GaBeech

Q: Late 2006 iMac, Lines, Kernel Panic, Freeze, Reboot, Restart, Serial W8 ?

Hello,

Let me start by explaining the method I am initially going to adopt in my search for answers;

•All of the keywords and more that would not fit in the title space, relate to my problem.
•I think the *iMac Serial* holds the key to mine and possibly a lot of other peoples search for answers.
•My second post will explain what I know about the Serial and the information it provides.
•I have a strong feeling that a lot of people who have the same or similar problems to me will have a Serial that begins with at least W8.
•I believe that a lot of affected machines will of been produced between 2006 & 2008, yet not confined to that window in time.
•So, to round up, I am looking for people who have had/are having the same/similar problems to the ones listed below.

•Small graphical glitches; Thin lines in random areas on the desktop, growing in number and intensity over time.
•Graphical glitches on, in and around Finder windows. Again, growing in number and intensity over time.
•Horizontal lines across entire screen. Again, growing in number and intensity over time.
•The odd Software Crash/System Freeze. (Which does not happen very often on the iMac we've grown to love)
•More frequent Software Crashes/System Freeze's. (Maybe it's all that freeware and plugins I've been playing with)
•Kernel Panic's, never had one before... it was a new one on me.
•Frequent Kernel Panics.
•System Freeze, recovering after being put to sleep and then woken.
•System Freeze, unrecoverable. Hard reset required.
•Exactly the same behavior after a full reinstall of OSX.
•Exactly the same behavior after wiping system drive with zero's, then a full reinstall of OSX.
•Exactly the same behavior after wiping system drive with zero's, then a full reinstall with a previous version of OSX.
•System Freeze requiring hard reset on nearly every occasion Time Machine was accessed.
•Shut iMac down completely, never to respond to Power Button being pressed again, even after trying to reset the SMC.


The above is a simplified list of key events on a relatively short journey from Perfect Machine to, 'will not power up'.


If you or anyone you know has gone through anything similar, I would love you to join this topic.

Yours,
GaBeech

iMac (20-inch Late 2006) 2.16 GHz Intel Core 2 Duo ~ x1600 Graphics, Mac OS X (10.6.3), Serial Number: W87070ACVUV (Check My Biography To See What A Serial Means)

Posted on May 26, 2010 8:36 PM

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Q: Late 2006 iMac, Lines, Kernel Panic, Freeze, Reboot, Restart, Serial W8 ?

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  • by dbax,

    dbax dbax Jul 15, 2010 4:09 PM in response to R C-R
    Level 1 (74 points)
    iPhone
    Jul 15, 2010 4:09 PM in response to R C-R
    RC-R,
    As you can see from my profile, I have a late 2006 iMac. It's been demonstrating the graphical artifacts and freezing, reported by many others, for about 6-9 months. Your comment to elice82@:
    R C-R wrote:
    Then devise another test that has repeatable results that demonstrates the problem.

    For what it's worth I've managed to get my hands on a copy of Tech Tool Deluxe (TTD), the diagnostic program included with Applecare for iMacs. Every time I run it, it reports "Video RAM Failed". Every other TTD test comes up "Passed". So, in my case at least, I can demonstrate a very repeatable error associated with the GPU.

    It would certainly be nice if other late 2006 iMac owners who are experiencing similar problems could get their hands on this program and give it a try. I could go a long way toward demonstrating the problem in a consistent way. Unfortunately I don't know if TTD was even included with Applecare back in 2006. That would be good to know.

    When I bought my iMac in November 2006 it was my 5th or 6th Mac since the 1980s. Since I had never had a failure with a previous Mac, I didn't think it was necessary to spend several $hundred for Applecare which would only extend my warranty for two years. In any event, the fact is Applecare would not have helped me, since my system failures began after Applecare would have run its course.

    BTW, AHT has NEVER reported any problem for my iMac.
  • by R C-R,

    R C-R R C-R Jul 15, 2010 4:52 PM in response to elice82@
    Level 6 (17,700 points)
    Jul 15, 2010 4:52 PM in response to elice82@
    Regarding the test, it doesn't matter what it is as long as essentially any user with a late 2006 iMac could perform it (so no commercial third party apps that not everyone might have or be able to afford) & that it produces clear, consistent results that could reasonably be attributed to a design or manufacturing defect instead of some other cause like normal attrition rates due to aging or third party software.

