>
> Rob,
>
> Perhaps it's better to controll the DC current throug the motor by the 
> PIC,
> instead of using PWM.
>
Absolutely. These fans are brushless motors with a hall effect sensor; 
feeding PWM to the DC input lines would do crazy things to the drive 
circuit. Lowering the voltage seen by the fan's DC input reduces the RPM 
quite reliably.

Regards,

Anand

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