2014 27" iMac Dying - Not Sure Why

[macmyworld]

My trusty 27" 2014 iMac started acting up last week. It started getting slow at times and finally had a grey screen panic. I ran the Apple Diagnostics and it said a RAM chip was going bad. So I yanked out the 4 x 4GB RAM and replaced them with two brand new 8GB chips.

Fired it up and all was fine.

Then the problem returned and is getting worse. This morning apps could not find the hard disk. They would start, but couldn't save anything to the drive (I have a 1 TB Fusion Drive). I finally had to hard reset to get it running again.

I ran diagnostics again and also ran another utility that checked the entire machine. Everything came up clean. I even looked at the SMART logs for the Hard Drive and Fusion Drive.

This feels like the Hard Drive or controller is going bad. Lots of possibilities and the machine is old enough that I'm not excited to get a large bill from Apple to fix it.

Any thoughts?

 

[nambuccaheadsau]

Go into Recovery Mode, then Utilities and run either Repair Disk or Disk First Aid depending on the operating system. Sounds like failing hard drive:-


https://support.apple.com/en-au/HT201314

 

[macmyworld]

Go into Recovery Mode, then Utilities and run either Repair Disk or Disk First Aid depending on the operating system. Sounds like failing hard drive:-


https://support.apple.com/en-au/HT201314

Did both, reports the drives are fine.

 

[06tb06]

Fusion Drives are known for not being the most reliable long-term. It's one reason I went "all flash" on my new iMac. If you're not looking into buying a new Mac or Apple's costly repair, you might want to perform a tear-down on your own and replace the drive completely. If you choose to do so, it would be a great opportunity to clean the internals (heatsink and fan), and maybe re-apply thermal paste, etc. while you're in there.

 

[macmyworld]

If I can’t figure out what is wrong I’ll end up buying a new machine. Too many possibilities right now. Could be the drives or the motherboard. Wish Apple sold a stock iMac with an SSD.

 

[lali]

If I can’t figure out what is wrong I’ll end up buying a new machine. Too many possibilities right now. Could be the drives or the motherboard. Wish Apple sold a stock iMac with an SSD.

Maybe try to call Apple support. They can help you do all the basic tests and resets pram etc and that can be a good starting point. If you have an external drive lying around (spinning or ssd) you can install osx on that drive and boot external, see if you experience same behavior by preventing a fusion drive boot. Best of luck!

 

[kschendel]

I don't know if it's worth the teardown effort, but you might try replacing the SATA cable. A lot of work but relatively inexpensive thing to try.

 

[Fishrrman]

One way to isolate whether or not the problem is "drive-related" would be to boot and run from an EXTERNAL USB3 drive for a few days. If the iMac "goes back to healthy" while booted externally, it would point at the internal drive setup (hardware, software, etc.).

Do you happen to have a spare external drive you could use?

 

[macmyworld]

I had an external thunderbolt drive connected to it. Just for kicks I have disconnected that drive and now the iMac appears to be happy again (and faster). The drive is a G-Drive mobile. I wonder if it is flaky? My tests would not have checked it. Too early to know though.

 

[Fishrrman]

"I had an external thunderbolt drive connected to it. Just for kicks I have disconnected that drive and now the iMac appears to be happy again (and faster). The drive is a G-Drive mobile. I wonder if it is flaky?"

Hmmm....
- You had a problem with the computer
- You removed external device, then...
- Problem disappears.

That would seem to be the logical conclusion.

Is the G-drive case "openable"?
If it is, I would TAKE THE DRIVE OUT OF the enclosure, then put it into a DIFFERENT enclosure (I suggest USB3) or use a USB3/SATA adapter/dongle like this:
https://www.amazon.com/Sabrent-2-5-...478&sr=1-2-spell&keywords=sabremt+usb3+to+ssd

Then, reconnect it.
Does the problem re-appear, or does it "remain gone"...?

 

[macmyworld]

Reading the reviews of the G-Drive they have a history of overheating. Based on how the iMac behaved, I think the electronics are bad in the G-Drive. I only used it for Time Machine liked it because it was a Thunderbolt Drive.

Replaced it with a USB 3 Western Digital and all is fine. So I found the problem as weird as it was.