The AM Forum

Hi all, Me again.   While I wait for a part for my Apache I have been posting about, I acquired a Johnson Viking II.  So I load the transmitter, everything works as the book says, but I am getting a carrier showing up on my panadapter at the same frequency as the crystal installed with the plate power turned off.  Im baffled.  I am including two pictures of the panadapter,  one with plate off, the other with plate on.  Transmitter is set up for max power at 230ma. The carrier is small, but is plenty to saturate my receiver and make it useless.  Any Ideas?  I have done internet searches and maybe I am not entering them right, but I can find nothing about this.  I have checked my grounds several times too.

Thanks
73
KC3GMQ Dave

Is the signal still there with the phone/cw switch in the phone position?

The signal is there in phone , or in CW key down,  both set ups with plate off.

KC3GMQ Dave

BIL is on point.

If you look at the Upper Left of your schematic for SW3C, you will see that in the CW position the cathode of V6 (6AU6) is grounded all the time because of J2. In the Phone position, the Osc. is only activated in Keydown.



Phil - AC0OB

I checked J2,  it is working,  But excuse my lack of knowledge,  I understand what you mean when you say it is grounded until keydown.  So are you saying, the issue is because it is not being grounded someplace and that is what I need to trace out and look for?

I think if you put a 1/4 plug into the keying jack, the osc may turn off?

I tried the 1/4 plug,  didnt work. My lack of experience in electronics isnt helping  :)

KC3GMQ Dave

For greatest confidence, be sure the 1/4" plug is unwired, meaning it's just a plug and that it's a three conductor (tip, ring, sleeve). That will ensure that the circuit is getting broken.

Ok, off to go find a Viking schematic ...

Ok  I tried an un-wired 3 three conductor 1/4 plug and it didnt help

Can you post a schematic? I thought it would be easy to find one online but for some reason it's not happening for me.

would you like me to email you a copy of the book?

That's a lot of fuss, but the schematic page would be super. Of course if you post it here then others can check it out as well.

Ok  Having minor issue uploading it,  Ill get it here shortly

Johnson Viking II Schematic.  Anyone who wants, needs manual I would be happy to send a copy.

Perfect! What's happening is that the oscillator is always running, and that could happen if the cathode of the oscillator tube has a path to ground. With the power OFF, measure the resistance from pin 8 of the accessory jack and ground. It's possible that a capacitor C15 or C50 is shorted. Or, they have a low enough resistance to allow enough current through the tube for oscillation.

Pin 8 to ground is open,  the accessory jack is the octal plug receptacle on the back I am assuming :)

I'm still thinking there's some resistance, even if just at high voltage. Ok, here's another test, measure the voltage at pin 8 with a sensitive voltmeter. Keying is not necessary. Switch between CW and AM and note any differences.

Ok  I have 40vdc in CW and 0 in Phone.  No plug in CW socket

While we are reaching for stars here, you might want to replace the osc tube. There may be a short from the cathode to the filament? I think it is a 6AU6 tube but me eyes aren't what they used to be.

I already replaced the 6AU6.  Figured it was worth a shot.  Thank you for the advice it is all welcome.


73 Dave

Are you getting any meter reading in the OSC setting? It is in the cathode circuit and if the reading is zero, I would think that there is a short in that circuit. That is what I think it is anyway since it is always on.  Too bad no one with the same rig as yours has not commented so far but they probably will, once they see your question.

Something is completing the cathode circuit. Does the frequency change with the selected crystals or VFO frequency? Also, can you tell if the frequency changes between CW and Phone? That would indicate a difference between a known hard closure and a leaky cap.

Unless someone has a better idea, I'd try unsoldering C15 and C50 to see if either is conducting.

Everything sets up just like the book tells you how to load it, once I got it loaded, I noticed a carrier.  So I have stopped to find the reason it has that carrier when the plate is not on.  It sets up real nice though,  better then any of my other radios.  I am used to the heathkit manuals,  made for dummies like me who are trying to learn all of this.  The components are fairly easy, its learning what is going on, why, and what is making things do what they do that is taking me some time.

