iMac(pc) fun

So over the last, oh lets say year, my iMac has been randomly not coming out of sleep mode and then was beginning to freeze up while awake(though the mouse moved around just fine, nothing else was interactive. So finally last Friday it went and would no longer boot up. So a brief amount of investigation tells me, most likely the GPU. So I researched and found that it would seem that the max iMac card that can be fit in my Late 09(a little snipping of a plastic support), and that’d be a pretty big jump up from the Radeon HD 4850, is the 6790m from the '11 iMac. Cost about $320 and maybe two hours of time. I could try figuring out how to reflash a regular PC version and stick even better(and expensive) cards in there but can’t spend that money now. More and more digging finally reveals, someone on bithub has collected and has linked to the AHT(Apple Hardware Test) that got canned back when OS Yosemite dropped it for the online versions. Made a bootable USB drive and ran the tests(normal was 6min, long one was 3 hours. Turns out, the only error is coming from the HDD cabling. So now with a tool kit coming in and armed with some compressed air, I should have this on lock down in opening the iMac and that should hopefully settle this matter(still wished I’d had the cash to upgrade everything else.)

Gonna edit this in:


My heart goes out to ya.

I live in this industry (IT Administration, Support and Hardware Servicing) and every time I touch an upgrading project (PC or Mac) for clients, it is a Russian Roulette on new components in older hardware and interaction with other components and OS.

If I can offer any help, let me know.


Yep. Been in this since the first Apple Ii and IBM PC and I never volunteer to help friends. I’ll do it if asked but otherwise I’d rather not get in the middle of a really long (days sometimes) spelunking process looking for the combo of hardware & software (& settings) that will work. Even then they’re usually wondering why it took so long.


I’m troubleshooting an HP for someone who tried to revert back to Windows 8 after upgrading to Windows 10.

Can’t access the hard drive. Haven’t tried a system restore disk because I don’t have one! I haven’t taken the time time. Playing dice, but I have backups of files. Guess it would be a good time to make one if I can just find a big enough flash drive. Haven’t tried it with Windows 10 before.


Ok, I think that’s the first time I’ve actually heard of someone doing that! Most people I know wanted off Windows 8 as soon as possible.


I was thinking the same thing.

1 Like

Could be a couple of issues.

Did they have the drive encrypted (BitLocker or a 3rd party)? Did the rollback begin from within Windows or did it start from recovery screen?

Also, you can only rollback from 10 to previous version for the first 30 days. After that point, you have to do a completely clean install of the previous OS.

What is the error message that you get when trying to start the computer? If no error message, what does it do?

Depending on whether a laptop or desktop, I would recommend an SSD replacement.

For the desktop, you can install a 250 or 500 ($95 or $165 Samsung, Kingston and some SanDisk are good - but I prefer the 850 EVO Samsung). With the desktop, you can recover and reuse the existing hard drive or put in a multi Terabyte spinning hard drive.

If it is a laptop, get a 1 TB SSD. A SATA to USB unit can be used to recover the data.

Let me know the make, model and any other details. If need be, I can do the data recovery and even provide you telephone tech support.

My support site is listed in my profile.


So I got the tools in and opened the ol’girl up and while dusty…wasn’t nearly as dirty as I thought it’d be so I may just have to buy a new HDD. Def a pain to pull apart but the HDD is the first thing accessible once the screen is removed.


The first time I opened up an iMac, I was terrified that I was lose my grip with the screen and have to buy a replacement.

You going with an SSD?

1 Like

the cheapness of a HDD is tempting as not too much money on hand(the 09 is only SATAII so 50$ will get me a 1TB replacement). Though double the money will net a SSHDD hybrid drive. Don’t think I can afford going full SSD nor would I see much benefit in doing so as it’s been a couple years since I’ve had to do any real video editing. The most I do these days is convert video using Handbrake. (though don’t get me wrong, if I had the disposable income…a nice 2TB SSD would be nice, but it’s 4 times the cost)

Only fun thing now is when I get the new drive, I have to utilize the only one to boot up into recovery mode to make the new one bootable and install via internet. Undecided if I’ll keep it a clean install and go through the effort of finding all the programs to install(i’ve got all the .dmgs around somewhere) or load the latest Time Machine image.


