G5 Fans Erratic after update to 10.4.3

[TxAg]

Hello.

I have a G5 tower, and have been running Tiger 10.4.2
(as well as earlier incarnations of OSX since 2004) without
problems. A few days ago, I updated to 10.4.3.

Now, I am noticing that one of my fans is revving up
relatively loudly for about 15 seconds, and then revving down,
for no apparent reason. I am not taxing the CPU as far as
I can tell. I've opened the box and visually verified that
all fans are indeed running. Could this indicate that something
is overheating, or that the fan controller is going bad?
Or might this have something to do with the OS update itself?

Anyone else experiencing this?

Tx

 

[bobw]

From MacFixIt;

Fan problems (continued) Users continue to report problems with increased fan activity after installation of Mac OS X 10.4.3. As noted yesterday, the most effective workarounds for this issue are resetting the SMU, zapping NVRAM and changing processor performance settings.

 

[TxAg]

Thanks. Just so I am not missing something, is there
anything more to "zapping NVRAM" than the obvious
system shut-down followed by a restart?

Tx

 

[bobw]

Start up in Open Firmware mode (by restarting your Mac then immediately holding down the Command, Option, O and F keys simultaneously) then entering the following commands, pressing return after each:

reset-nvram
set-defaults
reset-all