[ICOM] 756 ProII Temp Problem

[Bill Archer]

Mike,

Sorry I was unclear.  The cooling fan only runs during TX ( or at least that
is my understanding). By applying a lower voltage to the fan during RX you
will get some airflow without the noise of a full speed fan and when the fan
control calls for max cooling the full 12v is delivered to the fan. I have
been reading the suggestions for externally mounted fans to provide RX
cooling and it seemed using the internal fan made more sense if it were
possible.

Did that make any more sense?

Bill
----- Original Message ----- 
From: "MikeR" <nf4l at nf4l.com>
To: "ICOM Reflector" <icom at mailman.qth.net>
Sent: Wednesday, September 22, 2004 17:26 PM
Subject: Re: [ICOM] 756 ProII Temp Problem


> Bill -
> I'm puzzled as to how a slower running fan could result in more cooling.
> Less noise, sure. BTW I have a PROII and it does get very warm just
sitting
> there, but so far (crossed fingers) so good.
> 73, Mike NF4L
> ----- Original Message ----- 
> From: "Bill Archer" <bfarcher at comcast.net>
> To: "ICOM Reflector" <icom at mailman.qth.net>
> Sent: Wednesday, September 22, 2004 9:08 AM
> Subject: [ICOM] 756 ProII Temp Problem
>
>
> > As the proud owner of both a 706MkIIG and a ProII I have been following
> the
> > discussion on cooling the ProII during extend RX periods.
> >
> > The 706 has a similar problem in that the case temp would get VERY warm
> > while in RX. A simple fan mod whereby a 200 ohm 1 Watt resister was
place
> > between a +12v source and the + lead on the cooling fan. This causes the
> > cooling fan to run at a low speed with about 4.7V applied to the fan.
The
> > effect of this mod is the case temp is reduced by  about 30° F.
> >
> > It would seem to me that a similar approach could be taken with the
ProII
> to
> > apply a reduced voltage to the cooling fan to achieve the same results.
> >
> > Since this reflector is blessed with an abundance of talented and
> > knowledgeable techno-wizards
> > would any of you care to comment on this approach?
> >
> > KC5GNB
> > Bill in Plano
> >
> >
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> >
>
>
> ----
> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
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>