As far as I can tell the crystals are the same in either CW or Phone.  I have 3 crystals 7295, 7290, and 7285.  All were about 3 k off from what my main modern radio was indicating.  I changed out the 6AU6 for a new one and that gap dropped to 1kz. The more I look the more I am finding.  The radio looks great inside, but I can see a mode or two added.  I am going to trace them out and most likely remove them.  Looks like some sort of transfer switch was added.  Think I will re cap also, all the caps are originals.  I would have done that first, but I dont see how any of them would cause this issue. I will do C15 and C50 right now.  If ones bad, I will have to get some.

The reason I asked if you were getting a reading on the OSC is if you are not, the problem may be down in the selector SW itself or something associated with it.

Like shorted caps at the meter C-46 & C-47

How much 'carrier' are you actually getting with the plate switch in the off position?

Just fer  sh@^$ and grins, what do the Johnson act like when your using the Xtal  on its 2nd harmonic?

klc

Please find the problem before I drag my Johnson out and put it on the bench.

As far as how much,  not sure.  Enough to shut down my receiver and to see on the panadapter.  I posted a pic earlier.  2nd harmonic,  I saw that in the manual, I double checked and made sure I loaded the finals correctly.

Dave

So what are you seeing on the panadapter? The primary frequency of the crystal or a second harmonic of the crystal frequency?

If the CW/Phone switch is in the CW position Keyup, remove the crystal and it should disappear.

If I am in CW, there is no carrier going out unless I key Down.  If I key down with plate off, the carrier shows up again.  it is the same frequency as the crystal.

Is the JV2 in or out of its case?

Ok,  I pulled C-15 and C-50.  checked them in Cap mode on a fluke 79 II in cap mode.  Both read 5.3 both directions.  Both read open in resistance mode .

Dave

That actually looks proper. According to the schematic, with a key inserted, the mode set to CW, and the Plate switch off, there should be no carrier on the SDR until the key is pressed. In Phone mode, there should be no carrier until the HV Plates are turned on.

I agree

Try with these removed. Another post mentioned C46 and C47. Try changing the meter switch to see if the mystery signal remains.

KB2WIG  Refresh me please on JV2?

Dave

If the CW/Phone switch is in the CW position Keyup, remove the crystal and it should disappear, or switch to VFO and it should disappear.

WIG was asking if the Johnson Viking II was out of the case.

DUH  lol,  I have the top and bottom off.  Yes, If I go to ) on the crystal the carrier goes away

If I go to 0 Zero, the carrier goes away

D,

I've pulled a lot of my hair out on my Viking 2. You really have to have all your ducks in a row, (buffer here, crank over there, driver ready and the infamous  hidden plate resistors)........

klc

But that's just selecting no crystals, right? Does changing the meter switch get rid of the carrier?

I just tried it and no, the meter switch has no effect.  Also verified it goes away if crystal is out of socket.

I know its hard to help someone without having it in front of you.  Thanks to all who are helping me.

Dave

We shall not be daunted!

Something is providing an electron path between the cathode of the oscillator and ground. So you still get a carrier with C15 and C50 disconnected? I wonder if SW2 has a carbon trace between its contacts.

Pin 7 is the cathode. Disconnecting leads to that pin can help isolate the bad component.

Oh...I had put the caps back in,  should i pull a lead and try it?

Yes because caps can conduct only at higher voltages.

Carrier still there with cap leads off

Ok, those are innocent and can be connected. Can you disconnect the lead to the accessory jack? That would isolate problems with L68 and the socket.

Nothing's connected to the socket, right?

I had both c-50 and c-15 off, so thats the tube and the socket both,  I'd have to lift the lead on the L68.  Actually, with the cap lifted, L-68 is going to the #8 on socket which is a dead end, not grounded with the cap lifted

Could you post a closeup of the lead connections to the 6AU6 socket? Seeing it might trigger ideas...

If these are not good enough Ill take some more

these should be clearer

Time for the gloves to come off. With the 6AU6 removed, is there any voltage between pin 5 (+) and pin 7 (-) ?

What this does is use the plate supply as a high voltage source and the meter would indicate if the cathode circuit has any resistance to ground. In theory it does, and that's what's causing the oscillation.

This may be easier (and safer) from the top unless you have steady fingers.

is it going to be DC or AC,  just so i preset meter right

D.C. Try a high range first

      I made popcorn; I'll be sticking around for this.


  klc

Ambulance chaser...


