Sostituzione CPU iMac Intel EMC 2639 27"

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.

First impressions so far: yes it can be a bit nerve wrecking if it is your first time doing this sort of thing and even with lots of experience with a 2011 model it’s still a bit unsettling haha (nervous laughter).

What I recommend: use a guitar pick to start cutting the glue. You’ll need a bit of pressure so do just the tip.

Once you’ve done the whole perimeter (minus bottom) do it again but now it should be easier to go deeper so go very slow and careful. Then get the old suction cups used to open older models and start lifting the display very carefully to see where it’s still glued and cut those as well.

Then you should be done and now the real fun begins! :D

It’s ridiculous. Apple should pay for doing this. Like glue parts together to block a repair / make difficult. I smashed my iMac. FU Apple. Seriously, every product I owned had hardware issues. For example, bad solder joints. Never again Apple. I’m happy with Windows and in 2018 / 2019 there are many other manufacturers with high quality stuff. Apple is dying, if they do not change …

NOTE: I followed every step word for word, but the adhesive strips supplied are as bad as double sided tape. Within 48hours the screen had slipped off and cracked. Now I need to fork out for a new screen and try again.

Not sure what to try next time with strips? Perhaps a bit of glue to help hold it??

After disconnecting the power cord and before cutting the panel adhesive, push and hold the power button for 10 seconds. This will discharge the power supply capacitors. In case you accidentally touch the solder joints on the board, you won't be shocked and drop the panel.

Just completed the Core i5 to i7 CPU upgrade and can strongly recommend getting the “pizza tool” to cut the display adhesive. It worked flawlessly and was done in less than 5 minutes. No inadvertent cables cut. No display problems.

Thank you very much for the tutorial. You are the best!

After reading all the post here I almost gave up doing this on my own. But I did it anyway and was succesful. I would recommend everyone to use the rollcutter. There is no risk of harming the screen if you use it. And in my case it was enough to open the imac. If you do not harm the screen connector or the screen the biggest part is done. It gets easier once you`ve stacked your screen somewhere safe. The parts inside are mostely not as delicate as the heavy and expensive screen!

Take your time and work carefully. It is definitely doable!

I think Dan is right as I decided it best to complete the process with the adhesive tapes to secure the screen. I just took some time to do a complete clean of the interior before sealing the display.

Ordered the full kit to replace my busted 3TB disc hard drive. All the tools work and are excellent. These pictorial and instructional install videos are complete, easy to use, and have good imagery. The 2TB SSD installed exactly as depicted. I used some 3M double sided automotive emblem tape to stick adapter to iMac case, no probs there. The adhesive strips also worked fine and stick firmly. Screen is solidly mounted, no falling out here. IFixit is awesome and this kit saved my over $1200 in getting another iMac. Highly recommended.

I concur, opening the screen a 2nd time is considerably more difficult because the adhesive strips are thinner than the original, which makes getting the cutting tool inserted much more difficult….as a result unknowingly I elongated a small crack to a much longer crack and somehow, the LCD now has a wide grey strip from top to bottom….The first time opening was easy, second time resulted in a ruined screen.. The cost of. a replacement LCD is the same has replacing the entire computer….I would recommend anyone attempting to remove the screen for any reason, do not use the aftermarket adhesive strips if you ever intend to open it up; again, or cut the strips much shorter, or possibly use a few pieces of scotch tape or similar to hold the screen in place….since the screen tilts back, this should not be a problem…Good luck…

I broke one too. And even if you think you did it correctly, you’ll not be able to see where you might have gone too far. You would think it’s very protected behind that metal plate, but no. Take special care with this offence to “right to repair” This should have been designed WAY better. I mean replacing a hardrive that is very likely to fail over the course of time, or even a simple desire to upgrade to an ssd!.

Bummer

I’m thinking I might just use vinyl tape to keep the screen in place for at least a little while after an upgrade. The extra strength of the replacement tape sounds scary.

Umm.. I’m not sure that I’d recommend using a repurposed credit card to open the display - I found that using the “pizza tool” to cut the old adhesive then using a pair of suction cups to gently pull the display up worked perfectly well.

The pizza roller tool is enough to cut through the adhesive. You dont need to cut in a lot further. So the cards are really not necessary.

No problems. I used two old credit cards and marked out a line using permanent marker so it was at the same depth as stipulated on this page. I even pushed it in a little deeper and no issues.

I agree, I’m using iFixit suction cups right now.

