[R-390] 390() vs 390(A)

[Barry Hauser]

Hi Roy & gang

Well, if you get one, YMMV.  Odds are the autotune doesn't work -- and it's
not a good idea to try it before overhauling the thing, no matter how
tempting.  Most owners of '391's use them like 390's and have never powered
up the autotune.  So, they've been sitting for ages.  The switch contacts in
the control unit are probably oxidized, and the stack of pawls -- they're
like a sandwich -- are all glued together by the petrified lube that is
needed to be super-slippery for the thing to have snowball's chance to work
in the first place.  Also, the thing probably needs to be re-synched -- 
after it's overhauled.  It is impossible to walk this gizmo through manually
in steps, though you can put a bristol wrench in the synch adjuster, lock
the knobs down and rotate it.  However, it's not a complete simulation as
the relay and control unit aren't doing their things. It's all hard-wired
together -- including the relay -- no socket.

So, having one offers no assurance of comprehending how it's supposed to
work, let alone mastery.  You have to walk through the manual explanation,
and that's lacking.  Actually, the equivalent manual section for the R-105
(ARR-15?) does a better job.  The mechanisms are similar.

The best procedure is to open up whatever you can, degrease, clean contacts,
re-lube, see if things move, set the synch.  Then, make darn sure that the
channel selector is set to the same number as shows in the window.  Lock the
locking keys down tight.  Then apply 24 vdc to the 4th pin -- use an outlet
strip to cut the supply if there isn't a handy switch.  Then change
channels --which will start the show.  Even if it's working, you'll be
startled at the noise and the gnashing of gears, slamming and banging.  It
is a wild experience the first time you see a '390's knobs turning by
themselves.  Both turn, then one stops, then the other turns.  If it was
past the point, it rewinds.  After what seems like a few minutes (or hours),
it will stop at some frequency.  If it runs amok and tries to
modify/remachine the 10-turn stop (to infinity), cut the DC.

The thing's a puzzle -- what's that saying? -- an enigma, wrapped in a
paradox -- never could get that right, either.  There was supposed to be an
R-391A, but there wasn't.  I suspect it was partly because by the time they
got around to it, there was some field experience with the first one.  Also,
it needs the beefier geartrain of the original item.

It's a good idea to take an 83 mg. aspirin about an hour before you start -- 
or a couple a' good snorts.  It's scary.  After we spend all the time
cleaning, lubing, replacing broken clamps, synching, aligning, recapping,
meditating over the ballast tube considerations, refinishing panels,
re-stuffing plugins, etc. we have a tendency to treat these things with some
delicacy and respect.  The autotune mechanism doesn't know from that.  If it
isn't working right or not synched up, it may well try to tune your '391
into the '389 range -- or to 2.4 ghz -- or maybe even 5.8 to listen into the
new cordless phones.  Yup, it'll wreck yer deck -- if the vibration doesn't
kill half your tubes.  (Make sure the filament in your ballast tube is nice
and flexible before powering up.)


Poll -- how many of you guys have R-391's with working autotuners?  How many
with non-working ones?  How many unknowns?  Actually, I think it was Paul
who rebuilt his '391, right?

Barry

----- Original Message ----- 
From: "Roy Morgan" <roy.morgan at nist.gov>
To: "Barry Hauser" <barry at hausernet.com>; <paul at pdq.com>
Cc: <r-390 at mailman.qth.net>
Sent: Monday, December 27, 2004 6:05 PM
Subject: Re: [R-390] 390() vs 390(A)


> At 05:46 PM 12/27/2004, Barry Hauser wrote:
> >Roy wrote:
> >  ... In the R-391, both the KC and MC setting mechanisms
> > > are moved by (separate) Motors and associated position setting
> > > mechanisms.
> >
> >Not so .. only one motor in the R-391.  I have two of the beasts.
>
> Barry,
>
> Thanks for the clarification.  I had some mis-conceptions.
>
> All the more reason to own one so I can learn the beast!
>
> 73,
> Roy
>
>
> - Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
> 7130 Panorama Drive, Derwood MD 20855
> Home: 301-330-8828 Cell 301-928-7794
> Work: Voice: 301-975-3254,  Fax: 301-948-6213
> roy.morgan at nist.gov --
>
>