Replace non-booting Late 2014 27” iMac Power Supply, Save data from Fusion Drive, Upgrade to SSD Help?

NGC1487 wrote:

Further, when you have to screw the four T10 screws to keep it in the housing, you have to force it in by (unfortunately) having to touch parts of the board and check that the Molex clips are snapped on.

Should be no forcing. There just needs to be gentle maneuvering until the board fits into the opening. Once in place, I usually start each of the four screws to help "hold" it in place.

The stock 3.5" Western Digital 1000GB Drive was put back in, the left metal brace was removed and the SATA cable was plugged back in, but there is no way the iMac can know it was removed as it hasn't had power since 2022.

Correct.

The original bottom adhesive is still on the screen so I can easily flip it open to access the interior in the event something goes wrong.

Don't rely on that original adhesive to hold the screen in place. I use painters tape at the top & sides of the screen to help hold it in place while I'm testing. Even that is risky since the tape has been known to come loose at times.

• If there is a rush against time to save the data, my guess is to do Command+Option+R to get to Internet Recovery and (hopefully) reinstall OSX Yosemite (it was the original OS that came running on the machine and never upgraded and several of my Applications had to use older versions of OSX)

The only "rush" would be not to force access to the Hard Drive if it is actually failing. The first step if the system powers on would be to check the health of the Hard Drive by using DriveDx (free trial period) since it can tell us if and how bad the failure really is. There are also other ways in case the iMac won't boot to the Fusion Drive (install to external drive or use non-Apple OS boot disk).

I'm not sure you have access to Internet Recovery Mode if this iMac was never upgraded to macOS 10.13+. That is when Apple introduced Internet Recovery Mode and the online Apple Diagnostics. You should still be able to use that key combination since it should allow you to access the local recovery mode installer which should bypass any need to authenticate with an AppleID (Apple's documentation was very vague here).

Also, if you need data from that Fusion Drive, then I would not try to reinstall macOS over top of itself....especially if the Hard Drive is failing. A better option would be to install macOS to an external USB3 SSD (or even a Hard Drive...for testing purposes) which would allow you to check the health of the internal Hard Drive and give you more options to analyze & evaluate the system including recovering any important files assuming the internal drive is not failing (or failing too badly yet).

• To assist with the above, I found and tested a working Mac Keyboard and a wired Microsoft USB Optical Mouse on my Macbook Pro, as I don't know that Bluetooth will on the iMac will work in Recovery or if it has failed over time. The iMac came with a Bluetooth Magic Mouse and Magic Keyboard, I still have them, but I'm guessing wired is the way to go

Yes, wired is best when trying to troubleshoot a system.

• I had an issue with Internet Recovery attempting to reinstall High Sierra on my Macbook Pro because I think it doesn't correctly reach the actual server anymore; there is a fix in Internet Recovery to open Terminal and type/edit a command line to an https server and then a few more lines have to be executed so it goes to the right place; is this the same for Yosemite?

AFAIK, that issue only seems to occur with High Sierra, but if one of the other online installers has that issue, then that same fix should work as well.

Continued....

• If the OS reinstallation is successful and I can access the desktop, the plan is to use Time Machine or Carbon Copy Cloner to copy the OS and files to a brand new 1TB SSHD 2.5" Laptop Drive, unless there is a better option?

Depends on whether the internal Hard Drive portion of the Fusion Drive is healthy.....or how bad the Hard Drive failure may be.

Once the above is done, I can proceed with the removal (and disposal) of the 3.5" Drive and the SSD Blade Drive to install the 2.5" SSD and buy a better/higher capacity blade drive, or do I need to do anything to 'remove' that Fusion link between the two on the computer?

FYI, you cannot use a third party NVMe blade style SSD internally when using Yosemite. A third party internal NVMe SSD requires macOS 10.13+. In fact, macOS 10.13+ must be installed prior to using/installing a third party SSD in order for the macOS 10.13+ installer to upgrade the system firmware to allow the use of an NVMe SSD internally.