Go very slowly when lifting the display – give time for the adhesive at the bottom edge to stretch and flow. If you lift too fast, the glass can crack. That’s what happened for me.

The stickiest location on my iMac was the mid-to-lower section of the right side. There are a couple of thicker areas that needed attention from the plastic cards.

WARNING!!! This is where you can crack you screen. TAKE YOUR TIME! Everything work fine for me because I took my time. I was very shocked at how fragile the screen is. It does have a small amount of flex but don’t push your luck. There were two things that made this easy for me #1 Once you have used the cutting wheel to your best judgement to cut the adhesive, start using the iFixIt plastic cards as spacers and space them evenly around the screen. I used 10 individual cards of and gently moved them up and down at each section two at a time. Once I started having less resistance, I combined 2(i.e. 5 sets total) cards evenly space to allow for move rigid and stronger movement to separate the screen. This really helped me to free up more adhesive. #2 before lifting the screen up fully, use tweezers to pull the adhesive like a string from around the entire monitor. This will make lifting the screen much easier since all adhesive will be removed. Finally when lifting the screen use the cards with your hands under them.

If not for iFixit tuts and tools, no way I could do this. iMac 27" takes the prize as the worst design ever for upgrades/maintenance, what were they smoking when they designed it like this?

I have always believed that a properly placed screw can be a beautiful thing. A few decorative, but functional, screws placed in the back of the iMac case to attach the screen would be awesome, but this method is anything but beautiful and borders on insane.

Is it possible to replace the power cable if its damaged? I can’t seem to find anything about this.

After finishing my hard drive replacement I reconnected these connectors to test my display before using new adhesive. Everything was working beautifully. But then when I applied the new adhesive and went to seal the display on for good - the display power cable somehow became disconnected! I had to reopen the Mac for a second time which was far more difficult with new adhesive. When reinstalling double and triple check that the cables are securely inserted before the final seal. Sounds obvious but it’s quite the annoyance if something goes wrong at this point.

Very difficult to work with these connectors.

Power cable very difficult to unplug - data cable veeeeery difficult to plug in.

I noticed that working with the iMac positioned vertically (and with a proper support for inclination) makes this step slightly easier…

Interesting comments.. personally, I didn’t find the cables particularly difficult to detach and reattach. You do have to be patient and gentle. Personally, I found that a rolled up beach towel gently wedged between the unit and back of the display helped keep the glass up. Also, a small flashlight can be helpful to see the cables and connectors if you’re lighting isn’t perfect.

I’d agree to John - not overly difficult. My workaround was to prep the screen for re-installation and then place it in front of the standing machine. The cables are long and flexible enough to be put in place even in this state. You can easily attach the cables and continue with fixing the screen to the housing.

I would not recommend doing this step as pictured. The cable you are removing has little tabs on the wide side that can be depressed inwards towards the center of the connector, releasing the cable. If you just grab the cable as pictured and yank it out, without depressing the side tabs, you are likely to damage something. Don’t pull on the wires, use your fingernails at the connector to squeeze the very small little tabs inward to release the cable from the connector.

The removal of the LCD power cable does require the left and right sides to be squeezed inwards towards each other first before removing, why this isn’t mentioned in the take apart can lead to damaging the iMac.

I agree with maccentric. DO NOT just pull the power cable. Use your fingernail or spudger and gently press the tiny notch inward and towards you gently and one side will disengage. Do the same for the other side and it will slide right out. The notches just have enough edge to catch your nail or spudger. Using your nail is better as you can better feel when you have caught the edge and can feel the cable move.

I lifted the display a few inches up and propped it open in the middle using my iPhone in portrait mode with its torch on. Did the job nicely:

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.

First: During reassembly, I highly recommend you connect these cables and do a test boot BEFORE you remove the protective tape on the adhesive strips. That way you can fix any issues(like a damaged cable) if something is not right and you have not re-glued the screen back down which will cause a problem. If you have a second person and everything is working after test boot, you can just leave the cables connected, lift the bottom of the screen and have 2nd person pull the protective tape on the adhesive strips and you can set the screen in place. Second I damaged the video data cable during reassembly on my late 2015 iMac- I did not get the connector straight and I damaged the wires on the cable. I recommend you have someone else hold the screen while you attach the cables - they are fragile. Luckily, the data cable was easily replaced for only about $20. If you must do this by yourself, just be careful I highly recommend have 2 people at this step during reassembly.

