iMac Intel 21.5" Retina 4K Display (2017) Logic Board Replacement

Written By: Adam O'Camb

Comments: 92

iMac Intel 21.5" Retina 4K Display (2017) Logic Board Replacement

Difficulty

Difficult

Steps

Time Required

1 - 2 hours

Introduction

Follow the steps in this guide to remove or replace the logic board in a 21.5" Retina 4K Late 2017 iMac.

Some images in this guide use a 2015 iMac, which has minor visual differences. These differences do not affect the repair procedure.

This guide is marked "potentially dangerous" because it 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.

Tools

Parts

iMac Intel 21.5" (2012-2019) Adhesive Strips

Step 1

With the hinge free to move, the iMac will be unbalanced and hard to work on. Repairs are fast and easy with an iMac service wedge, but can be completed without one.
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.

The wedge is an extremely tight fit for this model. I was worried that the amount of force needed to use it as shown might damage the stand, so I used it with the long side down instead. It worked fine that way and didn’t need anywhere near as much force to insert.

roberttrevellyan - 19/09/17

Here’s a good YouTube vid on upgrading the RAM: Can a Normal Person Upgrade the RAM in the 2017 21.5" iMac?

Dan - 12/02/18

Here are a couple tips from me:

1) Expose the adhesive to extreme temperatures. I did this by transporting my iMac in my car, screen-down on a piece of cardboard on a cold February morning (in Chicago). When I went to pick up the iMac, the screen practically fell off the chassis. I would have been distraught by this if I hadn’t already planned this replacement. So it was a happy accident.

2) Remember to expell the residual power from the power supply by pushing the power button while the iMac is unplugged. This does NOT guarantee it’s safe to touch, but when I accidentally brushed the solder and exposed capacitors, I didn’t get shocked.

jerrid_foiles - 31/03/19

Instead of using the wedge, I placed the iMac faced up with the top side (web cam) facing me while I ran the pizza roller around. It worked out great!

Sam Fung - 06/06/19

“All iMacs also come with a traditional hard drive” mine doesn’t!! it’s HDD bay is completely empty, no SATA cable or anything. I guess I’ll have to upgrade the PCIe SSD instead.

Chris Hughes - 10/11/19

There is no replacement glass for this model, it is part of the LCD and impossible to remove or replace- the entire LCD has to be replaced unfortunately if the glass is cracked or damaged. You will have to Google search for a replacement. Also be careful with some of the lock tight tork screws as I broke one of my screw mounts taking one out.

Phil Tesone - 18/01/21

I used this service wedge but also found it a very tight fit. The same stabilization can be achieved by using a big rolled up towel.

Ernst -

While this is a good instruction guide, I recommend to also look at OWC’s instruction video about drive installation, before starting the exercise. Those install videos are very detailed and useful.

Ernst -

Main advice: TAKE YOUR TIME with the pizza roller.

Make several passes, until you really feel like there's no more sticker in the way. Stay away from the camera though (approx. 1inch / 2.5cm on both sides). This will reduce the work left with the plastic card. Adhesive is really on the edge of the screen so there is absolutely no need to go any further than the recommended 1cm / 3/8inch depth.

Where are the sensitive parts?

Facing your iMac, imagine you're looking at a watch. There are antennas on 1, 2 and 4 o'clock. Do not insert any metal piece there (nor anywhere else, btw). Other than that AND the screen cables underneath the camera, not much danger.

Froggy Manny - 23/03/23

Step 2

Starting on the left 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.

Don’t get too worried about starting exactly where the picture says. The glue is stronger in some parts so just start wherever is easier and then work slowly and patiently around in the direction shown.

Richard Cook - 15/02/19

As this guide doesn’t cover replacing the adhesive strips, I found referring to the following was useful (noting that it’s not for the same model of iMac, so the modification they mention wasn’t necessary): iMac Intel 21.5" EMC 2544 Adhesive Strips Replacement

Alan Digby - 24/06/20

It is very easy to crack the glass in front of the LCD during this step. I used the guitar pick, maybe it was too thick… crack is just on the frame but anyway it is disappointing :(

Nikolay - 30/06/20

This part of the exercise should be done with extreme patience. I took my sweet time with the opening tool, rolling it through the entire panel and enclosure gap over and over again, until I was very sure no parts were sticking together anymore. And when I thought I was I done, I decided to do it over again.