;-)

lol  it was -366 hands were out lol,  i have grippers

There you go. Something is completing the circuit from pin 7 on that socket to ground.

so I need to trace that out....any other ideas,  shall we think about it and continue tomorrow, or another day?

That's up to you. Things need to be disconnected from pin 7 on that socket until the zombie oscillation stops.

I would start tracing from the 8 pin Octal Accessory Plug and then back to V6, Pin 7.

I had one on the bench one time that had Pin 1 of the 8 pin Octal Accessory Plug shorted to pin 8 of the 8 pin Octal Accessory Plug.

Phil - AC0OB

Ok 3 things on that #7, the cap, a blue wire, and a weird looking shunt :)  Ill start with the blue wire

Well it looks like the ground is on the line with the shunt SH3  I did disconnect the accessory socket,  ground was still there

C

That was mean --- no Weihenstephaner Hefe Weissebier for you. I'll drink all of it and you'll be sorry.... ..


 

It could then either be something with SW3 or the lead to the meter switch.

The shunt should be a 5.1 ohm resistor.

You could also have pinched or grounded meter wires.  Check those as well.


Phil - AC0OB

I'm going to assume that I'm "C", so as Jackie Gleason once said "You are stark, staring nuts".

Shut is 5.4 Ω

Good enough.

If it is not a shorted wire from the 8 pin Octal Accessory Plug, then the short has to be coming from the meter switch. I have seen bent pins on the meter switch making contact as well.


Phil - AC0OB

Ok Im off to the meter switch

bent pins meaning making contact when the switch is not aligned for it to make a contact? Quick inspection they all look straight,  I may have to take the rest of the case off to see it better

Remove V2 for a better view.

If not bent or broken pins at the meter switch, then you may have one of the two wires coming from the shunt resistor that has been scraped or burnt and is making contact with the chassis.

BTW, I have a Viking II-CDC and love it. :D


Got a small mirror and a bright light?

I love the transmitter,  just this one little issue to remedy and I am home free :)  I hope

yes i checked it with a mirror and bright light.  So back by the shunt,  the shunt connects to a standoff with two brown wires,  one wire goes to the pin 8 (its ok), the other brown wire has the ground, tracing it out now

Brown wire went to CW/phone switch where it met another brown wire .  So from the tube to the switch is good,  off tracing on the other brown wire now from the cw/phone switch

at cw/phone switch, the ground is now on the orange wire  following lol

Quite a tour of the rig, eh?

Traced orange wire to a relay,  this relay is not in my drawings hmmmm

Cathode is shorted to ground.  This should be simple to find.  Turn the xmtr off and unplug it.  This way you can't get electroplated.  Use you ohmmeter to trace the short.  Look close at the key jack it may be shorted to ground even with a 1/4" plug in it.  Look close at the accessory socket,  the RFC and cap connected to pin 8.  Check the wire running to pin 8 from the osc.  Check the switch that shorts the cathode to ground when in AM mode.  Look at the meter switch.  If you look long enough and far enough you will find the problem.  You may have to move things and connections with your finger while leaving the ohmmeter connected to the cathode.  Could be something shorting or touching ground somewhere.  You'll see the ohmmeter change when you hit the problem.

Fred

Interesting.

Guessing, that's a PTT relay that was added so that the rig can be set to transmit more easily than with the front panel switch. Theoretically, that contact shouldn't be grounded until the relay switches to Xmit.

When I had mic hooked up it didnt work PTT,  thats a lot of wires for PTT im thinking, heck who knows.  I did find an issue with the CW key socket,  you think that needs soldered?  If it does,  this unit never worked right

  In case you don't have it.

I did not, thank you

I did something similar when I upgraded my Viking II except I added a low voltage relay to control the Main relay.


Phil - AC0OB

That relay, the mic connection dont match up to that drawing.  It also looks like factory wiring or install.  Or the guy who built it was really good.  Not sure how to proceed now.  Think its time to call it a night and get back at it tomorrow   Thanks all for the help,  hope to see all of you tomorrow :)

Looking at that relay modification,  could be the PTT is closed, look at the mike.  Or, disconnect the mike.  The relay would only be closed when the set is turned on.  So, if the relay is the problem (remaining closed when in CW)  the problem would not show up if you were using an ohmmeter to trace the problem with the set turned off.

