i know a lot of you are still cutting the + wire on the fans and just wiring it to a 12v spot on the board, altho this dose work there is an easier way that doesn't require modifying the fans.
for a lesser fan speed cut the ground of both fans and run both ground wires to a power source (after doing the 12v fan mod).
for 7v ground to this point:
Xenon,
Zephyr/Falcon/Opus/Jasper for 9v ground to this point:
Xenon,
Zeyphr/Falcon/Opus/JasperXenon:Bottom of the Board:Yellow=12v Black=CPU Red=GPU

(If your Having Trouble Understanding Click the Picture)
ORTop of the Board:Bridge Black for CPU, Bridge Red For GPU.
Zephyr, Falcon, Opus & Jasper:The Zephyr, Falcon, Opus and Jasper Board have the same voltage line to both fans
so it wont be possible to 12 or 7v just one fan w/o cutting the wires.
Bottom of the Board:

OR
Top of the Board:
Note: Sunon and Nidec Fans have Reversed Power Wires.
Trinity/Valhalla:Bottom of the Board:
Red=5v, Yellow=Fan Speed Control.
Bridge for Full Speed.
Potentiometer for Controlled speed.
If you plan to use a potentiometer to manually adjust the fan speed
here is one
that is close to the right strength and
here is how it should be used.
This post has been edited by Grim187: Sep 23 2011, 01:00 PM