iMac's fans went crazy after security update

After the restart the computer's fans went CRAZY. I've never heard them spin so fast.
Slipface wrote on :

Gang, I just installed some routine security update that Software Update put up. After the restart the computer's fans went CRAZY. I've never heard them spin so fast. This went on for about 3 minutes before I tried putting the machine to sleep then awakening it--the fans kicked up again to the same speed. I checked the Activity Monitor and nothing was working the CPU (Activity Monitor itself was the only real load on it).

I restarted the computer again, and aside from a peculiar extra bit of graphic at the bottom of the login "box" all was well. The fans are now quiet again.

Weird. Didn't see anything about this on Apple's support pages, but there were also about 150 hits on the word "fan" in the search engine, so I didn't wade through all.

BTW, this is on a G5 iMac running 10.4.11.

_dennis

Ian Gregory replied on :

On 2007-12-21, Slipface ask@redacted.invalid wrote:

I just installed some routine security update that Software Update put up. After the restart the computer's fans went CRAZY.

That reminds me. Very occasionally I hear a fan (or fans) turn on for a minute or so in my iMac Core 2 Duo . It doesn't seem to correspond to me working the machine hard or the length of time it has been on or high ambient temperature. I have assumed that machine has been designed to turn the fans on once in a while even if they are not needed for cooling, just to stop the bearings seizing up or to blow any dust out. Does anyone know whether this is the case?

Ian

John McWilliams replied on :

Ian Gregory wrote:

On 2007-12-21, Slipface ask@redacted.invalid wrote:

I just installed some routine security update that Software Update put up. After the restart the computer's fans went CRAZY.

That reminds me. Very occasionally I hear a fan (or fans) turn on for a minute or so in my iMac Core 2 Duo . It doesn't seem to correspond to me working the machine hard or the length of time it has been on or high ambient temperature. I have assumed that machine has been designed to turn the fans on once in a while even if they are not needed for cooling, just to stop the bearings seizing up or to blow any dust out. Does anyone know whether this is the case?

If it isn't true, it ought to be!

I experience the same on my older Dual 1.8 g5. Sometimes random, sometimes with a heavy load in PS.

== john mcwilliams

Grod replied on :

On Dec 21, 11:25 am, John McWilliams jp...@redacted.invalid wrote:

Ian Gregory wrote:

On 2007-12-21, Slipface a...@redacted.invalid wrote:

I just installed some routine security update that Software Update put up. After the restart the computer's fans went CRAZY.

That reminds me. Very occasionally I hear a fan (or fans) turn on for a minute or so in my iMac Core 2 Duo . It doesn't seem to correspond to me working the machine hard or the length of time it has been on or high ambient temperature. I have assumed that machine has been designed to turn the fans on once in a while even if they are not needed for cooling, just to stop the bearings seizing up or to blow any dust out. Does anyone know whether this is the case?

If it isn't true, it ought to be!

I experience the same on my older Dual 1.8 g5. Sometimes random, sometimes with a heavy load in PS.

== john mcwilliams

My '06 IMac Core2 Duo has done this once or twice in the one plus year I have owned it. It's always whisper quiet, except for these times. I've really worked the CPU and heard a smaller (or low speed) fan kick on, but yes, I've once or twice had "the big one" kick on).