display wont turn on, fans full speed...

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Level 2

327 points

display wont turn on, fans full speed...

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

Posted on Jan 28, 2013 9:55 PM

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Answer 1

BDAqua

Level 10

239,495 points

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) ...

http://support.apple.com/kb/HT1436

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

http://docs.info.apple.com/article.html?artnum=42642

reset-nvram (press Enter)

set-defaults (press Enter)

reset-all (press Enter)

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Answer 2

guitar guy Author

Level 2

327 points

Feb 1, 2013 9:23 AM in response to BDAqua

hey Aqua. Thanks for always offering to help.

So here is where I am with this.

It seems that the keyboard isn't communicating with the G5 either.

When I boot up the computer, I push the eject button, but the door to the super drive won't open.

I was going to try and boot up from the startup disk, but I can't open the drive door. The same thing always happens. Fans full speed after 30 secs, and no monitor.

I also can't zap the PRAM. I hold down the apple+option+P+R, but i don't hear the "chime"(is that what we call it?). And then again the fans go full speed after 30 seconds, and with no monitor.

Same thing when I try your suggestion of trying to boot into open firmware.

The computer was not without AC power for any length of time.

So no monitor, and keyboard is unresponsive. Even to open the dvd drive door doesn't work.(is there a way to get that drive door open manually?)

I appreciate any further suggestions.

I do believe that the PRAM battery can go dead that quick, but it seems odd.

Maybe I'll jsut order one and try it. It is certainly cheap enough!

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Answer 3

BDAqua

Level 10

239,495 points

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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