) Screws

Screws

923-0323 923-00829 923-00830 923-0327

T10 T10 T10 T10

Hard drive bracket (1) Hard drive bracket (2) Hard drive bracket (1) Heat sink, upper (2)

923-0331 923-0333 923-0334 923-0335

T8 T10 T10 Phillips #00

Logic board (4) Fan (3) Mechanism (4) Chin strap - short, center (1)
Hard drive cradle (1) Right speaker (2)
Power supply (2) Left speaker (2)

923-0336 923-0338 923-0339 923-00529

T8 Phillips #00 T5 T8

Heat sink, lower (2) Chin strap - long (4) Camera (2) Stand (7)
Flash storage (1)

© 2019 Apple Inc. All rights reserved. 073-00161-A | 11

iMac (Retina 4K, 21.5-inch, 2019) Screws

923-00831 923-02294 923-03082

T4 T5 T5

Bluetooth antenna (2) Antenna cowling (2) Memory cover (2)

Middle Wi-Fi antenna (2)
Lower Wi-Fi antenna (2)

© 2019 Apple Inc. All rights reserved. 073-00161-A | 12

iMac (Retina 4K, 21.5-inch, 2019) Display Cleaning

Display Cleaning

1. Clean the front of the

display with a clean, damp,
lint-free cloth.
Note: Do not use IPA wipes
to clean the display.

2. Polish the display with a microfiber polishing cloth.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 13

iMac (Retina 4K, 21.5-inch, 2019) Electrical Safety

Electrical Safety

Danger
The power supply remains powered when the computer is plugged in whether or not the computer has
been turned on. Use extreme caution when the display is removed. Avoid touching the logic board or
power supply while the computer is plugged into an electrical outlet.

Take the following additional precautions:

• Never remove or install any parts while the computer is plugged into an electrical outlet.
• Always wait at least 2 minutes after unplugging the computer to allow the power supply and logic
board time to discharge. You may then remove the display.
• Do not touch the logic board or power supply while the computer is plugged in.
• Do not touch the logic board or power supply before the 2-minute discharge wait time has passed.

Follow these steps before working on a computer with exposed, potentially energized parts:
• Remove all metal accessories, including rings and glasses, from your body, as they increase your risk of
electric shock.
• Do not wear a cell phone or other signaling device.
• If the computer needs to be plugged in for indicator light checks or similar troubleshooting, do not wear
an ESD wrist strap. Wearing ESD grounding systems while the computer is plugged in increases your risk
of electric shock.
• Remain alert, focused on the work you are performing, and aware of the grounded objects near your body.
• Use tools as instructed for connecting or disconnecting cables to keep fingers away from potentially
energized parts.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 14

iMac (Retina 4K, 21.5-inch, 2019) Broken Display

Broken Display

Warning
If the display breaks and glass
gets in your eye, perform the
following steps:
• Immediately seek medical
attention.
• Do not rub your eye.
• Do not wash your eye.
Washing your eye can move
the shard of glass and cause
more damage.
• Keep your eye closed or
loosely patch it to keep it still.

Handling a Broken Display

• The display glass is untempered and will break into pieces if mishandled. Removing the display
requires special tools.
• Use safety glasses when removing a broken display.

Tools

• Display cleaning starter kit

• Safety glasses
• Packing tape

© 2019 Apple Inc. All rights reserved. 073-00161-A | 15

iMac (Retina 4K, 21.5-inch, 2019) Broken Display

1. Put on safety glasses and cut-resistant gloves.

2. If the display is broken and is still attached to the rear housing, secure the broken glass with packing
tape and refer to the Display section.

3. Lay the display on a smooth, clean work surface.

4. Thoroughly cover the broken

display with packing tape.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 16

iMac (Retina 4K, 21.5-inch, 2019) First Steps

First Steps

Only Apple-certified technicians should repair Apple computers.

Always perform the following steps before starting a repair:

• Turn off the computer.
• Unplug the power cord from the electrical outlet.
• Disconnect all cables.
• Put on an ESD wrist strap and attach it to a properly grounded ESD mat.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 17

iMac (Retina 4K, 21.5-inch, 2019) Display

Display

Tools
• Service wedge
• ESD bag
• Black stick
• Display removal tool and
replacement wheels
• Safety glasses
• IPA wipes
• Silicone display roller
• Painters tape
• Clean, damp, lint-free cloth

The display is attached to the rear housing with adhesive strips.

Each VHB strip has one foam layer surrounded by two adhesive
layers. To remove the display, you must use the display removal tool
to cut the VHB strips. When you cut the VHB strips, you are cutting
mostly through the foam layer. The display removal tool has
replaceable wheels that you can use 5 to 10 times. If a wheel is
nicked, it must be replaced.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 18

iMac (Retina 4K, 21.5-inch, 2019) Display

Steps for Removal

1. Place the service wedge

on the stand with the stand
hole covered. Rotate the
computer so the display is
facing you.

Caution
Keep the service wedge in
place for all procedures.

2. Insert the display removal

tool at a 90-degree angle in
the top left corner between
the display and rear
housing. Roll the tool across
the top of the computer,
avoiding the 3-inch area
surrounding the camera.

Caution
Failure to lift the tool out of
the computer to avoid the
camera could damage the
display and the camera.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 19

iMac (Retina 4K, 21.5-inch, 2019) Display

3. Continue to roll the tool

around the top right corner
and down the right side of
the computer.

Note: Ensure that the tool

makes steady contact
with the display and rear
housing at the top corners.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 20

iMac (Retina 4K, 21.5-inch, 2019) Display

4. Roll the tool around the top

left corner and down the
left side of the computer.

