[R-390] R390A to R725 conversion question

[Larry Haney]

Hi All,  Tom Marcotte made a nice post on this subject on  Sun, 21 Aug 2005
16:14:25 -0700 (PDT).  It's in the Pearls 'IF_Deck' section and titled
'R-725, How To Make Your Own'.  This would  be a good place to start and
there are many other posts in there on this subject, also.

Perhaps a document on this subject would be beneficial to put on our
website, if someone would put one together.

Tom,

You had a number of links in your R-725 posts referencing 'geocities,com',
but those seem to be gone now.  Do you still have them somewhere?  Thanks.

Regards, Larry



On Wed, Oct 30, 2024 at 5:38 PM Tom M. via R-390 <r-390 at mailman.qth.net>
wrote:

>  Perry,
> The added transformer in the R-725 was for PTO hum bucking, not filaments.
> sk Wally Chambers informed me of that fact.
>
> The R-725 had the rewired R-390 filaments.  I've done this myself and
> wrote a procedure how to do it. I agree with you it was a bit of a PITA.
> I use the converted IF deck in my daily driver R-390A to this day.
> Tom
>
>
>
>
>     On Wednesday, October 30, 2024 at 04:31:35 PM CDT, Perry Sandeen via
> R-390 <r-390 at mailman.qth.net> wrote:
>
>  List,
> IIRC I've seen 3 published articles for r390a to r725 conversion all using
> the re-wiring of the R390 IF to 6 volt filaments.  This seems to be a big
> PITA.
> When the military did the original they just added another 26 volt
> filament xformer. This seems a much easier approach especially when we have
> small SRPS's available.
>
> If anyone would have the schematics or TM addendum I would appreciate it
> if they would contact me off list.
> TIA
> Perry
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