[Johnson] Viking 1 "gotchas" ?

[Carl]

> Hello All,
>
> It looks like I might be acquiring a Viking 1 in "restore-able" condition. 
> Just wanted to check to see if there are any "gotchas" before I take on 
> the project, like unobtainable replacement parts, or whatever.
>
> Cheers,
>
> Brian Burns  Ex: W5BRO, K6UCD



Brian I ran a V-I from 57-61 and it worked flawlessly, even thru a teenagers 
misstuning, that 4D32 is a very forgiving tube unlike the 6146's in the V-II

These days I have a V-1 and V-II CDC which is a modifed V-II that covers 1.5 
to 33 MHz continuously, has PTT and a speech clipper which is a splatter 
generator. Easy to remove.

Both models share almost all the same circuitry and the only reasons the V-I 
was discontinued was TVI and the Korean War. Raytheon was the sole source of 
the 4D32 and the only commercial ham use was Johnson, Hallicrafters very low 
production HT-20, and all the Collins 32V series.

The USAF used that tube as a radar modulator and required Raytheon to 
provide to them only. Obviously Collins paid someone off since they were 
joined at the hip with the USAF.

A few late model V-1's were shipped with the 829B (or no tube since it was 
plentiful in WW2 surplus) and modification instructions were available to 
others. The V-II was a rush job and RCA saved the day with the 1951 6146. A 
modification kit was also available to V-I owners.
A sign of our government in action was that radar was scrapped shortly after 
Korea but the initial 4D32 contract specified all new ones every few years 
into the early 90's when some smart procurement officer caught it. Most out 
of date ones were scrapped over the years (along with enough 5 finger 
discounts by serving ham entrepenuers to keep many rigs running) but when 
the final release to dealers was made it contained several later date codes. 
I have enough to keep the V-1, 32V2 and eventual HT-20 acquistion happy. A 
pair will also make a nice 250W HB rig as prices havent climbed much over 
the $20 a pair I paid a few times on Fleabay.

Weak links are:

All the paper caps, even those in plastic; dont bother to cherry pick as all 
are high leakers at some point especially after B+ has been regularly 
applied to accelerate the chemical action.

Out of tolerance resistors, even some low values as vendors changed. Use 1W 
film in place of 1/2W carbon as the size is similar, I dont care for the 
looks of the wimpy 1/2W!

All electrolytics, even the small ones in the audio.
The 8uF 1000V oil cap develops leakage. The one in my CDC was so bad it had 
severe paint discoloration on the bottom side; I replaced with a fairly new 
pair of 100uF Sprague TVA ATOMs I had on hand and with 100K 3W equalizers.
I have found similar caps in other rigs that fail a 1000V leakage test.

The modulation transformer is marginal in reliability and iron and should 
not be subjected to highly processed audio or more than the rated plate 
current for 100W AM from the 4D32, the same for the V-II since all the iron 
is identical. A V-II loaded and driven to the max can be heard all over the 
band.

The 6AQ5 clamp and 6AL5 bias rectifier are high failure items after years of 
use, I use the 6AL5W/5726 and 6AQ5W/6005, both cheap and reasily available.

The 5R4 sockets can arc when contanimated or pins loose tension from 
resistance heating. Clean with 90-95% Isopropyl alcohol or replace with USA 
made for HV rated use only; the Chinese ceramics contain lead. I do not use 
SS since the resultant higher voltage and hard switching every cycle places 
uneeded strain on the transformer. If the tubes are weak/bad use the 5R4WGB 
potato mashers which have a higher PIV rating and dont fuss when you drop 
the rig.

The audio sounds like it is from the space shuttle or Highway Patrol reruns 
due to the ARRL's insistence that AM restrict its bandwidth. The V-I 
shipments were delayed while the audio section was redesigned. The only 
postwar TX I know of that had "hi-fi" audio was the gray Hallicrafters HT-9 
which was an almost carbon copy of the 1940 black one and was there only to 
hold the fort until the HT-20 was ready. ER had a 3 month V-II series in 
1998 for making a huge improvement in audio and CW. I ran on the air A-B 
comparisons between a stock V-I and modified V-II for a few weeks 160-10 and 
the mods won hands down as expected by test equipment results. The mike in 
both cases were late model CB D-104's that I bypassed the preamp.

That 15K bleeder is a failure PITA in both models and the ER series has work 
arounds.

There are several articles on adding PTT; my CDC still has the noisy stocker 
but the V-I is almost silent. The clunker will be replaced when the spirit 
moves me to take out a zillion screws again.
 Both rigs now use the Johnson 250-39 electronic T-R switch since a HT-9 is 
used for 160.

Mouser has always been my primary supplier when I dont have luck at my 
industrial surplus dealers.

Switch contacts have a habit of becoming intermittent. I start with Tarn-X 
on a Q-Tip and gently wipe the rotors and then a quick rinse with fast 
evaporating disc brake cleaner. For the tough ones a tiny drop of DeOxit 
D-100 on the rotors and rotating several times works; finish with the brake 
cleaner as that stuff does not like RF or B+. For stiff detents use PB 
Blaster or Kroil sparingly.

I also use Tarn-X on the roller coil and wheel and rod, plus the brake 
cleaner. Lightly oil the gear train if needed.

The V-I sat in a basement for many decades and while the chassis and 
everything else was protected by a nicotine layer and dust (a pita to clean) 
the tube pins and sockets needed the D-100 treatment and several insertions.

Carl
KM1H