G5 starts with loud fan noise?

Discussion in 'PowerPC Macs' started by Patth9, Feb 3, 2014.

  1. Patth9, Feb 3, 2014
    Last edited: Feb 3, 2014

    Patth9 macrumors regular

    Patth9

    Joined:
    Jun 28, 2007
    #1
    I have a Power G5 Mac, and I'm using Tiger. Can anyone tell me why, when I first start the Mac up, the fan comes on loudly and stays on, sometimes reeving a few times, but returns to the loud noise untill I shut down? I can maneuver a little, but it's scary!

    I should add that there have been many times when the Mac would start quietly, and without notice the fans would turn on and stay on. I'm not 100% sure it is the fan, but I can't imagine what else it would be.

    If anyone has an answer or needs more information from, I'd sure be obliged if you would share your knowledge with me.

    Patt

    Using 10.4.11
    Processor Dual 2 GHz PowerPC G5
    1 GB DDR SDRAM,
    POWER MAC7,3
     
  2. Zotaccian macrumors 6502a

    Zotaccian

    Joined:
    Apr 25, 2012
    #2
    I may remember wrong but there should be red led lit if overheating condition is reached. You could try removing the aluminium door (but not the plastic cover) and using the machine. Also if the plastic cover is not securely in place it might trigger fans.
     
  3. WMD macrumors regular

    Joined:
    Jun 12, 2013
    Location:
    Florida, USA
    #3
    Possibly a bad temperature sensor. Also, the fans always run at full speed when the plastic inside cover is not in place.
     
  4. mrpointy macrumors newbie

    Joined:
    Feb 4, 2007
    #4
    I have the same machine and recently had the same problem, or a similar one.

    I unplugged it for a day or so, took out the little half battery, reset the PMU by pressing the little button down on the lower edge of the logic board (NB Be careful here with this, read info on the net how to do it ), then put in a new battery.
    Started her up and my racing fans were gone, or it's been good for the last few days.

    Have read you can do the PMU reset with the battery in, but I wanted to make sure I had a good battery in there so that is why I did it this way.
    Battery looked like it was an original from 2003, and in the end it was, when I took it out I looked at the date.

    I've got 8GB's of ram in this, so next thing I was going to do was do some testing on taking out ram etc.
    Thought the battery though was a good place to start troubleshooting the noisy fans, and in my case it seems to have solving the issue I had.
     
  5. Altemose macrumors G3

    Altemose

    Joined:
    Mar 26, 2013
    Location:
    Elkton, Maryland
    #5
    Reset the PMU and PRAM. Also swap the battery out. On the front, can you see a bright red LED inside the case illuminated?
     
  6. jlofgr macrumors newbie

    Joined:
    Jan 24, 2014
    #6
    Overheating?

    Download "Hardware Monitor Lite" It's a free program and will tell you if you have a cpu overheating issue. If one or both CPU's are overheating (+65 degrees C) the fans will run continuously. I just fixed this issue.
     
  7. AmestrisXServe macrumors 6502

    Joined:
    Feb 6, 2014
    #7
    The fans will go into overdrive if the reflective surface over the light sensor (on the back tab of the clear, plastic, airflow cover) is scratched or defective.

    Try this:

    1. Open the G5
    2. Remove the clear, plastic air panel.
    3. Take a strip of paper, 1 1/4" wide, and gently slide it into the slot normally occupied by the rear tab of the airflow cover.
    4. Now, reset the PMU, if desired.
    5. Power the machine on, without closing it first.
    6. Report if the problem has ceased.

    Check the tab on that clear panel to see if the reflective tape has degraded, or fallen off. It should refract light, like a translucent hologram film.

    If this doesn't help, the light sensor itself may be dirty, and needs to be cleaned.
     
  8. Patth9 thread starter macrumors regular

    Patth9

    Joined:
    Jun 28, 2007
    #8
    AmestrisXServ, it's been a while since I was able to get back to the noise fan problem. I want to follow your instructions, but I'm a bit muddled.
    You instruct:

    3. Take a strip of paper, 1 1/4" wide, and gently slide it into the slot normally occupied by the rear tab of the airflow cover.

    4. Now, reset the PMU, if desired.

    Well, I don't know how to follow your #3 step. I have the outer cover off and the clear plastic panel is removed. Where is the "rear tab of the airflow cover?

