[Johnson] Re: Johnson digest, Vol 4 #96 - 2 msgs
Eddy Swynar
[email protected]
Wed, 18 Jun 2003 07:31:32 -0400
Hi Ed,
Very interesting comments re. your Viking II---I know you will be VERY
pleased with it when it's finally all restored.
I can speak with some authority here, as I now have TWO of them! Mind you,
the first is the "C-C" model (or, "Continous Coverage).
My C-C needs the mic gain set to LESS than the #2 position on the knob. I
use a non-amplified D-104 CERAMIC element with mine (the ceramic mic had
more output than the crystal type).
I keep grid drive at about 6 ma. (the book says 8 MAX)---drive has a big
impact on final output with mine.
One interesting aside: the "C-C" has parasitic suppressor resistors in the
807 plate leads---the "regular" V2 here doesn't (they're not even shown on
the V2 schematic, in fact). The C-C benefited from the "...usual" audio
mods---i.e. fatter coupling caps, bigger bypass caps, elimination of caps in
across audio transformer windings---but the stock V2 sounds FB "as is".
I like these rigs. Although I'll end up eventually selling off the V2---I
bought it only to get my mitts on the 122 VFO that accompanied it---they're
attractive, well-built, & function fabulously, AND at a good power
level...sound great on CW, too!
Enjoy yours...
~73~ Eddy VE3CUI - VE3XZ
--- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Wednesday, June 18, 2003 4:03 AM
Subject: Johnson digest, Vol 4 #96 - 2 msgs
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> Message: 2
> From: [email protected]
> To: [email protected]
> Date: Tue, 17 Jun 2003 17:45:20 +0000
> Subject: [Johnson] Viking II
>
>
> Have finally gotten around to working on my Viking II I got for 40 bucks.
> Seeking comments on some questions. But first:
>
> Replaced the R13 50 watt divider. Question on that in a moment.
>
> Replaced the LV caps, had only 20 MF instead of 15MF.
>
> Replaced the bias caps with 15/250 caps.
>
> Installed two chassis mount fuse holders underneath and a three-wire
grounded
> power cord.
>
> Question 1. Noticed in the Johnson assembly manual (from BAMA) there is
mention
> of TWO sliders on R13. This is not shown on the schematic in the Johnson
> Operator's manual, but the one slider that is shown is labeled "A", which
would
> suggest there could be a "B". However, the assy manual says the front
slider (A
> or B?) is for screen voltage on the 6146s. But the schematic doesn't
agree with
> that, as the clamper tube controls screen voltage and is set with the R30
pot
> and the single slider that is present, per operator's manual.
>
> Question 2. With the new caps at 20 MF each in the LV supply, LV is abot
360
> VDC. I get 355 VDC to the VFO, which does not so far appear to be a
problem at
> all. But it does give me a higher than anticipated 6146 screen voltage,
about
> 220 instead of the specified 195 V.
>
> However, after adjusting the bias pot (R30) both 6146 and 807 idling
current is
> exactly where it should be, with the higher screen voltage.
>
> Question (not really) 3. Grid current. I get full output from the finals
at
> about 3 ma total grid current, perhaps a dab less, on 80 meters, using the
VFO
> to drive it. (Same on 40) Tunes beautifully with 2.5 to 3 ma grid
current.
> Just seeking any comment here, but I suspect that's a good thing.
>
> I'm getting about 100 watts output on AM to a dummy load. Can load it to
more,
> but that is about where it falls with the factory specified settings. And
I am
> of the nature I prefer less power to more, to conserve these old rigs.
>
> As much as I HATE amplified microphones ... I latched onto a D-104 very
cheaply,
> and in excellent condition, but it is amplified. I crank it almost all
the way
> down to use on the Kenwood TS520, but on the Viking II I crank it to
around 70
> percent of its control. This gives me modulation that is peaking at about
120
> ma mod current, and sounds terrific, but the Viking AF gain is set at 6.
Comments?
>
> Modulation looks good as set up above on the scope and sounds good, with
zero
> hum, at a station about three miles away. Any higher on the D104 and I
can see
> distortion and a bit of splatter showing up.
>
> Any comments welcome.
>
> (As an aside, I put the G76 Gonset on the same frequency chatting with my
amigo
> up the road, using a Shure 444, and the Johnson's audio is much stronger,
though
> the G76 sounds good, just lower modulation. I may need to adapt the D104
to it!)
>
> 73
> Ed
>
> --
> Ed Brooks, W5HTW
> http://w5htw.home.att.net/index.html
> Active since June 1956 Extra since
> Jan 1970
>
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