iMac G4 2GB RAM not recognised

Discussion in 'PowerPC Macs' started by CooperBox, Jul 2, 2016.

  1. CooperBox macrumors 6502a


    Nov 28, 2010
    France - between Ricard & Absinthe
    I wanted to max out my 20" G4 iMac with 2MB RAM. It had 1Gb stick in the inner (factory installed) location.
    Both MacTracker and EveryMac state, "Apple officially supports 1 GB of RAM in these models, but unofficially these models support 2 GB of RAM."

    So I added a 1GB SODIMM stick of PC2700 (200pin) into the user accessible location. Booted, but noticed it wasn't recognised. Re-installed it, same result. Inspected and cleaned the connector contacts with correct product spray can, and lightly cleaned the SODIMM stick contacts with a pencil eraser, reinstalled and booted. The result was the same, still only 1Gb recognised in the inner location. (See following screen shot).


    The following screen shots show the additional info given. The OS on this iMac is in French - but you get the gist.
    The first correctly details the 1Gb PC2700 184pin SDRAM stick at the inner location (DIMM1/J20).
    The second curiously shows the outer location (DIMM0/J22 as 'vide' (empty) although there is a 1Gb SODIMM PC2700 (200pin) stick installed.

    Memory-1a.jpg Memory-1b.jpg

    Thinking there may be incompatibility with different brands of memory, I then purchased further 1GB brand-new sticks from Amazon, both were 'Komputer Bay' manufacture (a brand I have purchased several times before, with never a problem). Installed both into the iMac.
    The results were identical to before. The inner 1GB memory is recognised, but not the outer 1Gb memory.

    Can anyone shed any light on this anomaly of non-identified RAM at the outer user accessible location?
    Is it possible that although not indicated, both memory sticks are in use? The machine is pretty damn quick, but there again it was even with only 1GB memory installed.
    My other 20" iMac is currently boxed and not immediately accessible, otherwise I would have already done a cross-check to understand further.
  2. oi! Suspended

    Jan 10, 2016
    First instinct, "Do you have a dead stick?" you seam to have covered that.
    Second instinct, do you have a dead slot?
  3. Altemose macrumors G3


    Mar 26, 2013
    Elkton, Maryland
    Verify that the slot itself is not bad and also ensure that the Mac is running the latest firmware. I know it is hard to believe, but these Macs were before the days of Software Update taking care of everything like firmware upgrades. It is rare to see, but I have seen one or two old PowerPCs with out of date firmwares, and if the testing and results on Mactracker is based off of the latest firmware then it could be the reason for your issue.
  4. oi! Suspended

    Jan 10, 2016
    First up, visual inspection, take a good look at the possibly dead slot, check for debris, dust, fluff, contaminants, damaged or missing pins.
    Blow out with a can of air as necessary.
    Place 1 stick of ram in that slot, switch on, if it boots fine and reports 1gb of ram, it's firmware. If it doesn't boot it's the slot.

    Article on G4 imac disassembly/upgrade found on xlr8yourmac...
  5. imthatmvrk macrumors newbie


    Jun 6, 2016
    Georgia, U.S
    I had the same problem with my PowerMac G4 and I just cleaned my slot with a can of air and it didn't work. I returned the ram sticks and got a new pair and that did the trick.
  6. oi! Suspended

    Jan 10, 2016
  7. MysticCow macrumors 6502a

    May 27, 2013
    For some reason, my Macs have always been pickier with RAM sticks than my Windows PC's. Especially under OS X usage--Mac OS 9 isn't nearly as picky.

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