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Power PC G5 Fan issue

V

viper42391

macrumors newbie
Original poster
Jul 30, 2011
9
0
I just bought a refurbished G5 and have been using it for a few days with no problems. It is an early 2005 dual 2.3ghz. Anyways, yesterday, I left it on for a few hours while I was gone to download something, and when I came back, the fans were at full speed. Thinking it had a memory leak or something that was causing it to max out the cpus, I felt the air coming out, and it was cold. I then remembered seeing a lot of talk about fan troubles with the g5.

I have tried to reset the pram, nvram, pmu, and reset-all in open firmware. I have also pulled the motherboard battery, which is the only thing that did anything to the fans. Other than after pulling the battery, the fans start at full speed from when I press the power button. After the battery being pulled, it takes like 5 seconds after i press power, almost in unison with the boot sound, for the fans to turn on and ramp up to full speed.

I have been trying to find a solution to this since it started yesterday with no luck. I also downloaded istat (i believe that's what its called) and a few widgets that monitor temps and fans, but none of them seem to be able to read the fan speeds. The temps are low (120 for cpus, 80 ambient, 130 memory heatsink), so it's not overheating, but the fans are stuck at full.

Is the last step trying to contact apple and see if they can run a diagnostic to identify the problem, or is there any other way to try to fix it?
 
viper42391 said:
I just bought a refurbished G5 and have been using it for a few days with no problems. It is an early 2005 dual 2.3ghz. Anyways, yesterday, I left it on for a few hours while I was gone to download something, and when I came back, the fans were at full speed. Thinking it had a memory leak or something that was causing it to max out the cpus, I felt the air coming out, and it was cold. I then remembered seeing a lot of talk about fan troubles with the g5.

I have tried to reset the pram, nvram, pmu, and reset-all in open firmware. I have also pulled the motherboard battery, which is the only thing that did anything to the fans. Other than after pulling the battery, the fans start at full speed from when I press the power button. After the battery being pulled, it takes like 5 seconds after i press power, almost in unison with the boot sound, for the fans to turn on and ramp up to full speed.

I have been trying to find a solution to this since it started yesterday with no luck. I also downloaded istat (i believe that's what its called) and a few widgets that monitor temps and fans, but none of them seem to be able to read the fan speeds. The temps are low (120 for cpus, 80 ambient, 130 memory heatsink), so it's not overheating, but the fans are stuck at full.

Is the last step trying to contact apple and see if they can run a diagnostic to identify the problem, or is there any other way to try to fix it?
Click to expand...

I'd try a thermal recalibration... You also might try (if a recalibration doesn't help) replacing the battery.
 
It definitely needs recalibrated. Take it to your nearest AASP and have them do it for you. You'll probably have to leave it overnight as it takes a while to do.
 
h0ser81 said:
No need to take it to an Apple Store to do it. Apple Service Diagnostics CDs can be found for download if you know where to look.
Click to expand...

Indeed. Mine actually came with a (burned) ASD in the drive, when I bought it, I was tickled.
 
Well, doesn't hurt to try! I had already downloaded ASD to test the fans, so I just started the thermal calibration... Hopefully I come back to a quiet computer in the morning! I just photographed a wedding, so going through 1400 pictures with an airplane beside me may drive me insane.
 
Update: It has been running for a while and just finished with CPU0.. It says:

ERROR CPU0 - CPU Intake Fan speed error

Check that inner door is secure and in place then rerun calibration.

I am sure that it is in place and secure. I'm guessing it's going to say the same thing about CPU1 when it finishes with this one. Any suggestions on what to do?
 
10.5.8

And it had an error for the other CPU as well, so thermal calibration didn't work because the fans evidently aren't spinning fast enough! I sure do think they're going fast enough!
 
The rearmost of the 3 tabs on the bottom of the clear plastic cover should have opaque tape over it. Make sure that it's still there- that's what triggers the sensor that tells the computer the cover is in place.
 
Yeah, it is still there and when I remove the inner door when the computer is on, the motherboard light comes on
 
may sounds dumb, but have you got the cpu fan slot bracket that slots in on the front side of the case. Ie there are the two fans are the rear of the case, but there should also be a fan section in front of the cpu.. My mate bought one and it didnt have the fans in front of the cpus. Still ran fine, but was very loud as all the fans ramped up..

just checking....
 
Yeah, it has those two in there. Is there something that would cause it not to be able to read the speed of the fans? None of the utilities or widgets that I have can read them. In my mind, if the computer can't read the speeds, it would detect an error and speed them up just in case..

Also, is there anywhere to get firmware updates for this model? I haven't been able to find any.
 
Yeah, it has those two in there. Is there something that would cause it not to be able to read the speed of the fans? None of the utilities or widgets that I have can read them. In my mind, if the computer can't read the speeds, it would detect an error and speed them up just in case..

