[kupan787]

This is something that just started happening recently. My G5's drive bay fan will kick up to 4000RPM and run constantly at that speed. No other fans kick up that high. And the funny thing is that the drive bay temperature is the lowest of all the temperature readings! My machine was asleep all night, and I woke it up, and the drive bay fan just kicks right on. I don't know what is causing this, or what could be causing this. Sometimes, it will not happen on a wake up, and I can go all day without it kicking on. Any ideas on what could be wrong, or what I can do to quiet it back down would be appreciated.

Here are some readouts:

CPU A: 48
CPU B: 40
CPU A ambient: 47
CPU B ambient: 42
U3 Heatsink: 63
Drive Bay: 33
Backside: 43

CPU A Intake: 1144 rpm
CPU A Exhaust: 1180 rpm
CPU B Intake: 1074 rpm
CPU B Exhaust: 1100 rpm
Drive Bay: 4000 rpm
Slots: 76 rpm
Backside: 51 rpm

[Leonard]

Have you shutdown the Mac and started it up again. It could be a software glitch that a restart could fix. What model G5? CPU speed, GPU type, # of HDs, etc... MacOS X version. Have you tried running the hardware test? Have you installed anything new lately?

[kupan787]

Originally Posted by Leonard

Have you shutdown the Mac and started it up again. It could be a software glitch that a restart could fix.[/b]

Yep, tried that. And it starts off at about 1000 rpm, and then slowly climbs up to 4000rpm.

What model G5? CPU speed, GPU type, # of HDs, etc... MacOS X version.

Rev B dual 2.0GHz.
Radeon 9600xt
2 HDs
1GB RAM
MacOS X 10.4.7

Have you tried running the hardware test?

Yep, and it reports no errors.

Have you installed anything new lately?

Nope.

The only thing I could remotely think of, is that we are in the middle of a heat wave here in California, and so it has been warmer than usual. But the reason I doubt this to be an issue, is none of the other fans are acting up,

[Leonard]

Sounds like you've done alot of trouble-shooting. The only other things I can think of is to take it into an Apple Store (since your in the USA) or try an archive and reinstall of MacOS X. I'd be more tempted to take it into the Apple Store. They may be able to simply recalibrate the fans or they may find out that the sensor for that fan is causing problems (but I would have thought a bad sensor would have been detected by the hardware test). Hopefully it's still under warrantee.

Maybe someone else has some suggestions?

[Frank888]

This started happening to me recently, and I'm pretty sure I have it figured out. Once it started getting hotter here, the room with my G5 has been considerably hotter during the day. When I get home late afternoon, my drive bay fan is going 4000 RPM. Once I get the AC running for a while, it stops. I've noticed a temp of about 89 degrees F will cause the fan to run; temps of 87 degrees or lower will cause it to shut off. I was surprised that the room temperature could make a difference, but I'm pretty sure that's what's going on. I called AppleCare and did a billion things including a system re-install, but nothing got it to stop. I finally figured it out (I think...).

Of course, your problem may be different...

[kupan787]

Originally Posted by Frank888

This started happening to me recently, and I'm pretty sure I have it figured out. Once it started getting hotter here, the room with my G5 has been considerably hotter during the day. When I get home late afternoon, my drive bay fan is going 4000 RPM. Once I get the AC running for a while, it stops. I've noticed a temp of about 89 degrees F will cause the fan to run; temps of 87 degrees or lower will cause it to shut off. I was surprised that the room temperature could make a difference, but I'm pretty sure that's what's going on. I called AppleCare and did a billion things including a system re-install, but nothing got it to stop. I finally figured it out (I think...).

Of course, your problem may be different...

I think that is what it was. We just had this heat wave here in California (and Sacramento sucks ass for heat). But the last two days it has cooled down, and my G5 has been silent yet again So I am guessing it was just related to the heat recently.

[cms]

Originally Posted by kupan787

I think that is what it was. We just had this heat wave here in California (and Sacramento sucks ass for heat). But the last two days it has cooled down, and my G5 has been silent yet again So I am guessing it was just related to the heat recently.

The exact same thing has been happening to my G5 here in the UK during the recent heatwave. With daytime temperatures approaching 100F on several successive days, the fans have been very much in evidence by about 11:00 AM, only quietening down again after the temperature drops appreciably in the late evening. The heatwave broke here in the Southeast on Thursday afternoon, and since then my G5 fans have been as silent as before. The critical point for my system seems to be when the ambient temp. rises to just above 30C (86F). This is pretty much in line with Frank888's sytem.

Like you, I thought I had a problem with my system when this started happening some weeks back. We've had several very hot spells here in the Southeast of England since the beginning of July, so I have been able to identify a very definite pattern, and have satisfied myself as to its cause and effect!

[asagai]

SAME PROBLEM!!

I have a PowerMac G5 and the slot fans...the ones that sit in the lower bay in front of the machine just stopped working altogether. I have used the Apple Diagnostic CD and it states that the fans are running when they are NOT! I have contacted Apple about this MANY times, but they will not fix the box because problem was not reportrd before the warrenty lapsed.
I litterally called ONE WEEK TOO LATE!

I am PISSED about this because what most likely cause this problem was an Updated from Apple. The update was to address issues with the fans on G5 machines, but many people reported MORE problems after the update.

I now have a small fan that sits in front of my G5 to push air through the lower portions of the box so that the Power Supply does not over heat and crah the computer.

REALLY, the PowerMac G5 was the worst machine that I have ever purchased. Not simply because of the problems, but because of the way in which Apple did not provide a solution for a problem that they caused.

Best regards,
B. Asagai