Powermac G5 Fans go full speed

I see that some of you have an ongoing fan issue, and I'm not sure what to say about that.

However, for anyone with an intermittent problem of fans at full blast, I have had that, too, recently and have attibuted it to very hot days. It only seems to happen when my office gets very hot.

Having a fan in the room, that is aimed at the G-5 seems to move the air around enough that they return to normal.

Not to be funny or anything but, It IS summertime and my fans run a lot more in the summer than in the winter or fall.

If this is a Dual Processor G5 (not Dual Core), they tend to run hot and it turns on the thermal internal fans to keep cranking pretty quickly. I have squeezed as much as I can out of my AppleCare to keep those fans quiet; Apple's response...this is how this machine is going to run. (I have a Kona LH in my dual 2.7.) I have not had my performance affected. I have an air conditioner feeding air to my rack mounted G5 with a good air flow out the back and it stays in check now.

My issue is that the coming back to my machine after the machine has gone to sleep, I find that my fans are running full blast and I can't wake the machine.

I reinstalled 10.4.7 with the combo updater, and I've also done the Open Firmware trick.

Where I'm at right now is that I've changed my Maxtor External Firewire drive from Firewire to USB2. Now, I haven't had the fan problem, but I'm still unable to wake the machine from sleep.

Odd

Dual 2.7 GHz PowerPC G5 Mac OS X (10.4.7) 2 GB DDR SDRAM

G4 400 Mac OS X (10.3)

Your replacement of the logic board peaked my interest as I have been unsuccessfull resolving the issue of my G5 fans always on full speed after the 10.4.7 update. Does your G5 have a PMU or a SMU? Did the Apple hardware test pass the test of the logic board? Is there any troubleshooting tips you can provide to isolate the logic board?

This problem has suddenly surfaced on my system also. My details:

- Happens only when the CPU goes into Sleep
- Fans suddenly run full speed
- Impossible to exit Sleep. Computer must be restarted from power button on tower
- Settiing Sleep to Never in Energy Saver System Preferences prevents the problem
- The behavior started suddenly today after 18 months of normal operation
- No recent changes of any sort to hardware or software.

However, a visitor has been using a Guest account on the machine to visit websites. A virus, perhaps?

I had the same problem intermitently for 3 months or so, called apple care, tried everything, and the problem solved when i just took off the ventilators and clean a huge screen of dust off from the radiators, now it's a quiet computer again 🙂. Hope this helps some people.

Cheers.

Fran.

Barcelona, Spain.

Quad G5, 2GB Ram, nVidia Quadro Mac OS X (10.4.7)

Having read MANY posts about excessive fan speed (especially the drive bay fan), I offer these suggestions:
1. install iStat Pro widget to track fan speeds and internal temps
2. check your room temperature and air circulation around the g5
3. if drive bay temp is >32 deg C, drive bay fan will run 2,000-4,000 rpm (noisy)
4. to test whether ambient temp is the problem, try placing a household fan near the g5 and setting room temp at 76 deg or less. drive bay temp should drop below 32 deg, and drive bay fan rpm should drop to +- 1,000 rpm (pretty quiet)
Hope this helps anyone.

dual 2ghz G5 1.5gb LaCie externals 20" cinema Mac OS X (10.4.7)

I also had one of our 13 G5's run full speed fans after the 10.4.7 update. The fans did not speed up or slow down at all. They went full speed as soon as the power button was hit and stayed that way. I went as far as swapping the drive with another identical G5 that was working fine, it did not help.

The logic board was replaced at a cost of $874.00. It works fine now.

Chris

I had the same issue with my fans running full speed. Then, I started getting a red light at the front of the tower and I'd have to reboot. Some investigation led me to find No.2 LED (high temperature) was the red light shining. I called Apple Support and they said take it to the Apple Store. I dropped it off and picked it up a week later. I asked the guy what they did and he said they ran the diagnostic software for 2 hours and found nothing wrong and here's my computer back. I took it home and within 24 hours the red light was back and the fans were still maxed out at 3300 rpm. I called Apple this time and he said take it back to the same dealer and I said no way. I asked if he could send someone to my house and he said yes. The on-site service guy (who'd never worked on a Mac, let alone a Quad) replaced the processor/fan assembly and did a thermal calibration and now the fans run around 1100 rpm and I'm a happy camper. I wonder if the thermal calibration isn't the key to many of the fan issues for everyone.

G5 Quad 2.5 w 3G Mac OS X (10.4.6) Since '84

I hope so...
My PMG5 SP1,8 (late 2004) is at the reparator for the same problem.
I hope that a thermal calibration (or at the worst a fan replacement) will fix the problem.
But I wonder if the following message with the Apple Hardware test CD is a big problem :
2FAN/4/7 : Rear Fan 1
???

I've isolated the issue for me. I would come in in the morning to find my sleeping Mac fans on full speed. Machine unresponsive.

Since then I have ejected and turned off my external Maxtor 500 HD. No problem. I come in, computer functions normally, and wakes up.

This happens with a FW or USB2 connection. So solution is to eject the external.

What a Pain

Dual 2.7 GHz Power PC G5 Mac OS X (10.4.7) Plenty O RAM

I have this problem too , I installed the isat widget and the temperatures are HIGH !

51 C on the heat sink ! it must be reading it wrong .... the demon that it !