Looks like you're closing in on the issue!  With the Viking unplugged, check the resistance/continuity between the relay lug with the orange wire and the chassis. What's odd is that it *looks like* the Normally Open (N.O.) and Normally Closed (N.C.) lugs are jumpered across.

Try slipping a thin piece of paper between the top contact and the wiper to break the N.C. connection. If that stops the unwanted oscillation in "standby" then unsoldering that jumper (it looks like a jumper) should solve your issue!

If you look back a few at the CW jack, it has a black wire snaked through a eyelet and I asked if that should be soldered. If I move that wire to were it's not contacting the socket, the ground goes away. I am going to remove it from the eyelet later and test things. Very odd. That relay is not ptt, only one wire and ground at Mic connection. Dave

According to the schematic, the wire going to the CW key jack will be grounded whenever the jack has nothing plugged into it *and* when the mode is set to CW. Inserting a plug into the jack should break that connection.

Setting the mode to Phone bypasses the key jack and should break the ground connection of the 6AU6 oscillator, stopping the signal.

The theory is that when operating Phone, you can switch over to CW to zero-beat your transmitter to the frequency you want to operate on. Then, switching back to Phone should stop the oscillation. If that's not happening then there's something making a connection to ground through the Phone setting of the mode switch.

Either the oscillator side of SW2 is faulty (conducting regardless of setting) or you're getting a ground via that relay with the orange wire.

At this point, all troubleshooting should be done with the mode set to Phone since the CW setting seems to be functioning correctly.

I had this exact same problem with a Johnson Ranger that someone had wired a PTT relay into.  I never could find the source of the short that was causing the VFO to stay
keyed.  I finally wired another relay in parallel with the PTT relay coil and let that one turn the VFO plate voltage off when the transmitter is unkeyed.  It may not be conventional, but
it works FB.

Ok,  I put the piece of paper in, loaded it up in CW,  cant in phone now because the carrier is gone :)  then switched over to phone, plate on, buffed up the finals, adjusted the modulation, all seems to work..... which is GREAT.  So now,  I guess i need to clip that jumper?  I still have no idea what this relay does besides activate the finals.  Not the mic or a PTT for sure.  I am adding some more pics in another post so you can see the other mods on this thing.  So I guess,  what next?

more pics

and one more

I'm a bit confused by this line. It's working fine in CW, but what doesn't work in Phone now because the carrier is gone?

We gotta find out what that relay does. Somehow, the wires from the coil need to be traced, which could be challenging because of them being bundled with the other wires. One is likely grounded, which should be obvious. Once the other connection is traced, we can figure out what controls it. Regardless, the way it's wired will always cause the oscillator to run, so I vote for removing the jumper. The orange wire would logically remain on the normally open lug.

If I had to guess as to the purpose of that jumper across the relay terminals, I'd say it was because the previous owner used an external VFO only and wanted the 6AU6 to run continuously as a buffer, stabilizing the load on the external VFO.

What I am saying is, in CW you key it and use that carrier with plate off, to do the intial set up of the finals.  In phone, you have to set up in CW first (per the book) and then switch to phone to load the finals.  I think it is working correctly in that aspect...am I wrong?

It may just be the terminology ;-)  By "loading up" I think of the finals.

The way you describe it now sounds quite plausible. All the paper has done is to simulate that jumper being removed.

So, you'd use the CW position to adjust the oscillator and buffer tuning, then switch back to AM, key up, and adjust PA tuning and loading.

Sounds good to me!

Yes I agree.  There is a socket looks added to the back,  one I would normally see for a Dow Key set up, also a 1/4 mono plug,  i think for power.  Plus the other relay which is splitting the coax to the RF out 239 connection, I am tracing wires now. Jumper is removed also

Yikes. Looking at a previous pic you posted, it seems like the two conductor jack by the antenna connector is wired to a tube socket via RF chokes?

Can you tell what the 1/4" jack is wired to?

BTW, are you seeing the xtal frequencies above or below where they should be?

