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SheerGold

macrumors regular
Original poster
Apr 20, 2006
112
0
My G5 tower is one of the early models.

Today I turned it on. Immediately the drive bay fan was running at maximum speed. The Mac's temperature was cold as it had not been used for 12 hours. So the speeding fan could not have been due to the drive bay being overheated.

The fan never slows down.

Even after a restart it immediately spins at its maximum. Plus it stays at maximum speed all the time.

Anyone know what is causing this & how to make it work properly?
 

lamina

macrumors 68000
Mar 9, 2006
1,756
67
Niagara
Shot in the dark here... turn it off, hold down the power button until you hear BOOOOOOOOOOOOOOOP and all the fans spin up to max, and release.

Also, hold down -Opt-P-R to reset PRAM.

Let us know.
 

andy.barron

macrumors 6502
Nov 30, 2006
441
0
Bedford, England
Hi. I had the very same problem ages ago. Set the processor performance to best or fastest (sorry i'm not in front of my G5) instead of automatic.

I believe this will sort it for you:)
 

farrers

macrumors newbie
Jan 2, 2012
2
0
Thank you!

Shot in the dark here... turn it off, hold down the power button until you hear BOOOOOOOOOOOOOOOP and all the fans spin up to max, and release.

Also, hold down -Opt-P-R to reset PRAM.

Let us know.



I know this forum is 4 years old, but I found it today b/c I was having this same problem. Your advice, lamina, did the trick! Thank you! Incidentally, what does holding the power button until you hear the "BOOOOOOOOOOOP" do exactly?

Thanks again!!! :)
 

havokalien

macrumors 6502a
Apr 27, 2006
649
51
Kelso, Wa
G5 fan speed

When the pram gets corrupted or battery goes dead and resetting does not fix the issue you need the ASD for it to reset fan speed control and test hardware. Make sure to replace the battery before you do use the asd or it will forget again and fans will spin to max. Also if you have a dual processor G5 one processor maybe dead. Happens a lot, and can be checked in the ASD menu. Good luck.
 

lamina

macrumors 68000
Mar 9, 2006
1,756
67
Niagara
I know this forum is 4 years old, but I found it today b/c I was having this same problem. Your advice, lamina, did the trick! Thank you! Incidentally, what does holding the power button until you hear the "BOOOOOOOOOOOP" do exactly?

Thanks again!!! :)

Wow! Glad I could help. Doing that resets the power management unit, as far as I understand. Cheers!
 
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