Introduction
Use this guide to replace the power supply.
What you need
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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.
A thin razor blade works well, but be careful to angle the sharp edge AWAY from the glass. Whatever tool you use you can easily scratch the paint on the back of the glass, which will show up when you look at he reassembled Mac on an angle later.
This was a great guide!
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Tool used on this step:Plastic Cards$2.99
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Starting from the top right corner of the iMac, wedge a plastic card between the display and frame.
So sorry. Thanks for that caution.
Using suction cups (the ones that were made for removing the magnetic front glass on the 2011 and earlier iMacs) work well too. Place one in each top corner, while the Mac is lying face up on a table, and gently pull and it will separate the display from the main body. You might need to do a little more slicing around the edges if you did not get all the way through the first time with the roller. Then you can lift the display up at an angle to disconnect the cables.
This was a great idea, worked well for me. Thanks!
Florin -
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With both plastic cards inserted as shown near the corners, gently twist the cards sideways to increase the gap between display and case.
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Begin to lift the top of the display up from the frame.
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While holding the display up with one hand, use the other hand to unplug the display power cable. Make sure that you pull the cable out from the plastic tab, and not by pulling on the color wires.
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Lift the display up to a near-vertical position.
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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.
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Repeat this step with the other adhesive strip and remove it.
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.
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Lift the display up from the frame and remove it from the iMac.
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It may be necessary to slowly lift from one side, to peel against 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.
Mitch has the exact method that works a treat. You don’t need to follow steps 24-37 and also 40-63. Step 51 is the step to remove the camera cable and is needed. Steps 38 and 39 are for the Fan. That is all that is needed. Done quite a few like this.
Be careful not to drop the RAM down the back of the logic board!
By NOT removing all the other stuff you can avoid either damaging it or forgetting to plug in a cable.
I just trued this shortcut and it was not successful. I was not able to seat both RAM chips with this shortcut, and managed to slightly damage one of the retainer clips. I simply could not manipulate the chips into and out of the slots effectively without taking everything apart as described in the full set of steps.. I ended up retracing my steps and following the entire procedure, carefully, and that worked without incident. So, bottomline, it is definitely more work to follow all the steps but from my experience, it is decidedly safer. Your mileage may, of course, vary. It was successful in the end, and I swapped out the hard drive with an ssd during the same procedure and my machine is very, very much faster.
I have completed by following the Mitch K post and it is much easier than stripping down the whole thing, just be aware that to remove and replace the ram chips means working in a tight space, you need slim fingers and don’t be tempted to use force, take your time.
Well, I have slim fingers, but they are 60 years old, and they don’t work like they used to! LOL.
Agree with Mitch K’s procedure. The only added tip I would throw in is to use two 45 degree tweezers with their plastic covers still installed to easily pop loose the RAM. I couldn’t get the plastic spudger tool to work myself, but the tweezers easily reach the RAM clips. Just make sure the plastic covers are installed and you won’t be in danger of scratching or shorting anything out.
So thankful I discovered these comments. Saved me a TON of time! Thank you!!
These comments were very useful. Thank you. I just needed to modify a pair of tweezers to allow me to seat the new RAM more easily. The ifixit screwdriver wasn't able to turn some of the screws as they were installed too tightly, and I didn't want to wait to order and reveive a pair of right angled Torx screwdrivers that would give me more leverage to get those boards off.
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Remove the following five Phillips screws holding the lower support bracket in place:
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Four 3.2 mm screws
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One 1.7 mm screw
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Remove the lower support bracket from the iMac enclosure.
Of all the parts of this entire procedure, replacing this one piece is the hardest part! The screws are tiny and they just don’t seem to want to grab the support piece. Also it seems to perform no function which is also annoying.
I left mine out. LOL
Line up the screw holes and press on the bracket from the back to help the screws grab. If your fingers are too big, press with the flat side of your spudger. As long as there’s no gap between the bracket and the iMac’s frame, the screws should grab easily.
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...
Voces mudaram de modelo iMac, desta foto para proxima, esse modelo desta foto nao tem slot nvme. O da proxima foto sim. Voces me fizeram comprar un nvme por engano...
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Remove the following screws securing the hard drive bracket to the rear enclosure:
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Two 21 mm T10 Torx screws from the left-hand hard drive bracket.
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One 9 mm T10 Torx screw.
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One 27 mm T10 Torx screw.
Pay attention to this photo and where the fan is. It is 180° from where the previous step shows it is oriented to you.
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Use the tip of a spudger to push each side of the power button cable connector and gently "walk" it out of its socket.
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Remove the two 7.2 mm T10 screws securing the power supply to the rear enclosure.
What if these are too tight to remove?
Hi Rafael,
Be very careful not to strip these screws. Use a new, accurate T10 bit and a driver with good leverage to loosen these screws.
They are T9 in my iMac
They were T8 screws on my machine.
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Squeeze the DC power cable connector tab and pull it straight out of its socket on the back of the logic board.
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 loosened the logic board attached to the power supply board. I then could easily remove the 2 power cables.
In the photo above, the index finger is shown squeezing the connector locking tab. Do this while using the flat end of a spudger to release the latch. Once the connector is moved about an eigth of an inch the latch is released and the connector should come out freely.
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To reassemble your device, follow these instructions in reverse and use our Adhesive Strips Guide to reattach the display glass.
To reassemble your device, follow these instructions in reverse and use our Adhesive Strips Guide to reattach the display glass.
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5 Comments
You can use a wattmeter for a first diagnostic. If the PSU uses 0 then it's dead. It should use a couple of watts, when the Mac is turned off
After replacing the PSU, be careful that it is put back in place correctly. If it is not perfectly flat, it may slightly lift the screen which will not adhere properly
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??
Narendra Verma - Reply
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!
Ross Elkins - Reply
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!
Ross Elkins - Reply