[TenTec] Loud fan PS 963

[Martin Ewing]

Greg,

I agree that the fan is too loud.  I have lived with it for a long time, but
now you're making me think that action may be required!

You could take Tony's approach, but another way to do it would be to put a
resistor in series with the fan.  That would limit its maximum speed (noise
is a rapidly increasing function of rpm).  The cooling would be less, and
the thermal switch would stay "on" for a greater percentage of the time, but
the noise would be less.

You could also bypass the thermal switch and let the fan run continuously,
but more slowly.  You'd have to satisfy yourself that the PS is cool enough
under max. load and at max. ambient temperature.  You might replace the fan
with a slower, quieter model if you ran it continuously.

The on-off "bang bang" temperature controller is cheap, but rather crude.  A
proportional controller that adjusts rpm smoothly would be a lot friendlier
- similar to what you get with some computer systems.

73 Martin AA6E

On Sun, Sep 27, 2009 at 8:25 AM, Tony Berg <tony.w1ot at gmail.com> wrote:

> Hi Greg,
>
> As a last ditch measure, you could try putting a resistor across the
> thermal switch whose contacts are turning the fan on and off. This
> will make the fan run all the time, but at a slower speed. Experiment
> with the resistor's value to slow down the fan as much as is desired.
> If this does not provide sufficient cooling, and the thermal switch
> closes, it will short out the resistor, and the fan will run at full
> speed as before.
>
> I did this to my Astron SS-30, and I have used it this way for over a
> year. No guarantees, though, as some fans are not rated for running at
> lower than normal voltage, and if the fan fails, the 963 could
> overheat and fail.
>
> 73, Tony  W1OT
>
> On 9/26/09, Gregory & Kristin Palfe <gpalfe at comcast.net> wrote:
> > Has anyone found a way to quite the rather loud fan on the 963 power
> > supply?  Its constant on-off while sitting on the desk top is quite a
> > distraction.
> > Greg
> > wa0bnx
> > _______________________________________________
> > TenTec mailing list
> > TenTec at contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
> >
> _______________________________________________
> TenTec mailing list
> TenTec at contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>