Early 2006 20" iMac: Freezing During Use

[geekboy2000]

Lately (and becoming more frequent), my iMac will suddenly just lock solid, and require a hard reboot to recover. I've reviewed the console logs, and thought that I had removed a few potential offenders (HP Trap Monitor among them), yet the problem persists. If this even gets written to a log, which log or logs would I look at, and if I capture log data, what might I be looking for?

FWIW, it seems that most, if not every time, this occurs during actual use. It can sit idle forever w/screensaver running, open apps, etc. But, a mouse move, scroll down a web page, etc, will usually trigger it (might be coincidence). Sometimes I'll notice video distortion at the instant of the hang as well. I just applied the 10.5.6 update, but it had been occuring prior to that as well. Thanks!

 

[Alexis]

Have you done a full disk repair by booting from the OS X CD?

 

[geekboy2000]

Have you done a full disk repair by booting from the OS X CD?

No, I haven't, as fortunately, until recently, I've hever had a problem. What all is involved? Is my current data safe? And, can I use an earlier version disk (I have 10.5.6 on the iMac, and the most recent release I have on disk is 10.5.1)? Man, it happened again, just as I started replying to this message. I'm about ready to toss this thing.

 

[hughvane]

You can run Disk Utility from Disk 1 of the original disks that came with your iMac. If you don't have those, a retail Leopard install disk is necessary. From Disk Utility, you can verify the HD, and repair if necessary. You can also verify and repair permissions, but the latter is not the likely cause of the problem.

Something else you can do is check the RAM. Pull the modules out and swap them over, making sure they're re-seated securely.

If Disk Repair is required, you should not lose any of your data, but I would suggest you start backing up valuable files a.s.a.p.

 

[geekboy2000]

You can run Disk Utility from Disk 1 of the original disks that came with your iMac. If you don't have those, a retail Leopard install disk is necessary. From Disk Utility, you can verify the HD, and repair if necessary. You can also verify and repair permissions, but the latter is not the likely cause of the problem.

Something else you can do is check the RAM. Pull the modules out and swap them over, making sure they're re-seated securely.

If Disk Repair is required, you should not lose any of your data, but I would suggest you start backing up valuable files a.s.a.p.

Thanks. I do a SuperDuper backup regularly, and my MacBook is basically a clone of this machine, so my data is pretty safe. I'll give the suggestions a shot tonight. PRAM reset? Might that also be of help?

 

[geekboy2000]

Well, you learn something new every day. Tonight, I discovered that the aluminum keyboard isn't recognized at startup on an early 2006 iMac. Workaround: Hold down the menu button on the Apple remote during restart to choose your startup device.

Anyway, the disk repair determined that the drive was OK. Nothing repaired. I connected my old Apple keyboard so that I could do a PRAM reset. Too early to tell if that did anything, but I'm not optimistic.

Any other suggestions as to where to look, or should I take it to the Genius Bar, and let them figure it out? Being intermittent though, I'm not sure they'll find anything.

 

[chscag]

Sure sounds like you've got problems with the video in that machine. I'm guessing it has something to do with your video card - either the card is intermittent and getting ready to die or memory on the card is acting up. Either way it'll require replacing the entire card. Not a job you can easily do yourself.

Probably best to take it on in to the Genius bar and let them look at it. If it's really intermittent, it may be difficult to track down.

Regards.

 

[geekboy2000]

Sure sounds like you've got problems with the video in that machine. I'm guessing it has something to do with your video card - either the card is intermittent and getting ready to die or memory on the card is acting up. Either way it'll require replacing the entire card. Not a job you can easily do yourself.

Probably best to take it on in to the Genius bar and let them look at it. If it's really intermittent, it may be difficult to track down.

Regards.

Thanks. That's looking like the only choice I have now. I eliminated the mouse/mouse driver, and also booted from my external firewire/cloned drive. Once up and running, I un-mounted MacintoshHD, and had the same problem. I'd really like to be able to rule out the install itself though, but prefer not to wipe everything clean to do it. I might take my clone if my iMac drive, and see if that works when I boot to it from this machine. Surely, if all it takes is a clean install to remedy the problem, I have no problem doing it, but I don't want to do it for no reason. So far though, yes, it really is looking like it's got to be the video or logic board.

 

[geekboy2000]

This thing seized up repeatedly this morning, but since pulling the power cord and re-starting, it's been solid for quite awhile. Still, I'm feeling like it'll lock-up again, but that is odd.

 

[geekboy2000]

Took the iMac into the Apple Store on 12/24, and was called to pick it up yesterday (27th). They replaced the logic board (under Apple Care), and it's now fine.

 

[waiton]

Hey there

Thanks for following up with what you did / how they fixed it.

I've only this week got the same problem that you had. Leaving updates on or running something unattended works fine, but once I even move the window across the screen or click a link to another site, the iMac freezes and needs a hard reboot. I've also noticed over a dozen bright/stuck pixels scattered all over the screen and horizontal bands appearing as if random on reboots. I think it is also heat related as a fresh start in the morning after leaving it off overnight shows no problems until about 40 minutes of use.