Also, is there anywhere to get firmware updates for this model? I haven't been able to find any.
 
I ran the tests on ASD last night and got three errors on three of the fans.. the intake, drive bay, and one that's not labeled. They all said they were spinning slower than expected. Now to find out what's causing this...
 
If you're up to it, try pulling all the fan assemblies to see if they're dirty and clean them. There could be dust or pet hair or whatever wrapped around the spindles.

I take all the fans out of my old (and soon to be retired) G5 2.0 GHz dualie once a year for a good cleaning - not just the blades but the whole assembly.

If they're not dirty - I don't know if they can / should be lubricated in case the interior of the machine gets contaminated. Perhaps someone else can chime in on this.
 
Doga said:
If they're not dirty - I don't know if they can / should be lubricated in case the interior of the machine gets contaminated. Perhaps someone else can chime in on this.
Click to expand...

Computer fans are typically sleeve bearing or ball bearing (or a specialized variant thereof). These are pre-lubricated and often sealed with no end-user maintenance required on the bearing.
Most computer fans however use a stainless steel shaft and a brass bearing surface, for which those metals expand at different rates with temperature, and the brass surface evenually deforms and wears (planned failure).
This typically results in fans that loudly click or whir when the bearing goes. Dissassembly and lubrication cannot repair the bearing surface, so while this may sometimes alleviate the noise for the short term, it is not a fix and the fans must be replaced when the bearing surface wears.

I have never physically broken one apart to look but the G5 fans "feel" like ball bearings.


viper42391 said:
Is there something that would cause it not to be able to read the speed of the fans?
Click to expand...

If the logic board has an issue then the fan speed controls might not be able to be read.

I use iStat Pro on the Dashboard to read my system temps and fans.

If the G5 fans are not running at the proper RPM, assuming that there are no issues with room ambient, venting, or overheating components, this usually indicates either the clear plastic Air Deflector is dislodged which causes the fans to spin up, or there is an issue with the fan speed control circuitry or temperature sensors on the logic board.
The Thermal Calibration only refers to the symptom when all fans run at high speed and the air deflector sensor is ruled out as the cause. If thermal calibration fails to fix the issue, or the issue is other than high speed fans, then the logic board must be replaced.
Assuming that everything else in the system is correct and working, in all other cases of fan issues, the logic board must be replaced.
 
Hi there,

I had recently a crazy experience with one of my client powermacs G5. The problem was that the fans starts sometimes kick in on full speed and then whole system was going down destroying raid arrays. We have clean all the fans and finally i did a test using Apple Diagnose DVD. One of the sensors were giving wrong readings and system was forced to behave that way. Anyway I've started to clean all the sensors and the found about that one of them in actually missing. :) I did recalibration and there is no problem ever since :). We have ordered new sensor to put it back in and then will recalibrate it again and that should do :). I thought that this info could help somehow to diagnose the problem.

Funny enough the testing software gave a crazy error which apple suggest to "ignore", but it did actually cause a lot of problem .
 
csiguy said:
Computer fans are typically sleeve bearing or ball bearing (or a specialized variant thereof). These are pre-lubricated and often sealed with no end-user maintenance required on the bearing.
Most computer fans however use a stainless steel shaft and a brass bearing surface, for which those metals expand at different rates with temperature, and the brass surface evenually deforms and wears (planned failure).
This typically results in fans that loudly click or whir when the bearing goes. Dissassembly and lubrication cannot repair the bearing surface, so while this may sometimes alleviate the noise for the short term, it is not a fix and the fans must be replaced when the bearing surface wears.

I have never physically broken one apart to look but the G5 fans "feel" like ball bearings.




If the logic board has an issue then the fan speed controls might not be able to be read.

I use iStat Pro on the Dashboard to read my system temps and fans.

If the G5 fans are not running at the proper RPM, assuming that there are no issues with room ambient, venting, or overheating components, this usually indicates either the clear plastic Air Deflector is dislodged which causes the fans to spin up, or there is an issue with the fan speed control circuitry or temperature sensors on the logic board.
The Thermal Calibration only refers to the symptom when all fans run at high speed and the air deflector sensor is ruled out as the cause. If thermal calibration fails to fix the issue, or the issue is other than high speed fans, then the logic board must be replaced.
Assuming that everything else in the system is correct and working, in all other cases of fan issues, the logic board must be replaced.
Click to expand...

Yeah, it is weird because it was fine for the first few days and then it went crazy. I had it for a day, installed extra ram and a hard drive, and then a day after that, it went crazy with its fans. I didn't have any software to see if it could read the fan speeds beforehand because I didn't have a need.

Anyways, hopefully I can get a trade from the seller or maybe try to sell it on craigslist for what I bought it for and get a different one.. I don't want to dump hundreds of dollars into this to get it working rather than put that money towards a newer intel mac...
 
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