iMac Intel 27" EMC 2639 CPU Replacement

Removing the original adhesive is easier than removing newly applied adhesive (e.g., if you have to reopen iMac).  If you should happen to need to reopen the iMac, please use extreme caution and highly consider my suggestions below.

When using the pizza cutter tool, do the first few steps in reverse starting with step 8.  Starting on the left side is better since this is where the adhesive is narrowest.  The right side has two antennas and the top right has one, see the pictures for step 18-21, they are the brass colored metal rectangles near the edges.  The adhesive on these pieces are wider and therefore have more holding power.  The thickness of the pizza cutter tool is enough to crack the glass.

Continuing from my previous comment.  To remove the adhesive on the right side you’ll need to create a very slight gap to give the pizza cutter some more room.  Do this by cutting the adhesive on the left side up and around to the camera.  Before attempting to cut the right side. Carefully slide the plastic cards (I purchased two sets) to ensure the adhesive on the left top and side is completely free.  Now slowly move towards the right side.  After every inch or two of removing new adhesive, slide the card over to create this slight gap.  Be careful to not move the card too close to where the adhesive has not been cut.  You want to create a very slight gap without creating too much pressure.  Use extra caution with approaching the areas where the antenna are since the adhesive is stronger here and will need some additional cutting.  Follow this approach all the way around the right side.  Be careful to not create too much pressure at any one time.  Good Luck!.

I would highly, highly, highly recommend AGAINST doing this at home. I followed these instructions to a T, and still somehow managed to have the screen not be able to turn on after the hard drive replacement. Then, once you’ve opened your Mac yourself, Apple will refuse to fix anything on the computer, and even other third party, Apple-authorized repair facility will refuse to repair it for you, and you will have to locate a non-authorized Apple repair facility. There, I am having to pay ~$600 to fix things that got screwed up, even though I followed the instructions here to a T, step by step, and did everything slowly and methodically.

Beware, if you’ve never done this before, that be locked out of ever being able to use an Apple repair facility, or Apple-authorized repair facility, if you mess things up here now.

I performed this on a Late 2015 iMac and there weren’t any significant differences to these steps, but I did find the repair to be nerve-wracking. My model cost nearly $3,000 and about 10 steps into this guide (which I did fully read ahead of time) I was thinking, “what have I got myself into?” But I didn’t rush and happily I’m typing this on my repaired iMac! I found a video from OWC that was more useful than the photos in this guide for certain steps: https://vimeo.com/139364064

I found the 'pizza cutter' surprisingly smooth at cutting through four-year-old adhesive.

The pizza cutter will sink in all the way to the tool handle when the adhesive is full cut, but don’t feel you have to do this in one motion. Some parts cut easier and some require a lot (like 20x) of gentle back and forth.

I actually DESTROYED my display (black vertical strips) by pushing the card in a bit TOO DEEP. So it is REALLY important to insert the card only a bit (1-2mm) more than the cutter wheel, in particular at the top side, where many flat cables connect the panel with the PCB. These can be damaged very easily!

Same thing with me…. Pushed cards to far…. new panel needed…€600…..

i think ifixit needs to place a bigger caveat, as I have missed it the first time

i successfully upgraded two imacs. one opened with ifixit pizza knife and another with a regular paper knife. however, when i had to open the first one once again i broke its screen glass. it seems ifixit adhesive strips are too strong. next time i’ll try to use heater to weaken glue tension.

My children tend to collect cards like this from hotels, Disneyland, old IDs, iTunes cards, gift cards etc. They came in handy for this step. After wedging in the first card into the left corner, I wedged the left corner, then added cards along the bottom edge. Finally I continued to push in additional cards to existing cards and found that this created a smooth even pressure along the display top. At 2-3 card-thickness the last of the adhesive let go, gentle as a baby.

was denn jetzt? Vor der Kamera aufhören, oder in Richtung Bildschirmmitte schieben, um DEN REST zu entfernen? Wenn ich vor der Kamera aufhöre, kann ich nicht alles an Kleber entfernen.

I would recommend using suction cups at this stage to lift the display.

Mark all cable connectors with a spot of white correction fluid before removal. This will remove the risk, when reinserting them later, of getting them the wrong way round. Yes - I know they will only plug in one way round, but it does make life easier if you are not in perfect lighting!

At this step, if you mess up anything with these 2 cables, especially when plugging them back in, even if you think you’re following the instructions here to a T, then you’re screwed.