    Regarding serial number codes, BTO (built to order) Macs get a factory code indicating where they were built just like any other Mac; whatever options are installed are done there. Cork, Ireland (CK) Macs are built there. I don't think there is an assembly plant in Japan, but there are several in China & I think one or possibly more in Taiwan. Apple refurbished Macs (I have two) get new serial numbers & I think (but am not sure) they are all refurbished in California. Otherwise, the serial number is permanent for the life of the Mac.

    It is the factory's responsibility to track the parts used. Few if any come directly from Apple. Most are supplied in large lots directly to the factory by subcontractors or other manufacturers. Everything is supposed to meet Apple's specifications & factories, subcontractors, & the other manufacturers are supposed to keep records adequate to track ones that don't back to the source. This is standard practice throughout the electronics industry.

    As I said, a design defect would be expected to affect all Macs of a given model; this is because the defect basically would be in the Apple specifications. This seems unlikely because of the number of iMacs not affected.

    A manufacturing defect would affect only some of them & be due to either an improperly done factory process or a defect in a supplied part or subassembly -- IOW, something that did not meet Apple's specifications. This kind of defect generally applies to a well defined group like all units built on an assembly line with a (usually temporary) problem like a contaminated solder bath or defective robotic assembly unit, or built with a particular lot of supplied parts that are in some way defective or substandard. Assembly line defects are usually spotted during routine testing at the factory. The factory is supposed to do this often enough that large numbers of defective units are not shipped -- since they are responsible for these defects, they are usually quite diligent about this. They are not directly responsible for flaws in supplied parts nor is it practical to test for every possible defect in them. This makes that the most likely type of manufacturing defect.

    Only a design or a manufacturing defect in what is usually a large group of units justifies a product recall. If say 10 out of a lot of 5000 parts is bad then it simply isn't practical to recall every unit made with parts from that lot -- the costs, which eventually would be passed on to the end user, prohibit that. Fortunately, this kind of problem is rare among mass-produced parts & more to the point, the failures they cause usually occur well within the warranty period.

    I know that is not much consolation if you happen to be among the unfortunate few for which this kind of defect shows up well after the warranty has expired, but that isn't what we are talking about here. We are looking for a problem reasonably attributable to a design defect (which is not likely for the reasons already given) or a widespread manufacturing defect.

    That is why the first 5 characters of the serial number are significant, but just one piece of the puzzle. I hope you understand what I'm saying because I'm getting writer's cramp going into all these details & really could use a break!
  • by knorven,

    knorven knorven Jul 15, 2010 5:22 PM in response to GaBeech
    Level 1 (0 points)
    iTunes
    Jul 15, 2010 5:22 PM in response to GaBeech
    My white iMac specs

    W8634…
    2.16GHz Intel Core2Duo CPU
    ATI X1600 GPU

    Horizontal multicolored lines, freezes with multicolored vertical lines. SmcFan Control no longer makes any difference. Damage done.
  • by R C-R,

    R C-R R C-R Jul 15, 2010 6:15 PM in response to dbax
    Level 6 (17,700 points)
    Jul 15, 2010 6:15 PM in response to dbax
    FWIW, I have an older G5 iMac with a confirmed video ram failure & the older Tech Tool Deluxe disc that I got with my extended Applecare plan for it.

    Neither AHT nor TTD could detect the problem at first, which was intermittent. Only after the VRAM problem got serious enough that it would appear within 30 seconds or so of booting up the G5 did either test detect it, & then both detected it at that point equally well.

    I can't say for sure, but I suspect both products run more or less the same kind of VRAM tests, although TTD may do more passes or use more patterns -- IIRC, back in the PPC & before days Tech Tool Pro (the more expensive cousin of TTD) did that. Anyway, I think gross defects in VRAM cells should be easily detected by either AHT or TTD, but only after they have degraded enough to be consistent & appear soon after starting up the iMac.

    Since I imagine affected users would rather not wait for that to happen, some test that stresses the graphics subsystem ahead of total failure would be useful, but I don't know what it would be.
  • by GaBeech,

    GaBeech GaBeech Jul 16, 2010 5:32 AM in response to elice82@
    Level 1 (0 points)
    Jul 16, 2010 5:32 AM in response to elice82@
    Hello,

    This post is not aimed directly at you elice82@, just clicked reply on last post...

