February 05, 2005

Furious George: Spastic Computer Fan. My Mac G4 is driving me nuts.

Of course now it just stopped. WTF!? Well, I shan't presume it will stay silent. It's played nice before. I have a blue-grey Mac G4. For the past week or so, it's been making an aggravating whirring noise. I've scanned all the help files I can find (keywords like FAN and NOISE and WHIR[RING], with G4 and MAC restricters). I bought canned air and dusted the heck out of everything I could get to. I've zapped the PRAM. Still it whirrs. Sometimes it's constant, sometimes it's periodic. Sometimes it's completely random. Short of taking it to a technician (repairing this would cost me more than just getting the freaking Mini I've got my eye on anyway), any suggestions? What's making the fan so spastic, anyway?

posted by scartol 19 years ago
  • Would you believe it just started whirring again?
  • scartol, you need to try resetting your power manager. I have a G4 Powerbook and occassionally it gets to a point when the fan kicks on full speed ahead and yet the machine will have been on for only 3 or 4 minutes. try a google search for reset power manager G4 (or your model number) or Mac (instead of G4) and see if you can come up with anything. It is usually done by shutting down the machine and holding down a combination of keys until you get a double start-up chime. Hope this helps a little. I'll poke around the web and see if I can find a proper link for you.
  • The power manager reset button is on the inside of the machine, on the motherboard (it's the only button on the board). Do not have the machine plugged into anything when you reset it. (Some suggest removing the PRAM battery as well.) When it makes noise, does the air output change? Fans do die, and I've had some start rattling and whirring and stuff before they finally gave up the ghost. Your MP3 definiately souns like the fan is dying. They can be replaced fairly easy if you can work a soldering iron - just unplug and remove the PSU from the machine, leave it sit for a day or two, and open it up and replace the fan. You should be able to find an exact replacement on the internets somewhere(try mouser or others, or Radioshack). The last time I had to do it I just snipped the wires to the fan in th emiddle and grafted the new fan on suchly. If you opt to do the fan replacement and can't find a suitable fan, let me know (email in profile) and I can shoot you a fan. I have a grey G4 that has a completely dead PSU but the fan's ok. We Love Macs will sell you an Apple replacement PSU for your machine. It will be very expensive. You can also use an ATX power supply but you have to do a lot more work - ATX pinout is different and Macs require a +28V line and there's lots of wiring and stuff but it can be done.
  • Wow, scartol, I missed the MP3 earlier. I have to agree with mrg that your fan sounds like it's about to give up the ghost. You may have better luck just replacing it. Good luck-
  • That's a bad noise. Is the fan hitting anything? If not, there's something very wrong with the fan itself and it will need to be replaced.
  • I just have to say that I read "Spastic Computer Fan" as a person who loves Macs whose computer was driving them crazy. Not far from the actual case, but I enjoyed the image of a happy computer user suddenly having a spastic spell at the keyboard. /tangent
  • The most likely problem is, as others have indicated, the cooling fan or fans. It depends on which model it is what you're looking at. If it's the infamous Mirrored Drive Door chassis, then there were replacement fans because it was noisy and you may be looking at $20 and a user-replaceable part. For accuracy of your diagnosis, though, open the chassis while the machine is making the noise. Other things could be causing it. 1: Something like a piece of loose paper or plastic sticking into the fan like unto a baseball card in the spokes of a bicycle. 2: a dead or dying optical or zip drive. 3: something (ps, motherboard, drive) that has worked it's way loose over time via vibration that can be screwed back down. If it is the power supply fan, you may want to call Shreve Systems, PowerMax, and Small Dog (or other national resellers of used macs) and see what they have that they're not advertising. They may have something. I don't know which macs would have the same power supply, but (if you can find that it's the same ps) you may be able to get a G3 Yosemite on the cheap (there's one on ebay for about $90 right now) and cannibalize it for parts.
  • if the G4 is not the first-gen PCI Graphics G4 (the one that's really just the B&W G3 motherboard w/ a G4 on it) then a PSU from a B&W G3 won't work.. the PSU provides some extra power on "Gigabit Ethernet" (everything after) models. however, there were like 4-5 different graphite G4 models inbetween the PCI Graphics and the Quicksilver (much lighter silvery grey) models.