Results 1 to 9 of 9

Thread: More B&W memory voodoo

  1. #1
    Join Date
    Apr 2001
    Location
    Albury, NSW, Australia
    Posts
    135

    Default More B&W memory voodoo

    I'm running 10.3.5, 9.2.2 & YDL on a B&W G3/450 and have had a few random freezes especially trying to run Open Office via X11.

    Ram Config (DIMM First Aid)
    Model: PowerMac1,1
    PowerMac G3 (B&W)
    DIMM0/J19
    DIMM configured for 256MB
    8008040D0A02400001705400800800018F04060101000E7554 0000150F152D40
    15081508FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFF127D
    FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFFFFFF
    FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFF64F7
    7.0ns PC133-233
    DIMM checks out OK

    DIMM1/J20
    DIMM configured for 64MB
    8008040C0901400001755400800800018F04060101000EA060 0000140F142D10
    15081508000000000000000000000000000000000000000000 0000000000129E
    ADFFFFFFFFFFFFFF0237365638363335484754382D48202020 20204141286500
    4AC1E000000000000000000000000000000000000000000000 000000000064AF
    7.5ns PC133-333
    DIMM checks out OK

    DIMM2/J21
    DIMM configured for 256MB
    8008040C0B01400001755400800400010F04060101000EA060 0000140F142D40
    15081508000000000000000000000000000000000000000000 0000000000124C
    00000000000000000000000000000000000000000000000000 00000000000000
    00000000000000000000000000000000000000000000000000 000000000064AF
    7.5ns PC133-333
    Note: the number of column address bits is not compatible with newer Macs
    DIMM checks out OK


    I read this...

    http://macgurus.com/forums/showthread.php?t=21035

    and changed my ram config swapping 256MB DIMM in J19 (reported as the slowest) with DIMM in J21 which is a 512MB DIMM.

    OSX wouldn't boot, OS9 would but no SCSI HDD's. I'm guessing the 512MB DIMM is the problem but I'm not sure. I swapped them back and everything is back to where I started.

    Could someone recommend what I should do?

    Thanks
    Bernard
    The Meek Won't Want It!

  2. #2
    Join Date
    Sep 2002
    Location
    Milan - Italy
    Posts
    525

    Default

    Dear Bernard,

    Quote Originally Posted by All Systems Go
    ...and changed my ram config swapping 256MB DIMM in J19 (reported as the slowest) with DIMM in J21 which is a 512MB DIMM...
    DIMM First Aid reports your 512MB DIMM as a 256MB one. That brings me to think that, if you bought such DIMM as a 512MB capable one, bears the wrong density for your machine. But that may not be the issue for what you are experiencing IMHO.

    Let's first give you the suggestion of "what I would do in your shoes":
    1. Put the DIMM you have reported in J20, in your first slot J19.
    2. Put the DIMM you have reported in J21, in your second slot J20.
    3. Put the DIMM you have reported in J19, in your third slot J21.
    4. Upon re-booting your Mac, reset the NVRAM. This should force the booting sequence to rescan all the motherboard buses (including the one where you RAM expansion modules are) to re-establish the current hardware set-up.
    5. In case you are still experiencing problems under OSX, boot your Mac from the OSX CD (by holding down the "C" key during the booting sequence), and run Disk Utility from the OSX CD on your internal booting hard disk. When in Disk Utiltiy, run "Repair Permissions" on such hard disk.
    6. Report back here for us your findings, so we can check "how good" our suggestions have been and, in case, advise you further troubleshooting sequences.


    About 512MB DIMMs, these are usually NOT fully recognized by your machine, as the maximum density DIMM you can fit inside your B&W machine is a 256MB one.
    You should be aware, in fact, that the density of a DIMM module is dictated by the Memory Controller soldered onto your motherboard. The particular MC model inside your machine is capable to address data onto DRAM modules (those little, bug-like, black chips soldered on the green TSOP SDRAM module), with maximum data density of 128Mbits (NOT to be confused with MBytes).
    So, as each 128Mbits DRAM chip bears 16MBytes of RAM addresses, to form a 256MBytes module, you will need 16 of them, 8 on each side of the green TSOP module.
    Your 512MB DIMM is probably fitted with all 16 of those DRAM chips, 8 on each side, but are built to a total density of 256Mbits, instead of 128Mbits.
    Your internal MC will address data up to fill the first 128Mbits on each of those "bugs", totally ignoring the extra 128Mbits of space availability.
    Thus, you have paid extra money for something your machine will never be able to use.
    Other than that, such DIMM "should" work fine just the same.