    AND:
    CAN NOT FIGURE OUT WHERE THE TAB IS ON THE CLEAR PANEL in you rest of your instuctions.

    "Check the tab on that clear panel to see if the reflective tape has degraded, or fallen off. It should refract light, like a translucent hologram film."

    I looked up PMU and will deal with that after I find where to put the 1 ¼ piece of paper.


    I did unplug the hard drive fan, which really lowered the noise, but I don't think this is wise to run the Mac without this particular fan running.

    Please set me straight, if you please.

    Patt
     
  9. Altemose macrumors G3

    Altemose

    Joined:
    Mar 26, 2013
    Location:
    Elkton, Maryland
    #9
    You should never run a G5 or any computer with one of its fans unplugged. By the tab he means on the clear shroud you remove.

    At the bottom you will see two notches in the plastic sticking out. On the one which is closer to the rear of the G5 apply his steps.
     
  10. Patth9 thread starter macrumors regular

    Patth9

    Joined:
    Jun 28, 2007
    #10
    Well, my o my, that was certainly a well hidden feature. Thanks, found with it no problem, but the tab cover is securely attached and no scratches. Would you suggest I use a Q-tip or possibly a can of air to clear away any dust down in the , which the inside of the computer certainly has a LOT of, dust that is.

    Thanks for the reminder about not running the CPU without a fan. I await the proper cleaning method...before trying other suggestions.

    Patt

    Patt
     
  11. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #11
    You may want to run Apple's processor calibration.

    That's on the ASD (Apple Service Diagnostic) v.2.5.8 for the PowerMac G5.

    You'll need to find someplace to download that.
     
  12. jbarley macrumors 68030

    jbarley

    Joined:
    Jul 1, 2006
    Location:
    Vancouver Island
  13. Altemose macrumors G3

    Altemose

    Joined:
    Mar 26, 2013
    Location:
    Elkton, Maryland
    #13
    I would use some compressed air on it then. Ensure you hold it a safe distance away and don't tilt the can. If you put it too close and on an angle it will spray liquid out :mad: . You may need to calibrate the CPUs as mentioned by DeltaMac. Jbarley posted a link for the file you need to do so. When you power it on, look through the front of the case by the USB ports. You should be able to see inside and see if a red light is on. It will be rather obvious.
     
  14. AmestrisXServe macrumors 6502

    Joined:
    Feb 6, 2014
    #14
    Now that you have located that tab, take a strip of white paper, tear off a 1" strip, and fold it, then slide it into the slot where that plastic tab normally fits.

    This is to diffuse the light of the sensor, and may help diagnose if the tab on the air shield is faulty.

    I have had the actual sensor fail on systems in the past as well, but you want to test it first, as it is a very big undertaking to replace the sensor module.

    Resetting the PMU is usually easy on a G5, unless you have a late-2005 model. Unplug the system from power, wait 30-seconds, and reattach it to power. You must remove the power plug from the system, not merely shut the power off.

    I have a Dual 2GHz system here at present with a dead sensor board, that does essentially the same thing. I tested the sensor with the piece of paper, and it may shock you that this is the stated procedure in the Apple Service Source manual.

    If the paper trick doesn't work, you may have a bad sensor, or your fan load balance may be wrong, in which case, you will need to run the Apple Service Source calibration process as mentioned above.

    It is usually wise to run a calibration, prior to dismantling the system to change the sensor module, as you need to strip away many components to change it out.

    If you have an air compressor tank, use that, with a tapered nozzle, to clean out the system.
     
  15. Patth9 thread starter macrumors regular

    Patth9

    Joined:
    Jun 28, 2007
    #15
    I am a very happy camper, very happy. I used the air can and blew the daylights out of the really dusty innards. I have run the Mac for two days, less the night, and it purrs softer than a kitten. I backed up my second hard drive, which is also on the Mac until I find a replacement for my exterior holder, and the fans only kicked in with noise for a few moments. I didn't try the paper trick as it worked right off the bat.

    I will keep this link, from which I have received so many have suggestions, in case I need to start following some of the additional steps down the road.

    I am most grateful for all the help. I still want to use my G5 because it contains programs that I still use. I was afraid it was a goner, and now the G5 is the MOST quite it has ever been.

    Thank YOU'LL,
    Patt
     
  16. AmestrisXServe macrumors 6502

    Joined:
    Feb 6, 2014
    #16
    I think the light sensor was probably dusty. :)

    Good to hear mate.
     

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