5. Roll the tool back and forth

along the top and sides
of the computer until the
wheel moves with minimal
resistance.

Caution
Use the display removal tool
only along the top and sides
of the computer.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 21

iMac (Retina 4K, 21.5-inch, 2019) Display

6. Insert the flat end of a

black stick up to its notch
between the display and rear
housing. Slide the black stick
along the edge to cut any
remaining adhesive.

Caution
Do not twist, pry, or insert
the black stick past its notch.
Forcing the black stick
between the display and the
rear housing may fracture
the display.
Use caution with the black
stick along the antenna
sections.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 22

iMac (Retina 4K, 21.5-inch, 2019) Display

7. Separate the display from

the top of the rear housing.
If there is resistance, repeat
steps 2 through 6.

8. Tilt open the display

just enough for your
hand to reach the cables
connecting the display to
the logic board.

Caution
Do not attempt to remove
the display. Its bottom
edge is still attached with
display adhesive. Do not
stress the display cables
and connectors on the
logic board when tilting
the display open. If the
connectors on the logic
board are damaged, you
will need to replace the
logic board.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 23

iMac (Retina 4K, 21.5-inch, 2019) Display

9. Disconnect the embedded

DisplayPort (eDP) cable
and the display backlight
power cable.

Caution
The display backlight power
cable is part of the display
and is not available as a
separate part.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 24

iMac (Retina 4K, 21.5-inch, 2019) Display

10. Use your hand to support

the display and tilt it further
toward you.

11. Locate the display adhesive

tabs at the bottom corners
of the display and pull each
toward the center to release
the display from the rear
housing.
Note: If the display sticks to
the rear housing, use a black
stick to break the display
adhesive bond.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 25

iMac (Retina 4K, 21.5-inch, 2019) Display

12. Pull the display from the

rear housing and set it face
down on a soft cloth on the
display support stand.

13. Use your fingers and the

flat end of a black stick
to peel residual adhesive
outward from the top center
of the rear housing.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 26

iMac (Retina 4K, 21.5-inch, 2019) Display

14. Use your fingers and the flat

end of a black stick to peel
residual adhesive outward
from the top center
of the display.

Caution
To prevent damage to the
Mylar protective film on
the display, do not peel
residual adhesive inward
or downward from the top
corners of the display.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 27

iMac (Retina 4K, 21.5-inch, 2019) Display

15. Use your fingers and the

flat end of a black stick
to peel residual adhesive
upward from the bottom
sides of the rear housing.

Caution
Do not use IPA wipes on the
display or to remove anything
other than residual adhesive.

16. Use your fingers and the

flat end of a black stick
to peel residual adhesive
upward from the bottom
sides of the display.

Caution
If the Mylar film is peeling or
wrinkled, press it back onto
the panel with your finger.
Ensure that it is smooth and
undamaged. If the Mylar is
pulled away from the display,
you may need to replace
the display.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 28

iMac (Retina 4K, 21.5-inch, 2019) Display

17. Use an IPA wipe to remove

any remaining adhesive
from the rear housing and
display edges. Allow the
surfaces to dry for 1 minute.

Caution
Residual adhesive can be
anywhere along the top,
sides, and chin of the rear
housing.

18. Recheck the display and rear housing for any residual adhesive.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 29

iMac (Retina 4K, 21.5-inch, 2019) Display

Steps for Reassembly

1. Lay out the adhesive

strips and inspect them
for damage, wrinkles, or
exposed sections. Damage
can cause cosmetic gaps
and leakage and weaken
the bond.

Note: The adhesive strips have a foam layer with a removable liner
on the underside and a clear plastic liner on the top side.

Important
Use the eight alignment
holes on the top and sides of
the rear housing to align the
new display adhesive strips.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 30

iMac (Retina 4K, 21.5-inch, 2019) Display

2. Use the pull tab on the back of the display adhesive strip to remove the top portion of the paper liner.
Leave the remaining paper liner on the bottom portion of the strip.

3. Use the pointed end of

a black stick to align the
display adhesive strip on one
side of the rear housing.
Note: The paper liner side
faces the rear housing.

4. As you position the display

adhesive, use the pull tab
to peel the remaining paper
liner from the underside of
the display adhesive strip.

5. Use your finger to press the

display adhesive strip into
place on the rear housing.
Note: If the display
adhesive strip does not line
up correctly, remove it and
start again.

Important
Do not remove the clear
plastic liners from the top
layer of the strip at this time.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 31

iMac (Retina 4K, 21.5-inch, 2019) Display

6. Repeat steps 2 through 5

along the top inside edge
and other side of the
rear housing.

7. Use the two strips of display

adhesive along the bottom
edge. There are no guide
holes on the display adhesive
strips or along the bottom of
the rear housing, so align the
strips by hand.

Important
If a display adhesive strip
does not line up correctly,
remove it, clean the rear
housing, and start again.
Ensure there are no wrinkles
or exposed sections on
the strip.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 32

iMac (Retina 4K, 21.5-inch, 2019) Display

8. Place the display on the chin

of the rear housing. Align
the panel and check that it is
centered and seated.

9. Hold the display removal

tool against the sides of
the display to check the
alignment. Adjust the
display placement
if necessary.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 33

iMac (Retina 4K, 21.5-inch, 2019) Display

10. Anchor the display with a

strip of painters tape.
Place the tape horizontally
where the bottom of the
display meets the chin.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 34

iMac (Retina 4K, 21.5-inch, 2019) Display

11. Step back and check the Incorrect alignment

alignment of the display. If
the display is not flush with
the rear housing, adjust
the display and recheck
alignment.

