AFAIK the only fan in the PCI G4 (you men the 350Mhz Yikes model right?) is in the power supply and will always stay on. It shouldn't be very loud though. I have one of those machines at work and the fan is nearly silent. You might just need to blow the dust and other cruft out of the power supply with some canned air. I have heard of people replacing the fans in power supplies with ball bearing fans to silence them. You might want to try that if it really bothers you and you are comfortable disecting the power supply.
Macs are actually quite intricate to take apart, be careful! There should be a large fan in the side of the case to cool the mobo/processor in addition to the fan in the PS
There should be a large fan in the side of the case to cool the mobo/processor in addition to the fan in the PS
You are right, I take back part of what I said. I just checked and there is a fan in that model of G4 that blows accross the processor and PCI slots. I never noticed it for some reason.
apart from the fact that it is several inches across. I missed it the first time too.
Also, if you add a CD or other drive to the front panel, you don't get the drives out thru the inside of the case. Pop of the plastic drive cover bezel on the front and undo three (?) screws. I was set to take the machine apart in all sorts of horrible ways to add a drive to my dad's Yikes mac.