Ernst -

You can "warm up" the adhesive before try to cut it with the tool using a hair dryer. Heat the edges for about a minute, keep moving it so you don't cause stress in the glass. Also the above note.. use the tool and then the cards. Do not use a guitar pick or other objects as the thickness will cause you to break the front glass, which is a bonded part of the display (expensive).

Carl Schultz -

Merci pour ce conseil

bry nicolas -

Step 3

Use the tool like a pizza cutter—roll it along through the gap, and it will cut the foam adhesive through the center.
Be sure to always push with the handle behind the cutting wheel. If you pull, the wheel might get pulled out of the handle.
Run the tool up along the left side of the display.

Erreur de traduction: "de bas en haut" et non de" haut en bas" sur le côté gauche de l'écran

Moreau - 15/04/17

If re-opening a screen that was opened and re-attached using iFixit’s adhesive strips, I would strongly recommend heating it first with an iOpener, heat gun or hair dryer. 20 minutes after attaching with the iFixit adhesive I tried to open it again with the pizza slicer to fix something and cracked the screen on the left-hand side.

plasticpool - 08/12/20

Step 4

Continue running the tool up around the top left corner.

Ne pincez pas l’écran avec l’autre main. Vous exercez une pression inutile sur le verre et empêchez la roulette de couper le joint.

phfoglia -

Step 5

Cut the adhesive along the top left of the display.

Step 6

Continue along the top of the display.
You may want to run the tool back and forth through what you've already cut a few times, to ensure you get as much of the adhesive separated as possible.

In this step can I cut along the display without make any damage to the front camera?

arisnordico - 22/01/15

Hi! Actually - there is no need to cut the tape around the camera area - there is no tape to cut at all! And so, the way go is easy - just pass 10 mm to the left and to the right from camera and start cutting!

P.S. Just did the whole procedure to replace a RAM and to add SSD on PSIe an hour ago! Seems to be different reading the instructions... you know - 2/10 and so on. But it's really not that hard, trust me. I'll give it 5/10.

P.P.S. By the way there is one trick to pass the difficult steps. Any action which requires pulling smth (motherboard, speaker, power supply unit) from the narrow crack (or should i say - slit?) at the bottom of your Imac is really not so easy.

And the trick is to first remove a thin metal stripe with some kind of insulation on it which held by 5 small (very small!!) screws at the bottom of your Imac. After you done it - it's easy to pull everything! Pay attention to the fact that one of this 5 screws at the center are more shortly than others.

dv1977 - 24/01/15

I did all steps like this manuell but now the Display wont work only some colered strips are to see! Whats happend??

Can anybody help me ? Maybe the connector cable is broken?

djfanta - 28/05/15

Check both connectors, probably one of them not seated well

pzhivulin - 12/06/15

You can add a SATA SSD if you already have a PCIe SSD Factory?

kaserlik - 30/05/15

If you're changing cracked EMC 2638 display to new assembly, there's two more steps:

Step 24: Use the tip of a spudger to flip up the metal retaining bracket on the display data cable.

Carefully pull the display data cable from its socket on the display assembly.

Step 25: Use the tip of a spudger to unplug bracket of the thermal sensor small cable near display data cable.

Carefully remove scotch tape covering thermal sensor. Using iSesamo or flat tip of the spudger carefully peel the thermal sensor away.

pzhivulin - 12/06/15

omg - forgot to switch the termal sensor from the old display...

now fan runs like crazy...

Andrei Balotescu - 05/02/16

The key thing is to never put any force on the opening tool when working through the tape. Just roll it back and forth with ease.

Ernst -

Step 7

Push the tool around the top right corner of the display.

Step 8

Wheel the tool down along the right side of the display.

Step 9

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.

Yes, do it many times to loosen the adhesive.

Noah Ralston - 19/07/18

Would be good data to show the 3 areas (wifi antennas where the "tape" is larger and covers them. The rest of the "tape" is 1.4" and easy. Also after removing the display, be sure to remove the old "tape" from both the display and the rubber parts of the case. Use the spudger to start an end and it should pull off easily. Careful on the baackside of the display as you can scratch off the black paint/covering.