Correct alignment

© 2019 Apple Inc. All rights reserved. 073-00161-A | 35

iMac (Retina 4K, 21.5-inch, 2019) Display

12. Anchor the display further

with a vertical strip of
painters tape on both ends of
the horizontal strip.

13. Use one hand to tilt the display while steadying it with the other hand.

14. While continuing to steady

the display with one hand,
use the other hand to pull
the clear release liners from
the adhesive strips at the
bottom of the display.

Caution
Slowly pull the release liners
so they do not tear.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 36

iMac (Retina 4K, 21.5-inch, 2019) Display

15. Remove the remaining

release liners from the
top and sides of the
display.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 37

iMac (Retina 4K, 21.5-inch, 2019) Display

16. Tilt up the display, leaving

enough room to connect
the eDP cable and the
display backlight power
cable to the logic board.
Ensure the connectors are
firmly seated.

Caution
Do not stress the display
cables and connectors on
the logic board when tilting
the display open. If the
connectors are damaged,
you will need to replace the
logic board.
The display backlight
power cable is part of the
display assembly and is not
available as a separate part.

17. After you’ve removed all the release liners, lean the display against the rear housing.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 38

iMac (Retina 4K, 21.5-inch, 2019) Display

18. Use the silicone display

roller to adhere the display
adhesive strips to the glass.
To prevent image quality
issues, only roll upward.

19. Roll the silicone display

roller along the top in a
horizontal back-and-
forth motion.

20. Wipe the front of the display with a clean, damp, lint-free cloth.
Note: Do not use IPA wipes to clean the display. Only use IPA wipes to remove any
residual display adhesive.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 39

iMac (Retina 4K, 21.5-inch, 2019) Embedded DisplayPort (eDP) Cable

Embedded DisplayPort (eDP) Cable

Remove the following part

before you begin:
• Display

Tools
• ESD wrist strap and mat
• Black stick

© 2019 Apple Inc. All rights reserved. 073-00161-A | 40

iMac (Retina 4K, 21.5-inch, 2019) Embedded DisplayPort (eDP) Cable

Steps for Removal

1. Remove any tape securing the eDP cable to the display.

2. Use a black stick to flip the locking bar on the eDP cable.

3. Gently pull the eDP cable

out of the connector.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 41

iMac (Retina 4K, 21.5-inch, 2019) Embedded DisplayPort (eDP) Cable

Steps for Reassembly

1. Reinsert the eDP cable into

the connector on the display.
Flip the locking bar and press
the pull tab to secure
the cable.

2. Replace any tape that you removed from the eDP cable.
Note: Press the area of the cable with the adhesive to secure the cable to the display.

Reinstall the following part to complete reassembly:

• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 42

iMac (Retina 4K, 21.5-inch, 2019) Display Thermal Sensor Cable

Display Thermal Sensor Cable

Remove the following part

before you begin:
• Display

Tools

• ESD wrist strap and mat

• Black stick

© 2019 Apple Inc. All rights reserved. 073-00161-A | 43

iMac (Retina 4K, 21.5-inch, 2019) Display Thermal Sensor Cable

Steps for Removal

1. Remove any tape that

secures the display thermal
sensor cable to the display.

2. Use the pointed end of a

black stick to gently push the
display thermal sensor cable
out of its connector.

3. Use a black stick to peel off the square sensor board from the display.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 44

iMac (Retina 4K, 21.5-inch, 2019) Display Thermal Sensor Cable

Steps for Reassembly

1. Peel the adhesive liner from the replacement thermal sensor board and adhere the board to the back
of the display.

2. Reinsert the thermal sensor

cable into the connector on
the display.

3. Secure the thermal sensor

board and cable with tape.

Reinstall the following part to complete reassembly:

• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 45

iMac (Retina 4K, 21.5-inch, 2019) Camera

Camera

Remove the following part

before you begin:
• Display

Tools

• ESD wrist strap and mat

• Torx T5 screwdriver
• Black stick

© 2019 Apple Inc. All rights reserved. 073-00161-A | 46

iMac (Retina 4K, 21.5-inch, 2019) Camera

Steps for Removal

1. Use a black stick to flip the

locking bar on the camera
cable. Pull the camera
cable straight out from the
connector on the
camera board.

2. Remove the two T5 screws

from the camera board.

3. If the camera cable needs

to be replaced, use a black
stick to flip the locking bar
on the camera cable. Pull
the camera cable straight
out from the connector on
the logic board.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 47

iMac (Retina 4K, 21.5-inch, 2019) Camera

Steps for Reassembly

1. Reinstall the two T5 screws

in the camera board.
Note: If installing a
replacement camera,
remove the protective film
covering the lens.

2. Reinsert the camera cable in

the camera board connector.
Flip the locking bar to secure
the cable.

3. If the camera cable was replaced, connect the camera cable to the logic board connector. Flip the
locking bar to secure the cable.

Reinstall the following part to complete reassembly:

• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 48

iMac (Retina 4K, 21.5-inch, 2019) Fan

Fan

Remove the following part

before you begin:
• Display

Tools
• ESD wrist strap and mat
• Torx T10 screwdriver
• Black stick

© 2019 Apple Inc. All rights reserved. 073-00161-A | 49

iMac (Retina 4K, 21.5-inch, 2019) Fan

Steps for Removal

1. Remove the spacer from

the fan screw and save it for
reuse.

