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Philip S

macrumors newbie
Original poster
Mar 21, 2014
18
0
Hi guys. I wonder if anyone can give me advice about some serious iMac problems I'm having. Sorry for the long post, but I'm hoping to cover everything here to save time in the long run

My machine is a chipset model ATI Radeon HD 2600 Pro, Processor: 2.66GHz Intel Core 2 Duo running Mac OS 10.5.8
There are two distinct problems which may or may not be related. I'd appreciate any advice related to either problem.

The lesser problem is that I can only boot up in safe mode. This is not a major problem when working with graphics (although with seriously hampered vision - see below), but since I also sometimes work with music and safe mode disables sound along with several other things, it's quite a handicap.

ATTEMPTED SOLUTIONS SO FAR:
Followed the textbook advice, removed all hardware devices except keyboard and mouse and tried rebooting - still got blue screen of death. I booted up holding down D to do a hardware check and it says everything appears to be OK. Also run disk verify (appears to be ok) and repaired permissions. Also reset pram. Also disabled startup items. Still only booted in safe mode... I finally backed up data, erased my HD and reinstalled my OS, all to no avail... Safe mode or nothing :(


But the main problem is that my monitor screen looks like this:

(see attachment)

Pretty horrible, right? And this obviously IS a major problem when working with graphics...

On some advice threads people have linked only being able to boot in safe mode with a "bad video card", so I'm guessing this might explain the two problems, but I found conflicting advice in several areas. Some say "graphics card" and some say "video card" -- this may not be a big deal. Maybe they are just two names for the same thing? But another conflict is that some say the graphics card cannot be replaced because it is soldered to the motherboard, while others say that is easily replaceable with another card, if you can find one. They say Apple themselves do not sell parts (presumably because they don't want people messing about with their computers) but the parts are available in several places online.

ATTEMPTED SOLUTIONS: I did a web search for iMac ATI Radeon graphics cards and did find a few, at vastly different prices and some quite different-looking to others. I figured the only way to be sure it was the same type of card was to open up my machine. OK, I know, I can imagine red flags going up right now. "Don't do it! It'll void your warranty!" Trust me, my warranty is well past it's "use by" date, so I weighed up all the pros and cons.
I heard stories about Apple stores charging so much to repair a past-warranty machine that you'd be better off buying a new one. Besides, one advice thread said that if there was nothing wrong with either software or hardware from the computer's point of view, graphics card problems might simply be related to dust build-up inside, and slowing down of fans causing overheating.

I figured I could kill two birds with one stone by opening it up to have a look at the video card, and to clean out the inside of accumulated dust at the same time. So I bought a set of Torx screwdrivers and simple suction cups to prize the screen off, and went ahead into uncharted territory, following this pretty detailed guide: http://www.ifixit.com/Guide/iMac+Intel+20-Inch+EMC+2133+and+2210+Video+Card+Replacement/1014
There was a LOT of dust in there and I cleaned it out as best as I could, but it was more time consuming than I'd expected, going carefully through each layer, so I didn't get as far as the video card, and took a rest... OK, I chickened out (for fear I had already gone too far and broken something) and then put it all back together, to see if it still worked, with a view to going back in at a later date. Alas, it was exactly the same as before, even after removing all that dust.

Anyway, I realise some of you might strongly disapprove of opening up an iMac, and I can understand why, but it really was my last option. Considering how much I spent on the machine when I bought it (not THAT long ago, really), and that the warranty is already past, I felt I had nothing to lose. Simply consigning it to the scrapheap would make it a pretty expensive piece of garbage to just toss away. Especially when it keeps telling me all its hardware and software "appears to be OK"... :(
 

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I think you have come to the correct conclusion that the the video card is bad.

This looks like your machine here and according to this link the video card (same as graphics card) is replaceable.

I think I found the card here for $329 :)eek:)... but you should call them to make sure you have the right part.

If it was me, I don't think I would invest $329 on that iMac, still with no guarantee that would even fix it. That video card replacement process scared me just reading it. I would have checked out also. :)

Might be time to give it the heave ho' and buy a new Mac. You could probably get some money for it on eBay even with it broken. Just fully disclose the problem and there are people that will buy these broken Macs and fix them up.
 
Weaselboy, thanks for the advice. I've decided to take the plunge and ordered a new video card. It's due to arrive within the next day.

I'll post on this thread to let you know how it worked out. If you don't hear anything from me within a few days, it probably means I'm tearing my hair out somewhere...

LOL, just kidding. I'll post the outcome, whatever it is, for future reference. And don't worry, if it doesn't work out I'm not going to point the blame stick at you. I accept full responsibility for taking the risk.

You sensibly recommended not buying a card because if it doesn't solve the problem it's an expensive mistake. But I figure if it DOES solve the problem it'll save me quite a lot of money.

If not, I'll count my losses and buy a cheap Mac to compensate.

Watch this space. :)
 
Hi Weaselboy. It wasn't very easy - had to go through the disassembly/reassembly process four times! http://www.ifixit.com/Answers/View/172093/Black+screen+after+video+card+replacement.
- but I finally got it fixed. I now have a beautiful display that looks even crisper than before.
Thank you for linking to that parts seller. They delivered quickly and provided the video card in mint condition.
If you are ever passing through Tokyo give me a shout - I owe you a few beers! :)
 
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Hi Weaselboy. It wasn't very easy - had to go through the disassembly/reassembly process four times! http://www.ifixit.com/Answers/View/172093/Black+screen+after+video+card+replacement.
- but I finally got it fixed. I now have a beautiful display that looks even crisper than before.
Thank you for linking to that parts seller. They delivered quickly and provided the video card in mint condition.
If you are ever passing through Tokyo give me a shout - I owe you a few beers! :)

Excellent... glad you got it fixed up! :)
 
Hi Weaselboy, it's me again - Phil in Tokyo. Really sorry to bother you but I have a new problem. I'm posting a new thread about it (related to iMac not starting up after power outage)... If you have any ideas I'd be grateful to hear them... Sorry again!
 
This comes too late to save you any money, but it might help others. Your video card was slightly, but not fatally, defective, and it was interacting badly with the device driver for it. Move that device driver out of the way, so it doesn't get inserted into the kernel, and you should be able to boot normally, have sound, wifi, firewire, dvd playing, extra fonts and everything else that safe mode disables.

On my system (a mid-2010 iMac) the driver was under /System/Library/Extensions/ATIRadeonX2000.ext. So I did this:
$ sudo mv /System/Library/Extensions/ATIRadeonX2000.ext ~/

Your driver may be something else (though possibly with a similar name). To figure out what it is, run kextstat twice -- once after booting into safe mode, and once after booting normally (and of course in this case you'll need to come in from another machine, e.g. "ssh me@mybadcomputer"). Save the kextstat outputs and compare them. The list from the normal boot will be longer by some two dozen items; look through these until you see something that sounds like a video card (in my case, of course, it was "ATIRadeonX2000.ext"). That's your evil driver! Move it out of the way as I described above, and you should be good to go.

Of course without that video driver, your system won't play games and movies quite as snappily as before, but as far as I'm concerned (well, I'm not a gamer and "movies" to me means Youtube), it's still fine.
 
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This comes too late to save you any money, but it might help others. Your video card was slightly, but not fatally, defective, and it was interacting badly with the device driver for it. Move that device driver out of the way, so it doesn't get inserted into the kernel, and you should be able to boot normally, have sound, wifi, firewire, dvd playing, extra fonts and everything else that safe mode disables.

On my system (a mid-2010 iMac) the driver was under /System/Library/Extensions/ATIRadeonX2000.ext. So I did this:
$ sudo mv /System/Library/Extensions/ATIRadeonX2000.ext ~/

Your driver may be something else (though possibly with a similar name). To figure out what it is, run kextstat twice -- once after booting into safe mode, and once after booting normally (and of course in this case you'll need to come in from another machine, e.g. "ssh me@mybadcomputer"). Save the kextstat outputs and compare them. The list from the normal boot will be longer by some two dozen items; look through these until you see something that sounds like a video card (in my case, of course, it was "ATIRadeonX2000.ext"). That's your evil driver! Move it out of the way as I described above, and you should be good to go.

Of course without that video driver, your system won't play games and movies quite as snappily as before, but as far as I'm concerned (well, I'm not a gamer and "movies" to me means Youtube), it's still fine.

It has taken me a while to catch up to this thread. I discovered I have an ATI Radeon HD 4850 and tried to insert that into your txt. i.e. sudo mv /System/Library/Extensions/ATIRadeonHD4850.kext ~/ but it still says "no such file or directory" can you help me out? Thanks!
 
It has taken me a while to catch up to this thread. I discovered I have an ATI Radeon HD 4850 and tried to insert that into your txt. i.e. sudo mv /System/Library/Extensions/ATIRadeonHD4850.kext ~/ but it still says "no such file or directory" can you help me out? Thanks!

Hey buddy, I am having the same problem with my friends iMac 27 with the ATI Radeon HD 4850. I noticed you had the same problem. were you able to fix the problem? any help will be really appreciated.
 
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