12 Replies Latest reply: Apr 27, 2011 12:46 PM by Nina R
Nina R Level 1 (10 points)

My normally whisper-quiet PM G5 revved its fan(s?) a bit on first start-up today. I haven't heard fan noise since the last time it pitched a diva fit, at least a year ago. My stomach turned.


I shut down, wiped some dust off the front grill with my hand, restarted. Turned on my external drive, which the G5 couldn't mount the first time for whatever reason but did when told "back up now." Completed backup. Fan noise came and went. It sometimes makes that sickening up/down sound.


Reset my SpiralBound Pro app not to launch at login. I had set it to do that about 3 days ago, with some trepidation. It seems that every time I set any app to launch at startup, I soon begin having trouble with this machine. Restarted. Still have fan noise. Fairly low volume, steady now. Man, do I hate this sound. It has always been associated with serious problems throughout the almost 6 years I've had the machine.


I'm going to shut down, disconnect AC from the rear for a few minutes, check my manual, look inside and see if I see any gross dust problems or cockroaches (possible—I know, ugh) in there, then power on again.


Meanwhile, can someone give me bullet points on what diagnostics I should be doing?


Am I correct in thinking this is unlikely to have anything to do with the hard drive?


In the last few minutes, it has quieted down to the normal almost inaudible level three times, but then revved again gently for a few minutes. Quiet now. I wonder if it is working its way out of something…


I'm long term unemployed, can't afford to have my old friend die right now. Thanks…



Power Mac G5 2.0 (late '05), two PM 7600s (bless 'em), beige G3, CDMA iPhone 4, Mac OS X (10.5.8)
  • Nina R Level 1 (10 points)

    …FYI, I'm logged in here on my iPhone ;)

  • BDAqua Level 10 (122,276 points)

    Hi Nina,


    Be sure to blow out the dust from the interior,

    Get Temperature Monitor to see if it's heat related...




    And/or iStat Pro...




    If you have any temps in the 70°C/160°F range, that's likely it.


    >Am I correct in thinking this is unlikely to have anything to do with the hard drive?


    Not the likeliest suspect at the moment.

  • old comm guy Level 4 (2,240 points)

    To add to BD's comments, is your machine liquid cooled?  In your case, I think that would only be the Quad 2.5.  See what temp monitor or iStat report for sure, as that is the first indication of problems.  If the CPU die temps are high and you have the quad, then you need to examine for coolant issues.  Let's hope that isn't the case.

  • Nina R Level 1 (10 points)

    OK, thanks guys. Going to Radio Shack to get some compressed air. BTW for anyone who may be interested, there's a pretty good how-to on YouTube for cleaning inside a G5 by user leviasay. (Too much of a challenge for me to harvest & post the link in mobile mode :).)

  • Nina R Level 1 (10 points)

    P.S. It's a dual core 2.0, I'm 99% certain it is not liquid cooled.

  • WAM2 Level 1 (5 points)

    My powermac g5 has just started doing this something today, I have fixed mine by shutting off the mac, opening the side of the case and pressing the PMU reset button on the logic board... Though if you are on a quad  then this May not fix the problem and your liquid coolant system may be getting old ( and failing) causing the fans to take over and since it is. Quad the fans are going to be loud because of the liquid cooling system failing. I have the dual 2ghz and still love it, though I just replaced it with a new iMac. Try pressing that PMU button and see if that helps, and if your on a quad look for leaks.. Hope I helped.


    Typed on an iPad 2.

  • Nina R Level 1 (10 points)

    I was planning on hitting that button, if it's in there, which official documentation here seems to indicate it should be—although I was under the impression you could reset power management on a late '05 dual core 2.0 simply by unplugging it. Appreciate you shining a ray of hope on this. I just left Radio Shack empty handed because I'll be damned if I'm buying compressed air that will release a nice dose of carcinogenic refrigerant chemicals into the atmosphere of my small and not-all-that-well-ventilated apartment. There has to be another way, or if there isn't and the PMU button doesn't solve this, I'll consider paying the local Mac shop to inhale that stuff. Maybe a little of the YouTube guy's paintbrush technique on the fan blades and elsewhere will suffice. Yes, I'm the most chemophobic person who ever lived :)

  • Nina R Level 1 (10 points)

    Apparently my half-baked cleaning with the paintbrush didn't help much, or enough. I hope I didn't make matters worse by trying to poke the PMU button with a metal letter opener. I did have an antistatic wristband on. I tried first with a pencil eraser (no metal in the pencil—plastic twist-up), then the letter opener, then my finger. It never felt like the button yielded at all. Don't know if it should have?


    After all that I ran the machine for about 20 minutes. The fan(s) seemed less active than during the day's previous sessions. But it did rev up twice. I passed out for a while, exhausted from worry, which is why I'm writing at this hour (3 a.m. ET).


    Wondering if this could be a household power problem. Track light strip that I believe is on the same circuit has been flickering occasionally—better since I replaced all the bulbs but still not right.


    Could the G5 respond to power fluctuations with intermittent fan activity? Yes, I do have a decent surge protector but it doesn't have that extra feature that's supposed to correct for fluctuation. No, I am not buying a UPS. BTDT (see above re: chemophobia, and can't handle the expense anyway).


    Writing this from my beige G3 (on the same circuit, FWIW), which hasn't been used for a while. Excruciating. It is time to yank the hard drives and get rid of the old Macs, I'm afraid. Safari is a cripple on this thing. Thank god for Firefox. Opera works great for 10 minutes, then freezes.


    Probably going to have to make the G5 run for a few days whether it's happy or not, because I must continue job search activities or risk getting thrown off unemployment. At least long enough to get résumés transferred over to this turtle. Next session I will try Temperature Monitor, which I think I may have downloaded previously.


    Thoughts, anyone?


    P.S. Never could post this from the G3—kept getting a site error. Had to copy text, webmail it and pick it up on my iPhone. Sigh.

  • old comm guy Level 4 (2,240 points)

    Nina R wrote:


    P.S. It's a dual core 2.0, I'm 99% certain it is not liquid cooled.


    As am I.  See what temperature monitor is saying.  Especially look at the history window.  You will need to assign different colors to different sensors (makes it kind of artistic, in a way) but you will be able to see what is going on and what, if anything is rising in temperature.


    Also, another thing you can use is Activity Monitor and just keep the CPU Usage monitor running in the corner of your display.  That will tell you if a CPU is getting overly busy and you can track that down by looking at the full A-M display and sorting on CPU usage.

  • Nina R Level 1 (10 points)

    Thanks for the reminder about Activity Monitor, sounds like a good idea. Maybe even better than you thought, because it just so happens that I was looking at it not too long ago (a month?) when I thought my hard drive was chattering too much. I killed some process or other, and the hard drive noise went back to normal, but I seem to recall still thinking  AM was showing excessive activity somewhere. If I did, I neglected to pursue it further…too many alligators.


    BTW, looks like "helpful" points can only be given on the first round under the new forum design? That doesn't make a lot of sense—agree? Apple devices old and new present problems that have to be unraveled stepwise—more so the less the technical proficiency of the user seeking help—and the best answers often come after more information has emerged via diagnostic procedures or clarification. Oh well. I think the "like" button is nice—though I wish they could have thought of another label for it ;)—since there must be hordes of people like me who often come here to search on something and wind up benefiting from questions they didn't ask.

  • Appaloosa mac man Level 5 (4,330 points)



    Compressed air has a second side effect.  Too much velocity creates static electricity.  A gentle vacuum is much better around electronics.


    As for the fan.  Our G5 cycles up and down a lot and it is not a sign of impending CPU failure.  Take a look at 'Activity Monitor' to see if some application is ramping up in the background and causing the fans to anticipate the need to cool.  Activity Monitor is found in the Utilities folder of the Applications folder.


    Hope that helps.



  • Nina R Level 1 (10 points)

    Jim, I thought that vacuums were not recommended for that same reason (generating static)? Doesn't any electrical device that either pulls or pushes air have that potential? Maybe I'll start a separate thread on the cleaning issue… not today though—getting ready to wrestle a big alligator tomorrow and racing to make up for time lost agonizing over this machine and fussing with the G3.


    But, wanted to report that the computer seems fine now, and I'm embarrassed to say I think it was all because I accidentally turned Bluetooth on without realizing it, which I discovered about 5 minutes into last night's session. I assume that the computer was hunting for Bluetooth devices. Not sure why that would stress it enough to make the fans rev up, but there's no other plausible explanation I can think of. It ran several applications quite happily for 3 hours last night in its normal whisper-quiet fashion—not a peep from the fans. Whew.


    I'll try to be more mindful of Activity Monitor's potential value—thanks to everyone who brought that up. Had I checked it right away instead of freaking out, maybe I would have noticed the Bluetooth issue. Will also try to check Temperature Monitor soon to be on the safe side.


    I did end up having some fun with the G3 yesterday… seemed like it just needed some (figurative) dust knocked off it. Performed much better than it had on Monday night. I even got my old HP Deskjet 6122 partnered with it. I recently set up a Canon Pixma MX860 with the G5 and had considered getting rid of the HP, but my instinct was not to, and it was correct. Hoarding, schmoarding.