Major crashes with OS X 10.4 (on a G5 iMac). Bad hardware?

June 1, 2008 3:49 PM

Major crashes with OS X 10.4 (on a G5 iMac). Bad hardware? It looks like I'll have to take it in for repairs, but maybe there's a software fix?

My iMac G5 crashes: not the nice multilingual Mac Screen Of Death but really serious crashes -- the screen turns into regular patterns of noise and I have to reboot. When this began happening it would boot up, run for five minutes and then it would happen again. Then it got worse.

I looked into the system.log and the panic.log and there were messages there about Graphics Card errors, mentions of Frames, and the messages were coming from kernel level (I wish I could post them here but it won't even boot any more).

I did all the obvious things I could think of, zapped the PRAM, fixed permissions, verified the disk, and I even reinstalled the whole OS.

I'm assuming that I have some hardware problem, i.e. a bad graphics card.

But one thing's nagging at me. During the reinstall of the OS, which took a good twenty minutes to half an hour, the computer stayed up and running just fine, when it was working off the kernel/drivers on the DVD.

So, is that a clue that there could still be a software fix? Something to do with the drivers that I could fix without taking it in to a shop to repair?

Grateful for any suggestions.

posted by AmbroseChapel to computers & internet (13 comments total)

Sounds like bad video memory to me- just guessing, when the OS is installing, it's using a different graphics mode that doesn't use the bad spot on the memory.
posted by gjc at 4:41 PM on June 1, 2008

This sounds like a hardware problem; there probably isn't a software fix. Reinstalling the OS would probably have fixed it if it was just a software issue.

(The OS installer runs under a somewhat different environment than normal -- for instance, it can't use the hard disk as swap space -- so the fact that it works fine is a clue, but not a very suggestive one.)

I suspect bad RAM more than a bad video card (or, as gjc suggests, bad memory on the video card itself). Did you install any extra memory in the machine? If so, what happens if you take it out?
posted by xil at 5:47 PM on June 1, 2008

I upgraded the memory a couple of years ago. But general RAM issues didn't even occur to me. Good point, thank you.
posted by AmbroseChapel at 6:28 PM on June 1, 2008

Now I'm in two minds because I've packed up the computer and it's in my car and there's a Mac repair place a few blocks away ... do I unpack it, take it home and fiddle with the RAM, then pack it all up again if that doesn't help and it is something I can't fix/diagnose, like the video card?

I guess if I do that, I lose a day, and if I'm successful, that's the end of it...

And if I take it in for repair, even if it's something simple and straightforward, I'm going to lose the use of it for at least a week...

I don't suppose there's something on a Mac OSX install disk which can diagnose bad RAM/Hardware? I have a dim memory (no pun intended) of something like that.
posted by AmbroseChapel at 6:34 PM on June 1, 2008

It's pretty unlikely that the added RAM just went bad after a couple of years. You would most likely have noticed problems before now. Let the repair guys figure it out.
posted by xil at 6:48 PM on June 1, 2008

If you still have the original disks that came with the computer, the Hardware Test software is on the first installation disc, I believe. If you can find the disc, try inserting it and boot holding down the 'D' key. Then you'll be able to run the hardware test. Go ahead and run the Advanced test, which takes longer, but is more thorough. I just had someone do this last night who had been having crashes whenever she used graphics-intensive processes, and the hardware test CD was able to confirm that there was bad RAM. You'll get an error like 4mem4/4/40000000.

If you can get it to boot to the OS, there's an application called Rember that you can use to test your RAM. Another thing to try is to open up your RAM cover, remove the RAM and then re-seat it. Sometimes this will either fix the problem or at least buy you a little time to limp along until you can get another stick of RAM. Prolly not, but worth a try.

Good luck!
posted by al_fresco at 7:33 PM on June 1, 2008

iMac G5s are notorious for having logic board problems. Just recently I went through a similar experience with an iMac, where it seemed that the hard drive was beginning to fail. The problems were intermittent, in this case, until one day it wouldn't boot up anymore, no matter what software fixes we tried. Fortunately, the repair tech figured out that it was the logic board, which Apple has been good about replacing because of the high number of defects associated with iMac G5s. YMMV, of course.
posted by trouserlouse at 7:43 PM on June 1, 2008

As someone who deals with Macs for a living, I see this more often then I'd like to. Unfortunately it's mainly more times likely to be a hardware problem. There is a Repair Extention Program (REP) for certain models of iMac G5s. It has to do with bad capacitors on the logic board and power supply.

Take it to your local Apple repair shop and have them see if any caps are bad. Check and see if your serial number matches but because this only covers machine made up to the 22nd week of 2005, most are past the "three years from date of original purchase" number given as the cut-off. Even then, some of my clients have had luck calling Apple Care or Customer Relations and complaining.

Really, take it in ASAP. Your data is probably ok (but you already backed that up when wiping and reinstalling, right?).

PS - Oh, and the "multilingual Mac Screen Of Death"? It's called a kernel panic.
posted by now i'm piste at 8:44 PM on June 1, 2008

Err.... MANY, it's MANY more times likely to be a hardware problem. Or smoother: "It's more likely to be...."
posted by now i'm piste at 8:47 PM on June 1, 2008

Thanks everyone for your help. I will take it in for repair, that seems to be the sensible thing to do.

Just on this technical note:

>the "multilingual Mac Screen Of Death"? It's called a kernel panic.

is what's happening not also a kernel panic? Only, not one which the OS can trap in time to give me the non-scary message?
posted by AmbroseChapel at 9:02 PM on June 1, 2008

is what's happening not also a kernel panic? Only, not one which the OS can trap in time to give me the non-scary message?

No. By definition, if the OS doesn't trap it, it's not a kernel panic. What you have is simply a hardware failure.
posted by jjg at 12:01 AM on June 2, 2008

Sounds like the logic board, the apple Repair Extention Program is only 3 years from date of purchase, so don't delay taking it to an approved repair centre.
posted by Lanark at 1:16 PM on June 2, 2008

Follow-up filter: I took it in for repairs, it is indeed a dodgy Logic Board (capacitor), and the repair guy (who could have just said "that'll be $300") encouraged me to take it up with Apple.

It turns out I can have the repair free under the Repair Extension Program.
posted by AmbroseChapel at 8:35 PM on June 3, 2008