I would highly, highly, highly recommend AGAINST doing this at home. I followed these instructions to a T, and still somehow managed to have the screen not be able to turn on after the hard drive replacement. Then, once you’ve opened your Mac yourself, Apple will refuse to fix anything on the computer, and even other third party, Apple-authorized repair facility will refuse to repair it for you, and you will have to locate a non-authorized Apple repair facility. There, I am having to pay ~$600 to fix things that got screwed up, even though I followed the instructions here to a T, step by step, and did everything slowly and methodically.

Beware, if you’ve never done this before, that be locked out of ever being able to use an Apple repair facility, or Apple-authorized repair facility, if you mess things up here now.

The display cable, the wider one, has a lock on it , usually a plastic tape lift tab to release it, once thats flipped it should come out fairly easily, if your experiencing resistance and the cable isn’t coming out then check for this lock/latch, the power cable just pulls out, just don’t rush it everything should go fine, fairly easy to do with the end result a working iMac

At this step, if you mess up anything with these 2 cables, especially when plugging them back in, even if you think you’re following the instructions here to a T, then you’re screwed.

I would highly, highly, highly recommend AGAINST doing this at home. I followed these instructions to a T, and still somehow managed to have the screen not be able to turn on after the hard drive replacement. Then, once you’ve opened your Mac yourself, Apple will refuse to fix anything on the computer, and even other third party, Apple-authorized repair facility will refuse to repair it for you, and you will have to locate a non-authorized Apple repair facility. There, I am having to pay ~$600 to fix things that got screwed up, even though I followed the instructions here to a T, step by step, and did everything slowly and methodically.

Beware, if you’ve never done this before, that be locked out of ever being able to use an Apple repair facility, or Apple-authorized repair facility, if you mess things up here now.

Can anybody upload an image of how the display can get damaged from removing it? I find it hard to believe (though I’m reading the horror stories here) that a whole display can get damaged. Especially when many of us were following to a T and being VERY CAREFUL.

Thanks.

Thank you Stef, that's what i will do next time, i cracked the lower part of the screen went opening very slowly, that's probably why those "tabs are for !!

Thanks Stef, this has saved me! Simple yet very effective.

Yep, I cracked the lower corner of the display as well. I failed to work the adhesive enough to loosen it sufficiently. Be careful, I just had to buy my customer another screen!

There seems to be missing a step or two. As I was removing the old display, there are two wires that need to get transferred to the new replacement display. There is not note about these two wires located at the top of the display. The 1.128-inch ribbon cable and then this other 4-inch long, two-wire cable that goes to a very small circuit board that is 1/4 by 3/8 of an inch and seems to be adhered to the panel.I have not been able to get this cable off the old display. There is a port for it on the replacement display.

Note: When ordering this screen, and plastic cards as noted tools, ifixit.com did not list the pizza cutter or the new replacement adhesive strips. So now I’m not sure how to get the new one on and secure.

The adhesive strip along the bottom is designed with a pull tab on each outer end. Rather than lever and pull the screen simply carefully pull the tab which removes that half of the lower adhesive strip and frees up the screen.

Would have been helpful to box the same red area when using the plastic card to separate the glue. Since the red blocked picture is inverted, if someone doesn't pay close attention it may not be obvious that the area of concern is at the right top of the graphic pictures in which the plastic card use is being demonstrated..

you don't need to cut the bottom part as the bottom tape is stuck on each side and you can easily pull it out

What is the twisted wire taped to the back of the display that can bee seen in the upper right of the first two pictures? I have an 27” iMac without a screen an my replacement does not have this wire. I think it is a temperature sensor but do not know where it connects to.

[|I opened up my iMac and there’s no HDD or SSD in that spot. its just empty.]

Please update the picture to include the RED BOXED IN AREA that you refer to on all three pictures in this step. I have had a few zaps from these supplies and it is not pleasant.

hey Simon, I used 2-sided tape….this is assuming the new sensor doesn’t already come with an adhesive surface already applied.

a roll of kapton tape for your own peace of mind will make sure nothing detaches from thermally-induced adhesive crystallization

make sure you position it in such a way that you can easily plug the lead back into the mobo….not a lot of length to that wire

Howdy folks,

Thanks for all the tips, LCD sensor fitted and iMac back in action.

Never again!

Simon

If you just want access to the HD, there is no need to remove any speaker wires - it slides over enough to access the HD screws.

