Changing an IMac's HDD




Introduction: Changing an IMac's HDD

Hey everybody and welcome to my very first instructable for you to enjoy! I hope it is of good value to you my dear fellows!

Recently I got me an old iMac 20" (version 7.1) for a reasonable price on eBay and was delighted about how well in shape it was. Alas, the hard disk was a little small for my needs (video editing & color grading) so I decided to exchange the internal 500 GB disk with a new 2000 GB drive.

I am really not that good with (dis)assembling electronics but I didn't find it really hard, you just need to take some time and everything works out just swell :)

WARNING: Changing the hard drive of your iMac will most certainly terminate any warranties you might have on your iMac, so only do this if you already have no warranty anymore or you're such a badass that you just don't care -- hell yeah!

Step 1: What You Need

Not much, in fact. When I was examining the case I thought I needed an awful lot of different screwdriver-bits and went to the nearest hardware store to get me a big set. But as was I was working on it I only needed one.

* A new 3.5-inch S-ATA hard drive. I chose the largest one at the time of writing, a Western Digital Caviar Green with 2000 GB capacity.
* A torx 8 (T8) screwdriver you will use A LOT.
* (Something with) a suction cap, the bigger the better.
* A standard screwdriver (slot or Phillips, both will work) to use once or twice.
* A clean table, ideally with a soft pad to work on.
* About 40 minutes of time. It took me 90 mins with talking all the photos and probably would take me 15 to 20 minutes without.

OPTIONALLY have handy
* a marker to mark some connectors.
* cleaning utilities such as a compressed gas duster, Windex & paper towels.
* Thermal compound if you have some around. I had some left from my CPU cooler.
* some music to keep you entertained

Got everything ready? Then let's go!

Step 2: One Preparational Step

When I first did this I forgot to take off the cover of the RAM slot and had immense troubles later getting the frame back on. So I advise you to remove the RAM slot on the bottom prior to anything else.

It is located below the Apple logo and held in place by a single screw for which you can use either the slot or Phillips screwdriver, both work. The screw will also not come off and the slot-cover might be jammed a little. If you can't manage to get it off now, you can do it after we remove the frame.

Step 3: Removing the Glass

Put the computer down and have it facing you top down as well, the screen turned up (see picture). This is the best and most comfortable way to work on it during the whole procedure except for removing and attaching the frame. But we'll get to that.

Any directions I give (such as top-left) are based on the assumption that you have your Mac like this in front of you.

Figuring out how to get started took the longest, but after a hearty attempt with the suction cap it proved to be the right way to go.

I used the suction cap of my cell phone's car mount and it worked just fine. It doesn't really matter where you apply it and begin to pull, yet I recommend doing so near a corner.

The glass is held in place by a couple of magnets on the frame so at first it will be little stubborn before getting off quite easily. Now support the glass with a hand because you don't want to rely on the suction cap alone and there's no replacement in case you break the glass. Also be now a bit cautious near the screen because it is now unprotected and won't forgive you any mishaps with a screwdriver. So take your time and enjoy your music :)

Step 4: Removing the Frame

Once the glass is off you can see the screws of the frame. It's 12 of them in two different lengths. This marks the begin of your long lasting friendship with the TORX T8 screwdriver. Again, be careful not to slip and damage the unprotected screen.

When all the screws are undone and removed put the iMac back upright on its stand and grip with both hands the upper corners of the frame, your thumbs resting on the black foamy corners of screen. If you push now gently, the frame will come off -- with the rewarding smacking sound of a warranty just being terminated. ;)

Don't pull it off already because the iSight camera's activity LED is still connected to the frame. Gently pull the connector off downwards. Now you can remove the frame.

If you examine its inside, you will see a couple of round-cornered metal pieces. Those are the magnets that hold the glass in place. And you really want to avoid your new (or old) hard disk getting too close to them. So better put the frame a bit further away. It probably needs some cleaning on the inside as well.

Step 5: Removing the Screen

Now you can see what's inside your iMac and probably its a lot of dust so here's the first opportunity to take to dust off especially the cooling fan and the rest of the motherboard thoroughly with the compressed gas duster before moving on.

Now put the iMac on the table like before and behold its magnificent innards.

With your best friend unscrew the 8 screws holding the screen in place and be really careful not to slip off.

I read that some people suggest to unplug the screen from the mainboard entirely, others say that you only need to disconnect a single plug. I am not sure whether this is *really* necessary but better safe than sorry: Unplug the connector labeled LCD TEMP on the motherboard, it's on a cyan-ish colored circuit board near the top right corner and shouldn't give you much trouble.

Now lift the screen a bit with both your index fingers pushing up the corners facing you, but don't overdo it: There still are four white connectors on the left to unplug, two on each side of the optical drive.
This is where I used my marker and drew distinct shapes on the connectors so know later what to plug into in what way and so on. Then unplug them gently but don't lift the screen yet.
I suggest that you pull off two or three paper towels and fold them together until you have a thick soft pad. Lift the screen now entirely and fold it back. Put now the soft pad where the screen's unprotected surface would touch the foot-stand. This is optional but highly advisable!

Step 6: Removing the Hard Disk

Before moving on, let's orient ourselves inside the iMac's bowels: Facing you now is a standard 3.5" HDD with S-ATA connector, to its left is the optical drive, to its right a dark-blue circuit board darn close to the power supply reading "CAUTION HIGH VOLTAGE"; and I urge you stay the fudge away from that board entirely. I was such curious as to tap it with the screwdriver and there was a blue arc from the square shaped thing in the middle of it! This could damage you, or worse, your iMac!

From the optical drives there's a small string of sensor-cables leading into the motherboard and an odd foamy thing on the hard disk itself. This foam protects the temperature-sensor that's right on the disk. Remove it and the sticky tape holding down the cable from the optical drive will peel off as well. The actual heat sensor is tiny,shaped like half a cylinder, one side round, the other bears the part’s number. The black plastic clip that's also stuck to the drive just holds it in place.
Remove the black plastic clip too and put the cables, foam-strip and sticky tape aside. We finally want to get our eager hands on the HDD for good!

Facing you, there's a black handle mounted on the drive. If you push it away from you and then lift it while still pushing, you can get the drive out. Note that there are two screws on the other side in some rubber sockets. Pull out the drive now just a little and remove the S-ATA and power connectors.

FINALLY it's free!

Step 7: Preparing the New Hard Disk

Yet we're not done screwing around (pun not intended). The HDD still has two screws on one side and the black handle on the other, also fastened with two screws. Despite my first assumption, all of them are T8 screws which you should undo. The ones on the left side have a blue mark on them. I don't know why but I guess it could be a means of warranty violation confirmation ;)

Optionally you can also remove the soft gray papery thing on the top of the drive, it is just another protection slip for it.

You should have now a total of 24 screws lying around: 12 of the frame, 8 of the screen and 4 of the drive. Additionally there's the handle for the HDD and the black plastic placement clip for the temperature sensor.

Now unwrap your new drive and put the screws in the same places where they had been in the old drive just before. The handle goes on the right.

Place the drive now that you can easily connect the S-ATA and power plug. Now make sure both screws are inserted in the rubber sockets before you can push the handle down until it locks with a reassuring click.

Step 8: Reconnecting

Now you can re-apply the plastic clip of the temperature sensor in the same spot as on the original disk. That's why I took pictures.

The temperature sensor has to be as tight as possible with its flat side on the hard disk or else the Mac OS gets really whiny or even won't start up! That's why I decided to walk the extra mile and apply a layer of thermal compound on the sensor before sticking it with the plastic back onto the HDD.

If you have done this as well and made sure that it really is placed tightly, apply the sticky tape with the cables to the optical drive and the foam protection strip. Try to avoid the edges of the drive's casing for the cables to cross as good as possible.

Inspect everything one last time for forgotten tools, missing screws, trash and fluffs of dust. The first time I put it back together I was a bit sloppy and somehow one of the frame's protection-foam thingies made its way into the cooling fan causing one hell of a racket. I had to open up everything all over again to get it out. So please don’t make the same mistake.

If you're done with your inspection, it is time to lower the screen down while reconnecting the white plugs next to the optical drive. If you have done a good job with the marker, they shouldn't be too hard to match. What will probably cost you more time to connect are the two connectors closer to you because you won't have as much headroom -- and hand-room for that matter. I held the cables from the screen just above the plugs between index and middle finger, thumb an ring finger held the part coming from the drive. Pinky was taking a break, although he should have helped too. ;)

Now make sure that the screen is back in place by checking the holes for the screws. At this point you should also make sure that the cable running on the left of the screen is really tightly connected to the circuit board or you might experience funky pixels or a gradient of decreasing brightness (that's what I had at first).

