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Thread: G4 450 Sawtooth--how do you tell a lemon? (LONG)

  1. #1
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    Hello troubleshooters, mac techs, and mystery fans, may I interest you in a saga?

    Some years ago my girlfriend bought a brand new Sawtooth G4 450. This computer has had numerous minor problems over the years, all of which seem to point (to my mind, at least) to some quirky hardware. Before we start, though, let me assure everybody that I'm handy with Disk Warrior & Tech Tool Pro, I know how to zap p-ram and reset open firmware. I'm a believer in matenience, and have few, if any, troubles with my 933 Quicksilver, or either of our Pismo powerbooks.

    That said---this computer has always acted a bit weird, but rarely offered repeatable problems (something I always rely on for troubleshooting). It crashes fairly often in 9.2--usually while running Entourage. Running airport (as a software base station), it would lose network connectivity when waking from sleep. Odd, and annoying, but not tragic. But occasionally it would crash hard, and then lose its boot ability--the boot sector would get messed up. After running a disk utiltiy, I could usually bring it back, although a few times we had to reinstall everything from backups after total data loss.

    Over the years we upgraded the hard disk (for space, and out of being wary of the original one), upgraded the RAM from 128 to 1250mb, and bought some exterior peripherals. The other day she decided she was ready for OS X on the machine, so I planned on spending the morning installing Jaguar. The install worked fine (just adding it to the disk that 9.2 was on), but on boot I was getting a weird kernel panic--horizontal lines across the grey screen. Hmmm--that's not right.

    I booted into 9, and after trial and error found a bad RAM chip. It was a fairly recent add, so it couldn't be the cause of all my problems, but obviously the install ones. Since I was having install problems, I decided to start fresh and just install X on a fresh drive. I reinitialized the drive and installed 9 (for classic), and then X. Groovy--works fine--I start up, run software update, and during which the computer crashes--NOT a kernal panic, but a OS X "bomb"--the screen dims and the box says "you must reboot your computer..."

    Damn. Okay. Reboot computer--can't find hard drive. Lovely new graphic, though, the little "busters" sigh. much more effective than the flashing question mark folder. Start up in 9, run disk warrior--nothing. Damn Damn.

    Okay--reinitialize hard drive--write zeros to the entire drive. Install X alone. Works fine, update computer to 10.2.3, and computer crashes while I'm scrolling through the screen effects. Just locks up, not kernel panic, total freeze. Restarts okay--start up again (thankfully), run fsck. Start installing and playing with things--screen goes blue (wha? Shades of windows!)--but the mouse still moves, I can't do anything, a few seconds later the finder starts up--oh, a finder crash. Okay.

    On our way we go--but since we've had a few other lockups. This computer is just too unstable, but I've tried every hardware test I can think of, disconnected ALL periphs, disconnected the extra internal hard drive (yes, the jumpers are all set right).

    So--is there some tools that a tech might have that I don't to test hardware? She really just feels like she can't trust it, and I'm at my wits end trying to troubleshoot it. It seems okay for awhile, and then crash crash crash. I don't trust data on it--I'm just out of ideas. Short of replacing it, how can we figure out what's going on?

    Thanks for any ideas. I'm stumped!

  2. #2
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    Start with RAM. Run DIMM First Aid. Making sure it all gives an "okay." PC100, 125 MHz, 8 nanosecond, or PC133. Then go from there.

  3. #3
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    Thanks Gregory!--

    I didn't know about DIMM first aid, but all appears to be well. Since I removed one chip that kept failing under the Tech Tool Pro RAM test, here's the breakdown:

    DIMM0/J21
    DIMM configured for 128MB
    8.0ns PC100-222
    DIMM checks out OK

    DIMM1/J22
    DIMM configured for 128MB
    8.0ns PC100-322
    DIMM checks out OK

    DIMM2/J23
    DIMM configured for 512MB
    7.5ns PC133-333
    Note: CL2 not supported
    DIMM checks out OK

    The only thing odd is the "CL2 not supported" bit--and would the fact that some ram is 100, and some is 133 matter? I wouldn't think so, but then again, I'm not sure...

    What's the next step?

  4. #4
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    I'd consider that a real test of mixed RAM working together! I'd say that since they're all 128's to go buy a pair of PC133 CAS2 from a good reliable source, don't worry about saving $15, and see if you then have a solid system.

    I assume that you have all the firmware updates, some of which were suppose to improve memory reliability (tightening restrictions on what is acceptable) as OS X is very sensitive to RAM.

    Entourage is another question. Database rebuild. Moving libraries out of Extensions folder. Using Conflict catcher to scan for damaged or corrupt system resources. Corrupt cache.waf files or a corrupt internet preference file (both IE and OE/Entourage are "hard" on all of those). Allocating more memory to programs.

    When installing, best to do a clean system install and of any drivers etc. Sleep is another buggy area for Macs and whether network connections are lost or not. A router and DHCP lessens that issue. Only trust a backup if the system was known to be rock solid, otherwise, install and maybe merge system folders using CC9 or gingerly by hand.

    My B&W G3 doesn't like to mix different memory, lacks the firmware to deal with it I suspect, so I have all identical chips bought from one source. G4's have gotten better, but still worth a shot. RAM prices have inched up from their below cost rock bottom. Don't know if its worth $75+ to buy some RAM, but I'd think that would help. I thought it was "normal" to crash 1-3 times a week, too, mostly IE because it used the system and RAM the most. Replacing RAM solved that.

    If you can afford to, another hard drive so the original can act as backup and rule that out also. A PCI IDE RAID card would boost performance at the same time.

    Do you have the latest TTPro 3? You used DW to repair boot blocks AND to update the driver? It is possible for the driver itself to get damaged, easy enough to run Drive Setup to update it.

  5. #5
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    Hey Gregory--

    Thanks for all the tips. I decided to strip it down to the single 512mb chip, and see if things move a little better. Open case, put 512 chip alone in slot 0, close case, start up, reset open firmware, zap p-ram--goes right into 10.2.3 no prob.

    Since I crashed more than once in "screen effects" I open it up in control panels, and just clicking on the different previews locks the system. Mouse moves, but the screen is hopelessly locked.

    Looks like the same issue even with one 512 RAM chip--maybe something else might be wrong?

    Is there any serious diagnostics, beyond TT3 (latest version, 3.0.9) to test individual components? it seems that the crashes often occur when the video card is being taxed?

    Once again, I'm baffled--what do we check after RAM?

    Thanks!

  6. #6
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    ...don't use screen effects then? Seriously, I think it was known to be trouble, but then sleep and other things were also.

    I actually didn't think 512MB of CAS 3-3-3 was, well, recommended or supported.

    check what the Crucial guide suggests and has to say about SDRAM, its a good background library.

    Sure seems like that chip should be taken out.

  7. #7
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    Don't forget the Hardware Test CD that came with your G4...you still have it somewhere, right? It's the only other multi-function Mac hardware diagnostic software I am aware of (that you can get your hands on without being an Apple tech).

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