iMac G4 not addressing all my ram

Discussion in 'PowerPC Macs' started by tuxdude, Feb 3, 2017.

  1. tuxdude macrumors newbie

    tuxdude

    Joined:
    Jun 8, 2016
    Location:
    New Zealand
    #1
    So I recently got my hands on an iMac G4 700mhz machine. Very nice computer. However ever since I have got it I've been having issues with the ram, more specifically, the fact that the computer doesn't want to address all of the ram installed.

    I've done extensive troubleshooting on this machine from installing different operating systems to trying all possible combinations I could do with the SDRAM chips I have and to no avail.

    I ran apple hardware test which reported a memory error of post/16/2048 but when I ran a quick and extended memory test they both came back with a pass. On top of this Apple Hardware Test does detect the actual full capacity of the installed DIMMS. I've attached pictures of this to the post. It is also important to note that in both os9 and os x the chips are identified as PC-100 when in fact they are PC-133 chips.

    Despite the computer reporting these ram errors I haven't actually had any problems with the machine. No Kernel panics or crashes or anything which just makes things even more confusing to me. I have also tested some of the ram chips in my iMac G3 and Apple Hardware Test hasn't returned any issues (I could only test the full sized ram chips though since I don't have a powerbook or ibook machine to test the laptop sized dimms)

    The only other theory I really have is that it has something to do with the firmware. I booted the machine into openfirmware and it says it's running version 4.3.5 (or 4.3.5f1 as it says) built on 03/16/02 at 21:45:18

    I've tried researching this version of the firmware but I haven't been able to dig up much on the internet about it. If anyone knows anything about this particular version of the firmware, if this version causes any issues and if there are any firmware updates for the iMac G4 available then that would be much appreciated.

    I'd love to get this all sorted out properly since I want to try bump the ram to 1 gig at some point when I get round to finding some 512mb chips.

    Thanks in advance!
     

    Attached Files:

  2. Guiyon macrumors 6502a

    Joined:
    Mar 19, 2008
    Location:
    North Shore, MA
    #2
    Can you post pictures of the SODIMMs you have installed? A close up of the markings on the chips and both sides of the SODIMMs would be useful.
     
  3. DeltaMac, Feb 3, 2017
    Last edited: Feb 3, 2017

    DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #3
    I suspect that the RAM sticks that you have, are just not the correct specs for your old iMac G4. The fact that they both are recognized as 128/256 in the Hardware Test may mean that they could be high-density chips, and may not be supported fully.
    When you get the larger capacity chips, get them from a respected memory supplier known to support Apple, such as Data Memory Systems. Correct memory for your iMac G4 700 MHz is listed on this page - http://www.datamemorysystems.com/ap...z-15-m8672ll/bm7677ll/b-2002-memory-upgrades/

    Note that there is only one SO-DIMM. The second slot is the full-sized SDRAM stick.
    I would likely get the correct SO-DIMM first, try that out to see if that fixes your issue. That will be a much quicker test to just swap out that SO-DIMM, unless you enjoy the mess to get at the internal SDRAM stick.
    Replacing one with known-good stick will also quickly tell you if that's all you need, or (with the same result) you have a memory controller issue (meaning the logic board has a problem, and not just the memory sticks.)
    Let us know what you find out. :D
     
  4. tuxdude, Feb 3, 2017
    Last edited: Feb 3, 2017

    tuxdude thread starter macrumors newbie

    tuxdude

    Joined:
    Jun 8, 2016
    Location:
    New Zealand
    #4
    The ram setup I'm using uses one chip that came preinstalled in the G4 and another PC-133 ram chip pulled out of an iMac G3 which I'm pretty sure doesn't support high density ram either (correct me if I'm wrong). Said stick of ram worked perfectly in the G3 iMac yet started throwing a little hissy fit in the iMac G4 which I find odd.
    --- Post Merged, Feb 3, 2017 ---
    I can do that. Just give me some time to snap some photos.

    EDIT:

    Here you are. These were the two chips I had installed at the time of writing and when I took those pictures.
     

    Attached Files:

  5. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #5
    I looked through some of my old files to find your "post/16/2048" error. The troubleshooting for that error tells you to either reseat the RAM sticks, or replace with known good sticks.

    The Viking-brand SO-DIMM is marked "PC-133 compliant", and neither stick appear to be original to an iMac, even though the SO-DIMM might have been installed in the iMac when you bought it. The Apple sticker that you see on the SO-DIMM could be bogus, and doesn't necessarily assure you that it is Apple-certified, and the other stick has that big blue sticker which is likely one sold as "compatible", which doesn't always mean "works in all Macs". You always want to consider that some Mac models are known to be picky about RAM

    Try testing with only one chip installed. Your iMac G4 will run just fine with only the SO-DIMM installed, for example.

    As I was looking for information, I did find an old utility, called DIMM First Aid.
    If you boot to OS 9, and run that utility, it may give you another method to make sure that your RAM is working OK. The utility also has the capability to repair certain issues on memory used in Macs. I think it is worth trying, as the app may tell you that the memory is not programmed properly to be reliable in your iMac.
     
  6. tuxdude thread starter macrumors newbie

    tuxdude

    Joined:
    Jun 8, 2016
    Location:
    New Zealand
    #6
    Already tried dimmfirstaid but it throws an error at me saying this model of machine isn't compatible with the program so that's not gonna work.

    I've already tried running it with just one chip installed as I mentioned earlier. Same problem still persists
     
  7. CooperBox macrumors 6502a

    CooperBox

    Joined:
    Nov 28, 2010
    Location:
    France - between Ricard & Absinthe
    #7
    Having 'played around' frequently with G4 iMacs of all flavours, one annoying feature is that they do not all use similar RAM. I confirm that your early 700MHz model uses PC-133 144-pin SO-DIMM (at outer 'user accessible' location), and PC-133 168-pin SDRAM (at inner 'factory installed' location).
    It's true that these iMacs can be finnicky when it comes to different makes of RAM, and sometimes it can be trial and error, but that can work out expensive.
    I have frequently purchased 'Komputerbay' sticks from Amazon, and so far never had a problem. One sometimes reads negative user reviews on this make, but for every negative review I'll bet there are dozens of silent satisfied users.
    https://www.amazon.co.uk/Komputerba...2&keywords=komputerbay+PC-133+144-pin+SO-DIMM

    https://www.amazon.co.uk/Komputerba...1-1&keywords=komputerbay+PC-133+168-pin+SDRAM
     
  8. tuxdude thread starter macrumors newbie

    tuxdude

    Joined:
    Jun 8, 2016
    Location:
    New Zealand
    #8
    Thank you very much! I'll have a look at getting something like that once I got some spare change lying around (shipping costs to New Zealand are mental).

    I can also confirm that tiger DOES see the ram as PC-133 so it looks like it might just be a problem with the ram being picky as heck
     
  9. tuxdude thread starter macrumors newbie

    tuxdude

    Joined:
    Jun 8, 2016
    Location:
    New Zealand
    #9
    UPDATE!

    Ok so from the research I have done and the reports you guys have given me I'm leaning towards it being more a problem with the machine being picky about ram than anything else. AFAIK this machine was the 128mb model originally and that 256 chip was added later into the SODIMM slot which would explain why the computer didn't like it and the 256 chip I put in later on was pulled out of an imac G3 which would explain the potential incompatibility.

    If these macs are indeed as picky as you guys say with ram then that is probably the root cause of the issue so for now I'm gonna leave the chips setup the way they are now (so I at least have 256 meg of ram) and I'll order some proper tested 512 meg chips for this model of iMac and get back to you all on what happens!
    Thank you very much for all your help! If you have any other suggestions, ideas etc then please feel free to post them!
     

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