When you see everything well and fit, screw the screen back on. I drew a bit on the photos to show you what holes to use on each side, in case you forgot.

When you're done with that, reconnect the other cable coming from the screen with the LCD TEMP pin-connector on the upper right of your Mac.

Step 9: Closing Up

After the screen is back in place you're almost home free. Getting the frame on may be a bit frustrating because of the protection paper slips on the frame where the RAM slot is located. If you are patient enough you will eventually get it back on, I however, grew so annoyed that I just ripped them off -- warranty good-bye, part 3.

Before closing the frame for good, don't forget to reconnect the iSight plug again and make sure you don't jam the cable on a hard edge between the frame and screen!

Now you can screw the frame back on but not too tight in case, god forbid, you need to go back in. Your tools will thank you. Also pay attention and don't accidentally drop a screw on the lens of the iSight cam or you might scratch it badly!

Also don't forget to screw the RAM cover on the bottom back on, you might miss it.

By the time there will now probably be quite some dust on your precious screen and that's totally okay. Blow the thickest dust away with the compressed air. It is crucial that you get any fragments off the screen that could damage it when wiping it with the paper towels, such as tiny metal swarf from screws etc.

Only then you should make extensive use of the paper towels and window cleaner. Do not spray the screen directly, rather spray a folded paper towel lightly, let it sink in for a couple of seconds and then wipe it over the screen. You might want to do the same on the inside of the glass. Take your time for this step because, believe me, overlooked fibers or prominent dust specs will make you mad when you are constantly reminded of their existence when working on your Mac.

The glass should fit tight and seamless thanks to the magnets and you can finally put your Mac back upright on its stand and reconnect the power.

Step 10: Using Your New HDD

Switch on your Mac, feed it your Mac OS System Disc and pray to Cthulhu that it still works. No worries, most likely it does unless you really pulled some stunt in the last half hour.

If you see the Apple logo -- good. If you see the circle below it, indicating activity and not freezing -- even better. Now wait. It could take a couple of minutes until your iMac finally greets you with the installer.

After selecting a language hit "Continue" until the menu-bar appears and there under "Utilities" you will find the "Disk Utility" which lets you partition and format your new drive, additionally you can even restore a disk image from a file onto the brand new disk.

I went with two partitions and a complete fresh re-setup of everything but what you prefer is totally up to you.

I hope this instructable proved of good use to you and if you have any comments or suggestions, please feel free to share!

Thank you for reading!


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    7 years ago on Introduction

    Hello, you are rally a genius!

    In a Mac Store in Belgium they told me that my iMac from begin 2008 was a "vintage" and that it was no really possible te replace my HHD. The technician told me that he'll ask to his colleague if he "accepts to try" to repair it. Who is the customer? He's not a king... So, I decided to take my iMac back.

    I discovered you instructable, so I dared to replace my HDD by myself. It's a success, I have now an iMac in perfect state with a HDD of higher capacity. Cost: 70€ for a 1T HHD + transport.

    Many thanks for you very good explanations.


    Reply 7 years ago on Introduction

    Hi Jean!

    Thanks heaps for your nice feedback! Yes, Apple has a reputation of neglecting their old products because they want you to get their newest one.

    I’m glad you found this old tutorial useful and got some more room for your stuff on your iMac. The one shown in my instructible still runs without any problems for more than four years now, so I guess I didn’t break anything with the screwdriver ;)


    8 years ago on Introduction

    Excellent instructable. This configuration worked for me:

    My iMac is: iMac 20"/2.0Ghz/1GB/250GB/SD/AP/BT, Model No: A1224

    My original HDD died but I successfully installed a Mushkin Chronos Deluxe 480GB 2.5"SSD, formatted to Journaled HFS+ and restored from Time Machine without losing any data. The SSD model is MKNSSDCR480GB-DX7. I used the Newer Technology's AdaptaDrive (2.5" to 3.5" SATA Drive Converter Bracket). I strongly recommend it since it gets the drive connectors where they need to be for the short cables from the motherboard.