Yes my frequency is about 1 kz on the high side.....7285 crystal is 7286, same with my 7290 and 7295  .  It was worse, but I put in a new 6AU6 and it dropped to where it is now.  Yes the socket is wired to the tube socket,  That is easy,  I will remove it, it looks like its a stand alone mod HAHA.  Yes the 1/4 has on one wire connected in the picture attached.

If that jack is wired to a rectifier socket, it's either got high A.C. or D.C. on it, and I don't mean 120V...

So the 1/4" jack is wired to that choke coil. That's to block RF from exiting through that lead. Where does the white wire with red and slate(?) stripes lead? If I were a gambler, I'd guess it went to the mystery relay and inserting a 1/4" plug into that jack and providing an external closure will key the transmitter...

...or take out the power supply. That's why I don't gamble.

For the crystal frequencies, you could add a small value cap between the grid connected side and ground. Real low, like 5 or 10pF, but that's for after the celebration...

No, wait!  I just took a closer look at those pix and it appears that while those red chokes *do* go to a rectifier socket, they connect to socket leads that are not used by the tube. Kind of a cheesy way to make a connection, in my opinion.

So, we're back to what that jack is for. The clue is where the leads it connects to run...

LOL  I pulled those chokes.  Yes I want to know what they did,  but I would rather have the transmitter original if possible.  Your thoughts?

Picture attached with where the choke wires go....

red and slate wire is grounded,  i will have to trace it out inch by inch,  may have to open wire bundle,  its deep lol

Actually, if the rig functions at this point, perhaps it's a good time to try it out for a bit. You'll need to key it with the Plate switch, but that's how it was done.

Antenna switching and receiver muting will be another item for the To Do list...

Ok I will warm it up.  Ill try 7285,  Might be ok this time of day.  Picture below is the red/slate wire. Goes up to a standoff next to the other relay,  turns green and goes to the plate relay, comes out of the plate relay and goes to the plate switch.

If I hear you I'll throw the Valiant on, although I hear SSB activity on 7285, here at least. 7295 seems clear...

Well I smoked something.  When I flipped the plate on,  looking for it now

The relay smoked when I turned on the plate.  Hope that is all I smoked.

Thinking this through... if that relay wasn't being purposely controlled, then it's possible that turning on the plate supply might not also activate the Oscillator. With no drive, the plate current can soar unless a clamper circuit is active (more on that later).

Here's a test: with the rig off, unplugged, and caps safely discharged, check the resistance from pin 7 (cathode) of the 6AU6 and ground. It will likely be an open circuit. Then turn the plate switch on. The resistance *should* drop, indicating that the oscillator is active.

I dont think that will work,  remember, that relay had the power wire to the plate going thru it,  not that it is fried lol, its open in the middle,  actually I guess I can jumper around it for the test.  New pictures, the green wire on each side of relay is the red/slate wire .

Sure, jumper around the relay as a test to make sure everything is ok. The constant oscillation will be back, but at least the transmitter will make power.

8.6Ω  both  readings the same

Ooops,  It was open in both positions,  Sorry, I still had it in CW

Yeah, that's it. That relay has to be energized on xmit if those terminals aren't shorted.

lol that relay is fried haha,  we should just get rid of it :) or I will have to order one

It's fried? Meaning the coil?  Does replacing the jumper get the rig working again?

I can get everything back to the point where you turn on the plate,  with the jumper that will only allow me to turn on the plate, the coil is gone on the relay.  It stinks lol,  my wife is not impressed either :)  So I am afraid what will happen if I turn on the play without those connections being made.

How in the world did the coil fry? So frustrating...

well i think I had bumped one of the dial settings,  when I flipped on the plate it was way to high and it smoked before I could turn things down.  I think thats what happened?  I should have started from scratch and loaded it like normal.

I get why the plate current would have slammed but I'm not seeing how that would toast the relay. Replacing the jumper should put everything back to the way it was, right?

I jumped the green wires,  that was the wire that came from the red/slate wire that turned green.  It goes in one side of the relay, the other side goes to the plate switch.  After it fried, nothing would pass thru it anymore

It looks like the green wires go to the coil of the relay. Jumping across those would be dangerous as it would short out whatever was supplying power to the coil. To bypass the relay, jumpers would have to be added across the switching contacts (same as what was on the right but also added to the left).

