[ICOM] Re: IC781 Power Supply
n6lrv at cox.net
n6lrv at cox.net
Thu May 3 11:43:08 EDT 2007
Mel,
this was discussed on this list just a couple of weeks ago. Floyd has supplied a new link to his report but here it is again;
http://home.earthlink.net/~fsense/k8ac/781Temperatur.html
Gary
---- mel martin <ve2dc at videotron.ca> 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.
>
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