[1000mp] Compare FT990

[Bert Garcia]

My FT-One has a card cage with five plug-in slots.  There are three more
"boxes" and two circuit cards, not counting the power supply.  Very elegant
design.  Since Yaesu abandoned this design approach after the 990, I gotta
believe it was for cost reasons.

Two decades later my FT-One performs flawlessly.

Bert N8NN

----- Original Message -----
From: "Mike Gilmer, N2MG" <n2mg@eham.net>
To: <1000mp@mailman.qth.net>
Sent: Thursday, July 11, 2002 20:51 PM
Subject: RE: [1000mp] Compare FT990


> Having never seen a 990, I cannot say how Yaesu approached the problem,
> but having witnessed a few plug-in designs...
>
> 1. If there are a LOT of coaxial interconnects, these are fairly
> expensive in the form you are advocating.
> 2. The PC boards would need to be designed so that all the leads came
> out the connecter edge (including the problematic 50ohm runs) - this
> takes some doing (multi-layer might be needed) and can have performance
> problems.
> 3. The "motherboard" can get to be quite complex - multi-layer again.
> Adding a new interconnect requires the MB be modified as well as the
> destination boards.
> 4. Overall packaging is constrained by the plug-in concept - with
> the "MP" for example, they can and do put boards anywhere and
> everywhere and they can be all different sizes.  With the plug-in
> design, juggling functions around because one runs out of room on
> cookie-cutter-sized boards can be a pain.
>
> IMO, plug-in boards lend themselves more to very high volume, or very
> expensive designs. Even though the 1000MP/D/MPV/MPVF are several grand,
> they are NOT expensive by my definition (well, yes, they are to me and
> my hobby, but I'm talking about $10K, $20K and up devices).
>
> My guess is that they may have had too many problems (cost or
> development time or...) on the 990 that they abandoned the concept.
> Maybe the chief advocate for that kind of design is no longer there to
> champion the cause.  Too bad.  Troubleshooting to the board level can
> sure be easy if one can swap boards with a friend!  Surely you can't
> think Yaesu cares much about that.
>
> 73 Mike N2MG
>
> The following message was sent by "Garry Shapiro" <garry@ni6t.com> on Thu,
11 Jul 2002 19:36:21 -0000.
>
> > One might ask how that is so considering all the added cables/headers,
the
> > assembly time for the interconnects, and the extra testing.
> >
> > Garry
> >
> > Joe Hanna:
> > >
> > > Cost!
> > >
> > > Garry Shapiro wrote:
> > >
> > > > What I recall of the FT990 (from Conway Reef, 1995) was that it
> > > had a fine
> > > > RX, and that it was constructed like a quality computer, i.e. it had
a
> > > > backplane and plug-in cards. That meant a minimum of
> > > interconnecting cables,
> > > > headers and coax leads, and easy access/replacement, which
> > > suggested higher
> > > > reliability. I recall being surprised and nonplussed that Yaesu's
> > > > contemporary and subsequent efforts abandoned that approach and
> > > returned to
> > > > multiple boards in every nook and cranny, interconnected with
> > > (far too many)
> > > > cables. Anyone who has removed the main board in an MP to
> > > replace or add a
> > > > component will appreciate this.
> > > >
> > > > Perhaps someone out there in MP-land can tell me why the
> > > card-and-backplane
> > > > approach was abandoned.
> > > >
> > > > Garry, NI6T
>
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