This project has been the talk of 3885 tonight. Someone familiar with the Viking II said they had one with an open relay coil.

I can barley hear it, Ill go off channel and try and turn up better.  So does that relay belong in there?  Should I get a new one?  Iv also looked for the assembly manual with no luck,  i just dont know these schematics well yet, The Heathkit ones a 5 year old can follow, and I am feeling about 5 right now haha.

LOL and that is NOT me tuning up on top of everyone on 3885 haha.

I'm going to toss out another guess here... I'm starting to think that relay was a factory install by how neat the wiring is. At some point in time, the coil opened up and the owner jumpered across the oscillator relay contacts. The plate circuit was handled by the Plate switch.

Removing that jumper today prevented drive to the finals which would have pinned the current meter. Restoring the jumper as it was should return the transmitter to how it was before, working fine but having the Oscillator always running.

Is that not the case,

I think your right.  The coil being factory, your right it does look good, but here is why it may be in question.  All of the wiring used one type of tie cord.  It was neat and uniform throughout.  When you get to that coil, its a different type of tie cord on the wiring harness.  Still looks excellent.  Maybe got sent back for the upgrade?  I dont know. So I need to order another coil?  Will that old one have numbers?

Also, You can tell the hole was drilled after the fact.  The slot for tang on the coil to sit in for it to hold the coil in position, you can see it was made by drilling two holes side by side,  factory?  I dont know

Kevin WIG posted the Johnson PTT schematic several pages back. You should check that the wires going to the relay contacts all go to SW2 to be sure that is what this relay is *supposed to* do.

If it is, the relay will merely parallel the switch so turning on the Plate would operate the transmitter normally. Is there a chance that the only thing wrong right now is that the plate tuning and loading are way off resulting in high plate current?

Perhaps switching back to CW and using a key to transmit will allow things to get tuned up as they were before. Once that's working as expected, we can revisit the Phone mode.

Incidentally, this would be a FB++ time for real Viking II ops to chime in. I'm a Valiant owner pretending to have a clue...

Ok first off, the drawing WIG posted  on the PTT,  My rig does not have it.  I have the coil, but the PTT set up to the mic I do not have.  I tried to load the finals in CW,  It let me do the preliminary set up, but will not turn on the plate, I noticed before, when I turned on the plate, that coil pulled into the contacts..  Im pretty sure that coil has to be replaced.

The original was a Potter & Brumfield LM-11 DPDT with a 10k Ohm coil, however, other DPDT relays could be substituted depending on the supply source voltage. I'm not thrilled about 100 volts of PTT voltage running through the mic cord but it was all the rage in the 50s just as was operating AC/DC radios from the bathtub.

This guy on you tube says his PTT system is teh best

https://youtu.be/Vr4DiyxjiPo

The Coil is Tyco KR11A 115vac

Alright then. The lead coming from the line cord will go to one of the coil terminals. The other coil terminal will (does) go to the Plate switch. The other side of the switch should go to the other line cord lead. **** one of these should be on the fused and switched side of the line cord.

I'd suggest adding a fuse after SW1, going to the low voltage transformer and adding another fuse for the HV transformer. The single fuse , F1 doesn't seem to protect a crap out if there is a " low current short" bubblin away.

You might as well add a 3 prong plug and switch the hot side. Do it for safety. Do it for the children.

The rest of the guys/gals disappointed me. I ended up dragging my VK2 out and putting it on the bench. With out the shielding. I loaded her up and turned off the HV.

I was able to receive the osc signal on a Toshiba portable at a distance of 15 feet. I figured that distance was enough. While this doesn't directly address the problem with Dave's VK2, it may be helpful to others.

KLC

That has to be one dangerous mucked-up relay system there.

I still like mine better. Use a low voltage relay to control the Main 110V DC relay.

I never liked 110V or more going through a mike cord.


Phil AC0OB

If I haven't said it in a while, thanks you all for the help. Wig, what size fuses do you suggest? Fast or slow blow?  Did you mount them on an open chassis fuse holder, or the enclosed type. I am going to get it fused, and 3 prong plug installed next. I do not want to be chasing down transformers or anything else bad happening. I want to do this thing once, and do it correctly.

