Sostituzione CPU iMac Intel 21.5" EMC 2544

I have (21.5 inch, mid 2017, 2.3 ghz) base model same as this but not 4k. How much max ram can I install in my iMac??

This guide contains many extra steps for what should be a straight forward, simple parts replacement without disturbing more than the display, left hand speaker and removal of 4 logic board screws for play. Nothing else except for the left hand speaker wire & iSight cable from logic board, the lower support bracket and loosening the speaker so as to move it around a bit.

For the ram, I bent a pair of cheap tweezers long ago supplied with these replacement kits to the perfect angle for holding, locating and inserting the ram into the slots under the logic bd after moving each retainer w/spudger and popping out the old. Pay attention to the orientation of the ram when removing/inserting the ram! An automotive mirror is handy along with a small flashlight for closeups. Once the ram is aligned properly substitute your fingers for the tweezers, ease it into the slot, push up & engage! Reinstall screws and all else. I have done this job successfully this way countless times. For a tweezers pic contact me!

Additionally, if a blade is present, I install the OSx system on the blade and everything else, apps and home folders on the new SSD. You get the very fast boot off of the blade and the full ssd for all else!

Always use a hairdryer!! I cracked my glass

Don't forget to place the mac face up on the table. Unlike older models, there is no more flap at the bottom holding the display in place. If you do these steps with the Mac upright, the screen will pop out, hit your table, and shatter :( Don't ask me how I know.

So sorry. Thanks for that caution.

Ne forcez surtout pas et soulevez l’écran par les deux extrémités ! Il faut que tous les adhésifs soient bien découpés pour que l’écran se dégage du boitier sans effort. Toute torsion de l’écran peut entraîner une superbe fissure sur le verre :-/

As seen in photo:

bottom cable pulls up

top cable cable pulls right, after safety clip opened

There are pull tabs at each side off the bottom edge to allow easy release of the tape

DarrenG’s observation about the pull tabs saved me a ton of time trying to pry the display as per the original instructions. Thanks!

The roller tool for slicing open the display works great for this step. Get in there like using the card and roll across the bottom to slice through the remaining adhesive.

After removing the display, I also removed the 3 screws for the processor fan, disconnected the power connector for it and set the fan shroud aside. Disconnecting the remaining cable (similar style to 1 of the cables for the display) that is in the way of the RAM chips is all that's left to do. I was then able to access and quickly remove the two Apple-provided RAM chips, and replace them with 3rd party RAM. Turning the iMac on its side, so that it's in a position where you're physically putting the RAM chips DOWNWARD into their respective slots is the best way to go about uninstalling and reinstalling the chips. Using a narrow but long'ish plastic spudger tool is the best way to defeat the spring-tabs which hold the RAM chips in place. After removing the LCD display, changing the RAM is about a 10 minute process!! And I'd SURE prefer not to remove all the parts and risk damage to the iMac via the standard procedure listed. As per usual, take your time and work gently :-)

Teardown the whole machine just to change RAM? While preparing to comment on this procedure I just noticed the comment made by Mitch K above. I ran pretty much the same procedure that he describes this afternoon (steps 1-23, 43-45, and step 55). Then I swapped out the original 2x4GB RAM chips for 2x8GB chips by reaching behind the logic board, releasing the spring retaining clips one chip at a time (starting with the chip further away from the logic board), pivoting the RAM towards the back of the machine, and then carefully sliding it out of the slot. I easily slid in the new chips and then pivoted them to lock them down. No hassle, no time lost. As Mitch K states above, not only is this “shortcut” method much quicker and easier, but it provides less risk of damaging cables, sockets and other delicate components during a total teardown. Why mess with the power supply board just to change RAM? I do not advise to follow the current iFixit.com procedure written by Sam Lionheart, regardless of user skill-level.

THAT sounds one !&&* of a lot easier than the full tear down. I wonder if there’s a video of the process described by Mitch K? Adding that to these verbal instructions would really help relieve the apprehension and anxiety around the process! I do sometimes find the additional warnings, though appreciated from a “safety first” perspective, are somewhat overstated. It’s been a very long time since I shorted out RAM, or fried a PCB, or broke a connector, regardless of how finicky, fragile or awkwardly designed and positioned. I may have WANTED to break something, and the air might be blue for a few seconds, but inevitably, things go back together, the start button gets pressed, the startup chime sounds, and we’re in business. Practice DOES make as close to perfect we are likely to get.

