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Thread: G5 problem

  1. #1
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    Default G5 problem

    I have a very subtle G5 problem involving the fans on CPU A revving up and locking at max speed (3200 rpm). After the process of elimination, I am sure that it is a hardware problem, but Apple refuses to fix it. So, in order to get the machine to quiet down for a bit, I need the Apple Service Diagnostic 2.5.5 (not earlier version). This SW can force a thermal recal. Can anyone lead me in the right direction ?

    thanks,

    Mad Dog

  2. #2
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    Default

    Hi MadDog,

    Don't have what you are looking for, but I was wondering what OX version is this happening with, and does it very by OS version (have you tried different versions, say 10.3.6 vs. 10.3.9?)?
    "Imagine if every Thursday your shoes exploded if you tied them the usual way. This happens to us all the time with computers, and nobody thinks of complaining." -- Jef Raskin

  3. #3
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    Default oh yah

    I noticed the problem in 10.3.8, went back to 10.3.4, worked up to 10.3.9, I even tried an external firewire drive with a fresh install of 10.3.4. I zapped the PRAM, reset the SMU, the PMU, the NVRAM in OF. I dusted it out.

    None of does anything. A thermal recal or letting it sit unplugged overnight does something.

    It isnt OS. I am 99% sure its hardware. One time when the fans were screwed up, I ran the ASD 2.5.2 and it picked up a thermal sensor error, but when I brought the machine to the tech (after unpluggin overnight....) the fans were quieter and ASD 2.5.5 didnt pick anything up.

    Its a subtle intermittant problem.

    Mad Dog

  4. #4
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    Default

    OK, good you already worked that out. Just thought I's ask so we can cross it off.

    Now it gets difficult.

    Wish I had answers, but only more questions.... It sure would be nice if the Console logs (or *some* log....) had the info as to why the fans are kicking into high. Perhaps enough to chase down which of the sensors (I wanna say there are 9 different ones in G5 towers) is sending the signal that something is overheating, so we could check out the component in question, and the sensor itself. That would sure help narrow it down I would think.

    The only other thing that comes to mind is that if memory serves, the early G5 towers had a firmware update that had some effect on fans, which should lead us to believe that besides the actual hardware involved, and the OS, there may be a firmware component that could malfunction too. Only a hunch, and don't know how to verify off the top of my head, much less remedy wonky firmware.....

    Or perhaps the software you mentioned can handle either of these two therories? Have not heard of it....is this a "Apple server provider" only tool?
    "Imagine if every Thursday your shoes exploded if you tied them the usual way. This happens to us all the time with computers, and nobody thinks of complaining." -- Jef Raskin

  5. #5
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    Default

    There are some prefs in /Library/SystemConfiguration/

    com.apple.PowerManagement.plist
    AutoWake

    Those can become corrupt.

    there may be plists in ~/Library/Preferences also (I couldn't find any).

    I have also use AppleJack to clear cache folders, you could use Tiger Cache Cleaner (10.2.8 or later) or another utility but I'd look at the above, seeing you've done all the other OF nvram and I assume set-defaults which seems to address Energy Saver settings (not documented but has helped others and my MDD).

  6. #6
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    Default tried that....

    I tried tossing the plist too, that didnt help.

    Another sign of it being a HW problem is that when it happens, the A fans will ramp up hard while the B fans idle at 300 rpm, even under equal CPU load. Bizzarre. One time when the fans were running hard, I rebooted, and 10 minutes later when I came back, I could see that right after boot, the A fans were maxed out immediately and kept that way.

    The odd thing is that it is intermittant and the temp readings are all fine.

    It took me a week to convince myself I had a problem, and I would be delighted find that I did not.

    Mad Dog

    :jollyroger:
    Last edited by MadDog; 05-10-2005 at 05:50 PM. Reason: added info

  7. #7
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    Default

    when you boot into Open Firmware do you use

    > set-defaults

    along with

    > reset-nvram

  8. #8
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    Default yup....

    I tried both of those commands.

    This is getting more and more odd. I got the machine back and the tech couldnt find any error. I am now in the process of trying to figure out if anything on my end is causing this. I cant see how the USB hubs I have or the APS could cause this, but I have to try.

    So, noone has the 2.5.5 ASD ?

    Mad Dog

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