I'm not really sure it is worth the time, effort, risk, and money to replace the blade SSD for a 2014 Mac. Installing a 2.5" SATA III SSD internally will give you the same & likely better performance than the Fusion Drive (up to 500MB/s transfers).

However, how long do I need to wait before opening and disconnecting the Power Supply Board;

At least an hour. I would also press & hold the power button for a few seconds after disconnecting the AC Cord in order to help drain the power. Even then you may still sometimes encounter a residual charge.

NGC1487 wrote:

Servant of Cats,

Thanks for the quick reply. Some time around Sept. 2022, the computer stopped turning on so I recently opened it up to see if it was the power button or something else; the culprit seems to be the Power Supply Board as none of the LEDs turned on despite there being power supplied to the machine.

The PRAM battery may be a problem as well. Unfortunately on some iMacs, this battery is on the back side of the Logic Board. I honestly don't know if it would prevent the power LED from lighting up on the MLB, but it could definitely affect the power on & boot process (rare, but it does happen).

I removed the SATA hard drive but never put it in a drive enclosure or anything else for fear of doing something destructive. There are backups of some (but not all) of the files and programs so I'd like to see if its possible to perhaps leave the Blade SSD in as it already is, put the SATA hard drive back, and replace the Power Supply Board, see if it turns on and then attempt a reinstall of OSX (I think perhaps it got corrupted over time?) with internet recovery.

I would leave the original drives installed until you have finished trying to recover data from the Fusion Drive. This is the safest option. Theoretically it may be possible to remove both drives and access them externally on another Mac, but this is very risky since so much can go wrong if macOS does not recognize both drives in a timely manner which would result in a broken Fusion Drive.

Is this what I need to do before doing any of the upgrades to the hardware like the blade drive SSD in addition to the SSD 2.5" drive upgrade with the kit from OWC?

When troubleshooting issues, you should make minimal changes. As soon as you make changes you quickly create many possible new issues.

If there is no power, then that is completely separate from any drive related issues (it is rare that a hard drive will cause a no power issue).

A no power issue can be caused by the power supply, or the Logic Board, or by a tiny cable on the front of the power supply connecting the Power Supply & Logic Board. You could also have a poor fitting AC cord, bad AC Cord, or bad electrical outlet or power/surge strip. Disconnecting the display assembly would be Ok in order to see if it may be causing a power related issue.

Continued....

The other thing I'm having trouble understanding is when people talk about 'breaking' the Fusion drive; is that a command or series of commands in Terminal or is it merely by removing either/or, putting in new drive(s) and then reinstalling OSX via recovery or some other method?

If macOS does not see both drives in a Fusion Drive setup within a certain amount of time, then it may cause the Fusion Drive to become split. A failing hard drive can produce enough I/O Errors to cause the Fusion Drive to split as well. Damage to the file system on either drive can cause it as well.

You need to resolve the power issue first. Personally I would not spend too much money on this old system beyond the cost of the power supply. Just make sure to reattach the small cable that connects to both the power supply & logic board (on the front of both boards). Also, it can be tricky to disconnect & even reconnect the main power supply cable that connects to the back of the Logic Board (very awkward, with very little room to maneuver. That cable should be nice & tight when connected....usually there is a snap once the release mechanism slides over the protrusion & literally snaps into place.

If the iMac is dead, I would recommend having a professional data recovery service assist you to recover the data since you have a Fusion Drive setup. More than likely the Hard Drive is failing, but even if it is still healthy it doesn't take much to break the Fusion Drive setup. If the Hard Drive is failing, then many times the I/O Errors produced by the failing drive will prevent most data recovery apps from working and macOS also gets in the ways because it is unable to handle the I/O Errors.

