After removing most of the innards, I removed the PSCB to show the location of the J3 12V male connection point (indicated by red arrow).

The Panasonic Panaflo fan (which I installed, see photos below) did not come with any connectors (only bare wires). Thus, a female connector was needed in order to link the fan to the PSCB (12V DC Power Supply).

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I used a female connector from an old HardDrive LED cable I pulled from a PC (something I hamstered away for parts). I knew it would come in handy one day!

You can find these connectors at most electronic shops.
It's a Molex 1.25mm plug (CONN 2POS HOUSING 1.25MM
Part# WM1720-ND $0.34 ea at www.digikey.com)

TERMINALS CRIMP 1.25MM 28-32AWG
Part# WM1775-ND $0.59 (10 connector strip) also from www.digikey.com.

It fits just perfect into the J3 PSCB (male) connector. I cut the red LED end off and then I soldered the wires to the bare ends of the fan (red to red, black to black).

*MAKE SURE YOU MEASURE THE LENGTH YOU NEED BEFORE CUTTING ANYTHING...

These are close-ups of the female connector that plugs into J3.

The Panasonic Panaflo (specification in PDF) is a high quality ball bearing fan (NOT Sleeve bearing) 80mm X 80mm X 15mm, there are 2 models available from DigiKey (ask for Nikki, she's a "babe"); 2000RPM (P/N P9732-ND) and 3100RPM (P/N P9734-ND). I chose the 2000RPM for keep the Cube as quite as possible. It fits perfectly into the shoe that was already built by Apple. Four screws hold the fan in place.

Click on image to enlarge

I bought the screws at Home Depot, they are stainless steel 6x32x3/4 (P/N 127948). These screws are the perfect length but the thread is not the exact same, some "self-tapping" will be required here but it's not a big deal. I think it is maybe a finer thread. It is probably the same thread as the one used by the larger T-10 Torx fasteners that hold the core case together. The V-shaped head ensures a snug and tight fit. It looks factory installed!!

The Cube in its final assembly stage. Note the location of the J3 connector and the fan connector cable plugged into it.

RESULTS:
The Cube works and the fan is incredibly silent!! Mostly due to the ball bearing and low RPM design. I can't hear the fan at all above the hum of the GPU fan or HDD. There is a very subtle but noticeable flow of air from the top of the Cube vent, which means I installed the FAN the right way!!

Before: 52°C -> After: 24°C
(G4Strip 1.1.4 temp readings)
I have not noticed any fluctaution in temp. with the fan installed, whereas before I could see the temp. fluctuate several degrees during a regular working day.

FUTURE UPGRADE PATHS:
If installing a Dual 1GHz processor is feasable, perhaps someone should look into liquid cooling the processors. There's a bit of space on the back of the DVDROM drive to handle a water resevoir and if you remove the fan (if one is installed) from the base you could theoretically install a small 12 V DC pump and circulate the coolant through a modified heatsink...wouldn't that be "cool".

8(|:-)

Click on image to enlarge

LOCATION OF CD/DVD ROM EMERGENCY EJECT BUTTON
I recently heard several people on the Cube list requesting the location of the emergency CD release button.

As I was disassembling my Cube, I located the button (circled in red). This is NOT a mechanical button!! It is an electronic membrane button and uses a soft rubber pad as the contact point, similar to most modern handheld calculators. Therefore little effort is needed to activate the button.

Click on image to enlarge