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 Post subject: Johnson Viking II restoration
PostPosted: Feb Sat 24, 2018 2:45 am 
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Location: Costa Mesa, California
I am working on a Viking II which has been on a shelf in my garage for over a year. It is in pretty good condition--except some paint issues on the case. This one was wired by C.H. Nelson Company in Waseca, Minn. Waseca was the home of the E.F. Johnson Company as well. It has a 12AU7 circuit added at a partition next to the crystal deck.

I have replaced many resistors and all the electrolytics and paper caps (except the big oil can). So far everything else looks pretty good. What about the doorknob plate cap for the pA tubes? I have some .002 1KV ceramics. Should I leave it or order some 3KV caps. Or use a pair of .001 3KV ceramics which I have.

I read some of the posts from previous restorations on this website, so am aware of the fact that these transmitters were heavily modified. Mine has several generations of resistors. The 12AU7 mod looks like it was more recent, as it has modern carbon resistors. I do have the Johnson VFO but haven't got it on the bench yet. This transmitter came with a few crystals and I have some from previous transmitter restorations.

Any advice would be appreciated. I will post some photos Sunday when I get back to civilization.

Norm

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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Sat 24, 2018 3:13 am 
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Location: Roslyn,Pa 19001
The 12au7 is more than likely a differential keying circuit. It's in the Johnson Viking I and II literature.
http://bama.edebris.com/manuals/johnson/keyermod/

Terry N3GTE


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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Sat 24, 2018 3:26 am 
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Norm,

The 5R4 sockets are prone to carbon tracks if they aren't kept clean so check them and the bottom surface of the tube base to make sure there isn't dust buildup.

A fairly common issue is the switch driven by the 160 in/out control will get stiff to turn and the drive pulley will shear off easily. Make sure that this switch operates freely and put a couple of drops of synthetic oil where the shaft goes through the bushing.

The 12AU7 addition probably is the Johnson factory kit for adding a differential keyer (or a copy of the Johnson kit), see documentation here: http://bama.edebris.com/manuals/johnson/keyermod/

Note that the external VFO has the same problematic dropping resistor as the Ranger/Valiant/500 so change to a higher wattage rating when you have the VFO open.

I don't operate full break-in so I use a spare set of contacts on my T/R relay to key the VFO whenever the transmitter is in transmit mode and do the actual keying in the rest of the exciter chain; with the keyer circuit added it will definitely have less chirping than a standard Viking 1 or 2 / VFO-122 setup but still more than just leaving the VFO keyed while in transmit mode.

The Viking 1 and 2 is susceptible to the same warbling on 40 meters due to RF getting into the VFO (on 40 both VFO and final are on the same frequency). It isn't as noticeable with the separate boxes but depending upon your antenna and ground situation you may notice it. If this is a problem you can operate the VFO in the 160/80 position and multiply up to 40.

Have fun. The Viking 1 and 2 are the best built of any of the Johnson gear.

Rodger WQ9E


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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Sat 24, 2018 4:15 am 
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I would leave the doorknob alone unless there is a problem. Doorknobs handle more RF current than discs, which is why it is that type at that location.

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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Sat 24, 2018 7:13 am 
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Location: Costa Mesa, California
Thanks all for your help. The door knob stays. One of the 5R4 tube sockets had what appeared to be traces of metal deposit between some pins. Those I chipped off and it is now clean. The other HV tube socket is fine. I lubricated the shaft of the 160 meter In Out switch per Rodger's suggestion. I removed the meter and fixed a loose glass, cleaned some old packing tape glue residue off the face with mineral spirits, and replaced the meter looking beautiful. All the knobs have been cleaned and the front panel rubbed out. I gave the transmitter some preliminary tests and read the tune up protocol. Tomorrow I will fire it up.

Norm

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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Sat 24, 2018 1:24 pm 
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Location: Roslyn,Pa 19001
I took and drilled out the rivet for the receptacle for pin 5 and removed it from the socket as it would sometimes arc from pin 4 to 5 and over to 6. This eliminated the problem.

