PowerMac G4 won't start

Discussion in 'PowerPC Macs' started by Dcentuori, Dec 30, 2014.

  1. Dcentuori macrumors newbie

    Joined:
    Nov 19, 2011
    Location:
    Cleveland, OH
    #1
    I've kept an old G4/466 under my desk at work so I can access legacy files from time to time. Just the other day I tried to turn it on and it wouldn't start. It worked as recently as September. I tried the reset button on the front and the CUDA button inside. (Couldn't do the keyboard stuff since I'm using a PC keyboard) Still nothing. I tested the internal battery and it is low--2.6 volts--but not dead. Could that be it?

    I'm pretty sure it's the Digital Audio G4: model # M5183, EMC 1862.

    Thanks,
    Dante
     
  2. 128keaton macrumors 68020

    128keaton

    Joined:
    Jan 13, 2013
    #2

    That battery would need to be replaced. The G4s are VERY finicky when it comes to booting up. If you need any more parts for it, let me know, mine has a dead motherboard.

    I put one of these in my iMac G3, it will work for yours too: http://www.amazon.com/Saft-LS14250-...9959216&sr=1-2&keywords=half+double+a+battery
     
  3. Dcentuori thread starter macrumors newbie

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    Nov 19, 2011
    Location:
    Cleveland, OH
    #3
    Ah, great, that's what I needed to know! I'll get two so I can also replace the one in my G3 Beige Desktop I have at home, before that craps out too.

    Thanks,

    Dante
     
  4. Altemose macrumors G3

    Altemose

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    Mar 26, 2013
    Location:
    Elkton, Maryland
    #4
    Since G4s are so finicky you can remove the battery as a test measure.
     
  5. Dcentuori thread starter macrumors newbie

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    Nov 19, 2011
    Location:
    Cleveland, OH
    #5
    So, it can run without the battery? I thought that powered the internal clock or something like that.

    I'll give that a try; shouldn't take too long with that great user-accessible G4 design!

    Dante
     
  6. Altemose macrumors G3

    Altemose

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    Mar 26, 2013
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    Elkton, Maryland
    #6
    Most can start without a PRAM battery but it will not retain the PRAM information.
     
  7. 128keaton macrumors 68020

    128keaton

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    Jan 13, 2013
    #7
    Ah, good call Alte.
     
  8. Altemose macrumors G3

    Altemose

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    Mar 26, 2013
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    Elkton, Maryland
    #8
    That being said 128k, not all PowerPC Macs can start without a battery installed.
     
  9. bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #9
    What happens when you try to power it up?

    Does the power button light up? Do you get a startup chime or any other sound from the speaker? Do the fans(either the PSU fan or the main case fan) spin or at least "twitch"?
     
  10. Dcentuori thread starter macrumors newbie

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    Nov 19, 2011
    Location:
    Cleveland, OH
    #10
    First, I tried starting w/o the battery, and nothing.

    Second, in answer to bunnspecial's questions, absolutely nothing happens when I try to start it. No twitch, light, fan, sound--nothing. With apologies to Charles Dickens, the Old G4 is as dead as a door-nail.

    Does that make a difference?

    Thanks,
    Dante
     
  11. 128keaton macrumors 68020

    128keaton

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    Jan 13, 2013
    #11

    Interesting, sounds as if the PSU or the power button isn't working.

    [​IMG]

    I think if you jump the PWROK pin to COM it will turn on, this will test the PSU, it should spin fans, drives, etc.

    EDIT: or (if applicable) PSU_ON to COM.
     
  12. comda macrumors 6502a

    comda

    Joined:
    Mar 15, 2011
    #12
    I hate to interfere here but whats with all the lies? This site says free shipping and when i get to the end to ship 2 of these it says $4.50 shipping. Im in Canada. but still what the heck?!
     
  13. 128keaton macrumors 68020

    128keaton

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    Jan 13, 2013
    #13
  14. poiihy macrumors 68020

    poiihy

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    Aug 22, 2014
    #14
    You have a 466Mhz PowerMac G4 DA, and a Beige G3 desktop?! I have those same machines too!


