[ICOM] Re: IC781 Power Supply

[Don\]

Good graphics but I can't help wonder if the whole test is meaningless given 
the highest temp of 125F can't reasonably be expected to do any damage to a 
baby's bottom, never mind a power supply board component.
Am I missing something?
Don/K1VSK


----- Original Message ----- 
From: "Glen Rosenthal" <n0nr at hotmail.com>
To: <icom at mailman.qth.net>
Sent: Thursday, May 03, 2007 9:41 PM
Subject: Re: [ICOM] Re: IC781 Power Supply


>
> 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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