Speed up the PS Two fan!

[shepd]

As you may have noticed, the PS Two doesn't use a "normal" PS2 fan, so if you want more airflow (to prevent overheating, etc) you can't just up the voltage and get what you want so easily.

This mod worked well for me to speed up the fan, you might want to give it a try also:

Cut the yellow wire going to the fan (preferrably somewhere in the middle, you'll be soldering to both ends after.)

Wire a 0.1 uf capacitor from ground (black wire or sheild) to the yellow wire you just cut (the side that connects to the motherboard). At this solder joint, add a 33 kOhm resistor. The other leg of the resistor should connect to the yellow wire on the fan. Tape everything up so it doesn't short out.

Adjusting the capacitor and resistor values will achieve different results. I was quite happy with the results from these values. YMMV.

For those that want to know the technical reason this works, here it is:

The PS2 fan is pulse width modulated. The PS2 outputs a 70 kHz (give or take) signal at between 33% (fast) to 15% (slow) duty cycle. Adding the capacitor increases the duty cycle, and the resistor increases it further.

One note: When I attached used a rather large capacitor in place of the 0.1 uf capacitor, the fan would tend to shut down. I figure the circuit in the PS2 is designed to shut down the fan control in case of a short, and likely this shows up as a short on the PS2 with a capacitor draining that much current.

[reZz]

Good thinking. I'll definitely be doing this mod...when I actually own a psTwo...

by 33kOhm resistor do you mean 33,000...and how many watts?

[shepd]

A 33 kOhm resistor is 33,000 Ohms, yes.

The wattage is not important, the current draw from the fan on the sense line is very little. A standard 1/4 watt resistor works fine.

This circuit might be improved by the addition of a diode in series with the input signal from the PS2 -- I think when the PS2 drives the signal low it may be drawing the charge out of the capacitor again. The diode should prevent this. I'll give it a try on the next PS2 I work on and see if it makes a difference.