2. Use a black stick to

disconnect the fan cable
from the logic board.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 50

iMac (Retina 4K, 21.5-inch, 2019) Fan

3. Remove the three T10

screws from the fan.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 51

iMac (Retina 4K, 21.5-inch, 2019) Fan

Steps for Reassembly

1. Reinstall the three T10
screws in the fan.

2. Reconnect the fan cable to

the logic board. Ensure
the cable is routed
as shown.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 52

iMac (Retina 4K, 21.5-inch, 2019) Fan

3. Reinstall the spacer on the

top screw.

Reinstall the following part to complete reassembly:

• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 53

iMac (Retina 4K, 21.5-inch, 2019) Hard Drive

Hard Drive

Remove the following part

before you begin:
• Display

Tools

• ESD wrist strap and mat

• Torx T10 screwdriver

© 2019 Apple Inc. All rights reserved. 073-00161-A | 54

iMac (Retina 4K, 21.5-inch, 2019) Hard Drive

Steps for Removal

1. Loosen the two T10 left

speaker screws and move
the speaker to the left for
easier access to the hard
drive data and power
cable connector.

2. Remove the four T10

screws from the hard
drive brackets.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 55

iMac (Retina 4K, 21.5-inch, 2019) Hard Drive

3. Remove the hard drive

brackets. Do not remove
the bumpers.

4. Disconnect the hard drive

power and data cable from
the hard drive.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 56

iMac (Retina 4K, 21.5-inch, 2019) Hard Drive

Steps for Reassembly

1. Plug the hard drive power

and hard drive data cable
back into the hard drive.

2. Position the hard drive brackets as shown. The brackets will only Left Bracket Right Bracket
install one way.

Caution
When reinstalling the brackets, ensure that none of the hard drive
bumpers are pinched between the hard drive and the brackets.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 57

iMac (Retina 4K, 21.5-inch, 2019) Hard Drive

3. Reinstall the four T10

screws into the hard drive
brackets.
Note: If installing a
replacement camera,
remove the protective film
covering the lens.

4. Move left speaker back into

place and tighten the two
speaker screws.

Reinstall the following part to complete reassembly:

• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 58

iMac (Retina 4K, 21.5-inch, 2019) Chin Strap

Chin Strap

Remove the following part

before you begin:
• Display

Important
You must remove the chin strap
in order to repair any part that
sits below the chin.

The chin strap is located in the

bottom edge of the rear housing
behind the chin, as shown.

Tools
• ESD wrist strap and mat
• Phillips #00 screwdriver
• Black stick

© 2019 Apple Inc. All rights reserved. 073-00161-A | 59

iMac (Retina 4K, 21.5-inch, 2019) Chin Strap

Steps for Removal

1. Remove the five Phillips

#00 screws from the
chin strap.

2. Pull up the chin strap from

behind the chin and save it
for reuse.

Important
Do not bend the chin strap.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 60

iMac (Retina 4K, 21.5-inch, 2019) Chin Strap

Steps for Reassembly

1. Insert the chin strap with
the screw holes facing
outward and the Mylar ridge
facing left.

2. Reinstall the five screws in

the chin strap.
Note: One of the five chin
strap screws is shorter than
the other screws. Install the
shortest chin strap screw in
the center hole.

(image from J133)

Note: For easier installation

of the small chin strap
screws, use a black stick to
press the chin strap against
the front frame if needed.
Do not press on the chin.
Always press on the
back of the chin strap to
bring it toward the screw.

Reinstall the following part to complete reassembly:

• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 61

iMac (Retina 4K, 21.5-inch, 2019) Left Speaker

Left Speaker

Remove the following parts

before you begin:
• Display
• Fan

Important
You must replace the speakers
in pairs. If you replace the left
speaker, then you must also
replace the right speaker. For
right speaker removal and
reassembly instructions,
refer to the Right Speaker
section.

Tools
• ESD wrist strap and mat
• Torx T8 screwdriver
• Black stick
• Phillips #00 screwdriver

© 2019 Apple Inc. All rights reserved. 073-00161-A | 62

iMac (Retina 4K, 21.5-inch, 2019) Left Speaker

Steps for Removal

1. Loosen the two T8 screws
from the hard drive brackets.

2. Disconnect the speaker

cable from the logic board.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 63

iMac (Retina 4K, 21.5-inch, 2019) Left Speaker

3. Remove the sticker that

adheres the speaker cable
to the hard drive data and
power cable; then remove it
from the clip.

4. Use a black stick to

disconnect the power
button cable from the
power supply.

Caution
The power button cable is
part of the rear housing. If
the cable breaks, the rear
housing will need to be
replaced.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 64

iMac (Retina 4K, 21.5-inch, 2019) Left Speaker

5. Remove the power button

cable from the groove in the
speaker.

6. Remove the two T10 screws

from the left speaker.
Note: The screws tighten
into rubber grommets and
may remain in the screw
holes when the speaker is
removed.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 65

iMac (Retina 4K, 21.5-inch, 2019) Left Speaker

7. Pull the left speaker up just

enough to see the power
button cable. Remove the
power button cable from
the channel.

Caution
Failure to remove the
power button cable from
its channel can result in a
damaged cable.

8. Remove the left speaker

from the rear housing.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 66

iMac (Retina 4K, 21.5-inch, 2019) Left Speaker

Steps for Reassembly

1. Partially reinsert the left speaker in the rear housing chin.

2. Reinstall the power button

cable into its channel on the
bottom of the left speaker.

3. Continue to reroute the

power button cable along
the side of the left speaker.