At least on my “late 2013” model, the smaller display cable connector has tiny, tiny clips on the outside edges. These must be squeezed to unlatch it. Don't pull on the cable itself or the wires can be pulled out. Even with my small fingers, it was hard to grip the clips. When reconnecting, the connector will lightly snap into place.

I managed this step without any problems, but I had my wife hold the screen up while I disconnected/connected the cables. I STRONGLY encourage another pair of hands here so you can focus your full attention on being ultra careful with the cables.

does anybody know how the Display Cabel pin assignment is? I want to try if I can attach the Panel to another grafic card

That display cable connector is common to many Macs of the 2012 era. I’ve destroyed 2 in 38 years of servicing all types of computer equipment.

As stated, there is a latch on this connector. If you put any incorrect force on the cable or connector during disassembly or reassembly, you will break the cable and possibly the connector. The cables can be purchased online and the video connector on the display is exactly the same.

I repeat, if you pull out on the video cable after it has been unlatched instead of parallel to the logic board, YOU WILL BREAK IT.

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.

Niemals den unteren Klebestreifen mit einem scharfen Gegenstand wie Rasierklinge oder so versuchen zu trennen, davon geht die Beschichtung des Displays kaputt und man hat hässliche Streifen unten hinter dem Glas. Stattdessen lieber versuchen, das Display nach oben zu klappen und abzuziehen.

translation from Bas Ti because this is very important:

Never try to separate the bottom adhesive strip with a sharp object such as a razor blade or something, the coating on the display will break and you will have ugly strips at the bottom behind the glass. Instead, try to flip up and pull off the display.

As mentioned before you can pull out the lower adhesive strip. Dont cut it or move the display up and down. This is even more dangerous. On the lower side of mac where the display glass ends is a offset. When moving the display up and down you might crack it over that offset.

When removing the adhesive from the top of the screen, be sure to start at the iSight camera location (= in the middle). If you start at an upper egde of the glass (side doesn’t matter) towards the middle, you risk removing the black background foil from the screen, which will result in ugly stripes behind the glass.

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.

J’ai réussi à intervenir dans l’iMac sans décoller l’ensemble de l’écran. Je l’ai ouvert en laissant la dernière partie collée (vers le logo Apple) et qui sert comme une charnière. Bien calé et assuré l’écran n’a pas bougé et j’ai pu changer mon disque dur facilement. Le grand avantage et d’avoir l’écran toute suite juste quand on le recolle par la suite.

Well, I of course touched a soldering point in the red area as my hand slipped. I heard and felt a tiny “click” and after replacing the HDD with SSD etc I can not power the iMac up anymore. Not a sign of life :-( I suppose I broke the power supply. Can someone confirm? Or could something else have broken too?

I took my time and pulled both tabs slowly gently. Easily removed and glass came right off.

Hello all. So I’m trying to pinpoint my backlight issue on my 2015 retina 5k - I noticed I’m missing my thermal sensor on the LCD. Would this help with the backlight? I’m sure it will keep my fans from going crazy. Any help would be appreciated! Note: I have LEDs except the 4th one. Thanks!

Be careful when removing the adhesive residue!

I didn’t know it, but I ended up leaving slight scratch marks that can be seen from the front side.

I used Max Z tweezers technique but screwed one screw in at the end and then worked my way to the other end.

make sure you’ve actually unplugged the mac when running this cable, and not had it plugged in to test the diagnostic LEDs, because one of those wee silver spots is carrying 230v, and its 6mm away from the place the cable runs, So if you have fat fingers like mine, that’s a free wake up zap

The trick with removing the left speaker is that you have to slide it up toward the top of the iMac (continuing to de-route the power button cable carefully as you go) to get it out from under the chin before you lift it up to remove it.

Thank you iFixit for sending a T10 with magnetic tip. You saved me!

mine were T8s

Bracket to iMac case screws,T8.

Which is fine.

Just as in the next step, T8 or T10.

I simultaneously used the fingernails on my 2 index fingers to dislodge the tabs and continue to pull the cable out. It took a couple seconds.

ultimately the trick for me was to just pull hard enough, but that part is the scariest part. any tips welcome

These connectors seem pretty tough to remove until one understands the latch. Each side of the plug are two little sprung tabs (the tab is part of the spring clip which runs down the side of the plug on each side - makes sense once you see the removed plug!). Squeeze them in towards each other and then gently pull the plug from the socket. No great force, or even the spudger, needed once that is done.