    This so as to be complete.

    Let us know and all the best.
    Costa
    ________________________

    Ab ovo usque ad mala

  3. #3
    Join Date
    Apr 2001
    Location
    Albury, NSW, Australia
    Posts
    135

    Default

    Thanks Costa
    So far so good. I have X11/Open Office and Firefox running. I'll let you know if I still get any random freezes but for now at least, AOK.

    I did read your previous post re: 512 DIMMS and I purchased this ram so I could swap it to a G4 when I upgrade. Trying to save money in the longer term.

    Gurus Still Rock!

    Thank you.
    Bernard
    The Meek Won't Want It!

  4. #4
    Join Date
    Apr 2001
    Location
    Albury, NSW, Australia
    Posts
    135

    Default

    Hi Costa
    Well it seems I spoke too soon and didn't follow your suggestions correctly.
    After repositioning the ram I reset the pram and it booted from the CD OK. I repaired permissions and rebooted. Just after posting I noticed my SCSI drives did not mount and the SCSI card wasn't recognised.

    So I then reset nvram and now it won't boot at all. I get the startup chime, the monitor light goes green for a second and then back to orange. I tried booting from Disk Warrior but still nothing. I tried resetting pram again but only get the first chime then nothing.

    I need a break now but in the morning I'll try putting ram back to where it was origionally to see if it will boot. Could resetting nvram upset yaboot, the YDL bootloader?

    Bernard
    The Meek Won't Want It!

  5. #5
    Join Date
    Jan 2002
    Location
    NW Montana
    Posts
    8,197

    Default

    I have been doing some of the same troubleshooting for different reasons to my DA/533 I have had some of the same problems as you have described. Try pulling the battery, let sit 30 minutes, press the power button once while the power cord disconnected, reboot. Better do this over night and pull your RAM also. (drain all the power)

    The FAQ's have a ton of good BW trouble shooting info but there is a lot of it and can seem overwhelming to wade through. - Randy

  6. #6
    Join Date
    Apr 2001
    Location
    Albury, NSW, Australia
    Posts
    135

    Default

    Hey Randy and Costa
    Thanks for the info. I did as you suggested and can now boot and SCSI is back. I'm still getting a few random freezes although far less, like one per 6 hr session, and not particular to any software running. Overall things are BETTER.

    It's possible that because I'm running linux, 9.2.2 & OSX and trying to have ext3 drives mount reliably in OSX, there might be some other buggy thing going on.

    Anyways, thanks for the help, it's much appreciated.
    The Meek Won't Want It!

  7. #7
    Join Date
    Sep 2002
    Location
    Milan - Italy
    Posts
    525

    Default

    Dear Bernard,

    sorry for my temporary "dissappearance", but I was away on a business trip until a few minutes ago.

    Quote Originally Posted by All Systems Go
    ...It's possible that because I'm running linux, 9.2.2 & OSX and trying to have ext3 drives mount reliably in OSX, there might be some other buggy thing going on...
    You should be aware to the fact that the B&W machine is well known to sport a buggy FireWire port. Thus, if you are using 3 external drives via such port, my suggestion is to install a third party FireWire Host card, like, for example, any of these ones, and run your external drives from such card, rather than from your buggy internal FireWire port.

    You can ready more about such "buggy" B&W FW port in this article.

    Glad to see, though, that you RAM outfit isn't the main problem.
    Seems like some progress has been done.

    Keep us adjurned.

    All the best
    Costa
    ________________________

    Ab ovo usque ad mala

  8. #8
    Join Date
    Apr 2001
    Location
    Albury, NSW, Australia
    Posts
    135

    Default

    Thanks Costa & Randy
    A few weeks on and no crashes.



    Cheers
    Bernard
    The Meek Won't Want It!

  9. #9
    Join Date
    Jan 2002
    Location
    NW Montana
    Posts
    8,197

    Thumbs up Good job we love a ending that fixes things.

    Lets hope that all stays well and if not... well were here again. - Randy

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •