I thought I’d post this here first since I know there are several Mac gurus lurking this forum.
I have a 3 year old 17" iMac that has been crashing, usually while running my Unity multi-player game, but more recently at odd moments for apparently no reason. I upgraded the RAM on this machine from 1 GB to 2 GB at the beginning of the year, but the crashing didn’t start until a few months ago. When the system crashes, I usually get a solid gray screen (nothing else on the screen), although recently I have gotten even weirder screen displays when it crashes (once it displayed vertical colored bars, and today it just locked up without changing the screen).
[I should add that this computer is no longer covered by Apple Care and the nearest Apple store is a 6 hour drive, so I’d really like to diagnose and repair this myself… if possible.]
I’m pretty sure my problem is a hardware issue, although I have tested the HD numerous times. I first suspected that it might be a faulty RAM problem, but I’ve run several RAM testing applications repeatedly and no issues are reported. I also suspected that it might be overheating and so installed a fan control app to keep the fan running, but I continue to get crashes.
My questions for the experts are:
Has anyone run into issues like this before, and if so what was the cause?
Although I have tested and re-tested the RAM ad nauseum, I still suspect it could be the problem. Any thoughts on this? The RAM has a “lifetime” warranty, but if the tests all show no errors will the manufacturer still honor the warranty?
Any other ideas / advice on how to diagnose this problem? I hate to put this puppy to pasture just yet, it’s served me well over the years. But I suspect that the cost of shipping + Apple repairs will be more than the cost of a comparable Windoze machine (which is what I’ll likely do if I have to replace it).
(1) Back up your data immediately. I also think this is a Hardware problem (but am no Guru)
(2) If you suspect it is the RAM, take out the new RAM and put back in the old RAM and see if the problem persists.
(3) If its not the RAM… I’m not sure what to test next.
I do not know what this problem is exactly. If it was a G5 iMac, I would suspect a faulty motherboard. But I guess from what you have said, that you have an early 2006, Core Duo, and I have not heard of any issues with those.
Another thing that is always helpful is to search Mac boards for people asking for help with the same problem. You might not still be covered by Apple Care, but I have taken machines in no longer covered and the guys serviced them. The issue was a well documented flaw that I had found on a board and on the Apple site. Also admittedly the “genius” was a nice guy. If you find that your problem is a well documented flaw and Apple offered to repair it once upon a time… maybe they’ll still do that for you. You can’t count on it, but its worked for me. Then again 6 hours driving for an uncertainty isn’t promising. Lets hope its the RAM.
Thanks Aaron, sounds like I’m thinking in the right direction. I’ve been backing up everything for a while now, so although I might loose one day’s work, I won’t loose everything.
I’ve also been googling for days and haven’t really found that many posts that sound evenly remotely similar, so I may have that “one in a million” machine that died a premature death.
I’ll try swapping the RAM later today. Good thing I didn’t give the old chips away as I had originally planned.
PC’s are becoming so cheap now-a-days that I’m almost certain to replace this iMac with one… shame though, I really enjoyed this puppy.
Yeah, I am sorry about that. I don’t want to sound negative, but it does sound like one of those one in a million machines. I’ve been fortunate enough never to get one of those and our office has a great track record too, but given stories like yours I suspect that I have been seduced by the illusion that Apple produces better hardware, and its only time until I end up in your shoes.
Anyway, if its the RAM your golden. RAM is cheap.
Also, I’ve never got around to trying this myself, but I suspect that you can reuse the iMac’s monitor. Those are very nice screens, and I can’t imagine its too much more complicated than connecting the right cables and port. Might involve soldering. But I dunno, there might be some problem with disconnecting the thing from the motherboard. If your computer dies though… I think it would be worth trying to salvage the monitor.
Early 2006 17" Intel iMac, you say? This sounds very familiar. I had the same machine and one of the memory slots on the logic board went fffft. It was the damndest this trying to pin it down though, because the memory seemed to be the culprit. In the end I just resorted to swapping the memory between the slots and between different machines to find out which combinations crashed - anything crashed the iMac in one of the slots, nothing crashed the other machine period, so therefore it was the slot itself.
Sucked too, because it was already out of warranty and the replacing the logic board cost more than the machine was worth at that point - it still runs ok, mind you, just now it’s limited to 1GB of RAM, since those machines don’t support any more on a single stick.
Edit: One more thought. You mention weird looking screens when it crashes now - does it leave strange artifacts on the screen when it’s running, too? Keep an eye out for that, it could be a sign that the VRAM is flaky, not the system RAM. It also might be a heat issue.
Ouch, I’d rather it was a RAM issue than a RAM -slot- issue. It doesn’t crash all that often, maybe once a day, or every other day, and almost always when I’m doing multiple tasks and using the network (ie. running Unity, networked to another machine running Unity, as well as Firefox, Thunderbird, Unitron, GIMP and maybe Blender). It happened one day when I was running two Unity stand-alones as well as Skype. That one was weird as the video / mouse / keyboard stopped responding, but the audio continued to work fine. I didn’t get a chance to swap RAM yesterday, hopefully will do it today.
Regarding the heat issue, one thing I noticed was that I never heard the fan running, no matter what i was running, so I ran AHD (Apple Hardware Diagnostics) and although it didn’t find any issues, I heard the fan run for the first time. So I downloaded a fan control app which now controls the fan speed. I’ve set it at about 50% higher than the default setting to see if it has any effect.
Not in anyway, shape or form an expert and this may be unrelated but have been having major issues with my graphics card causing crashing, weird graphical effects (some of them quite funky) and much misery for many months.
This is the Nvidia 8600 and the issues are known:
( http://support.apple.com/kb/TS2377)
Your machine is older and must have a different card but your description sounds familiar so I thought I’d add my pennies worth. Check out the graphics card?
Thanks, I’ll read that page. FWIW, the 17" iMac I have uses an ATI X1600 graphics card, so is different from the topic you linked to. I did some more homework yesterday and found a couple of very long threads on the official Apple support forums all discussing 2006 iMacs. The models were wide ranging, but all reported some sort of freezing issue. From what I read, it didn’t look like any one particular issue was identified, nor was Apple willing to do anything about it.
I also found a company in California that charges a flat fee of $600 to repair / replace the logic board on my model iMac. Considering that I can buy a new Mac Mini (with slightly better specs and a warranty) for the same amount of money, I don’t think I’ll be fixing this puppy… that is unless I find that it’s a memory chip.
I’ll say that it isn’t particularly comforting to know that so many people are having problems with their Macs.
I’m running on a 3 y/o 17 inch iMac … same problem. The screen will randomly bug up (mostly with apps using NSWindow), most of the time when listening to music + doing something in openGL the machine freezes, and it either crashes after a couple of minutes, or I have to restart it. I was hoping it was some weird software problem, but snow leopard didn’t help. Sometimes the screen glitches like you were describing before it bombs. 2 times when it bombed, it got stuck in the reboot cycle and I had to reboot it in the command line, 1 time when it bombed it got stuck in the reboot cycle, and messed up my HD, fortunately I had a back up, 14 hours later got it fixed. With snow leopard it doesn’t bomb as much, but it still bombs randomly.
Huh. I’ve had mine for a little over two years now without a single problem. Maybe next year, I guess.
It might just be the model you’ve got. I’m using the old middle-level MacBook Pro. I’ve had many more problems with desktop PCs dying than Mac desktop or laptops.
My 5 year old TiBook is still going strong, there were no problems with my previous computer, a Bondi Imac, either. It’s recently the build quality of the components seems to have dropped off badly.
Apple have just replaced the logic board in my MacBook Pro with what they call a “Revision 2” version.
We’ll see…
I ran some more tests last night and this morning. I ran 3 networked Unity stand-alones simultaneously with Thunderbird, Firefox and Skype to try and recreate the last crash I had. Although the frame rates slowed to a crawl, everything ran fine. I monitored component temperatures using iStat Nano and watched as the GPU rose from 40 degrees to 64 degrees C. The GPU on this iMac does not have a fan and was consequently running at 24+ degrees hotter than the CPU. I did a bit more googling and found this wiki post:
It seems, at least according to this poster and large number of forum posts I’ve found, that GPU issues and failure appears to be a systemic problem with the iMac design.
It’s unfortunate but true. I had to replace the graphics card on my most recent machine, a 2008 24" Aluminum iMac, and my wife’s 2007 iMac has locked up on more than a few occasions under heavy use as well.
The odd thing was that the repair techs couldn’t reproduce the problem with my machine at all, but I had been getting intermittent graphical artifacts and lockups for months before I took it in. Fan control apps weren’t able to detect a noticeable spike in temperature either, but after replacing the GPU, sure enough the artifacts and lockups stopped.
I yearn for the days of pre-Intel Mac build quality, to be honest. It just seemed to go kind of downhill from there.
Thats odd. We have an office filled with intel iMacs (core2duo) and they all work without a hitch. Not one problem with them in three years. We are particularly happy with the screen quality. Anyway, like I said before we might be due if failures are as common as this thread would suggest.
