Antec tri-LED fan modding


I bought myself four of those clear Antec blue tri-led Fans.

The problem is that the original Adda fans in my Lian Li PC-70 are powered through the (original) 3-speed switch for the front fans, an (additional) 4-speed switch for the rear fans and can be regulated somewhere between 6.5 and 12V. Therefore the luminosity of the blue leds varies proportionally with the applied voltage to the Antec fans.
Did some thinking about a mod... and here is the result. (this mod also works perfect with any kind of fanregulator or fanbus)

First: the schematic

The internal fan cabling - before & after

Above the original fan cabling. It's clearly visible that the leds are powered through an integrated 600 Ohm resistor from the same +12V voltage as the fanmotor.
Below the modified cabling. The 3 leds now are connected to a separate constant +12V voltage coming from the fourth pin of a Molex connector.

Second: the needed tools

A minidrill or a Dremel.

A file and some fine sandpaper.

A soldering iron with a very fine tip.

A magnifying glass and a mill.

A 4-pins female Molex connector. Afterwards this connector will be connected through an adapter cable with a 4-pins male Molex to my fanregulators.


Third: the modding

Original cabling visible after removing the sticker.

I already noticed that de propellerblades were finished very roughly...
Probably also the reason why these fans produce a little more noise and vibrations than my original Adda casefans.
Next step: Dismount the propeller to fix this.

Remove the little circlips on the propeller axe very carefully and remove the propeller. Remark the original cut for the wires to the fan PCB.

Propeller dismounted.
Here we use the file and the sandpaper to smoothen the edges of the propellor blades.

The result...

With the mill I widened the opening for the wires a bit to have access to the copper run beneath the round cut.

Cut the copper run indicated by the lower arrow, remove the green lacquer at the upper arrow and apply some solder to the freed copper.

Desolder the original wires except the two going to the leds.

Solder the 4 wires of the 4-pins Molex connector.
Orange = RPM signal
Red = +12V to fan motor
Brown = GND to motor and leds
Yellow = separate +12V line for the leds

Place wires in place.

View from other angle.

Place sticker back and finished!

Final test.
Just three other Antec fans to mod now...