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display wont turn on, fans full speed...

633 Views 3 Replies Latest reply: Feb 1, 2013 11:36 AM by BDAqua RSS
guitar guy Level 2 Level 2 (320 points)
Currently Being Moderated
Jan 28, 2013 9:55 PM

so I'm having a problem which i thought I fixed 6 months ago by replacing the pram battery.


I have a Power PC G5 quad running 10.5


I have the old apple cinema display with the adc to dvi adapter.

When I power up the G5, the display does nothing, and i hear the copmuter power up, but after about 30 seconds, the fans start running full speed and don't stop.

When I push the power button on the display, the power light (within the actual button) lights up, but goes dim when I release the power button. And the display never turns on.

And so without any monitor, i have to force shut down the computer.


I fixed this issue once by re-setting the PRAM.

That was temporary because the issue came back.

But then i replaced the pram battery and its been fine for 6 months.


Until now.


Oddly enough, i can't seem to reset the pram anymore. I hold down the apple-option-P-R, and then boot the computer up, but i don't hear the chime. And then the fans go full speed after 30 secs. (I can't do a re-start because i have no display. I have to reboot after a hard shut-down. PRAM should still reset this way, shouldn't it?)


Can the pram battery have gone dead after 6 months, when it took years to go dead previously?


Any thoughts?


Thank you all!!!

PowerMac, Mac OS X (10.5.8), quad core
  • BDAqua Level 10 Level 10 (114,790 points)
    Currently Being Moderated
    Jan 29, 2013 11:33 AM (in response to guitar guy)

    Not impossible a PRAM Battery can go dead that soon, was it without AC power for any length of time?


    How to reset the SMU/PMU on a Power Mac G5 (Late 2004) or Power Mac G5 (Late 2005) ...



    Does it boot into Open  Firmware with CMD+Option+o+f ?



    reset-nvram (press Enter)

    set-defaults (press Enter)

    reset-all (press Enter)

  • BDAqua Level 10 Level 10 (114,790 points)
    Currently Being Moderated
    Feb 1, 2013 11:36 AM (in response to guitar guy)

    Push the door covering the CD tray downward with your fingers, look for a tiny hole you can push a straightened out Paper Clip in to force the tray to open.


    Sadly, it sounds more serious than just the PRAM Battery, but stranger things have happened.


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