    The first five characters of the serial are very important for a number of reasons;

    1.Place of build
    2.Year of build
    3.Week of build
    Those 3 nuggets of info could narrow down many other thing, I suppose even down to the capacitors used on a 3rd party board.

    I forget how much info regarding the serial number I posted at the start of this thread... too much, some would say.

    Sorry for rushing, got an appointment to keep.
  • by hrabri.misek,

    hrabri.misek hrabri.misek Jul 16, 2010 7:28 AM in response to GaBeech
    Level 1 (0 points)
    Jul 16, 2010 7:28 AM in response to GaBeech
    Is it OK to have power supply temperature in iMAC 2,16 GF7300GT constant at 74 Celsius.
    I just bought the computer and I don't have experience with iMACs only MBP.
    When I disamble it, because of cleaning and to apply new Arctic silver paste, I discovered that on GPU RAM is some kind of sponge and was heating the RAM. I cleaned it end now everything is working as new.

    All that is desturbing me now is the power supply temp, because it can't be good for monitor.

    TEMP:
    GPU 57C
    Power Supply 75C
    CPU 45C
    HD 46C
    Ambient 31C
  • by pbcubed,

    pbcubed pbcubed Jul 16, 2010 8:27 AM in response to hrabri.misek
    Level 1 (20 points)
    Jul 16, 2010 8:27 AM in response to hrabri.misek
    Power Supply 75C

    Tho that may be getting high, some see > 80C. Having had to replace a PS (see sig) I researched it a bit and am not comfortable w/such temps:

    http://discussions.apple.com/thread.jspa?messageID=11633311&#11633311

    Since I imagine affected users would rather not wait for that to happen, some test that stresses the graphics subsystem ahead of total failure would be useful, but I don't know what it would be.

    Yes. And this would seem to put this in a circular logic / chicken & the egg situation.

    Related I've held off suggesting people confirm that apple's temp/fan speed defaults allows some temps hit 80C->90C under stressful conditions such as long video/gaming sessions/benchmarking or even artificial stressing ala:
    http://macfidelity.de/2009/05/10/mac-how-to-stress-test-your-cpu-in-mac-os-x/
    Because doing so over-stresses parts in proving the point.
    *E.g. w/Core Duo's maximum non-use/storage temp of 85C (same for operating temps of caps used throughout these units), and as actual temps may vary in the sensor region, it seems an obvious system/firmware defect to allow temps to exceed 75C/80C under any conditions (artificial or not) anywhere in these units*.

    R C-R - a while back you made an excellent post WRT where even hard data can lead (e.g. an attempted class action) and the very limited benefits one could expect (other than the law firm involved:) even in the best of circumstances.
    IOW, I wonder what the best end could possibly be to pursue correlating units ser #s w/defects, esp. 4 or 5-yr old ones.

    BTW, having said these things before *I bet one thing we can get consensus on is that I should stop posting:)*
  • by R C-R,

    R C-R R C-R Jul 16, 2010 10:21 AM in response to pbcubed
    Level 6 (17,700 points)
    Jul 16, 2010 10:21 AM in response to pbcubed
    IOW, I wonder what the best end could possibly be to pursue correlating units ser #s w/defects, esp. 4 or 5-yr old ones.


    So do I. I know a lot of people are hoping for free out-of-warranty repairs or replacements for any Late 2006 iMac with this loosely defined set of symptoms. The online petition asks for a product recall, but what that means is unclear: is this meant for all late 2006 iMacs? Are owners to get their money back, replacement computers, or what?

    None of these things seem very likely, at least as across-the-board, no-questions-asked remedies. Apple, like other companies, only does across-the-board product recalls when clear safety issues are involved, like with the defective Sony laptop batteries that could catch on fire that were used in some laptops some years ago.

    It does sometimes offer "Exchange and Repair Extension Programs" for specific issues, but typically those for Macs require taking them in for examination by Apple techs, who try to determine if the problem is caused by that specific issue. In addition, these programs are usually limited to a narrow range of Macs, like those made or sold over a particular time frame, use one particular part (like a hard drive of some specific revision number), or something like that.

