[R-390] PTO

[David C. Hallam]

The filament circuit for the VFO and BFO is identical in the R-390 and
R-390A.  The two tubes are in series with the ballast tube.

IMO the R-390 is much the better of the two receivers.  The mechanical
filters in the R-390A do not make that module superior to the R-390.  I set
up a R-390A IF module for use in my R-390.  After a few hours of use, I took
it out and put the original back in.

In general higher quality parts were used in the manufacture of the R-390.
The R-390 does not normally need have wholesale replacement of capacitors
(paper and electrolytic as does the R-390A.  The R-390A was designed to
reduce cost.  Longevity was not a consideration.

David
KC2JD

-----Original Message-----
From: Richard Loken [mailto:richardlo at admin.athabascau.ca]
Sent: Monday, December 05, 2005 5:07 PM
To: David C. Hallam
Cc: DW Holtman; R-390 at mailman.qth.net
Subject: RE: [R-390] PTO


On Mon, 5 Dec 2005, David C. Hallam wrote:

> According to the information I have, the only differences are the RF
> connector and the power cable.  I think the power connector itself is the
> same.

That is useful information.  This means that I can now look at certain R390A
parts with much more (malevolant) interest than I used to.  I always thought
that they were differant and I was encouraged in this belief by the 24V
filiment wiring more so than by the difference in RF connectors.

I would still recommend selling it and getting a much more common 390A (and
probably newer) 390A PTO.

--
   Richard Loken VE6BSV, Systems Programmer - VMS  : "Anybody can be a
father
   Athabasca University                            :  but you have to earn
   Athabasca, Alberta Canada                       :  the title of 'daddy'"
   ** richardlo at admin.athabascau.ca **             :  - Lynn Johnston