Updating an iMac 27" EMC 2546

iMac 27" open

Back in 2013 when my oldest son was 10 years old I wanted him to get into computers. He had already started gaming but the responsible thing seemed to ever-so-gently nudge him towards development and the world of creating your own applications. As I was already a converted Apple-fan (from Linux) the best choice was an iMac that everybody could use. A good sized screen of 27 inches with plenty of 'real estate', a hard drive to hold it all and RAM to last all the way (8GB).

Well, he did get a lot of 'milage' out of it but in the end he was more interested in serious gaming and that meant getting him on a Windows platform a couple of years later (much to the dismay of his father, but hey...). With that, the iMac was now going to my oldest daughter - not a gamer but not really interested in computers either. And she was - and is - able to do most everything with her smartphone!

So, there was basically an "orphaned" high quality desktop computer ready to be put to use. A little dated but working and running Mojave without sweating too much. Ok, it could definitely use more RAM but can you ever get enough of that? My primary work station is a laptop but at home it becomes pretty stationary and not as flexible as I would have hoped - in other words, sure, it would be great to have a desktop computer! That's when I cleared a very cluttered desk and made preparations to get started on this "new" machine - just gotta pick it up from upstairs and bring it down, hit the power-button and get started... not! Damn thing won't boot! Well, it starts, plays the tune and then turns off again. It's broken! Nothing! A six year old iMac headed for the eternal pasture?! Over a faulty hard drive! Damn!

Not my first repair rodeo

Well, we couldn't have that so I rushed to ifixit.com where I've ordered from in the past: A replacement screen for the aforementioned Macbook which I smashed when closing the lid over a toothpick and then more recently replacing a broken iPhone screen. Yeah, I'm a pretty good repairman and if I can fix something as fiddly as a Macbook and iPhone of course I can fix a big ole iMac! But why not take the opportunity to get some much needed upgrades in and extend the life of this trusted old computer? There's a hard drive replacement kit that includes a SSD and since I'm waiting for the kit to arrive (from Stuttgart, Germany) why not upgrade the memory and go for the full 32GB that the iMac can support?! It all comes at a premium but this is a premium computer and it's worth it to keep running - no other brand will give you value like this over so many years and everything (else) works so I ordered the components: Replacement kit (the 500GB option to replace the 1TB HDD the was faulty) that included all the tools and spareparts needed from ifixit and 4 x 8GB RAM (Crucial DDR3L PC3-12800 204-pin) from Proshop in Denmark.

Opening box from ifixit
The box with tools, hard drive and gummy bears(!) from ifixit

After a couple of days all parts arrived and I was ready to get cracking on the upgrades. The RAM was easy enough as it only required moving a small hatch on the back just below the power cable. When power cable is removed a small tap can be pressed inside the "ring" and the hatch releases. True to Apple engineering prowess the memory banks are accessible after moving a lever giving easy way to remove or install modules. Quick and simple fix.
Next up is the complex operation of opening the darn thing, removing old hard drive, installing new, testing and then assembling everything back! There are no screws but only adhesive sticks along the edge of the screen so no room for mistakes - get this right or it can't be reassembled. With stakes high the repair guide was whipped out and the classification of "Difficult" was just an extra motivational factor. I got this!

Cracking it open

Using the roller-cutter supplied to release the screen from the casing was quite simple. The tool supplied was just the right size to cut the seal of the adhesive strip but a little bit of wiggling was necessarry. I would recommend doing this part on a soft surface in case the screen slips and falls. Getting the whole thing opened revealed that a good cleaning was way overdue. Be careful when sticking vacuum cleaners, fingers or anything else inside delicate electronics as static electricity will kill it.


Plenty of nasty stuff after six years - removed carefully with vacuum cleaner and anti-static towel

Just two small connectors keeps the screen attached to the rest of the machine and as per usual it's really fiddly and really delicate. Be very careful when detaching the connectors - not only can they break but poking around in the guts is an ESD-risk. Static electricity is a nightmare. Since everything is held together by adhesive strips and not "inter-locking" metal bits you really need an extra pair of hands just in case. My oldest son was really helpful when taking this apart and at 15 he's a "dust afficionado" judging by the state of his room...


Preparing the new SSD-disk for assembly, cleaning the inside

Moving the speaker and getting access to the disk was surprisingly easy. Never forget to go gently and triple-check that all wires are out of the way. Patience is so important as there are really a lot of sensitive stuff - but the build layout and -quality is very good so taking your time is well spent. The disk is not screwed in but suspended in brackets, one on each side so be careful when you take things apart or the disk will easily slip. The connection cable is just the right length so when installing the new hard drive be careful and plan how you want the connector to go. There's a temp sensor that goes in between to consider but the 'wiggle room' is just enough for it all to fit.

Making a list, checking it twice...

Biggest issue is that you really only have one shot at doing this right. If you're not certain order some extra adhesive strips from the beginning - and if you've never opened a Mac before it can seem a bit intimidating. It is not that difficult, just time consuming and requires attention. Here's my own little checklist for getting this done right the first time:

  • Make sure you have a couple of hours blocked out for doing this
  • Have all the tools readily available - all comes with the package deal from ifixit
  • Glue-removal. I use a bit of acetone (nailpolish-remover) on a q-tip for the residues around the edges
  • An extra pair of hands on call - have someone in the next room or so ready to assist

Getting the screen back in place was definitely the most sensitive part as all the old adhesive strips needed to be cleared off before you could reassemble things. Make sure you take extra special care when removing and don't rush it! First do the screen and make sure you get it all off with a little acetone or similar. Then repeat on the body of the computer - this is where the replacement adhesive sticks go so check it all and check it again.
When you apply the new sticks be very careful - you have one shot at this and it sticks the first time you try. Measure twice and cut stick once! Follow the instructions and you should be fine - especially the part of putting the screen back on can be challenging as you need to make sure the two cables are reconnected before removing the "glue protection". I did as adviced and fired up the mac while just having the screen secured with masking tape and that was a good thing! Turned out I hadn't fitted the screen connection cable just right and no picture!


Secure the screen with masking tape and test that everything works before finished the reassembling!

It was easy to remove the masking tape and take a second look inside to make sure that all connectors were firmly connected. Tried to fire things up and hey presto, it worked! I had installed the 32Gb of RAM earlier and now I could reinstall the MacOS (Mojave) to the new disk in a matter of minutes rather than hours. About 45 minutes after the picture was taken the iMac was back to normal with all systems go - and much quicker than before. With a clean bill of health I could gently remove all the adhesive protections from behind the screen (small pieces stick out) and give a little push on the screen so make it really stick.
The operation was over and the "patient" is better than ever!

In conclusion

I'm very impressed with this seven (7!) year old iMac - it still runs very well and with a faster disk and more memory practically indistinguishable from any newer model. Most work is not that CPU-intensive so I rarely hit any limits with processing power.
One other limit though is the screen: I have attached a 4K monitor and it will run 1080p at a reasonable refresh rate but no higher resolution - at 4K it's 30Hz and my eyesight is not good enough for that.
Besides that, it runs like a charm and have quickly become my new primary work station.