Old powermac G5, red light on logic board

Discussion in 'PowerPC Macs' started by Jordan1990, Jan 25, 2015.

  1. Jordan1990 macrumors member

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    Jan 17, 2015
    #1
    I have an old Powermac G5 which i bought just to use in conjunction with my 2010 mac pro and a piece of glass as a coffee table.

    However the other day i decided to plug it in to see if it actually powered up, it does... But it has no hard drive and only 1 ram chip in there, nothing shows on the screen and the logic board has a solid red light on, im sure this is not because there is no hard drive because i would imagine something would still show on the screen, could it be faulty ram? I thought i would try and get it working as a little project but would like to find out what the red light means before i spend any money
     
  2. redheeler macrumors 603

    redheeler

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    Oct 17, 2014
    #2
    The PowerMac G5 only takes RAM in matched pairs, having one stick installed is basically the same as having none.

    From my experience, the red light is usually caused by removing a plastic insert that goes in behind the access panel to help airflow. If yours is missing this insert that's probably why.
     
  3. MacCubed macrumors 68000

    MacCubed

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    #3
    The red light can be a result of many things. Where on the computer is the light located?
     
  4. Jordan1990 thread starter macrumors member

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    Jan 17, 2015
    #4
    As it turns out you where right! Putting the plastic cover back on stopped the red light and the fans slowed down, however i still have nothing at all on the screen. What i have now is the white power LED on the front flashing fairly slowly.

    As for nothing on the screen, could this be because I'm using a DVI to HDMI adaptor? However i know the adaptor works because I've tried it on my mac pro.
     
  5. DeltaMac macrumors 604

    DeltaMac

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    #5
    That long slow flash - about once every 5 seconds, means that either no memory is installed, or is installed incorrectly.
    Memory in the powermac g5 is installed in pairs, so a single stick would certainly be "incorrect"
    Single stick - can't work!
    And - won't proceed with the boot, which means the video won't come on, either.
    When you get a pair of sticks, then you should also try reseating the graphics card in its slot (if you haven't tried that already), the card might have been in that slot for 10 years or more.
     
  6. Jordan1990 thread starter macrumors member

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    Jan 17, 2015
    #6
    I thought as much, might buy some cheap RAM and see if i can coax some life into it. Is there anyway to identify which model it actually is? Ive tried putting the SN into apples site it comes up with powermac G5 but doesn't tell me the year or anything, no idea what the CPU is, although inside the cover over the heat sink on the CPU has 2 "G5" logos on, does this suggest its a duel CPU model?
     
  7. DeltaMac macrumors 604

    DeltaMac

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    #7
    The ID label, at the bottom edge of the side door - where you can see the serial number - should also show some information about the Mac's configuration - how it originally shipped. You can also enter the serial number to another web site, that might give you more information, such as: http://www.everymac.com/ultimate-mac-lookup/

    Another question, the 2 G5s tell you that it is a dual-CPU.
    The oldest G5s have a G5 cover over each CPU (two separate covers), and later G5s have a one-peice cover, still with two G5 logos. Or, one large cover, on the latest G5s, but with only one logo.) So two covers means that it's an older G5. ( The one-piece covers also mean that there's more to cover, such as the liquid cooling pumps on some G5s. )
     
  8. Jordan1990 thread starter macrumors member

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    Jan 17, 2015
    #8
    Thanks, it is one solid cover with 2 G5 logos, i tried everymac.com and the serial number didnt give me anything, but ill try the ID label.
     
  9. Jordan1990 thread starter macrumors member

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    Jan 17, 2015
    #10
    Funnily enough i never noticed that the ID badge told you the spec, according to that its a 2ghz dual CPU, 512mb ram (which someone must have changed because the single stick in there is 512mb) and 160gb drive. So i need to buy 3200 400mhz ram.
     
  10. Jordan1990 thread starter macrumors member

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    Jan 17, 2015
    #11
    So i bought this RAM http://m.ebay.co.uk/orderDetails?itemId=361071521657&txnId=624800752023

    The blinking situation has changed but i still get nothing on the screen. The LED on the front now stays light but flashes brighter 3 times, then pause, then 3 times etc. Apparently this means a RAM fault? So either the ram is faulty or ive bought the wrong RAM.
     
  11. DeltaMac, Feb 4, 2015
    Last edited: Feb 4, 2015

    DeltaMac macrumors 604

    DeltaMac

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    #12
    Could still be bad RAM.
    Did you purchase a pair of memory sticks, or just one stick? (the single original stick may be bad)
    Make sure that you are using the correct slots.
    One pair, same capacity, ideally from the same manufacturer. (Make sure that both are PC-3200. Older G5s will work with PC-2700, but still has to be equal in both size and speed.
    Correct slots are labeled on the logic board, slot 1 on both banks. If you just count all slots from the top down, then correct slots will be 4 & 5, as you count them. The PowerMac G5 always gets loaded with pairs from the center slots out... 4 and 5 are those center slots :D

    You won't get video if the RAM doesn't pass the boot test.
    However, be sure to reseat the video card in its slot, if you haven't done that yet.
     
  12. Jordan1990 thread starter macrumors member

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    Jan 17, 2015
    #13
    Thanks for the reply.

    Yes i bought 2 identical 512mb 3200 sticks and ditched the one that was in there, they are located in slots 4 and 5 so from the centre outwards.

    Must be bad RAM, or one bad chip at least.

    ----------

    Ive also just noticed that if i leave it running the fans keep getting gradually faster and faster until it sounds like an aeroplane!
     
  13. DeltaMac macrumors 604

    DeltaMac

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    #14
    The fans slowly building up is completely normal, for a system that doesn't pass the boot test. I remember reading that it is a fail-safe to prevent overheating, as the CPU doesn't know what the system is doing, and the power manager takes over. The memory that you purchased appears to be used, but tested. Doesn't necessarily mean that remains good when you first try it.
    Some sites that sell a lot of memory, will back up their sales with a nice warranty. It wouldn't hurt to go back to the seller to see if they can offer to swap yours out for a different pair.
    Another item to check - the G5 memory should be non-ECC. That may even be on the RAM label.
     
  14. Jordan1990 thread starter macrumors member

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    Jan 17, 2015
    #15
    Thanks good to know, is there anything else it could be before i send the RAM back?
     
  15. DeltaMac macrumors 604

    DeltaMac

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    #16
    Yes, could be bad memory slots, I suppose.
    You can test that (plus a lot of hardware in your G5) with the Apple Hardware test for that G5.
    Or, you can also test more by booting to Apple's Service Diagnostics.
    Search for ASD 2.5.8, and you can sometimes locate a link for a download disk image.
    Links for Apple's proprietary utilities tend to appear, then disappear.

    And, then you still run into your RAM issue. You can't test much until you get working memory.
    So, for you, it's a vicious circle. No RAM detected, so you can't boot. You can't test the memory until you get it to boot.
     
  16. archtopshop macrumors regular

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    #17

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