Of course if the iMac is dead & you want to risk recovering data from the Fusion Drive yourself, then you will need to remove both the Hard Drive and SSD and place them in USB3 enclosures to your working Mac. Make sure to have no other devices connected. It would be best to have power turned off to those external drives as you connect them to the Mac, then power off the Mac. Power on both external drives at the same time followed by powering on the Mac. Hopefully macOS will see both external drives as ready & recognize the Fusion Drive setup (no guarantees). Unfortunately the USB-C Macs tend to power on whenever you connect external devices, plus just pushing a key or the Trackpad will cause the new Macs to power on. Extreme care must be taken.

FYI, if the iMac powers on, but does not boot, then you have two options. Try installing macOS onto an external USB3 SSD so you can work from the external. Or put the iMac into Target Disk Mode so you can try accessing the Fusion Drive on your other Mac.

I've never tried to access a Fusion Drive outside of the Mac itself although I've seen one or two posts where people had success.

NGC1487 wrote:

HWTech,

What should the next course of action be? I waited doing anything to ask for advice, sorry for the delay.

I've already given you everything you need depending on the goal here. Which goal are you going for here?

How sure are you that the blade SSD has failed? I know it is 128GB but shows up as around 1.33GB,

Well, if the SSD is not always seen by the system, that is an indicator an SSD is failing.

Combined with the SSD reporting as 1.33GB......that shows the SSD has a problem, depending on how you got this information.

Would a Check Disk work? I read that people with a Prohibtory Symbol iMac do the following:

1.Restart computer

2 Hold Command and S key

3. Log in and in Terminal,

4. Type fsck -fy hit enter

5. type reboot

Would the above work?

That will only scan the boot drive. If it is the internal HD, then it depends if the HD is healthy or not. You are missing a step in there...Step #3.5 is to change the volume from mounted as read-only to read+write (I'm writing this from memory.....when booted into Single User Mode you will see all the commands needed to run fsck on the volume including the mount command):

mount  -uw  /

Also, I've done that file recovery before with Macs (I think I used Stellar Phoenix) and got the files back with no file names, e.g. just numbered files in the past. If you have particular software that you know works best with Fusion Drives, let me know and I can look into them. That would be better than nothing, to be completely honest, but I'd like to see if a Check Disk or Internet Recovery could work?

All data recovery apps behave the same way if a Deep Scan or Thorough Scan is used when recovering files from an Apple filesystem.

Also, from what I can tell, when I log into Recovery Mode on that iMac with 10.10 Yosemite, it looks like there 'is' an option for Internet Recovery; if I were to try it and to reinstall the operating system, e.g. just with Command R so that it ONLY reinstalls Yosemite, which came stock when that machine was new (and never upgraded to El Capitan, Catalina, etc.), is it safe to do? With Command Option R I believe it will reinstall the operating system to the latest stable OS, which is what I'd prefer not to do, but if it can work, I'd be willing to try it.

If macOS 10.13+ has never been installed, then you don't have Internet Recovery Mode. The firmware update included with installing macOS 10.13+ adds the Internet Recovery Mode feature to the Late-2009+ Macs.

If I do the above, which 'drive' do I select to reinstall the Operating System? Is it the Blade Drive, the 1000GB 3.5" Drive, or what? I ask since this is a 'Fusion Drive' and am unfamiliar with how the OS gets installed (or reinstalled) for these particular conventions.

How would I go about installing "macOS 10.13 and macOS 11.x" as you mentioned above?

To install macOS High Sierra for the first time requires an internal drive with a GUID partition and MacOS Extended (Journaled) file system. The drive can be completely empty. The macOS 10.13+ installers require a properly partitioned & formatted internal drive to stage the firmware update.

macOS 10.13+ can be installed to any drive, including an external drive as long as the above conditions are met.

My next question after all of this would be if I were to buy a brand new Blade Drive, which are compatible (I think they are Apple PCIe) and which are best for these machines? I'll have to open it back up again to take out the original Blade Drive (if it indeed has failed) and swap it with another one then put in the 2.5" HDD upgrade so I can seal it back up for good.

OWC provides a drop in replacement SSD which uses the Apple proprietary SSD connector. I do have to question why you want to go to such extremes on a 2014 iMac since it is very tricky removing & reinstalling the Logic Board.....there is a lot of risk to accidental damage.

