Okay, I have opened everything up and I'm getting ready to pick out what fans and/or power supplies to buy. In case anyone else is thinking of doing this, I'll post another cool link I found about swapping out the power supply in a pre-ADC connector G4. (G4's with the ADC video card can take this mod too, but you lose the functionality of the ADC connector). G4's use an ATX power supply with the standard 20 pin connector. You have to resolder 2 of the connections, but that's easy enough. So if you have a bad power supply to begin with, you can replace it with a "quiet" ATX supply. Here's the link:
http://xlr8yourmac.com/systems/ATX_G...e_pg2.htm#next
So, I actually have a total of 3 studio noisemakers I'm modding:
1. Magma 13 slot chassis:
a. has 3 92mm fans in front.
b. uses standard ATX power supply. depending on make, it may have one or two fans of various sizes. mine has one 80mm and one 92mm
2. G4 "sawtooth" AGP graphics 400 mhz
a. Apple ATX power supply has one 80mm fan. Since my power supply works, I think I'll just swap out the fan...
b. Case also has a 120mm fan located below/ behind the power supply.
3. G3 beige - desktop configuration
a. One single 120mm fan on the bottom of a MASSIVE power supply(with ATX connector).
Now, here's what I'm thinking... I have already taken the G3 out of it's ugly, crappy case long ago and mounted everything in a 4U server case, which sits below the magma. The magma's motherboard has 2 ATX connectors on it. Does anyone know why? If they are wired in parallel, It would be really nice to just put one big 500-600watt power supply in the magma, and then tap into the second ATX connector to power the G3. I haven't looked closely at cost yet, but it seems these days that a big power supply is usually almost the same price as a smaller one.
Also had another noisemaker, it was my UPS. It hummed 60 cycles annoyingly whenever it had a load on it. I couldn't hear it over all of the other fans, so up until now I let it be. But I checked into it while everything is apart right now, the design of the case was the problem. The noise was a vibration from the transformer resonating the top of the case. I took the top off and the hum went away. Putting caulk on all of the mating surfaces of the top and the rest of the case fixed the problem. I'll let everyone know how the new fans work out.