Terry


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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Sat 24, 2018 5:48 pm 
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Radioroslyn wrote:
I took and drilled out the rivet for the receptacle for pin 5 and removed it from the socket as it would sometimes arc from pin 4 to 5 and over to 6. This eliminated the problem.

Terry


You have that right. Those were the pins with the metal deposits. This one had some welding going on--apparently for some time.

Norm

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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Sat 24, 2018 6:03 pm 
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Location: SW WA state
Norm,

George beat me to the punch on the RF cap: Make sure you have one that will handle the RF current!
Drop me a PM: I have a fairly good selection of 40M FT-243 xtals, will gladly send you one. My stock of 75M & 160M xtals is getting low.
There is a guy on Ebay selling Johnson spray paint. He's getting ready to pull the plug, so I bought a can of his paint to touch up the Viking 500...
Best of Luck on the Viking II!

-Tom


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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Sat 24, 2018 7:04 pm 
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Joined: May Fri 01, 2015 2:33 am
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Location: Roslyn,Pa 19001
I'll mention one other tip if the 6AL5 has a collar for the shield don't put a shield on it. It's so close the pa rf choke it will arc and destroy the choke. Don't ask me how I know.

GL
Terry N3GTE


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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Sat 24, 2018 9:33 pm 
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Complete success! The transmitter is working perfectly. I tuned it up per manual and set the clamper tube. Everything went exactly as it should with good power output and all controls functioning correctly. Now I will return the transmitter to its case, which could take some wrist action with all the screws involved. This thing is really a return to another time, when AM and plate modulation ruled the day.

Next up is the Johnson VFO.

Norm

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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Sat 24, 2018 9:45 pm 
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Location: Liberty, Missorui
Excellent!!

Nice to see another veteran transmitter on the air. Real "Authorized Modulation", the best of all the voice modes.

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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Sat 24, 2018 11:19 pm 
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The VFO was a bit of a joke. Someone had been inside and replaced all the resistors except one. The power dropping resistor for the B+ was old and kind crispy looking. Above it the chassis had a brown smokey look. There was a nice cement 20K 5 watt between the plate and the screen of the 6AU6 so that one isn't going to fail any time soon.

I replaced a capacitor and the power resistor and the VFO is done and ready for testing.

Norm

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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Sun 25, 2018 3:51 am 
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Testing did not go as planned. After I couldn't get a signal, I looked closer at the wiring and it was not following the schematic. The key jack had been removed from the circuit and a few other changes, but the big problem was the grid bias resistor was going to a capacitor to ground instead of straight to ground. Once the circuit was back to original it worked. Then I needed to move the dial a little so the bands would adjust out correctly. All in all, this is a very stable VFO with almost no frequency fluctuation. No wonder it can be used for higher harmonic operation.

Norm

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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Sun 25, 2018 4:04 am 
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Norm,

It is a solid VFO design and is the basis for the Ranger/Valiant/500 VFO. Heathkit used a similar design for their VF-1 and the DX-100. Both are slightly more stable with a 6AH6 tube in place of the 6AU6.

Rodger WQ9E


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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Sun 25, 2018 11:57 pm 
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Here are the photos. I have not considered re-doing the case on this one. The wrinkle finish seems pretty hard to match, but there are paints out there and the method is to heat the paint after spraying. Everything else cleaned up very well except some spots on the chassis where some substance dripped into the radio and puddled up. I didn't want to scrape and none of my regular cleaners could touch the stuff.

Norm

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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Mon 26, 2018 12:22 am 
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Very nice! Your front panel is in good shape and that front panel is the least rugged part of that entire transmitter.

Rodger WQ9E


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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Mon 26, 2018 12:31 am 
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Nice looking pair for sure. Have fun with them.

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 Post subject: Re: Johnson Viking II restoration
PostPosted: Feb Wed 28, 2018 9:47 pm 
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Looking good Norm! I have a Viking 1 with a 122 VFO waiting for repair. Your post has got me inspired to get started.

Mike/KE5YTV

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