Caution
If the power button cable is
not securely routed in the
vertical channel, the cable
may come loose and may
be damaged by the power
supply. A damaged power
button cable requires rear
housing replacement.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 67

iMac (Retina 4K, 21.5-inch, 2019) Left Speaker

4. Fully reinsert the left speaker

into the rear housing chin.
Ensure that the power button
cable does not bind or slip
out of the routing channel as
you position the speaker.

Important
Push firmly to ensure that
the speaker sits down in the
chin as far as possible. If the
speaker is not positioned
correctly in the chin,
it can cause display
interference issues.

5. Reinstall the two T10 screws

in the left speaker.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 68

iMac (Retina 4K, 21.5-inch, 2019) Left Speaker

6. Reconnect the speaker

cable to the logic board.

7. Reconnect the power button

cable to the power supply.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 69

iMac (Retina 4K, 21.5-inch, 2019) Left Speaker

8. Reroute the cable between

the ledge and the screw
opening.

9. Reroute the speaker cable

as shown. Verify that it is
through the clip and adhere
it to the hard drive data and
power cable.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 70

iMac (Retina 4K, 21.5-inch, 2019) Left Speaker

10. Reinstall the two T8 screws

into the hard drive bracket.

Reinstall the following parts to complete reassembly:

• Chin Strap
• Fan
• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 71

iMac (Retina 4K, 21.5-inch, 2019) Power Supply

Power Supply

Remove the following parts

before you begin:
• Display
• Chin strap

Danger
The power supply remains powered when the computer is plugged in whether or not the computer has
been turned on. Use extreme caution when the display is removed. Avoid touching the logic board or
power supply while the computer is plugged into an electrical outlet.
Take the following additional precautions:
• Never remove or install any parts while the computer is plugged into an electrical outlet.
• Always wait at least 2 minutes after unplugging the computer to allow the power supply and logic board time
to discharge. You may then remove the display.
• Do not touch the logic board or power supply while the computer is plugged in, or after the computer has
been unplugged but before discharge wait time has passed.
• Do not touch the logic board or power supply before the 2-minute discharge wait time has passed.

Tools
• ESD wrist strap and mat
• Torx T8 screwdriver
• Black stick
• Phillips #00 screwdriver

© 2019 Apple Inc. All rights reserved. 073-00161-A | 72

iMac (Retina 4K, 21.5-inch, 2019) Power Supply

1. Remove the four T8 screws

from the hard drive brackets.

2. Use a black stick to

disconnect the power
button cable from the
power supply.

Caution
The power button cable is
part of the rear housing. If
the cable breaks, you will
need to replace the
rear housing.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 73

iMac (Retina 4K, 21.5-inch, 2019) Power Supply

3. Disconnect the power

supply signal cable.

4. Remove the two T8 screws

from the power supply.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 74

iMac (Retina 4K, 21.5-inch, 2019) Power Supply

5. Slide the power supply

out of the chin as far as it
will go. Disconnect the DC
cable from the logic board.

6. Disconnect the AC cable

from the AC filter in the
rear housing.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 75

iMac (Retina 4K, 21.5-inch, 2019) Power Supply

7. Lift the power supply up

and out of the chin well.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 76

iMac (Retina 4K, 21.5-inch, 2019) Power Supply

Steps for Reassembly

1. Reconnect the AC cable to

the AC filter in the
rear housing.

2. Slip the power supply under

the rear housing chin.
Reconnect the DC cable to
the logic board.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 77

iMac (Retina 4K, 21.5-inch, 2019) Power Supply

3. Reconnect the power

supply signal cable.

4. Reinstall the two T8 screws

in the power supply.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 78

iMac (Retina 4K, 21.5-inch, 2019) Power Supply

5. Reconnect the power button

cable to the power supply
and reroute it along the side
of the left speaker.

Caution
If the power button cable
breaks, you will need to
replace the rear housing.
The power button cable is
not available separately.

6. Position the hard drive brackets as shown. The brackets will only Left Bracket Right Bracket
install one way.

Caution
When reinstalling the brackets, ensure that none of the hard
drive bumpers are pinched between the hard drive and
the brackets.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 79

iMac (Retina 4K, 21.5-inch, 2019) Power Supply

7. Reinstall the four T8 screws

into the hard drive brackets.

Reinstall the following parts to complete reassembly:

• Chin strap
• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 80

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

Logic Board

Remove the following parts

before you begin:
• Display
• Fan
• Hard drive
• Power supply

Tools

• ESD wrist strap and mat

• Torx T5 screwdriver
• Torx T8 screwdriver
• Torx T10 screwdriver
• Black stick
• Wireless card support tool
• Antenna tool
• Apple Thunderbolt Cable, USB-C cable, or SD card

© 2019 Apple Inc. All rights reserved. 073-00161-A | 81

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

Steps for Removal

1. Disconnect the speaker
cable from the logic board.

2. Remove the two T10 screws

from the right speaker and
disconnect the speaker.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 82

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

3. Use a black stick to

disconnect the audio cable
from the lower right corner
of the logic board.

4. Disconnect the
camera cable.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 83

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

5. Flip the locking bar on

the bottom section of the
logic board. Gently pull the
microphone flex cable out of
the connector to disconnect it.

Caution
Disconnect the cable. A
broken microphone flex
cable requires a rear
housing replacement.

6. Bend the microphone flex

cable and tape it to the rear
housing to prevent damaging
it while performing the rest of
the procedure.

