g3 b/w dead from atx power supply?

Discussion in 'Macintosh Computers' started by andrew34kay, Jan 23, 2005.

  1. macrumors newbie

    Joined:
    Dec 30, 2004
    #1
    Hi

    here are my specs:
    g3 b/w powermac
    g3 400mhz cpu
    pc133 256 mb ram
    factory scsi hdd and factory cdrom

    by the way for any of those wondering, this is a different powermac than the othre one that i posted about the ram issue.

    ok here is my situation. My g3 would not turn on at all no leds, no noise, nothing. so i stupidly tried an atx psu which was unaltered. it turned on but no post, so i went back to the mac psu. worked fine. but after that a couplr of days later, the g3 turns on but no post, no chimes, or visual anything. the 3 leds light up. then a second later the led by the cpu turns off. I have tryed reseting the pram but it doesnt even post so... my question is did i kill it or whatever with the atx power supply move? i know now that im supposed to cut a wire or ground or somrthing like that. thanks for all ur replies. all of ur ideas are welcome, im totally stuck! lol thanks

    -ANDREW
     
  2. macrumors newbie

    Joined:
    Apr 26, 2004
    #2
    may be damaged, but...

    It's possible you did some damage by using the ATX PS, but if it worked for a few days, you might be OK. Have you tried unplugging the power cord, pressing the CUDA reset button once (near the battery on the logic board), waiting 15 seconds, then reconnecting the power cord? Sometimes power-on issues are resolved by this. You could also have a bad logic board or power supply.
     
  3. thread starter macrumors newbie

    Joined:
    Dec 30, 2004
    #3
    no luck, well i guess the logic board is dead then, but what about the cpu and ram that stuff should be unaffected right? thanks for all your replies.

    -ANDREW
     
  4. macrumors G4

    Mord

    Joined:
    Aug 24, 2003
    Location:
    Old York
    #4
    to use an ATX power supply you have to cut the white lead on the connecter, otherwise you may damage your equipment...... :eek:
     
  5. macrumors 68000

    dsharits

    Joined:
    Jun 19, 2004
    Location:
    The People's Republic of America
    #5
    Try pulling the white lead on the ATX PSU and see if it powers up with it that way. It sounds like it is doing exactly th same thing mine was doing when the PSU died. I just modded an ATX and put it in there, and I'm typing from my B&W right now.

    Daniel
     
  6. macrumors 6502a

    rhpenguin

    Joined:
    Jun 10, 2003
    Location:
    London, Ontario
    #6
    Hopefully this helps you figure out the problem.

    you mention that DS9 (led by cpu) turns on and goes out. That means that the cpu is accessing the data bus so thats good. Does any of the other LEDs go off?

    Better yet, is the hdd activity light blinking at all?
     
  7. macrumors G4

    Mord

    Joined:
    Aug 24, 2003
    Location:
    Old York
    #7
    beat you to it
     
  8. thread starter macrumors newbie

    Joined:
    Dec 30, 2004
    #8
    well all the leds do light up and only the cpu led turns off, the others stay on, so maybe the logic board is not dead? well i have yet to try th modded atx psu so i will let u guys know sometime tomorrow. thanks for ur quick responses.

    -ANDREW
     
  9. macrumors 68030

    ReanimationLP

    Joined:
    Jan 8, 2005
    Location:
    On the moon.
    #9
    The CPU LED is normally off, only blinks seldomly when its requesting the bus. If it stays solid, then the system has probably hung. - Thats what the Apple Service Source Manual says for the Blue and White.
     
  10. macrumors 68000

    dsharits

    Joined:
    Jun 19, 2004
    Location:
    The People's Republic of America
    #10
    Like I said, that is exactly what mine was doing before I replaced the PSU. I would be willing to bet that the logic board is fine and that the PSU is dead.

    Daniel
     
  11. thread starter macrumors newbie

    Joined:
    Dec 30, 2004
    #11
    well i got an atx psu adn cut the white wire and nothing happened, but i have not tryed messin wtihe batter and the reset stuff. can you guys tell me about that stuff, like if i need to reset anything what? all ideas are appreciated! i will mess with it some more and thanks for all your quick responses.

    -Andrew
     
  12. thread starter macrumors newbie

    Joined:
    Dec 30, 2004
    #12
    sorry about the typo, it was supposed to say: ... I have not tried messing with the battery and reset the pram... sorry about that. :)
     

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