I used the CR-V 4.0 standard screwdriver head to help peel away the adhesive lining. My fingers were too big to grab it, and my fingernails too short to get the removal started. This 4 screw head worked perfectly.

I put it in at a slight angle lining up the right hand side holes, screwed in the two screws and gently pressed my finger behind it on the rest

If you only want to replace the HD and RAM, take a big shortcut and leave the logic board in, as well as all the parts needed to remove it (speaker, power supply etc). Once the display is removed, just take out the fan and the top two logic board screw. There is than sufficient space to gently remove and insert the two ram modules. HD can easily be replaced with an SSD by just removing the HD mounting brackets...

I highly recommend doing steps 27 and 28 first and then pull out the cable. It will give you more room on the right side of the cable to work with making this step that much easier.

The two corners of the connector are latches that need to be pushed toward the center of the connector to release. This is easily done with the pointed end of the spudger. Once the two corner latches are released, the connector comes apart easily.

Th HP is VERY HARD to take off in this thin place

Pay attention to this photo and where the fan is. It is 180° from where the previous step shows it is oriented to you.

Accomplished with spudger on top and thumbnail on bottom. Otherwise couldn’t rock it loose.

Doing this with spudger on right and thumbnail on left seemed easier and safer.

They are T9 in my iMac

They were T8 screws on my machine.

what happens if you damage the power socket on the logic board?

The tab is on the bottom of the connector. You can’t see it. Squeeze the bottom of the connector close to the cables to properly release tab. Pulling straight out is important.

This step might be easier if you do the next step first (step 41) and then come back to this step.

I don’t like to pull on wires as shown in the photos above. I used my index fingernail on the top corner of the connector and the pointed end of a spudger on the bottom corner to pull the connector straight out of its socket.

2017 imac EMC 3069 this is a T9

Cables are routed through the backside of the tray. Take a picture for reassembly.

As noted in the right speaker cable section, the two corners of the connector are latches that need to be pushed toward the center of the connector to release. This is easily done with the pointed end of the spudger. Once the two corner latches are released, the connector comes apart easily.

As seen in the photo this clip clearly has a pull tab. Forget the spudger and just open the clip with the pull tab.

I broke off one of the antenna connectors when I took off the antenna wires, but the new 802.11ac card is working:) I seems the way to take off the wires is lifting it up from the wire side. In hindsight I just wasn´t careful enough.

how do I check a working logic board

I labeled mine with label printer labels prior to disconnection.

Unlike the rest of the connectors on the logic board, this one lifts up away from the board rather than to the side. That “Push the cable slightly to the right.” notation is after the connector is free.

Weirdly, these screws didn’t work with my T8 driver. Not with T6 or T10.

Every other screw (to this point) has been fine. Hmm.

??? The T8 worked fine for me. Not sure what the difference would be.

Fare molta attenzione alla vite in fondo a destra, è facile (soprattutto se la punta del proprio cacciavite non è magnetizzata) che la vite si perda sotto alla Logic board. Se la punta del cacciavite non è magnetizzata consiglio o di utilizzare un magnete esterno o di utilizzare delle pinze mentre si svita la vite in modo da non incorrere in questo problema.

When reinstalling the logic board, install four screws loose. Insert thumb drives into the back in all slots to ensure alignment. Once aligned, then tighten screws.

On some models there is a tiny microphone cable connector, just above the lower left logic board screw. Remove by carefully pulling straight down. There is also a piece of insulating plastic w/adhesive on top of the screw which can be pulled off prior to removal. Save and reuse with the same screw on installation.

Great technique. I plugged a cable into every port before tightening logic board screws.

ive gotten this far and i still have one question, i’m replacing my HDD With A SSD should i also remove the original Blade drive ? and run exclusively off the ssd, ? i wasn’t 100 on whether or not i was getting the fusion set up so i’m not in possession of a upgraded blade, so i though this was a good question id hadn’t seen asked.

This would also be a good time to replace the CMOS 2032 coin battery while you have access.

Update on logic board alignment - use two USB plugs one in each end of the connectors through the back to be sure alignment is good before tightening screws.