A fuse would make a great addition to the circuit.

I agree about low voltage control relays. You can reuse the 117V relay to a) power the HV power supply, and b) activate the oscillator, but you'll certainly want to add a low voltage relay to control this relay.

The more direct way requires purchasing a low voltage DPST relay and using the heater voltage to operate it. That relay would replace the toasted relay except for the Russian roulette connection to the non-polarized line cord.

So I will get this fused, and new grounded cord today. So what about adding a low voltage transformer like 117/6 and using a low voltage relay to do the work?

You can use the existing 6 VAC from the heater circuit. You'll need to add a diode and capacitor to get D.C. then run a lead to the mic connector.

D,

After you get things going, and get ON THE AIR, Electric Radio Magazine has several discussions on the JV2. Back issues should be available.

You may also wish to search here on the fone.

Check this out, its for the Ranger, but should be helpful.

http://www.crompton.com/hamradio/JohnsonRanger/RangerRestoration.html


klc

Well just an update,  Replaced mic connector to 4 pin, ordering caps, ordering new Plate switch, and replacing line cord :)

To clarify my suggestion, since you need to replace the toasted 117V DPST relay, you could reallocate the other one you're removing or obtain a relay with a low voltage coil.

The former would require a disconnect from the heater supply (readers are probably thinking HUH?!?... long story) and only be powered from the fused AC circuit. A separate LV relay would be needed for PTT.

The latter where a new relay is used would require a disconnect from the line voltage supply and some basic AC to DC conversion of the heater supply. A direct connection can be made to the Mic jack for closure to ground for PTT.

So,  no you will think I am nutz lol.  I was watching a youtube video and he  showed the wiring real well for the plate switch.  For now, I took out that relay, I took out the other one too .  I have put in a new coax, changed line cord to grounded 3 prong, (hot on the fused line), but now I need a new plate switch.  I cannot believe I cant find a DPDT switch with 4 terminals instead of 6. I may pull one out of my DX-100 just to get this working. So all I need for a test run is the switch.

Oh, Johnson and their practice of using 110 VAC for their antenna and other keying relays. As an innocent (and ignorant)  JN, how many times I've had catastrophic black soot on the back of my Johnson gear as a result... :-)

T

That returns the Viking to the original schematic wiring. You only need a DPST switch but a DPDT switch is fine also (the relay was a DPDT and two contacts went unused).

The downside is that PTT won't be possible and you'll need to manually throw the switch for xmit.

And "crystal sockets" for connecting the 117vac antenna relays...

It shows two sets,  the orange stripped wires go on two,  and the black and the orange go on the other two.... or is there something else i have to figure out hi hi

No, that's it. The switch just has to complete two circuits: 1) grounding the cathode of the oscillator, and 2) powering the HV supply. Each of those pairs would go to the contacts that are "off" when the switch is down. When switched "on", those pairs should separately be connected.

Ok so I do need the right switch?

That depends visually on aesthetics and electrically you need either a DPST (4 terms) or a DPDT (6 terms)

I can get 6 terminal,  So that would be and on off on then am I correct?

Just use one side of it. There are also DPDT's without a center off.

Phil

Thanks

Well I replaced the plate switch. All mods removed, turned it on and it loaded the finals fine, no issues there. Now the audio section is crap lol. CW no tone when transmitting but it does break the carrier. Phone works if I max out modulation but highly distorted. I wonder if I fried some other items when the relay fried. I'm currently checking components in the audio section. I get to use my signal tracer again yeah!!!

Turn the BFO on in your receiver. You can't hear CW tone in the transmitter.

LOL  Doh,  I got it, so I guess im putting out modulation, just not readable,  back to looking at things

Low distorted audio could be a few things. The easiest place to start is checking tubes. I've always thought that anyone with tube equipment should also have a tube tester (very handy!). The next step is to test socket voltages. The manual should list the expected voltages for each pin of each tube. Be sure to set everything the way the manual suggests for this test.

Check the value of all resistors for our-of-tolerance readings. Coupling caps from plates to grids should *not* show a resistance! Check them using a high resistance scale (100k Ohms).