Wow a lot braver than I :nerd_face:

You are awesome :smiley:

It’s honestly not bad. Only disconcerting part is taking off the glass front for the first time with the suction cups. There are a lot of magnets too keep it on quite securely. After that it’s pretty much a giant laptop and any experience with doing PC hardware will make you comfortable inside there.
(A couple of youtube videos before had about the cables behind the screen helped too.)


Just added a link for the github account of the gleaned AHTs if anyone ever needs them.

1 Like

I’ve opened up a few iMacs of that vintage. They certainly are a lot like laptops.

Newer ones are slightly more of a pain to open.

WAAAAY back when I first started in IT, I had to occasionally repair Apple laptops and absolutely HATED working on them. I always felt fortunate when I put one back together and it actually worked!

1 Like

As much as a WD fanboi I’ve been over the years(I’ve built many PCs and never had one fail on me though a buddy of mine who also builds has had a bunch over the years), I believe the price and 5 year warrenty on this one has won me over.

(geez, hitting Cmd+V on an Apple over the years makes so hard to not hit Alt+V on a PC keyboard)

Edit 1: Though I’d swear I have a spare 2Tb WD Green around here somewhere… though with all the parts I have, I may be thinking of the spare USB3 External drive slot…

Edit 2: Ooooh…20$ more for the 2Tb? :smiley:


Prices have really dropped!

Hello, I’m new to commenting in the group but felt that I had to as this is my area of expertise. If your going to repair it that is your choice but I would strongly recommend a SSD. I run a small Mac repair business and placing a SSD where ther was a spinning HD is a HUGE difference. I know that you are weary of buying a 1TB SSD but you could do just fine with a 500GB SSD. Now it would just take managing the space if you are a file hoarder like me. Have the 500GB SSD internal and then adding in a 1 or 2 TB drive external is just the best setup ever for a Mac. Also no matter what drive you put back into the Mac make sure that you dont forget to install the 3rd parity fan software (Some mac models have a temp sensor connected to the side or directly into the Apple/WD hard drive. This could require you to install a 3rd parity app to keep your cooling fan under control. If you need more help feel free to message me )

Just my 2¢ but would really encourage you to do the 500GB SSD Samsung EDO model

Enjoy and good job getting it open.


If I were still doing video editing I would absolutely spring for a full SSD but as I’m just hosting a substantial iTunes movie library to stream to my appleTvs the cheaper HDs really are a better option(also bought that 2Tb drive about 5min after finding it on Amazon). The only thing I use my iMac for anymore is video conversion via Handbrake and that would benefit from a CPU upgrade that I don’t need or am able to afford either. The joys of building up debt then going unemployed for 7 months. Had 1 job for 7 months and a second for 4 and am seeing the light but still pretty buried.

And yep, HDD temp wire right next to the power cable.
And on the fans, I’m probably going to go with SMC FanControl, maybe Macs fan control, or maybe find something else but I’ve seen a lot of people talk good things about SMC. It seems like a good idea as there seems to be many people with actual GPU issues and overheating and I’d rather not have anyother things go wrong with the mac for a while. … though I suppose I could figure out something I could do with this G5 that’s just chilling here. So far the only real use I’ve had for it is to SSH into my iMac when it wouldn’t screen on out of sleep mode and remote shut down via Terminal but the acrylic case was just too sweet to pass up on bringing home.


Okay. So the errors the AHT had been giving are no more. But the new drive didn’t fix the issue. Back to the video card or a logic board issue. Took forever but found the ASD(Apple Service Diagnostic) for my iMac(ASD 3S 138). Much harder to find. This is the one they used to use in store for diagnosing. @ericlan, I’m sure you’re familiar with them. Currently running the EFI version minus the full read test on the HD. If I get nothing there I’ve got the OS version but I’ll have to run it from safe mode. (Tried both a restored install from about a week before it crapped out and then a brand new install via internet.)
Kinda hoping for a video card issue as then I can upgrade it while replacing.

Ooooo… just came across the Tech manual for mine. :slight_smile: