G5 Won't Boot

Discussion in 'PowerPC Macs' started by evltek, Jul 7, 2013.

  1. evltek macrumors newbie

    Joined:
    Jul 7, 2013
    #1
    Hey Team,

    I have an older G5 (bought 2004), dual 2.7, liquid cooled.

    It no longer boots. It powers up but then nothing happens bar fans spinning. I can hear that it looks for CD, or something with the CD rom drives happens.

    I have removed ram, Hd and video card and plugged them all back in again (there was a video card issue that was resolved with it being reseated previously).

    Visually all is well, no leaks, no burns, nothing weird going on.

    I have a newer quad 2.5 G5 which I can steal parts off for testing although the video card is different as i tried that already.....

    Are there any common faults that I should be checking - I am hoping for a quick fix as it's not worth much but want to sell as part of a starter kit with some recording studio bits I am selling.

    Any help much appreciated.
     
  2. rabidz7 macrumors 65816

    rabidz7

    Joined:
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    Location:
    Ohio
    #2
    Have you checked the cooling system? If the cooling is ok, then this sounds like the PSU.
     
  3. evltek thread starter macrumors newbie

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    Jul 7, 2013
    #3
    Just visually - I can't see anything wrong but I am no mac guru......

    The computer does power up, light is on, fans are spinning so it is getting "some" power.....
     
  4. eyoungren macrumors P6

    eyoungren

    Joined:
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    #4
    When you say the fans are spinning, do you mean spinning normally or do they come on full blast?

    If you are getting power it can't be the PSU can it?

    I'd try a different video card just to rule that issue out. If you still don't get video, but are getting power my guess would be the logicboard.
     
  5. MisterKeeks macrumors 68000

    MisterKeeks

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  6. evltek thread starter macrumors newbie

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    Jul 7, 2013
    #6
    i am not sure what that is or where the lights are but having done a quick search it says they were included on late 05 machines and upwards so perhaps mine doesn't have them?

    I purchased my machine in 04.
     
  7. MisterKeeks macrumors 68000

    MisterKeeks

    Joined:
    Nov 15, 2012
    #7
    I have it on my Dual 2.7, and that was early 2005.

    It is near the RAM slots, you have to have the side panel open.
     
  8. macuser453787 macrumors 6502

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    Galatians 3:13-14
    #8
    Sounds like the PRAM battery may need to be replaced. Was it unplugged for a while before you started using it again? If not, has the PRAM battery ever been replaced since '04? If the answer to one or both of these is yes, then given the symptoms you describe, it's worth the minimal expense to buy a new PRAM battery and see if that works.
     
  9. Intell macrumors P6

    Intell

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    #9
    G5's can boot without a PRAM battery or a dead one without a problem. A faulty battery won't cause the problems the OP is having.
     
  10. macuser453787 macrumors 6502

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    #10
    Is that right? I didn't know that. Thanks for the tip - sincerely. Having never owned a G5, I was not aware of the difference. :)
     
  11. Intell macrumors P6

    Intell

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    #11
    Most Macs will boot just fine without a working PRAM battery. The few that I know of that do have problems are PowerMac G3's. Most else doesn't have problems though.
     
  12. evltek thread starter macrumors newbie

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    Jul 7, 2013
    #12
    i'll power up with cover off and see if any lights are active and report back.
     
  13. Frost7 macrumors regular

    Frost7

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    Republic of Texas
    #13
    Gut feeling is this sounds like a CPU may need reseating, but can't say without investigating.

    I assume you've already tried the obvious like resetting the PMU. If not, try that. The PMU button is located at the lower left of the logic board, under the bottom RAM banks, between the Power Supply Connector and Front Panel Board Connector. Press once only.

    If that does nothing, then: Does it fail Power-On Self Test (no startup chime)? If so, does the white status LED above the power button flash at all? If it does, how many times? Depending on the issue detected it can flash between 1 and 5 times.

    If it doesn't fail POST, even though you can't start up all the way, can you at least get to Open Firmware at all (hold Cmd-Option-O-F at startup)?
     
  14. macuser453787 macrumors 6502

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    #14
    I assume G4s are affected by it too, because the one time my Digital Audio's PRAM battery got used up, it had symptoms similar to what the OP stated. Hence my assumption that all Macs were that way. :)
     
  15. Intell macrumors P6

    Intell

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    #15
    I've never known any G4 to act like that, including DA's.
     
  16. Andropov macrumors regular

    Andropov

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    May 3, 2012
    Location:
    Spain
    #16
    I had a B&W G3, a G4 Yikes and a Cube. All of them had dead batteries, but they power on without a problem, apart from the known date and time reset. Actually, I thought the newest Mac with boot problems with dead batteries were the ones with Tanzania motherboards (basically, the Power Macintosh 4400 and some clones).
     
  17. SaberBlock macrumors newbie

    SaberBlock

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    Location:
    Cheshire, UK
    #17
    I'm noticing a lot of "My G5 won't boot" threads recently and it's making me get somewhat worried... is there anything I can do (there probably isn't) to reduce the chance of having my PSU fail on me?

    I'm guessing 7/8+ years is taking its toll :(
     
  18. Intell macrumors P6

    Intell

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    #18
    The machines that I've encountered that don't run with a bad battery are some early B&W G3's and non-B&W G3's. Never seen a G4 act strange, but maybe a Yikes might. There are some 68K Macs that need a battery as well, currently don't remember which ones.
     
  19. Andropov macrumors regular

    Andropov

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    #19
    Yikes and B&W G3's share the same motherboard, so if a dead battery makes an issue en B&W G3s, it'd also happen in Yikes. The point is, both my Rev.A B&W G3 and my G4 Yikes have dead betteries and they're running perfectly :p

    Yes. Take the power supply out of the G5. Open it. Clean all the dirt inside an reassemble everything. Year after year, the dirt accumulates inside the power supply and restricts air flow, increasing overall temperature of the components and reducing his lifetime, or directly 'burning' them.
     
  20. Intell macrumors P6

    Intell

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    #20
    There's a two revisions of the B&W G3 logicboard. The Yikes could be considered the third revision of the board. There are a few differences that enable someone to distinguish them.
     
  21. macuser453787 macrumors 6502

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    #21
    I can tell all of you from personal experience that my Digital Audio wouldn't run on a dead PRAM battery. I had to replace it to get it going again. This happened once many years back not long after I bought it, but not since then...

    And I'd like to add that I appreciate the info! I truly didn't know that it was possible for Macs to run with dead PRAM batteries. :)
     
  22. SaberBlock macrumors newbie

    SaberBlock

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    Feb 8, 2010
    Location:
    Cheshire, UK
    #22
    Thanks - I keep the fans, boards and inside of the case pretty much dust free (many an hour spent with a handheld hoover and a tin of compressed air) but I've never directly cleaned the PSU (which on reflection is a bit daft of me really) - will give me something to do this weekend if it stops being sunny! :cool:
     

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