I've also tried reinstalling OS X Tiger a couple times.

The strange thing is that I had my logic board replaced in 2007 because of video flickering. It is simply frustrating that it is the same part(s) that is repeatedly failing.

I will take it in for repair on Monday and update if it is good news for me.

 

[bhernandez]

Was there a recent update that's causing random freezes? My iMac G5 just started doing it as well this week...freezing from as simple as moving my mouse. My monitor also has been showing some strange pixels.

I called Apple support and they recommended an archive and install. But it hangs during the GarageBand installation. I'll call them again tomorrow and discuss these issues brought up in this thread.

 

[waiton]

delayed repair

So now that I've been off the iMac for long spells of time, the bright pixel and bands of tearing issues have subsided but the freezing and crashing still occurs, and yes, very randomly. I thought it would be related to how "busy" the computer was but it varies from time to time as to when it will freeze. Sometimes as simple as browsing in Finder to multitasking between browser and chat.

So I called the dealer where I bought the iMac from (3rd party warranty, non-applecare but still valid), and they said the repair technicians aren't working till next Monday at least, so I've decided to wait till then to drop it in. No point sending it in to sit in the office for a week when I can still semi-use it/try other options.

I don't think there's been a recent update that has triggered this experience. I've only reinstalled Tiger and updated to 10.4.11. Hmm... there was that security update released on 15 Dec 2008 but I don't know how that would relate... I did notice that my bright pixels defect and tearing began in November though.

bhernandez, any news on your front? geekboy, how's the new logicboard test out?

Will keep this forum updated.

EDIT: 06 Jan 09

Well, I've just upgraded to Leopard and have been using the iMac for the last 5 hours consistently now, ran WoW, downloads, backups (not all at once) and besides some minor graphics tearing, random bright pixels and WoW rendering issues, the iMac has not frozen once. Has it fixed itself? Not quite but it seems like it's handling everything ok. We'll see by the end of the week.

 

[waiton]

Well, it froze in Leopard as well. So I've done another fresh install of Tiger (reset PRAM, SMC) and still have the pixel glitches and freezing every hour or so. Also found the apple forum posts:

Apple - Support - Discussions - iMac Freezing ...

From the looks of things it's an overheating problem with the graphics card which in turn burns out the card & logic board. Hopefully I can get it repaired quick as because I need the machine for freelance work! I'll be dropping it in for sure on Monday.

 

[bhernandez]

Sorry, but I've been crazed since I first posted. Here's what happened:

My Mac was totally unresponsive from my attempts to archive and install - it appeared to just freeze, although I could hear the CD drive running. FYI...it's a 17-inch iMac G5. Probably got it in 2005.

I went to the Genius Bar Sunday morning. The consultant first wanted to do an archive and install from his hard drive. While that was going, a friend of mine came in for help with his Mac Air. While I was explaining my problem to him, his consultant said that my iMac has a known issue with the logic boards that causes these freezes. They opened up the iMac and the second consultant showed me how some of the capacitors have started to expand (flat tops are good, rounded tops are bad), indicating failure. Thankfully, the hard drive was fine.

So my options? Buy a new logic board, and with installation, it will be $850. Or buy a new model. Supposedly there was a program that ended in 2008 to help with the workaround.

Fortunately I can afford a new iMac (I got the 20-inch). Been working with Macs for 20 years, this was the first real problem I've had (other than one model back in the 90's where the monitor kept going green - the color, not the adjective - and Apple kept replacing for free).

Unfortunately, while doing a data transfer from my old iMac to my new, the crack technicians at the Apple Store somehow lost ALL my music on my hard drive - several days worth of music. I can't figure that out because all the other data is still there on the old HD. I have backup, so I guess I have to deal with it. They also didn't charge me like they said they would.

However, I can never figure out why only a handful of people know about known issues affecting a particular model. I remember this was the case with the green monitor issue I mentioned earlier...it seems to take countless calls before someone say - "oh yeah, we know about that issue and Apple has a program to rectify".

 

[waiton]

Well, I got a replacement iMac (entry level model) which is pretty much equivalent to the iMac I had. The warranty company decided it was too expensive to fix the original one I had, so now I have a shiny new aluminium iMac The logic board alone would have cost $1300 plus the superdrive was also not working properly. I didn't find out if it was a "known defect" but the repair accessor was sure it was the graphics & logic board fault.

I can't afford to buy an extended warranty again (have to get it within the first 7 days) but I'll see about AppleCare in the coming month.

All-in-all I'm pretty happy with the outcome. I just have to upgrade my RAM back up to max (warranty didn't cover RAM).

 

[Ddeecat]

Early 2006 imac freezes

Thanks for all the advice in this post. I have been having the same problems for about 5 months and now my Imac freezes daily - I also have the horizontal lines on screen and the strange 'screen shifting' prior to crash. I have archived and installed and I've re-installed all my applications to no avail.

I think it's now time to call in the experts and I'll be referring to this post when I do - thank you.