Carl Schultz -

Step 10

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.

this step is extremely important NOT to stick in the cards too far….. doing so, you risk a 600 euro replacement as I experienced………

Edgar Broekema - 18/11/17

I drew a 3/8” line on my cards with a marker first.

Max Romano - 27/09/20

I’m reading this on the EU store, please change all measurements to cm/mm.

Morgana Devina - 30/10/20

@ifixit The next batch of cards you create should have a line printed on the card 3/8” in from the edges. Would make a nice reference.

Richard Giratd -

Here’s where OWC provides glass removal suction cups, which is a better solution than plastic cards.

The suction cups help to easily lift the glass panel, without risking the damaging of any internal wiring that the plastic cards could cause.

Ernst -

Better to remove stand wedge at this point? Can’t see from pics

derekrobinson -

Step 11

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".

This part must be done very carefully or you can damage the flat cable from display, despite it was under a iron cover.

Cassio Machado - 17/09/16

Step 12

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.

You don't need to do it like this, simply open the iMac bendidng the LCD completely and use the pizza cutter to remove the adhesive.

Felix - 31/05/20

Using glass removal suction cups will avoid running this risk of damaging the camera (or any wiring).

Ernst -

Step 13

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

Step 14

Insert a second plastic card into the gap between the display and frame near the top left corner of the iMac.

Step 15

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.

Step 16

Slide the plastic card toward the center, again stopping just before the iSight camera.

Step 17

Wedge the plastic card back into the top left corner.

Step 18

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.

Step 19

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.

It was difficult to remove this connection. I ended up having to gently pull-up vertically a little on the wire side to unsnap it about 1mm and then horizontally wiggle it out.

delacrj2 - 22/12/17

I had a difficult time removing this connection. I had to lift the wire-side about 1mm before it unsnapped and then carefully wiggle it out horizontally.

delacrj2 - 22/12/17

Can this cable be replaced? I am worried mine is damaged. I have no display after the screen fell and stressed the display flex cables following an SSD upgrade.

Jeremy Brainard - 19/04/19

This step should be done with extreme caution and care, as this step 19 is not described in great detail (sorry, author).

The first (most outward) cable will slide out by gently pulling it by its tabs. The second (inner) cable is more tricky, as the locking lever must be moved backward first, before gently pulling backward on the cable connector. The angled tweezers are useful here, to help lift that locking lever, because fingers are too big for this.

Ernst -

be VERY careful and SLOW...take your time. These displays crack VERY easily when removing and they'll spider web on you. I've done probably 20 or so of these and cracked 3 being super careful.....ugh.

Faslane -

I found the best way to unplug this display power cable was to use my right hand, and the fingernails of my index finger and thumb to grab the ends of the tabs on either side of the connector, squeeze, and pull the connector out gently.

Phil McInnis -

i think the cable nearest the case edge is held in by friction and can be gently pulled, maybe with fingernails or a spudger. The next cable is held by a wire lever clip as described above it unlocks so the cable can be removed. These cables are also fiddly to re-insert, I didn't get one of them home and had no display after power-up, so at the end, don't re-seal the screen until tested.

Peter Taffs -

Step 20

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.

Cannot seem to find a replacement cable for this, as I suspect mine is damaged. Can’t even find a part number. Anyone know what it might be?

Jeremy Brainard - 19/04/19

https://www.amazon.com/gp/product/B08TTL...

That's the part I ordered for mine and it seems to work ok. I did make a point of contacting the seller and advising them of my requirement and they ensured I got the right part and it matches the description of the link. Bear in mind I bear no responsibility if yours does not work since I am just sharing what I did and what I ordered. Thanks.

Jim Stanford -

I also need that cable.

cameronjpu - 24/03/20

It's a little difficult to tell... but looking at the connection to the logic board on the video data cable, are the pins faced up or down?

On the display, same question since it appears you have to "twist" the cable during the reconnection step.

Jim Stanford - 09/05/22

For this particular cable, take a good look before pulling on anything. Plug is locked on its socket with a bracket. You can lift this bracket by holding the small, flat black plastic handle that is attached to it. If you're struggling to grab it, use the end of the pizza roller handle to lift it, or the tweezers. Cable then comes off by pulling parallel to the main board.

Froggy Manny -

How can I tell if either of this cable is bad? My iMac display won't turn on after reconnecting it. I'm using an external display and everything is working except for the iMac display. If I go to settings - display the built-in display is recognize. But again nothing shows up in the screen - not even the apple logo when turning it on.