    I should warn that the System Profiler tells me that this Mushkin Drive does not support TRIM, so I have to live with that. Everything has been working fine for a few months now but I don't have any before-and-after speed specs to share. Its certainly much faster though. The temp sensor is on the drive and there have been no issues, alarms, or strange behaviours from the fan (such as running high all the time). It all seems just fine.

    Thanks for posting this wonderful instructable. I hope my info helps out any one else who wants to give an old machine a second chance with a SSD.


    6 years ago

    This is inspiring me a lot into changing my mom's iMac 7.1 HDD for a SDD drive. Most probably your instructable refers to a replacement with an HDD drive because SSDs were not available/popular at the time you posted. In principle, can the procedure described by you here be adapted to a SSD? Specifically: where should one attach the temperature sensor? I have a samsung 850 EVO in mind, and that is all encapsulated in a plastic case. Would it make any sense attaching the sensor to the plastic case?

    On the other hand, a few months ago I replaced a HDD with a SSD on a 2008-ish MacBook. There was no temperature sensor there, so I did not even know that I needed to worry. And nothing strange ever happened on that computer ever since.

    Thank you very much for the instructions. You know that many have already said that, but one really has the feeling of having you on a side telling what to do at each step 8-)


    7 years ago on Introduction

    Great guide! I swapped in a 2TB into my 2009 iMac yesterday. I would have been lost without your instructions. I was most surprised by the magnetic glass attachment. I would never have imagined that that was how they held the screen cover on.

    Anyway, I was wondering: I swapped the drive to increase storage space *but* also I was hoping it would put a stop to some loud clicking sounds that have begun emanating from my iMac when it's running. Unfortunately, even with the new drive in the clicking noises continue just as loud as before. Has this happened to your iMac? Have you figured out a way to make it stop? I'm not using the optical drive, so I am thinking maybe it's the two fans... I can't think of any other moving parts that I saw inside the machine.

    Thanks again!

    -David Saxton


    7 years ago on Introduction

    Hi, thanks for the great guide!

    My question is about the software part. If I for example remove my drive, then format it, and put it back, will it start the installation? Is the installation/OS located somewhere else than the hard drive, or why does it start immediately after you put the new drive in?

    I'm asking since my old iMac is kinda dead, and it seems like formatting the hard drive and starting it up clean would be the right thing to do, since I'm not willing to put in any other resource than time to get it to work :) (it was working just fine 3 years ago when it was on the last time)

    Once again, thanks for your guide!


    7 years ago

    I have been ready your instructions for a couple of days now, trying to get the nerves to open up my iMac that isn't working.... I'm almost there and am thinking it's not working now so if I mess something up I'm no worse off than I am now. I am wondering however what year your Mac is? I have a 21.5" mid 2009 is it going to be the same steps as this? I can't find anywhere what model yours was. Thank you in advance.


    Reply 7 years ago on Introduction

    Hi Karen! Glad you like this instructible. The Mac I used it on was build in 2007 if I am not mistaken and was already past its warranty. But don't worry, if you take your time and follow the steps closely, there's really not that much you could screw up (only unscrew, but that's part of it ;)). Just make sure you don't scratch the unprotected display and that you refrain from poking arbitrary circuits on the motherboard inside with your screwdriver. You'll be fine!


    10 years ago on Introduction

    Excellent instructable, very well done. You sir, are a credit to the community!

    I can only imagine how apprehensive you must have been at opening up this remarkable computer.


    Reply 10 years ago on Introduction

    thank you very much! yes, i was quite shaky the first time i opened up my imac. that's why i photographed every step to be sure on how to put it back together. once i got it back together, i thought i might put the photos to good use and share my instructable with the community. so i hope it helped you and thanks again for your nice comment :)

    DIY  Dave
    DIY Dave

    11 years ago on Introduction

    When I first saw this instructable I thought it said you were trading a 500 GB HDD for a 200 GB HDD.


    Reply 11 years ago on Introduction

    hehe, i guess i should have put "2 TB" on the pic instead of "2000 GB" then ;)


    Reply 11 years ago on Introduction

    you were close with the "translation" 2 TB is 2048 GB, but manufactures never give you the exact bits that is said to be there, sorry if you already knew this.


    Reply 11 years ago on Introduction

    exactly. that's why i chose to write 2000 GB instead of 2 TB. i am really sick of these marketing gigabytes. in the end you have just 1.86 TB or so. nevertheless: good point :)