One more tip, has worked on other cables for me. Fish the skinniest spudger tip you have under the cable, and with a finger of your other hand put opposite pressure on the cable against the spudger and gently work it out

If u are right handed, i can recomend to use your index left nail to press de bottom sprung, and a flat spudger on the right hand, came off so easy

Davo Montiel's tip worked for me. Use the fingernail on your left index finger to press in the tab on the bottom side of the connector and with the right hand use a flat spudger to press in the tab on the top side of the connector.

If you have a insulated long nose pliers along with a splugger and can get underneath the cable WITH the long nose pliers on the RIGHT side of the cable, towards the logic board, with the splugger on the LEFT Side of the cable doing the same, you can get the leverage to GENTLY pull this cable out very easily.

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.

I'm struggling with this step. I presume that the tab to which you are referring is behind the connector. I can see a plastic protrusion there but it does not move when I push it. Just to get my finger behind it requires the power board to be moved quite a bit btw.

Pressing on the release on the back with my finger and at the same time using a needle nose pliers to wiggle the connector with my other hand worked for me.

i could not get it out by the force of my fingers, so what i did was slightly turn the imac 90 degrees so i could reach the area better, push up (so, vertically) the power control board, push in the tab on the bottom of the connector with my right hand, and slightly wiggle the connector out of its socket with a plier

removing the chin strap (the front bit of metal running along the bottom of where the screen was) makes this much easier as you can rotate the board and get to the underside

Needle nose and wiggling worked for us too. We were stuggling like heck with it when just using hands!

This is MUCH easier to do if the support bracket along the bottom is removed first - more space to angle the board upwards. See Sostituzione scheda logica iMac Intel 21.5" Display Retina 4K (2017) step 25.

Use a P00.

To replace it, introduce it like in the photo at the link to be able to hold the right most holes of the chassis and bracket. Replace the first screw, align the bracket to the horizontal and add the screws from right to left. Each one will bring up the next hole in the bracket close enough to screw through. Reverse those directions if you are a leftie.

I did as Andrew Gough did, per other videos reviewed. Removed it right away. Just makes things easier, more space for just a few screws :)

The tab is a pain in the a$$$ to get your finger in there. I was so horrified at the size of the capacitors that I put on gloves to reduce any amount of shock :-) . To get it loose I would pull out carefully the power board as far as I could than I wedge my index finger under and press the tab and slowly pull until I saw a slight gap between the end of the socket and the plug. I than place the flat part of the black spudger or blue one into the gap and use as it as a wedge to help move the plug forward as I kept the tab pressed.

For reassembly I had to undo the screws again, then plug in the cable with the speaker module slightly out of its final position and after that insert the module and fasten the screws.

Before I disconnect the cables, I use different color sharpies and draw a different color on each one’s head & then I take a picture of the cables connected to the board. Pic is my reference of which cable goes to what connector.

I have a 2017 and I agree with Tanya. There are 2 T4 screws fastening the airport card to the motherboard. It’s easier to remove these and gently pull the airport card straight up out of the motherboard while leaving the 4 antenna wires fastened. You can’t see the connector or the airport card as it’s on the back side of the motherboard but just wiggle it side to side while pulling straight up and you’ll have no problem. I’ve broken off those tiny airport connectors in the past and it’s no fun replacing them.

same as Greg, did with the torx t5

I have a 2019 iMac and we needed to use a T4 screw

My late 2015 has a Airport/Bluetooth card secured with two T5 screws. After removing them you can just wiggle and unplug it from the logic board, without needing to fiddle with the antenna connectors.

Same as the other comments, in my iMac 27” retina 2015, the WiFi/Bluetooth board is a bit longer and the 4 coax cables are fixed by 2 T5 screws…

When reassembling a removed WiFi card keep 4 antenna leads attached as mentioned by poster (tanya et al) when reassembling as you replace logic board keeping it tilted forward helps in aligning the notch on card for easy reassembly and T3 screws replacingonce card is firmly seated.

When reassembling a removed WiFi card keep 4 antenna leads attached as mentioned by poster (tanya et al) when reassembling as you replace logic board keeping it tilted forward helps in aligning the notch on card for easy reassembly and T3 screws replacingonce card is firmly seated.

Can also confirm it for a Late 2015 iMac, there’s just 2 T3 screws to remove, simple move out the WiFi/Bluetooth board and let cable on place.