Carlos Sosa -

Step 21

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.

The best way to remove the chin adhesive is to use the tabs at either end (there are two strips that run from each outside corner to near the centre). Carefully pull the tabs up and the strips should peel off.

Advance Technical Service - 03/04/19

Step 22

Be very careful not to touch the capacitor leads or any exposed solder joints on the back of the power supply (boxed in red).
Grasp the small tab at the end of one of the bottom edge display adhesive strips and pull the adhesive toward the top of the iMac to remove it.
Repeat this step with the other adhesive strip and remove it.
If either adhesive strip breaks before it's removed, use a plastic card to slice through the remaining adhesive.

At step 21-22, releasing the adhesive strips from the bottom of the display, I noticed a tab on the outer end of each strip. Pull the tab to remove the whole strip, no need to mess around with the plastic cards!

roberttrevellyan - 19/09/17

Instead of the plastic cards, use the flat end of a spudger. Use it as scraper. Be careful as there are antennas mounted on the inside edge of the frame on the right side (facing you), and the top right (facing you). The original adhesive strips are on those as well. - ECJ

ECJohansen -

A little bit of hot air (eg. hair dryer) will help soften the adhesive. Use a piece of cardboard or equivalent if you want to avoid blowing hot air towards the electronics.

Be careful to remove absolutely everything - any remainder will create a bump and prevent your screen from sticking back to the frame when reassembling.

Froggy Manny -

A little bit of hot air (eg. hair dryer) will help soften the adhesive. Use a piece of cardboard or equivalent if you want to avoid blowing hot air towards the electronics.

Be careful to remove absolutely everything - any remainder will create a bump and prevent your screen from sticking back to the frame when reassembling.

Froggy Manny -

Step 23

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.

Après l'étape 23, j'ai suivi les instructions de la vidéo intitulée: Upgrade RAM in a mid-2017 21-inch iMac without complete disassembly.

Lien: https://www.youtube.com/watch?v=_k9I7N9B...

J'ai pu upgrader la RAM en enlevant juste le ventilateur.

Koala -

Step 24

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.

I would recommend that those trying this have the project tray to contain all of the screws.

Mikkif - 30/03/20

2 notes for reassembly, carful with screws not to strip the heads as they are really really small, make note to cut a gap in the the adhesive over the whole for the microphone.

I managed to strip the head of one of the screws when putting it back in. So be carful with them when putting in / taking out. If you strip it on the way out you will need to take a fine drill and rill it out. Going back in, well as long as you never need to strip it down again not a problem.

The second problem is a real pain, you need to make sure to cut a gap in the adhesive just to the right of Center at the button to allow for the microphone opening. If you don’t, the adhesive tape will stop any real pick up on the Mic, so you just need to cut a small gap in it before putting on the screen. Unfortunately I didn’t find this out (or do my checked before sticking it all back down, so have to pull screen back off and reapply new adhesive with a cut out in it at an other time.

Andrew Taylor - 13/09/20

Refer her for more info on the mic / adhesive work around —> Muffled Microphone - iMac 21.5" (mid 2017) - Following Adhesive Strips

Andrew Taylor - 13/09/20

Step 25

Remove the lower support bracket (a.k.a. "chin strap") from the iMac enclosure.

Keep this long, aluminium part very straight when pulling it away or you might bend it

Froggy Manny -

que pasa si no coloca esta pieza?

CARLOS -

Step 26

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

At step 26, when reassembling, it's super easy to over-tighten the 9mm screw and strip the brass ferrule out of its hole in the plastic bracket (%#*@).

roberttrevellyan - 19/09/17

Mine has 4 different length screws, the two red colored 21mm screws in this guide are actually two differ lengths

anonymous 523 - 19/10/20

Mi imac does not have a HDrive whats the steps to follow?

Charlie - 05/02/21

buongiorno, l'imac del 2019, non monta alcuna ssd, ma monta una m2 direttamente sulla scheda madre!

pertanto nella guida andrebbe aggiunto il cavo sata con sensore temperatura da aggiungere sulla scheda madre, per poter collegare un nuovo hd ssd altrimenti rimarrete come me bloccati con un imac aperto e non assemblato, in attesa di ricevere il cavo acquistato su internet da amazon o terze parti.

vi consiglio inoltre di aggiungere una foto reale del ò'imac 2019 nella guida in cui manca l'ssd, renderà subito la problematica che avranno in molti!