Thanks again for all the help thus far, I'm committed to get it back up and running, given that it is exciting that just swapping out the Power Supply Board got it to turn back on for the first time in a few years!

Good to know the power supply resolved that problem.

If you need data from the Fusion DriveRun DriveDx on both internal drives and posting the complete text report here using the "Additional Text" icon which looks like a piece of paper. FYI, SSDs tend to fail by disappearing and not from actual errors, so a health report won't show anything wrong if that is the case. To run DriveDx does require you to be able to boot into a full macOS installation whether internal or external.

If data is not needed, then just replace the internal HD with your new SSD.

NGC1487 wrote:

The goal is to get the computer back up and running, with at least an attempt to either repair the Fusion Drive for one last recovery/backup, then get rid of one, or both of the previous Fusion Drives to have a fully working iMac

FYI, there is no way to restore a split Fusion Drive and retain the data stored on the two physical drives which make up the Fusion Drive. macOS will either see the two physical drives as a Fusion Drive, or it will not.

Once data recovery is no longer on the table, then you can create a new Fusion Drive as long as both drives are healthy.

How sure are you that the blade SSD has failed? I know it is 128GB but shows up as around 1.33GB,

Well, if the SSD is not always seen by the system, that is an indicator an SSD is failing.

Combined with the SSD reporting as 1.33GB......that shows the SSD has a problem, depending on how you got this information.

These are pictures from Command+R. The choices are Disk Utility and Reinstall OS X. If I choose Reinstall OS X, it shows a screen saying it can reinstall Yosemite 10.10 but I need Wifi to get on the internet; is this not like internet recovery? This was what I mentioned earlier.

For Disk Utility, please see the link containing the images, including when I select Reinstall OS X, it appears it may install the stock Yosemite 10.10 which came with the computer when it was brand new? If asked for a choice, what drive should it be installed to, but what should be expected since this was a Fusion Drive to begin with, so does this option know to 'fix' or reinstall the stock operating system without erasing my files, much like if you did this option for a Mac with a normal hard drive like an internal SATA drive?

I'm surprised that the Yosemite installer is not showing the physical drives. I thought Disk Utility with Yosemite always showed the physical drives, but your pictures only show "Macintosh HD" in red on the left pane of Disk Utility indicating a broken volume....in this case a broken Fusion Drive.

Unfortunately Disk Utility is a terrible app. While booted in Recovery Mode launch the Terminal app from the "Utilities" menu on the menu bar. Issue the following command to display the drives & their layouts....it will pause the output once the screen is full....up & down arrows can scroll the output to see more and press "Q" to quit & exit back to the command prompt.

diskutil  list  |  less

Ignore any external or virtual volumes as they are associated with the installer & are irrelevant. Usually the internal physical drives & volumes will be the first items on the list, but a failing drive may show up later on the list. A picture of the first page of output should be sufficient unless you see the 120/128GB SSD listed, then include a picture of it as well. Please use the "Image Insertion" tool located on the forum editing toolbar so the images will remain available with this thread since outside links break very quickly.

<DriveDxReport_APPLE HDD ST1000DM003_.log>

The health report for the Hard Drive looks good, but it shows the drive is only connected as SATA II 3Gb/s when it should be a SATA III 6Gb/s connection. I guess the missing SSD could be the cause of it since the internal OEM SSD is SATA based. I'm assuming DriveDx did not see the 120/128GB Apple SSD?

mount -uw /

So I add that command line you have there and it should read/write if necessary? Both drives, the blade SSD drive and the 3.5" Western Digital 1000GB are both internal.

Yes...remember Single User Mode lists the commands needed so follow the on screen instructions.

Unfortunately if you are not booting to the internal drive you want to fix, then Single User Mode is irrelevant. From everything I've seen here you have a broken Fusion Drive with a bad SSD. If you are booting to the internal drive with Single User Mode, then I'm not sure how you are even doing that since I don't believe it is possible without having installed macOS onto the Hard Drive.

Continued....

If macOS 10.13+ has never been installed, then you don't have Internet Recovery Mode. The firmware update included with installing macOS 10.13+ adds the Internet Recovery Mode feature to the Late-2009+ Macs.

See above; especially this picture: https://i.imgur.com/jzW4tEI.jpeg I have Wifi, and I can connect the iMac with an ethernet cable if need be; it has that slot and I know wired internet would be safer to reinstall the OS without internet disconnection.

macOS 10.10 Yosemite is very old now & the Internet has changed. Perhaps Apple has changed access to their online servers.....assuming it is not a problem with actually authenticating with your WiFi's SSID. Apple has been breaking access to their older online installers for quite a while now.

Can I take a blank 2.5" laptop SSHD I have and install 10.13 via an external drive connected to a working MacBook Pro or does the blank 2.5" laptop SSHD have to be put inside of the MacBook pro to install, if this is what you mean by specifically internally connected to the ribbon cable that connects it to the logic board

macOS can be installed to an internal or external drive....it does not matter to the Apple hardware or OS. The other Mac must be compatible with High Sierra.

However, what good will this do you? In order to use a third party NVMe PCIe blade style internal SSD in the iMac requires installing macOS 10.13+ on that Mac so that Mac's firmware can be updated to understand both an NVMe internal SSD and the new (at that time) APFS file system used by macOS 10.13+, plus providing access to Internet Recovery Mode to access the online Big Sur online installer. Booting macOS 10.13 external SSD on your iMac won't work because that external drive will most likely be using the APFS file system which your iMac's system firmware will not understand.

If you have another Mac model generally from Late-2009 to 2018, then you can create a bootable macOS 10.13 USB installer which can be used on your iMac to install High Sierra onto an internal or external drive. Technically your 2014 iMac can run up to macOS 11.x Big Sur so that could allow you to have more options for creating a bootable macOS 11.x USB installer by having a Mac model up to Mid-2021.

Also, let's just say 'if' that blade SSD drive is failing or could zap out? Wouldn't it be safest to remove a failing part from the board entirely, or could I really just leave it there, ignore it, take out the 3.5" 1000GB drive and just replace it with the 2.5" SSD OWC 2TB Mercury Electra 6G upgrade I still have and am waiting to decide if it is worth putting in or getting a better 2.5" SSD?

If the internal blade SSD isn't causing problems, then I would ignore it. Unfortunately only you can tell or decide if that SSD is causing any problems.

NGC1487 wrote:

I delayed doing these repairs because of any potential complications to the drive itself. I 'should' have attempted to reinstall OSX via Recovery when the iMac still turned on around and took very slow to get to the login screen around Summer/Fall 2022.

FYI, more than likely the internal Hard Drive was failing which was causing the performance issues. Or you have some third party software installed with is interfering with the normal operation of macOS....usually booting into Safe Mode will bypass those issues for troubleshooting purposes.

and the glass display folds up giving me access to seeing the inside; indeed all 4 LED lights don't turn on, on the Power Supply Board so I bought a replacement one for about ~$50 a few months ago.

FYI, there are no LEDs on the power supply itself. The diagnostic LEDs are located on the Logic Board.

My big worry is that no power has been supplied to the new board, nor has it been connected and I see and hear lots of warnings about major electric shock or death with this Power Supply, in addition to the visibly huge capacitors. This has deterred me from attempting anything so far.

Power supplies are extremely dangerous. It is best to wait at least an hour or two after unplugging the AC Cord before attempting to work on the computer....even then some of the capacitors could possibly still retain a charge.

Yes, for this model (Late 2014 iMac 27"), the battery is a 2032, I have replacements but I haven't attempted to go any further than just removing the left speaker, 3.5" Hard Drive and carriage slot, and the Power Supply (since it more than likely is the culprit why it doesn't turn on).