I broke mine…when inserted the speaker… How do I replace the headphone jack and cable?

Lift upwards with the spudger/fingernail, rocking it up back and forth.

(For those who have not seen this style of connector.)

+1 Missing the step on this 2019 iMac 27” guide to remove mic cable. It’s in other guides, just not here.

I cannot determine how to reconnect the headphone jack cable to the logic board. Are there better pictures anywhere that I could access?

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

Note: the T25 spacer is behind and to the left of the logic board and below the HDD bracket.

My 2017 had all T8’s, including the captive screw beneath the motherboard

My 2017 had 4 T8 screws along the bottom of the logic board, not 3

Late 2015 iMac - mine had all T8 screws and 4 along the bottom row

2017 here.

IMPORTANT - note Tanya’s comment. The narrow flat cable in the middle - it’s the mic cable on a *tiny* ZIF. See Sostituzione scheda logica iMac Intel 21.5" Display Retina 4K (2017)

Also has the extra bolt middle lower edge.

All T8 except the yellow T25.

In my iMac 27” retina 2015 all screws are T8.

There is also an another T8 screw between the left and central “orange” on bottom of the CPU board

Just completed and removed logic board. All my screws were T6. The screw beneath is a captive screw, stays retained in the fixture after unscrewing.

If I change the logic card on an imac 27’ 2020, will the computer's memory be affected?

There is a 25T stand off that is not listed. It is not on the board but beside or underneath the yellow/red on power supply side.

Jesse, no SATA cable inside. My iMac came only with the blade SSD and an empty HDD bay, so I have to buy the SATA cable separately.

the card drive cable is affixed to the heat sink with some sort of adhesive. If it is not placed back similarly, the system cannot sense the heat sink temperature, and the fan will run at full speed continuously. I used double sided tape and pushed it back in adhered position after re-attaching logic board.

the above should read “the hard drive cable” , not card drive (typo)!

Yes, there is a screw holding down the fan shroud it is an angled black part where the guy's left hand index finger is located in Step 56

The iMac 27” didn’t come with the PCIe SSD card so of course there wasn’t the necessary screw to mount one.

Here is the screw to order;

https://www.ebay.com/itm/283482947478?ch...

What I did was find a screw that fit. Happened to be the case screw from the iFixit external 2.5” case but since that was a countersunk screw, I fabricated a washer for it.

I do this job fairly frequently and I have a small box in my iMac tool kit containing a headphone jack, four USB drives, a short two-ended Thunderbolt cable and the end of a red moulded Ethernet cable to keep things aligned from the back when screwing the logic board back into place.

I loosely screw all the screws in, then tighten them gradually, going round the board several times to make sure it lands in exactly the right position.

Re the comments about it being hard to put the new i7 in.. I’ve done a few now and actually found it ok. Put one of the four bracket screws in but only by a few threads. Then put the diagonally opposite one in the same amount. Then put the remaining two in - the last one is always the hardest. Just apply a little pressure to the bracket. Then tighten the four screws a little at a time, always moving to an opposite screw, not the one next to it.

OK.. I nearly borked my system upgrade at this step. I have a 3.4 GHz Core i5 system and wanted to upgrade the CPU to a Core i7-4771. I found a new one on Amazon last week. Everything went very smoothly until I got to the final “Then, reinstall the heat sink over the top.” step. As others have pointed out - this is really difficult. I had a heck of a time getting the four screws in the tension plate back in. And, after reinstalling everything and hitting the power button, NOTHING happened. Nada. So, I tore the system back down and removed the heat sink. The CPU was stuck fast to the heat sink and it took a lot of twisting and pulling to dislodge it. The CPU looked OK, but when I checked the Haswell socket, I discovered that several of the delicate pins had been bent and were touching. I used a pair of fine pointed tweezers to VERY gently bend the pins back into place. Then, it was “lather, rinse, repeat”.. This time, when I plugged the iMac back in, I got the 3-chime error signal, so I reset the RAM (cont…)

(cont.) chips and hit the power button again. Nada. I started cursing Steve Jobs in his grave. After a couple minutes, it suddenly chimed and in a few seconds the Apple logo appeared and all was well. I’m writing this on my freshly upgraded iMac. What I learned was that as soon as the heat sink touches the CPU, the thermal paste “glues” it to the heat sink - if you twist or hog on the heat sink, the CPU goes with it. The trick is to make sure that the CPU is firmly seated in the socket and then KEEP it there. It takes a good deal of finesse. As “aboucher” pointed out - it is helpful to insert the first screw *just to the point of catching” - then start adding the others in an “X” pattern. Also, I found that removing the “hood” over the adjacent RAM bay (remove the three T5 screws) gives you just a bit more exposure of the CPU and heat sink. I am still amazed that there isn’t a single decent video tutorial that walks you through this step - this is where you’re at the greatest risk of damaging your system..