I didn’t unplug and de-route this cable. Later, Step 29, has you remove the left speaker. This isn’t necessary. If you can just move the speaker over to expose the hard drive mounting screws, so if you’re not going to remove the speaker, you don’t need to unplug it.

there is no need to disconnect the speaker, just unscrew it and move aside slightly to reach the HDD screws (about 5mm) - if you want to replace just the main HDD

Take note of exactly what direction this tiny little wire was.

If you have the iMac sitting upright, there is a potential risk of dropping the screws into the iMac casing. Be cautious or lay it down flat.

Been there done that. Had to flip it and shake the heck out of it to get that srew to fall out!

Left hard drive bracket screws are T8!! Had to remove HD first before derouting left speaker cable.

Full removal of the speaker is unnecessary - just very carefully unplug the two-conductor power button cable, which is routed through the groove along the edge of the speaker enclosure. Next, unfasten the two large torx screws holding the speaker enclosure to the chassis. Now you can easily scoot the speaker away from the drive mount - move it over just enough to reach the drive mount’s 2 torx fasteners beneath the edge of the speaker (a CM or two). There’s now enough room to easily remove and replace the drive assembly .

This step is unnecessary. Just leave the bracket in place and set the assembly aside.

I found this cable very difficult to disconnect, be very careful because the cable is between a black tape and it's stuck very hard to the logic board and the cable is very short and you don't have space to move and separate it from the connection! Be patient and take the time you need

I found than putting the flat end of the spudger at the center of the cable, and tilting it got the cable out without an issue.

I was able to use the flat end of the spudger on the sides. You can see a tiny little clip on each side. Be very gentle!

My late 2015 model has these as T8 screws.

Late 2015- T8 as well!! Check out this Powerbook Medic teardown video as a cross reference guide!!

https://www.youtube.com/watch?v=81PjGv8B...

Remember to push in the disconnect tab on the large connector. Carefully insert your finger and push on the tab before you pull on the connector.

Thank you Manuel, this was a tricky one.

Yes, I pulled the whole socket out because I didn’t know about the tab. Fortunately I was able to place it back in. Not sure if it was glued or how it was anchored but it seems to have a solid connection and I can’t easily pull it out by hand. Once I plug the power cable back in should be ok.

This connector was very difficult for me to remove (even after pushing the disconnect tab). Eventually I had to use a pair of needle nose pliers to wiggle it back and forth out of the socket. A lot of the cables on the my late 2015 model were very tight and a struggle to get out.

To reassemble, do the same in reverse but keep power supply board more upright than slanted down when re-inserting it in to the lower right corner. The lower right screw post has an protrusion under/behind it and the Power Supply's small 2 wire plug must fit between the front of your Mac and the obstruction. Then it just slides right in and then screw it down.

Use a piece of tape around the antenna cables to keep them in the same order, makes reassembly a little easier.

My iMac has a slightly different assembly. There are 2 - T5 torx screws holding little clamps for each cable (2 clamps per screw). Certainly more secure but another size screw to deal with…

My iMac also same with Greg mentioned. need to T5 torx driver. A1419. Late 2015, Korean Version.

My 2017 has long WI-Fi card, It’s It’s a M.2, cuz no remove antenna. Undo WI-Fi card fix screws and pull out card. Easy one.

During disassembly, I taped the cable up and out of the way, as it tends to get in front of things.

The central screw is very difficult to reach! Use a long and very thin T10 screw driver

On my late 2015 there is another T10 (approx 16 mm long) on the lower edge slightly left of the hole in the logic board giving a total of 4 screws along the bottom edge.

I’ve also found an extra T10 in my late 2015 iMac

My 2017 has small flat cable and connector on logic board. And all screws are changed to T 9

Anyone know if models that shipped with only a bladed SSD have the SATA cable still inside? I’m guessing probably not, but haven’t been able to confirm anywhere.

To help me line up the IO ports, I filled all the USB ports on the back with thumb drives before I screwed the Logic board back down. Worked like a charm!

Putting the heat sync back on your new CPU is really difficult. I over tightened and borked my new CPU. Also, it's quite possible that you're going to put a great deal of stress on your Logic Board if you are putting an i7 processor in an i5 board. There is extra cooling installed on the i7 boards with bigger graphics cards. I wound up getting new logic board designed for i7 and having a repair shop do the upgrade (Which is a difficult feat in itself as it's difficult to procure Apple parts on your own). I still came out ahead over buying new or buying a used model with the full specs. But only barely. I'd highly recommend working with a friend or someone that has taken an iMac apart before. Look very carefully at how much tension and is applied on the current CPU before disassembly of the heat sync and adding a new one. Once you've done it once it's not to complicated.