Donato Altomare -

Hi, mine doesn’t HAVE an HD/SSD to remove, the bay is empty (yes it was fully working yesterday. So what do we do ? I see someone else with the sane issue above….

Jeroen Speak -

Step 27

Remove the left and right hard drive brackets from the iMac.

Step 28

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.

Step 29

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.

Step 30

Remove the two 7.2 mm T8 Torx screws securing the power supply to the rear enclosure.

Step 31

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.

Step 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.

Step 33

Slide the power supply to the right to clear the screw posts on the rear enclosure.

Step 34

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.

Step 35

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.

Step 36

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.

I didn't bother to remover the power supply lead in this stage but simply flippedthe circuit board over onto the lower body of the iMac (NOT placing it directly onto the metal but onto a sheet of plastic)

Fettler -

Step 37

Remove the power supply from the iMac.

Step 38

Gently pull the fan cable connector straight out of its socket on the logic board.

Step 39

Remove the three 10 mm T10 Torx screws securing the fan to the rear enclosure.
The uppermost screw has a rubber standoff adhered to its head to support the display—leave this in place.

Step 40

Remove the fan from the iMac.

Step 41

Lift the hard drive from the edge nearest the logic board and pull it slightly out of its recess.
The hard drive is attached by a single SATA power/data cable—do not attempt to fully remove it from the iMac yet.

The newer drives have rubber ends and an adhesive side, be careful removing them if replacing the drive and be sure they are securely pushed back into the holder

Carl Schultz -

Step 42

Use a spudger to disconnect the single SATA power and data combo cable by gently prying its large plastic connector away from the hard drive.

When reconnecting the SATA cable, there is nothing to make the connector hold still, and it is hard to reach, so it took several tries. I ended up taking off the rubber baby buggy bumpers to get more room, and then jamming them back on after getting the SATA connector snugged up.

bstaud - 28/03/18

If by rubber baby buggy bumper, you mean left speaker, then yes, I agree. Reinstall the hard drive before the left speaker.

jerrid_foiles - 31/03/19

Kudo to @jerrid_foiles! I was going crazy trying to attach the SATA cable until I took the two screws out of the left speaker and slid the top end of it aside by about 3/4 inch. Make the whole process SO MUCH easier!!

jiclark - 11/07/19

We solved this by removing the hard drive tray screw, then inserting the cable into the SATA hard drive. Then hold the hard drive a bit out of the way to insert the 7.3mm hard drive tray screw.

Marjie - 25/07/19

Agree with this method, found it an impossible task to reconnect the SATA connector until removed the tray screw, then it was relatively easy to reconnect and then replace the tray screw.

daveedwards - 20/09/19

Also agree with this method!

jmorphett5 - 30/04/20

Step 43

Remove the hard drive assembly from the iMac.

When reassembling, I found it easier to loosen the HD tray screw from Step 48 and pull the tray outwards from the left side in order to plug the SATA cable in more easily.

Cool_Breeze - 10/05/17

Thanks! I, too, had a hard time reconnecting the SATA cable.

boboswell - 16/06/17

I found this helpful too!

Anwar - 07/02/21

And DON’T do what I did, which is to remove the left speaker - which can easily lead to breaking the cable between the power on button and the power supply. The cable is routed through a hidden slot at the very bottom of the left speaker

bsmith1 - 15/12/17

I did loosen the speaker so I could get a tool behind the SATA cable to push it on to the SSD drive. Otherwise hard to align cable.

Noah Ralston - 19/07/18

I found the easiest way to connect the SATA cable was to not screw the plastic hard drive tray down until you plug the drive in. That way you can easily push the connector in and due to the cable you’ve got some wiggle room. You can position the tray then just lift one end of the drive up and secure the screw. Then just push the drive down.

Chris Caldwell - 21/03/19

This was the step that I had the most trouble with. I’m used to replacing a hard drive in a MacBook Pro, where the “plug” that you plug the drive into is a rigid thing that you can firmly press the hard drive into.