Don't remove the Logic Board unless you absolutely have to do so. It is very tricky to remove & even more tricky to reinstall the Logic Board.

you're mentioning that time can also 'break' the Fusion Drives; so I'm learning about this as we go along.

Time only in the sense of whether macOS sees the two parts of the Fusion Drive in a timely manner, after which I believe macOS will start only utilizing the small SSD causing a break with the Hard Drive portion which to macOS has gone "missing".

Going with your advice, it will be trivial for me to put back the speaker, install the new Power Supply Board and connect the cable I suspect you mean; there is one that looks like a large ATX-style cable end that clips onto the connection socket and then I remember a smaller one, possibly square shaped. One of the two was a pain to disconnect as I was worried about getting electric shock not knowing if the capacitors had fully discharged.

Yes, that ATX style cable is very difficult to disconnect from the back of the Logic Board.

Since I will attempt this likely in a few hours after reading advice on this thread, are there any 'do's and don'ts' for installing the new Power Supply Board with paying heed to not getting electric shock, given that I may have to take the board out again to get to the battery and/or the Blade Drive I'd like to replace? Some people said only handle the Power Supply Board by the edges only and never the Board itself (never touch the capacitors or the chips) by the black printed board part (without components) I've seen people on repair videos doing different things.

People should never touch anything other than the edge of any electronic boards since you can damage the electronics. With a power supply board, if you touch anything other than the edge, you risk a dangerous electric shock from the capacitors.

Make sure to wait at least one hour after disconnecting the AC cord from the power supply before handling it. I also like to press the power button for a few seconds to help drain the capacitors as well.

My workspace is on stone tile floor with a wooden coffee table, humidity hovers at 30% or even lower during the daytime and lots of static 'zapping' if I walk to carpet areas or touch the electric switches after walking on the carpet.

That zapping is why people should not be touching anything other than the edges of any circuit board as it may cause damage to a chip.

Removing either the SATA hard drive or the blade SSD will break the Fusion Drive.

In a Fusion Drive, the SSD is not merely a "cache" for the hard drive. Data is spread across both drives, so neither drive alone has the complete filesystem. As far as I know, there are no external Fusion Drive enclosures - the only Fusion Drive enclosure is a working Mac in which both the SSD and the HDD are internally installed.

Were you keeping backups of your system?

It sounds like the internal blade SSD has failed (or possibly an issue with the MLB's support circuitry for the internal SSD...SSDs are usually the weakest link). Normally the internal blade SSD will be assigned the device identifier "disk0" since it is the fastest drive which will go ready first. Instead your internal Hard Drive appears to be assigned "disk0".

I don't think it is possible to recovery any data from a broken Fusion Drive. Of course you can try using data recovery software to see what can be gathered from the internal Hard Drive since many of those apps will allow you to scan a drive to see what is found, but you may need to pay for the app in order to recover the files (some may allow you to recover a few small files to show it is possible). FYI, if you have to do a deep or thorough scan, then you will not get any file names or folder/directory structures....you will be sifting through millions of unnamed files.....most of them temp & cache files related to web browsing.....everyone has given up trying to find the relevant files they need (same thing is likely to occur even with a professional data recovery service).

FYI, I would highly recommend installing macOS 10.13 and macOS 11.x so you get access to Internet Recovery Mode. You can then use & install whatever version of macOS you wish if you want to retain Yosemite or El Capitan for your older software & accessories.

Coming late to this party. Just wanted to make sure you are aware there is extensive repair information including detailed pictures & user experience on I FiX IT DOT COM

Look for iMac Intel 27" Retina 5K Display (Late 2014 & 2015) Repair

Model A1419 / EMC 2806 / Late 2014 or Mid 2015. 3.3 or 3.5 GHz Core i5 or 4.0 GHz Core i7 (ID iMac15,1); EMC 2834 late 2015 / 3.3 or 3.5 GHz Core i5 or 4.0 GHz Core i7 (iMac17,1) All with Retina 5K displays

(link not provided because it would probably be removed).