    It sounds like a bad PSU. PSUs can fail over time, even when not in use, especially if you are in a hot location (like in Nevada or Arizona). I had a beige G3 desktop and the PSU leaked LOTS of capacitors, just by sitting in a closet in a desert for a few years or so.
    Look inside the PSU with a flashlight. Look for leaked capacitors. If you find some then you know the PSU is bad.
     
  15. Dcentuori thread starter macrumors newbie

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    Nov 19, 2011
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    Cleveland, OH
    #15
    I'm off for a few days, so won't be able to check the G4 just yet. But I did pop out the battery and took it home. Tested it again and it is 3.6volts after all. (I got the 2.6 reading by testing it while still in the board--didn't remove it) So it's not the battery and looking more like the PSU--I'll know on Friday!

    Since I only have the G4 to open files I have on disc or thumbdrive, I'm not married to it and can find other means if the repair is too involved. I don't think we have other G4s lying around at work, but I'll check and see if I can swap out a PSU.

    As for my old G3, that one is our own and got it back in 1998, about 2 months before those sleek iMacs came out! I still occasionally need to go in there to open an old file. One day I may need to do a wholesale conversion, instead of case-by-case, since I know sooner or later it will get next to impossible to read the files. But that is for another post! Right know, I'm enjoying a bit of the "good old days" when you can open the case and get your hands dirty. Kind of like working on my car....

    Thanks,
    Dante
     
  16. Altemose macrumors G3

    Altemose

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    Elkton, Maryland
    #16
    Try unplugging the power cable and holding the power button for 30 seconds and plugging it back in. It will discharge all components.
     
  17. Dcentuori thread starter macrumors newbie

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    Nov 19, 2011
    Location:
    Cleveland, OH
    #17
    Now I wish I went into work today--all these things I need to try now!

    Back to the pinout jumper suggestion 128k posted.... Are you saying that I should run some jumper between the PWROK pin and any COM pin, then close it up and turn it on? Or is this a test that needs to be run while it is live? Like as soon as I jump the pin, it will start (if that component is still good). Just want to be sure about technique. (Of course, it may make more sense if the machine was in front of me....I should have brought it home....)

    Thanks,
    Dante
     
  18. 128keaton macrumors 68020

    128keaton

    Joined:
    Jan 13, 2013
    #18
    Just unplug the connector from the board and place a paper clip on the pins (one in PWROK the other end into COM). That should be how you do it. If it doesn't spin first, then wait for someone else to correct me because I could be wrong.

    Since yours is a DA, this diagram may help:
    [​IMG]
     
  19. Dcentuori thread starter macrumors newbie

    Joined:
    Nov 19, 2011
    Location:
    Cleveland, OH
    #19
    Hmmm. I'm not getting an image for the diagram you posted. Can you try again?

    Thanks!
     
  20. poiihy macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #20
    I just see a blue rectangle.


    @128keaton Whenever you post an image from a site, you should first upload it to an image host site (like as an attachment or on Postimage) rather than linking directly to it, because the image may change. Looks like that's what happened here.
     
  21. bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #21
    Just to rule out the possibility of a bad power button, there are alternate ways to power up a DA G4.

    One of these is to use a keyboard with a built-in power button. Probably the most common ones are the "compact" keyboards which shipped with the first few generations of iMac(and also with Powermac G3s and other computers until replaced by the Apple Pro Keyboard). The power button on these will work on any G4 tower except for the Mirrored Drive Door models.

    The second option is to use an ADC(Apple Display Connector) equipped display. If you look at the video card on your computer, you should have two ports on it, one of which is either a standard VGA or DVI connector, and the other of which is an ADC connector. This looks sort of like a DVI connector, but is wider, has rounded edges, and uses "hooks" to secure the connector rather than screw standoffs.

    In any case, ADC displays are powered entirely through the PSU/video card(they only have one cable coming out the back of them). Using a stock G4 card, pressing the power button on the front of the ADC display should power up the computer. Even if it doesn't, the power button will "glow" if the display is receiving +28V from the PSU.
     

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