With the iMac, the plug is situated on the end of a non-rigid cord, so the plug moves back when you try to snap a drive into it. Also, those two rubber gasket things that you adhere to the side of the drive really make it difficult to maneuver the now-overly-chubby drive towards the plug.

After must frustration/concern, what I ended up doing was temporarily removing the rubber gasket things, using the “spudger” as kind of a lever behind the “plug on a cord” so that it didn’t move as much, and then pushed the gasket-less SSD into the plug.

Once I got it connected, I put the rubber gaskets back on the sides of the SSD and kind of coaxed it down into place, using the pointy end of the spudger to get the chubby corner pieces to “sit” correctly in the rigid plastic tray that the SSD kind of rests in.

Jack OnFlickr - 29/05/19

From another comment elsewhere on this repair, I *highly* recommend removing the two screws holding the left speaker in place, then sliding it just a tad out of the way to be able to easily attach the SATA cable. You don’t have to move it much to make the whole process so much easier!

jiclark - 11/07/19

Step 44

Remove the 7.3 mm T8 Torx screw securing the hard drive tray to the rear enclosure.

it`s a t10 screw..! ;)

happymac venezuela - 31/03/19

I found it easier to connect SATA cable before fixing tray.

Mārtiņš Jansons - 29/11/20

Step 45

Remove the hard drive tray.

I am following these procedures for the following: iMac Retina 4K - 21.5" - 3GHz Quad Core - Radeon Pro 555 2GB - 4GB/4GB (8GB total - 2 slots) 2400MHz DDR4 SO-DIMM - Mid 2017 - Model: MNDY2LL/A - iMac18,2 - A1418 - 3069. In my case, the SATA cable is clipped into the bottom of the hard drive tray. Pull the hard drive tray up slightly and angle to reveal clips. SATA cable pops out from the side of each clip.

iannai29 -

Better yet, after reading Step 49 - no need to remove SATA cable from the bottom of the hard drive tray.

iannai29 -

Step 46

Gently pull the left speaker cable straight out of its socket on the logic board.

Step 47

De-route the left speaker cable by pulling it straight up out of the retaining clip in the back of the rear enclosure.

Step 48

Similarly to the previous step, de-route the SATA and power cables by pulling the braid straight up out of the retaining clip.

Step 49

Peel up the piece of tape connecting the left speaker connector to the SATA power and data cables.

Step 50

Flip up the metal retaining bracket on the FaceTime camera cable connector.
Pull the FaceTime camera cable straight out of its socket on the logic board.
This is a delicate connector that can be easily damaged.

Step 51

Remove the two 4.0 mm T5 Torx screws securing the four antenna connectors to the AirPort/Bluetooth card.

Step 52

Disconnect all four antenna connectors by prying them straight up from their sockets on the AirPort/Bluetooth card.

Step 53

Gently pull the right speaker cable connector straight down and out of its socket on the logic board.

Step 54

Use the flat edge of a spudger to pry the headphone jack cable connector from its socket on the logic board.
Push the cable slightly to the right.

Step 55

Peel off the tape covering the exhaust duct.

Step 56

Remove the following T8 Torx screws securing the exhaust duct to the rear enclosure:
Two 6.2 mm screws
Two 4.7 mm screws

Step 57

Use the tip of a spudger to flip open the retaining flap on the microphone ribbon cable ZIF socket.
Be sure you are prying up on the hinged retaining flap, not the socket itself.
Gently pull the microphone ribbon cable straight out of its socket.

Step 58

Remove the four 7.3 mm T8 Torx screws securing the logic board to the rear enclosure.

Step 59

Tilt the top of the logic board away from the rear enclosure.
As you tilt the logic board, pull the right speaker connector to the right and out of the way of the board.
Lift the logic board straight up and out of the iMac.
Be careful not to snag the board on any of the rear enclosure's screw posts.

When repairing, I accidentally broke a small piece of what it seems to be a resistor. Mac still works fine and diagnostics reports no errors. Be careful when removing the mother carefully so it doesn’t hit the aluminium cover.

Andres Urena - 30/01/21

Step 60

When reassembling your iMac, be very careful to align the exterior I/O ports correctly. The logic board can sit crooked even when secured with all its screws.
Use a USB flash drive and/or ethernet cable to keep the logic board seated correctly while you tighten the screws.

