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Thread: G3 B&W Motherboard or Processor

  1. #1
    Join Date
    Feb 2003
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    About a year ago you guys helped me with unexplained freezes on a G3 B&W 450.
    We tried about everything having to do with the memory trying to solve the problem.
    I tried several brands of 256 Mb chips and finally ended up with Crucial chips that meet Apple?s specs. This did not solve the problem with the freezes but I could reduce the number of freezes to a number that I could live with.

    The solution was to use two 128 Mb chips or one 256 Mb chip and turn Virtual Memory off. Although the chips can be used in any of the slots, no more than 256 Mbs can be used without freezes. If virtual memory is turned on, the machine will freeze. (Not during startup.)

    I was never able to get OS 10.2 operate successfully although I did get it to load 2 or 3 times after at least 50 attempts to get it to load. I gave up and continued to use OS 9.2.

    The old thread is here: (Memory Upgrades , Bailey, Feb 11,03)
    http://forums.macgurus.com/6/ubb.x?a...309&m=80460609

    Is the problem with the motherboard or the processor? If you think it is one of those, where would you recommend getting a motherboard or processor.

    What controls the way the memory chips are read? All slots appear to be good and all chips are good, but when more than 256 Mbs of total memory is used the computer freezes. It crashes whether the extra memory is ram or virtual memory.

  2. #2
    Join Date
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    RAM has to be filled from J19, then J20. No trouble using four 256's from Crucial. Just make sure it is all the same type.

    There are thousands of messages over the last three years on B&W, on OS X, on how to deal with rev 1's and all the rest. Jaguar and Panther are a breeze.

    I've seen Rev A Beige G3s install w/o trouble, but people who modified their Rev A and B's and used someone else's Rev C ROM (or something) have nothing but voodoo magic and trouble.

    B&W G4/500, 1024MB RAM, Radeon Mac, ATTO UL3S, OrangeMicro FW/USB, ACard ATA/133. IBM 120GXP 60GB, Cheetah 15K.2, Atlas 10K-IV, Atlas 15K. And Adaptec 39160 from time to time.

    Start by doing an Open Firmware reset. New battery. A minimum 512MB of RAM for OS X. And start with a new disk drive. Hitachi 7K250 40/80/160GB (you'll need a PCI IDE card for the latter), or give Serial ATA a shot, great drives, and only $69 for Gurus SeriTek/1S2.

  3. #3
    Join Date
    Feb 2003
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    ?
    TZ,
    In your post (February) concerning this problem, your conclusion was:
    "The memory controller? Seems like it. ... . New mobo or move on?
    You've been thorough and more in seeing this through".

    Since I had not noticed at that time that the machine ran better with virtual memory off, I want to know if the problem might be with the processor.

    The only tests that detect ram problems are the ram specific tests in Tech Tool Pro. Running from the CD, virtual memory off, extensions off, full memory and two or more Crucial 256 chips, the machine crashes or tests fail. With one 256 chip or two 128 chips, all tests are passed.


    BTW: I have moved on to a new G4 1.25 DP, but I gave the G3 to my son and he is willing to spend some of his money on it.

    Thanks for all your help.

  4. #4
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    I would download DIMM First Aid if you haven't and insure what you have is what Costa has provided in detail (PC100 CAS2 8 ns primarily). I would buy one stick of Crucial PC100 ($62) as my "test stick."

    Use a PCI controller along with a new disk drive. Start clean, set it up, install Panther, and enjoy. If you think the cpu is "A/THE" factor in all this, hard decision. Sonnet dropped the price on G4/500 to $199, so you might want to look at that option also. Runs great.

    You must have one stick of bad ram that lacks the proper SPD code and timing information to work properly. The B&W seems to pick up whatever is in J19 and use that for all the RAM chips.

    It took me a long while to unravel all the bugs and tips on how to get B&W to run stable. Now that it does, I'm reluctant to move on to G4 or G5. - A Sonnet G4/1000 and invest in ATTO UL4S might make sense (the UL4S can go in G5 as true PCI-X later).

    You may need someone who can help test the voltage and make sure the mobo is working and communicating properly. If you haven't done a ?F reset, that is a good first step.

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