searching for a wide alpha cpu heatsink (2nd request)
Alan Young
ayoung at teleport.com
Tue Nov 11 16:22:34 UTC 2008
Alexander Huemer wrote:
> hi tony,
>
> i have a 3 wires too.
> re-wiring a pc fan is not possible to my knowledge, because the signal
> is completely different.
> a pc wants to have pulses (as you said) so that they can measure the
> rotating speed of the fan.
> the original fan of my alpha (some strange panaflo) gives a certain
> voltage on one wire if the fan is turning. when you stop the fan, the
> voltage goes up and the alpha stops. when you remove the fan, the
> voltage is missing and the alpha does not run either.
>
> my "alpha fan simulator" does just provide the required voltage, that's
> all.
>
> building a heatsink from scratch is of course possible, but that's not
> the way i want to go, if i find somebody who has a BIG BIG heatsink for me.
You can rewire a PC fan to be used in a Alpha as long as it's a fan that
provides the sense line. All you need to do is pop the wires out of the
3 pin connector and rearrange them in the right order and pop them back
in. If you have a newer CPU FAN with the small 4 PIN connector that
provides the PWM line, that might work too, just leave pin 4 (PWM)
unconnected.
On a PC CPU fan, the pin order is
1 GND
2 +12V
3 Sense
On the Alpha CPU fan, the order is
1 +12V
2 Sense
3 GND
A couple of other things to look at is a FAN funnel adapter that can
allow you to mount a larger fan on a smaller heatsink and standard
PC sound quieting materials and components.
Alan
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