[Johnson] Viking II

[w5htw@att.net]

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