Caution
Do not crimp the flex cable.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 84

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

7. Remove the piece of Mylar tape covering the lower left logic board screw. Place the piece of Mylar tape
on the rear housing for later use.

8. Disconnect the left

speaker cable.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 85

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

9. Remove the T8 screw from

the hard drive cradle.

10. Remove the hard drive cable

from the back of the hard
drive cradle.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 86

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

11. Loosen the black tape that

adheres the speaker cable
to the hard drive data and
power cable. Remove the
speaker cable and the hard
drive data and power cable
from the clip on the rear
housing.

12. Hold the wireless card

support tool by the handle.
Lower the tool (1) so it
rests on the edge of the
logic board. Then slide the
tool to the right (2) behind
the logic board near the
antenna connectors.
Note: Keep the wireless
card support tool in position
as shown while removing
or replacing screws
and disconnecting or
reconnecting antenna
cables.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 87

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

13. Remove the two T5 screws

from the antenna cowling.

14. Remove the antenna cowling and save it for reuse.

15. Use the antenna tool to

disconnect the connector
from the wireless card.

Important
Avoid using a metal tool,
which could damage
the cable.

16. Remove the wireless card support tool from the rear housing.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 88

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

17. Remove the antenna cable

from the groove in the
right speaker.

18. Remove the four T8 screws

from the logic board and
the four T8 screws from the
heat sink.
Note: Lay the computer
down when removing the
heat sink screws so they do
not fall into the chin.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 89

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

19. Slide the right speaker off to

the right.

Note: The logic board can

not be removed until the right
speaker is out of the way.

20. Remove the logic board from the rear housing.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 90

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

Steps for Reassembly

1. If installing a replacement logic board, transfer the following parts from the existing logic board:
• Flash storage (if present)
• Hard drive data and power cable
• Memory
• Audio (lower right)
Note: If the Mylar on the heat sink is missing or damaged, replace it with the new Mylar included with
the replacement logic board.

2. Lower the logic board into

the rear housing, inserting
the input/output connector
alignment pins into the
blind holes.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 91

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

3. Plug in an Apple
Thunderbolt Cable or
USB-C cable or insert an
SD card into the logic board
to ensure it aligns with the
rear housing.

4. Support the logic board

with one hand and reinstall
the right speaker, sliding
it behind the logic board
and into the rear housing.
Reinstall the two T10
screws in the speaker and
connect the speaker cable.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 92

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

5. Tuck the antenna cable into

the channel on the right
side of the speaker.

6. Reinstall the four T8 screws

in the logic board and the
four T8 screws in the
heat sink.
Note: The two longer heat
sink screws secure the upper
part of the heat sink. The two
shorter screws secure the
lower part of the heat sink.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 93

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

7. Replace the piece of round

Mylar tape on the lower left
logic board screw. If the
Mylar tape is missing, cover
the screw with a small piece
of Kapton tape.

8. Reroute the hard drive data

and power cable through the
clips in the hard drive cradle.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 94

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

9. Reinstall the T8 screw in the

hard drive cradle.

10. Remove any cables used for alignment on the rear I/O ports.

11. Reconnect the following

cables to the logic board:
• Camera (top left)
• Left speaker (below the
camera connector)
• Microphone flex
(lower left)
• Audio (lower right)

© 2019 Apple Inc. All rights reserved. 073-00161-A | 95

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

12. Place the wireless card support tool behind the logic board.

13. Align the bracket holes with

the screw bosses on the
logic board.

14. Use the antenna tool to

reconnect the cable to the
logic board.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 96

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

15. Reinstall the antenna

cowling by engaging the
teeth at an angle; then lay
it down over the antenna
connectors.

16. Reinstall two T5 screws.

17. Remove the wireless card support tool from the rear housing.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 97

iMac (Retina 4K, 21.5-inch, 2019) Logic Board

18. Ensure the antenna cable is

rerouted in the channel on
the right speaker.

19. Use a black stick or tweezers to open any flattened loops along the airloop gasket.

Reinstall the following parts to complete reassembly:

• Chin strap
• Power supply
• Hard drive
• Fan
• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 98

iMac (Retina 4K, 21.5-inch, 2019) Right Speaker

Right Speaker

Remove the following parts

before you begin:
• Display
• Fan
• Hard drive
• Chin strap
• Power supply
• Logic board

Important
You must replace speakers in
pairs. If you replace the right
speaker, then you must also
replace the left speaker. For left
speaker removal and reassembly
instructions, refer to the
Left Speaker section.

Tools
• ESD wrist strap and mat

© 2019 Apple Inc. All rights reserved. 073-00161-A | 99

iMac (Retina 4K, 21.5-inch, 2019) Right Speaker

Steps for Removal

1. Pull the speaker up and out
of the rear housing.
Note: The two T10 right
speaker screws were
removed during the logic
board removal procedure.

Steps for Reassembly

1. Slide the speaker into the

rear housing.

Reinstall the following parts to complete reassembly:

• Logic board
• Power supply
• Chin strap
• Hard drive
• Fan
• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 100

iMac (Retina 4K, 21.5-inch, 2019) Hard Drive Data and Power Cable

Hard Drive Data and Power Cable

Remove the following parts

before you begin:
• Display
• Fan
• Hard drive
• Chin strap
• Power supply
• Logic board

Tools

• ESD wrist strap and mat

© 2019 Apple Inc. All rights reserved. 073-00161-A | 101

iMac (Retina 4K, 21.5-inch, 2019) Hard Drive Data and Power Cable

Steps for Removal

1. Pinch the metal clip on
the hard drive data cable
connector to release the
cable from the logic board.
Then pull up to disconnect it.