Step 61

The SATA data connector has a clip that must be pressed to allow removal.
While pressing on the clip with your thumb, lift and disconnect the SATA data connector from its socket on the logic board.

Step 62

Grasp the hard drive power connector and gently pull it out of its socket on the logic board.

Step 63

Two clips secure the RAM module in place, one on each side. Using your fingers, spread the clips away from the RAM module.
When released, the RAM module will pop up at a slight angle.

Step 64

Lift the RAM module to an angle of about 30 degrees and slide it out.
When handling the RAM module, touch only the outside edges. Take care not to touch the gold-colored contact points along the bottom edge.
To install a new RAM module, slide it in place at about the same angle until it is snug, and then swing it downward until the two clips snap into place.

Step 65

Peel off the four black tamper-evident stickers covering the heat sink mounting screws.
Remove the four T10 screws that secure the heat sink from the backside of the logic board.
During reassembly, tighten these screws one full turn at a time, alternating in a cross pattern. This will gradually increase the clamping pressure evenly across the surface of the CPU. Continue gradually tightening the screws until they're snug and the entire spring plate lays flat against the logic board.

Step 66

Lift the heat sink retaining spring and its bracket off the logic board.

Step 67

Fully loosen the three captive T8 screws securing the heat sink over the GPU.
Remove the two 5.4 mm T8 screws securing the heat pipe to the logic board.

Step 68

Note that the CPU will most likely remain stuck to the underside of the heat sink as it's lifted out. Take care not to damage it.
Lift and remove the heat sink assembly from the logic board.
When reassembling your iMac, remove the CPU from the heat sink and reinstall it separately from the heat sink. This will make sure it's installed correctly and prevent damage.
Follow our thermal paste application guide to reapply the thermal paste to the graphics processor (GPU). You should also replace the heavy thermal compound or apply thermal pads to the VRAM chips.

Step 69

Remove the two 3.3 mm T5 Torx screws securing the AirPort/Bluetooth card to the logic board.

Step 70

Slightly lift the AirPort/Bluetooth card and pull it straight out its socket.
Do not use excessive force to pull the end of the AirPort/Bluetooth card away from its socket on the logic board. Doing so may damage the socket.
When reinstalling the card, be sure it is properly seated before reinstalling the retaining screws.
If the AirPort/Bluetooth card is properly seated, its screw holes should align with those on the logic board.

Step 71

Only the logic board remains.
If your iMac is equipped with the Fusion Drive option, you will also need to remove the SSD from the back side of the logic board and transfer it to your new logic board. Remove the SSD by following these steps.
The logic board includes the PRAM battery. If your replacement logic board does not include the battery, you can transfer the battery over from your old logic board by following these steps.
When reassembling your iMac, remove the CPU from the heat sink and reinstall it separately from the heat sink. This will make sure it's installed correctly and prevent damage.
Follow our thermal paste application guide to reapply the thermal paste to the graphics processor (GPU). You should also replace the thermal compound or apply thermal pads to the VRAM chips.
During reassembly of the logic board, pay attention to the position of the I/O connectors. When the board is back in the case, insert a USB or Thunderbolt cable into one of the connectors to align it perfectly.

Conclusion

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

Author

Adam O'Camb

Member since: 11/04/15

195421 Reputation

5 comments

Hello, very good explanation .

Got a question please

I have the imac 4k 21.5 late 2015, can I change the motherboard? To be able to upgrade ram, does or fits in the 2015 body and with all parts?

Eleuterio Sousa Ramos - 06/07/19

I did it. Everything went very well, but the two thunderbolt plugs are not working after all. LAn and USb is doing well. Any suggestions about it?

Gunter Holder - 20/05/20

I am running into the same issue after upgrading the RAM and SSD. Have you found a fix?

William Sandidge - 02/09/20

Can the GPU be upgraded?

Mien Yockmann - 15/08/20

Re” I did it. Everything went very well, but the two thunderbolt plugs are not working after all. LAn and USb is doing well. Any suggestions about it?” You need to disassemble the iMac again to the point where the logic board is loose (step 58-59 on this guide). Connect a thunderbolt cable, a USB cable and and ethernet cable to the back of the iMac with the logic board in place but the logic board screws not tightened. This will ensure the ports are correctly lined. Tighten the logic board screws and finish the reassembly (at this point you can disconnect the cables.) . This should solve the problem.

jvilella -