[ICOM] Re: IC781 Power Supply

[Glen Rosenthal]

For your interest, here is a link that might provide additional insight 
regarding 120v vs. 100v supplied to the 781.
http://home.earthlink.net/~fsense/k8ac/781Temperatur.html

73,
Glen


>From: <n6lrv at cox.net>
>Reply-To: ICOM Reflector <icom at mailman.qth.net>
>To: ICOM Reflector <icom at mailman.qth.net>
>Subject: Re: [ICOM] Re: IC781 Power Supply
>Date: Thu, 3 May 2007 9:43:57 -0700
>
>Lee,
>Rob Sherwood's kit is available at this link;
>http://www.sherweng.com/IC781Fan.htm
>Gary
>---- "Lee Mairs (SAG)" <lmairs at sagcorp.com> wrote:
> > Can someone point me to the Sherwood mod mentioned below?  My 781 has
> > been going strong for about 15 years.  I'd hate to lose it now.
> > 73 de Lee
> > KM4YY/8
> >
> >
> >
> > mel martin wrote:
> > >> The PSU was designed for the Japanese 100V mains supply. When fed 
>from 120V
> > >>
> > > mains, the shunt-regulator dissipation increases by a whopping 44%!
> > >
> > > Hi Adam...
> > >
> > > A while back someone actually ran temperature tests on the 781 power 
>supply.
> > > I think the data was on this reflector... At least a link to it. I
> > > distinctly remember that the rise in ambient temperature with a 120V 
>mains
> > > supply as opposed to a 100V supply was trivial. The obvious conclusion 
>is
> > > that the mains supply not is not the issue... The power supply also 
>ran far
> > > too hot at 100V... So all those 781s out there running on Variacs are 
>at
> > > risk. What is needed is additional cool air. I use the Sherwood 
>Engineering
> > > kit... And it works very well.
> > >
> > > I wish I still had the reference. Perhaps someone can provide it.
> > >
> > > ----
> > > Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
> > > Icom Users Net: Sundays, 1700Z, 14.316 MHz
> > > Icom FAQ: http://www.qsl.net/icom/
> > >
> > >
> > >
> > ----
> > Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
> > Icom Users Net: Sundays, 1700Z, 14.316 MHz
> > Icom FAQ: http://www.qsl.net/icom/
>
>----
>Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
>Icom Users Net: Sundays, 1700Z, 14.316 MHz
>Icom FAQ: http://www.qsl.net/icom/

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