2. Gently pull the hard drive

power cable connector to
disconnect the cable from
the logic board.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 102

iMac (Retina 4K, 21.5-inch, 2019) Hard Drive Data and Power Cable

Steps for Reassembly

1. Reinsert the hard drive
power connector into the
logic board.

2. Reinsert the hard drive data

connector into the
logic board.

Reinstall the following parts to complete reassembly:

• Logic board
• Power supply
• Chin strap
• Hard drive
• Fan
• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 103

iMac (Retina 4K, 21.5-inch, 2019) Flash Storage

Flash Storage

Remove the following parts

before you begin:
• Display
• Fan
• Hard drive
• Chin strap
• Power supply
• Logic board

Tools
• ESD wrist strap and mat
• Torx T8 screwdriver

© 2019 Apple Inc. All rights reserved. 073-00161-A | 104

iMac (Retina 4K, 21.5-inch, 2019) Flash Storage

Steps for Removal

1. Remove the T8 screw from
the flash storage card.
Note: The flash storage is on
the back of the logic board.

Caution
Ensure that data is backed
up before removing the flash
storage.

2. Gently pull the flash

storage straight out of
the connector.

Caution
Do not lift the flash storage
at an angle when removing
it from the connector.
A damaged connector
requires a logic board
replacement.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 105

iMac (Retina 4K, 21.5-inch, 2019) Flash Storage

Steps for Reassembly

1. Reinsert the flash storage
straight into the connector
on the back of the
logic board.

2. Reinstall the T8 screw to

secure the flash
storage card.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 106

iMac (Retina 4K, 21.5-inch, 2019) Flash Storage

Reinstall the following parts to complete reassembly:

• Logic board
• Power supply
• Chin strap
• Hard drive
• Fan
• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 107

iMac (Retina 4K, 21.5-inch, 2019) Memory

Memory

Remove the following parts

before you begin:

• Display
• Fan
• Hard drive
• Chin strap
• Power supply
• Logic board

Tools
• Torx T4 screwdriver

© 2019 Apple Inc. All rights reserved. 073-00161-A | 108

iMac (Retina 4K, 21.5-inch, 2019) Memory

Steps for Removal

1. Remove the four T4 screws

from the memory cover.

2. Remove the memory cover and save it for reuse.

3. Press the metal latches

outward to release the
memory from the socket.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 109

iMac (Retina 4K, 21.5-inch, 2019) Memory

4. Hold the memory by the

edges and gently remove it
from the slot.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 110

iMac (Retina 4K, 21.5-inch, 2019) Memory

Steps for Reassembly

1. Install the replacement
DIMM in the lower slot first,
then replace the DIMM in
the upper slot. Insert each
DIMM into the slot; then
press the DIMM down to
lock it in place.

2. Reinstall the memory cover.

3. Reinstall the four T4 screws

to secure the memory cover
to the logic board.

Reinstall the following parts to complete reassembly:

• Logic board
• Power supply
• Chin strap
• Hard drive
• Fan
• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 111

iMac (Retina 4K, 21.5-inch, 2019) Battery

Battery

Remove the following parts

before you begin:
• Display
• Fan
• Hard drive
• Chin strap
• Power supply
• Logic board

Tools
• ESD wrist strap and mat

© 2019 Apple Inc. All rights reserved. 073-00161-A | 112

iMac (Retina 4K, 21.5-inch, 2019) Battery

Steps for Removal

1. Grasp the battery with two
fingers. Push it toward the
metal clip (1) and pull it up
from the socket to remove
it (2).

Steps for Reassembly

1. Ensure the battery socket is open and free of dust.

2. Reinsert the battery into the socket with the negative side (no
markings) facing the metal clip.

Warning
If you incorrectly reinstall a battery or replace the battery with
an incorrect one, you risk explosion. Dispose of used batteries
according to local environmental laws and guidelines.

Reinstall the following parts to complete reassembly:

• Logic board
• Power supply
• Chin strap
• Hard drive
• Fan
• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 113

iMac (Retina 4K, 21.5-inch, 2019) Bluetooth and Wi-Fi Antennas

Bluetooth and Wi-Fi Antennas

Remove the following part

before you begin
• Display

Tools

• ESD wrist strap

• Torx T4 screwdriver
• Torx T5 screwdriver
• Wireless card support tool
• Antenna tool
• Black stick

© 2019 Apple Inc. All rights reserved. 073-00161-A | 114

iMac (Retina 4K, 21.5-inch, 2019) Bluetooth and Wi-Fi Antennas

The procedure is the same for

all three antennas. Refer to the
following image to determine
the location and cable routing
of the antenna you intend to
replace.
• Bluetooth antenna (1)
• Middle Wi-Fi antenna (2)
• Lower Wi-Fi antenna (3)

© 2019 Apple Inc. All rights reserved. 073-00161-A | 115

iMac (Retina 4K, 21.5-inch, 2019) Bluetooth and Wi-Fi Antennas

Steps for Removal

1. Hold the wireless card
support tool by the handle,
lower the tool so it rests on
the edge of the logic board
(1). Then slide the tool to the
right behind the logic board
near theantenna
connectors (2).
Note: Keep the wireless
card support tool in position
shown while removing
or replacing screws
and disconnecting or
reconnecting antenna cables.

2. Remove the two T5 screws

from the antenna cowling.
Set the cowling aside
for reuse.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 116

iMac (Retina 4K, 21.5-inch, 2019) Bluetooth and Wi-Fi Antennas

3. Use the antenna tool to

disconnect the connector
from the logic board.