(cont.) and it’s where a detailed walk through would be the most helpful. Anyway, if you keep these precautions in mind, you should be able to get through this - but be prepared. And, as a side note, the upgrade from the Core i5 3.4 GHz (4670) to the Core i7 3.5 GHz (4771) didn’t exactly set off fireworks in terms of benchmarks. I saw a 15-20% increase in the Geekbench 5 Multi-Core Score and a nice 30% increase in performance with the Cinebench 20 Score - so, it’s probably going to be worth it in the long run to have upgraded the CPU. If you have a base Core i5 3.2 GHz CPU, you should really see a difference. If you have 3.4 GHz system, you may or may not want to risk going through the upgrade process, as the benefit is much more modest. Your call. I found the biggest bang to be upgrading the 7200 rpm HDD to a PCIe NVMe M.2 SSD drive (I used a Sabrent Rocket Q 1 TB 2280 drive). Personally, I’d do that first and make sure that you have at least 16 GB of memory. You might be happy at this point. Good luck! J

Part 1 of 3

Many thanks to you who’ve shared your experiences, happy to say they really helped make my cpu and ssd upgrade successful, though not without some trepidation. So here are a few things that helped me in case they help someone down the road.

Regarding the cpu grease and “gapping” compounds, I read a lot of discussion about what’s best and how much to use. I ended up using 2 rice grains of grease on the cpu, 1 rice grain on the gpu, and the equivalent of approx 6mm diameter ball of K5-Pro thermal paste on the Vram chips. K5-pro is essentially a “gapping” compound often used to replace thermal pads. After securing the heat sink I peaked underneath it and it appeared that amount was about the same as what was used at the factory.

part 2 of 3

Before re-securing the heat sink, I removed the cage around the ram for easier access. I laid the board off the edge of a table so the gpu was accessible to me working under it, and also far enough to get the awkward heat sink over the cpu off the table to avoid rocking. I laid a heavy book (nearly 5lbs) across the ports on the opposite side for stability. I secured the gpu side of the heat sink under the table looking up, and experienced no shifting of the board at all. After *completely* tightening those screws (i.e. until they stop) I was able to work with it back on the topside of the desk, again without any shifting. Regarding securing the heat sink over the cpu, of course follow good practice of tightening screws opposite one another, and like the gpu, tighten the screws all the way down or until they stop. This point was made clear by an iFixit rep who called attention to an image of the original position of that spring clip, which is *all the way down to the board* essentially (step 58).

Part 3 of 3

And finally the last step, re-securing the glass panel. I decided to not remove the tape backings after putting the adhesive strips in place, to avoid sealing the unit and have something wrong and have to tear it open again. With the iMac on its back on the table, I propped it up in a couple places so that the top edge of the iMac was at least level with the bottom edge, laid the bottom edge of the glass down and inserted the display power/data cables. I then set the glass down gently and made sure the iMac turned on and all was ok.

I just ordered a new i7 6700K to replace my i5 6600K. With your stories I will be extra careful with the pins…. I will tell you when I finished the job.

Just finished upgrading to an i7 6700K. All went well, but I had to take it apart again because the cooling wasn’t good of the CPU and the GPU. Starting a game and it got overheated and shutdown. I ordered heatpads for the gpu memorychips and thermal compound (1mm) from Arctic (MX-4). Also bought an app iStat Menus ($$) and an app called Intel Power Gadget (free). Real cool monitoring tool. CPU and GPU are cool now, 28-32 degr Celcius. Playing a game temperature climbs to max 90 degr Celcius.

Dont remove the thermal paste with the spudger. You might scratch the heatsink. Its not a great deal as the new paste will fill those scratches. But still better to not scratch it in the first place.

Attaching the CPU and the heatsink is actually not as hard as mentioned before, but you really need to take your time to put it all together.

Four hands are very helpful here. Two hands hold the CPU in place and the other two hands hold the GPU part. Start with screwing in the GPU side and then the CPU.