    My guess is something like that is the best that can come from this. It will still mean taking the Mac in for examination, & no free repairs or replacements will be done unless the failure can be directly attributed to some flaw Apple is responsible for.
  • by hrabri.misek,

    hrabri.misek hrabri.misek Jul 16, 2010 11:16 AM in response to pbcubed
    Level 1 (0 points)
    Jul 16, 2010 11:16 AM in response to pbcubed
    Also I forgot to mention that PSU is making sound when the computer is turned off but in electricity, if it is out of electricity the sound goes.

    Do I need to replace PSU?


    Thanks
  • by elice82@,

    elice82@ elice82@ Jul 16, 2010 1:46 PM in response to hrabri.misek
    Level 1 (9 points)
    Jul 16, 2010 1:46 PM in response to hrabri.misek
    @hrabri.misek
    Like this (http://www.youtube.com/watch?v=cSFWvtppcF4) sound?
    Mine iMac does this ticking when it's turn on and when turn off then for a few hours.
  • by hrabri.misek,

    hrabri.misek hrabri.misek Jul 16, 2010 5:45 PM in response to elice82@
    Level 1 (0 points)
    Jul 16, 2010 5:45 PM in response to elice82@
    @elice82@

    No. When is turned on you can't hear it anymore.
    When it's off you can hear that electicity sound (buzz).
  • by blooumpy,

    blooumpy blooumpy Jul 23, 2010 4:41 AM in response to GaBeech
    Level 1 (0 points)
    Jul 23, 2010 4:41 AM in response to GaBeech
    Serial W8639*VUV
    2.16 Ghz Core2Duo

    Basically the same thing, at one point where smcfancontrol stopped working, I rebuilt the iMac, reapplied new thermal grease on the heat sinks, had the machine running at a nice cool 31C idle and peak at 52C under load.

    It ran ok for another few weeks and now it rarely can boot completely without crashing, it's not heat anymore, as temperatures are low, well basically low 30's. Damage was done previously.

    This *****.


    <Edited by Host>
  • by odedia,

    odedia odedia Jul 23, 2010 9:16 AM in response to blooumpy
    Level 1 (5 points)
    Jul 23, 2010 9:16 AM in response to blooumpy
    You guys can add me to the list.

    I have some new info, though:

    1. I stopped using the internal hard drive as boot drive, that solved the problem for a few weeks. I use an external Firewire 800 drive to boot, it is actually faster and causes less heat on the machine.

    2. I installed Ubuntu 10.04 as a second boot (back when it was on the internal drive). I have no issues with Ubuntu! No weird lines, no slow hard drive, nothing. Everything was just fine. This makes me both angry and hopeful that this is a software problem.

    I have the GeForce 7600 upgraded GPU.
  • by pbcubed,

    pbcubed pbcubed Jul 23, 2010 11:17 AM in response to odedia
    Level 1 (20 points)
    Jul 23, 2010 11:17 AM in response to odedia
    odedia wrote:
    2. I installed Ubuntu 10.04 as a second boot (back when it was on the internal drive). I have no issues with Ubuntu! No weird lines, no slow hard drive, nothing. Everything was just fine. This makes me both angry and hopeful that this is a software problem.
    I have the GeForce 7600 upgraded GPU.


    Interesting findings. I'd think the only ways this may be possible (GPU/VRAM "damage" not visible under Ubuntu) are:

    1) you (or your drivers) are not making serious use of the GPU. IOW, enabling AND making use of hardware acceleration available in the GPU. Perhaps some tests like these would reveal this:

    http://www.phoronix.com/scan.php?page=article&item=mac1062_ubuntu1004&num=1

    2) GPU/VRAM speed/timing is not controlled through firmware in the iMac (someone other than I may know the clear answer to this). IOW, less "stressful" settings are somehow being used under Ubuntu vs OS X.

    BTW / IIRC, your 24" 2006 model has replaceable GPU (not soldered), the 2006 17"s & 20"s do not - it is expensive/impractical to replace GPU/VRAM in them.
  • by Lacazg,

    Lacazg Lacazg Jul 24, 2010 12:17 PM in response to GaBeech
    Level 1 (0 points)
    Jul 24, 2010 12:17 PM in response to GaBeech
    Hello,

    I just wanted to share that I have an iMac (with 10.5.8) that I purchased in early 2007 (I think) and it is experiencing simmilar symptoms (colored lines, pixels and triangles as well as freezing frequently). My serial number starts with W8650. My temporary solution is to run the computer in safe mode, it works perfectly in safe mode but won't run longer than 15 minutes in the normal mode.
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