Important
Avoid using a metal tool,
which could damage
the cable.

4. Use a black stick or your

fingers to gently remove the
antenna cable tape from the
rear housing.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 117

iMac (Retina 4K, 21.5-inch, 2019) Bluetooth and Wi-Fi Antennas

5. Remove the two T4 screws

from the antenna.

6. Remove the antenna from the rear housing.

Note: If you are replacing the

lower Wi-Fi antenna, remove
the antenna cable from the
channel in the right speaker.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 118

iMac (Retina 4K, 21.5-inch, 2019) Bluetooth and Wi-Fi Antennas

Steps for Reassembly

1. Reinstall the two T4 screws
in the antenna.

2. Reroute the antenna cable to the antenna connectors on the logic board.

3. Align the bracket holes with

the screw bosses on the
logic board

© 2019 Apple Inc. All rights reserved. 073-00161-A | 119

iMac (Retina 4K, 21.5-inch, 2019) Bluetooth and Wi-Fi Antennas

4. Use the blunt end of the

antenna tool to reconnect
the antenna to the
logic board.

5. Reinstall the antenna

cowling by engaging the
teeth at an angle. Then
position it over the antenna
connectors.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 120

iMac (Retina 4K, 21.5-inch, 2019) Bluetooth and Wi-Fi Antennas

6. Reinstall the two T5 screws

into the antenna cowling.

7. Remove the wireless card support tool from the rear housing.

8. If you replaced the lower Wi-Fi antenna, ensure the antenna cable is routed in the channel on the
right speaker.

9. Use a black stick to open

any flattened loops along
the airloop gasket.

Reinstall the following part to complete reassembly:

• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 121

iMac (Retina 4K, 21.5-inch, 2019) Stand

Stand

Remove the following parts

before you begin:
• Display
• Fan
• Hard drive
• Chin strap
• Power supply
• Logic board

Tools
• ESD wrist strap and mat
• Torx T8 screwdriver

© 2019 Apple Inc. All rights reserved. 073-00161-A | 122

iMac (Retina 4K, 21.5-inch, 2019) Stand

Steps for Removal

1. Remove the seven T8 screws

in the order shown.

2. Lift the rear housing off of the stand.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 123

iMac (Retina 4K, 21.5-inch, 2019) Stand

Steps for Reassembly

1. Align the two pins on the stand with the pin holes on the mechanism.

2. Reinstall the seven T8

screws in the mechanism in
the order shown.

Reinstall the following parts to complete reassembly:

• Logic board
• Power supply
• Chin strap
• Hard drive
• Fan
• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 124

iMac (Retina 4K, 21.5-inch, 2019) Mechanism

Mechanism

Remove the following parts

before you begin:
• Display
• Fan
• Left speaker
• Hard drive
• Chin strap
• Power supply
• Logic board
• Right speaker
• Stand

Tools
• ESD wrist strap and mat
• Torx T10 screwdriver
• Display support stand

© 2019 Apple Inc. All rights reserved. 073-00161-A | 125

iMac (Retina 4K, 21.5-inch, 2019) Mechanism

Steps for Removal

1. Place the rear housing in the display support stand.

2. Remove the four

T10 screws from the
mechanism.

3. Peel the tape from the top right of the mechanism and save it for reuse.

4. Lift the mechanism off of the rear housing.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 126

iMac (Retina 4K, 21.5-inch, 2019) Mechanism

Steps for Reassembly

1. Position the mechanism in the rear housing.

2. Reapply the tape to the top right of the mechanism.

3. Reinstall the four T10

screws in the mechanism.

Important
Ensure that the mechanism
is fully seated after
tightening the screws to
avoid hinge noise.

Reinstall the following parts to complete reassembly:

• Stand
• Right speaker
• Logic board
• Power supply
• Chin strap
• Hard drive
• Left speaker
• Fan

© 2019 Apple Inc. All rights reserved. 073-00161-A | 127

iMac (Retina 4K, 21.5-inch, 2019) Rear Housing

Rear Housing

Remove the following parts

before you begin:
• Display
• Camera
• Fan
• Hard drive
• Left speaker
• Power supply
• Logic board
• Right speaker
• Chin strap
• Stand
Note: After you have removed
the parts listed above, the
rear housing is the only
remaining part.

Tools
• ESD wrist strap and mat

© 2019 Apple Inc. All rights reserved. 073-00161-A | 128

iMac (Retina 4K, 21.5-inch, 2019) Rear Housing

The replacement rear housing includes the following removable parts, which are available
separately:

• Mechanism
• Mechanism screws
• Bluetooth antenna (upper antenna)
• Wi-Fi antennas (middle and lower antennas)

The rear housing includes the following nonremoveable parts, which are not available
separately:

• Wi-Fi antenna (in silver circle behind Apple logo)

• Microphone flex cable
• Power button and cable
• AC inlet
• Audio input jack and cable
• Airloop gasket

Caution
Always handle the rear housing with two hands: one hand on the lower left corner and one hand on the
lower right corner. Mishandling the rear housing could bend the aluminum and cause alignment issues.

© 2019 Apple Inc. All rights reserved. 073-00161-A | 129

iMac (Retina 4K, 21.5-inch, 2019) Rear Housing

Reinstall the following parts to complete reassembly:

• Stand
• Right speaker
• Chin strap
• Logic board
• Power supply
• Left speaker
• Hard drive
• Fan
• Camera
• Display

© 2019 Apple Inc. All rights reserved. 073-00161-A | 130