Johnson Viking Valiant ?

[K6RAD]

Greetings,

I am restoring a Valiant and it has an internal TR switch.  Its a little 2"X3" metal box bolted above C8 on the sheetmetal divide with one 7 pin tube socket on the top (has to be a short tube).  Its labled with TR swith and the wire hookup color code and nothing else. I bought this one with no tubes and I would like to buy the correct tube.  Does anyone one know of such option from Johnson or aftermarket?  I need to know the tube # and I would also like to buy the schematic.

Thanks,
K6RAD

[KB2WIG]

The skizmatic is free.


http://bama.edebris.com/manuals/johnson/valiant/


Oh ya, welcome a board.


klc

[Pete, WA2CWA]

The skizmatic is free.


http://bama.edebris.com/manuals/johnson/valiant/


Oh ya, welcome a board.


klc

I suspect he's looking for the schematic for the TR switch.

Give us a picture of the TR switch.

[Ed/KB1HYS]

Hmmm,  I don't recall a T/R switch for the Valiant.  Originally they had a relay that fed 110v out to trigger a reciever mute/ant relay.   I wonder if someone was using it an an amplifier at one time?  The valiant was designed to work as a linear for a low power SSB exciter (4watts or less in)  I suspect a few fell to CB types because of this and the 11m band availability on that rig.

You'll hear various disparaging remarks about valiants, but I found that mine is a work horse in the shack.

[K6RAD]

Attached is a picture of the internal TR switch.  They used one of the SSB connectors for reciever out.

[K6RAD]

Here is another photo of markings around the SSB connector.

[KB2WIG]

"  I suspect he's looking for the schematic for the TR switch. "


DUH!


klc

[Pete, WA2CWA]

I recall some homebrew TR switches used a 7 pin tube like a 6AK5 or 6CB6. I believe the early version of the Dow Key DKC-TRM-1 used a 7 pin tube and then went to a 9 pin dual triode.

[The Slab Bacon]

If you take a lookie in one of the older ARRL handbooks from the early / mid 60s you will find the info on the basic cathode follower T/R switch that was produced by Johnson and other mfrs, it's a pretty simple circuit. However......................

If you are planning a real "restoration" I would remove that crap out of there and any other "hammy hambone" mods you find and rewire it back to original to verify that it is operating properly. Then do some audio mods to improve the fidelity of it.

I have a Valiant, and like Ed said, it is a good workhorse, mine was the workhorse of the station till I built the 4X1 rig 10 years ago.

Many of those were kit-built and built by hams that really didnt have the wherewithall to build them properly. After many years you will probably find some reliability issues popping up as well. A good recapping, clean up, and redressing of the wiring harnesses and leaded components will go a long way. Not to mention touching up any crappy solder connections.

Be sure to check the drive pot and the Chernobyl resistor as well. do all of that and you'll be rewarded with a good 100w workhorse transmitter.

[Rob K2CU]

This may be a hambone version of the Johnson TR Switch, see:

http://bama.edebris.com/manuals/johnson/trswitch/

It used a 6BL7. This dual triode tube (Octal base) had an extremely high (200KV) peak anode rating. The first stage impedance match to drive the cathode of a grounded grid stage (all broadband). RF also runs into the grid of the second stage through high impedance to be rectified by the grid and provide cut off bias. The tube you use will have to sustain high voltages on grid and other elements depending on power level involved. With VSWR, you can get pretty high peak voltages from even a modestly powered rig like a Valiant.

My Valiant is a kit built back in 1960 and then put on the shelf  for fifty years by the original owner who had no idea how to build a kit, even with the good instructions they provided. She had at least 5 unsoldered joints and the builder had no idea about lead dress for parts, especially bypass caps. It did have correct insulation on xformer leads though and I plan to solid state the PS when I figure out a sub for the purple glow....maybe some violet leds.

[Pete, WA2CWA]

This may be a hambone version of the Johnson TR Switch, see:

http://bama.edebris.com/manuals/johnson/trswitch/

It used a 6BL7. This dual triode tube (Octal base) had an extremely high (200KV) peak anode rating. The first stage impedance match to drive the cathode of a grounded grid stage (all broadband). RF also runs into the grid of the second stage through high impedance to be rectified by the grid and provide cut off bias. The tube you use will have to sustain high voltages on grid and other elements depending on power level involved. With VSWR, you can get pretty high peak voltages from even a modestly powered rig like a Valiant.

If you look at his picture and his text, he indicates he has a 7 pin tube socket (6BL7 is eight pin) mounted there. Also, the socket looks riveted to the chassis; most homebrewers used screws/nuts. I don't see any reason why a sharp-cutoff pentode like a 7pin 6CB6 couldn't be used in TR switch design.

[K6RAD]

After a lot of searching on the internet I found some info on this TR switch.  The tube it uses is a 6AH6.  QST had a artical on it in 1957, however I still do not know the manufacturer, the URL is:

http://vacuumtubebrasil.profusehost.net/A%20novel%20electronic%20transmit-receive%20switch.pdf

It sounds good, I will try it before I rip it out.

73s