[R-390] Dayton experience

[Dan Merz]

Ed,  ok, I took a look at the bfo coil in the extra 390a i.f. chassis I
have.  If you point the shaft end toward your  eyes with the middle pin at
12 o'clock,  the terminals are numbered 1, 3, 2 in clockwise order with pin
1 at 11 o'clock, pin 3 at 12 o'clock and pin 2 at 1 o'clock.  On my Artisan
Electronics unit,  the pins are identified by a stamped number on the unit
and these numbers correspond to the schematic
Pin 1  goes to grid thru a capacitor
Pin 3  goes to ground
Pin 2 goes to cathode (center tap of bfo coil)

I checked the actual wiring on my unit in the chassis and the numbers
stamped on my unit indeed correspond as described.  
Hope this helps,  best regards, Dan. 

-----Original Message-----
From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
On Behalf Of DJED1 at aol.com
Sent: Thursday, May 26, 2005 1:01 PM
To: r-390 at mailman.qth.net
Subject: [R-390] Dayton experience

I thought I'd share a couple of impressions of my first journey to  Dayton.

It sounds like some of the list members came away with radios- I  resisted
the temptation, but had a good time.  Saw a handful of R-390s,  including a
nice black-face A, and a R-725, as well as the usual R-390s and As.  Looks
like most went for at or under $500, and all were in good shape including
original meters.  I was tempted by the black face, but the thought of
lugging it all day made me move on, and it was gone when I returned.
Of equal interest, I stopped at Fair Radio to see their stash of R-390
stuff.  I got a tour from Gary, who does all the restorations of "checked"
radios. 
 He showed me the stash, which consists of about 5 pallets of blue
stripers, and a small number of parts chassis of the non-A.  Gary said he
was having trouble finding good modules now, and will probably run out of
checked units in a year or so.  LOTS of parts around, but definitely
needing repair.  I think Fair does a lot of work (including painting the
front panel) on the checked radio for the extra couple of hundred they  get.
The most interesting comment was that Gary has had some success with
rebuilding the mechanical filters.  He finds that most have a broken wire
in one of the transducers, and he can repair or rewind the transducer and
then  replace the filter in the housing using new foam.  This may be
necessary in  the future as the filters start to fail more frequently.  
I picked up a BFO coil that I want to use in my external SSB adapter.
While 
Fair gave me the schematic for the current oscillator, I don't have any
information on which of the three terminals is which.  Can anyone identify
which 
of the terminals is the tap, which is the grid, and which is ground.
Thanks 
for the help.
Ed
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