  I found two resistors out, and the wax caps were totally shot.  Ordered caps for the entire transmitter, Already replaced resisters.  I will update once I get the area freshened up.  I do have a tube tester, all tested very good.  Thanks

Hello all, Well I have the Viking II re capped, audio resisters replaced and I tested the transmitter.  Everything looks good no as far as the extra carrier is gone, finals load nicely, but now I have very distorted audio.  I have tested to the first audio tube 6AU6.  My question...My Apache the audio circuits are operating with the plate off, is this true of the Viking II?  I have safety in mind here, so if I have to turn the plate on, I guess I would make my test hookup with power off, then power on to get a reading, then power off to connect the next tube pin?  I want to check voltages and also use my signal tracer, just want to know the safest way to do this.

Thanks
Dave KC3GMQ

Do you have an audio oscillator and an oscilloscope? A good way to check audio circuits is to insert a tone at the input and check the waveform amplitude and quality at each grid in succession.

There are free audio oscillator apps available. No free oscilloscope apps as far as I know.

What are you seeing for bias voltage at the grids of the modulator tubes?

I do have a scope and a signal generator,  just not real good using them hi hi.  I will figure it out

Well, set the signal generator for 1khz and a -40dB output level. Feed that into the mic jack and monitor the waveform at each grid. In theory, it should be a clean sinewave with increasing amplitude at each grid as you go from V1 to V2 to V3 and V4. Be SURE your oscilloscope is set for AC input!

Try connecting the oscilloscope probe to the signal generator first to get the hang of it.

voltages are off on the first two 6AU6,  I need to find that first I think

V1 and V2 should have B+ without the need for the Plate switch to be on. What's the DC voltage at the grids of V3 and V4?

On V2, the voltages are way out of whack. Screen is supposed to be +180 and its +370 lol

That could also mean you have a bad V2. What's the Plate voltage? That's going to be your LVB+ for the transmitter.

Plate is +370 vdc One resister going to pin 7 (cathode) was wrong, suppose to be 470Ω and it had 470K installed,  I have it replaced, rechecking things

Brown band, orange band, they can look similar. I sense a major improvement coming...

Tube tester said tube was real good,  but I have a lot of 6AU6's, I will replace with a new one.  Remember, V2 had the wire from the relay to the plate switch to this tube!!,  audio was crystal clear before I removed the relay that fried lol.

You replaced the resistor? Which tube connection did the relay go to?

Would be a yellow band instead of brown.  470K would have a yellow multiplier.  47K would have an orange multiplier.  The screen voltage is way up because the tube is nearly cut off due to the very high cathode resistor.

it was going to the heater , changing the tube made things a lot more responsive, but still sounds muffled and distorted, Ill check more parts.  Pin 7 cathode of V2 is at +5 vdc.  Pin 6 Screen Grid is over +300 vdc (should be aprox 180), Pin 5 Plateod V2 is +325 vdc which is close to what it should be (+300).

Absolutely. Yellow, not orange for 470k...

Also, I did verify the mic up to V1 was clear and strong.

The wire to the heater was to supply the relay with a coil voltage, I suspect. Are you getting 6 VAC on that terminal? Any improvement in the audio with the proper resistor installed? Also, there should be an electrolytic cap in parallel with the resistor.

R37 from plate to screen is 22k (red, red, orange) right?

The 470Ω resister went between pin 4 and pin 7, Pin 4 is heater ground... there is no, nor was there a cap on pin 7 to pin 4.  I do have a 10uf electrolitic going from pin 7 to ground, polarity checked also.  Ill look in assembly manual for a cap

Have you checked the value of the screen resistor?? It may be off value.  I don't have a schematic of this VII so I'm just making a few comments based on what these circuits usually are.  Maybe I can find a schematic to look at.

I have checked them, all good so far.  I will attach a copy of the schematic.

OK great, I just when back through all the pages of your thread backwards 8-7-etc.  Found the schematic on pg 1.  only to come back here and find you re-posted it again.  

Anyway, V2 6au6 is being run like a triode.  You will see the screen resistor (22K) is connected to the plate.  So the screen voltage is going to be high, almost the same as the plate voltage.  Don't worry about that, just make sure the screen resistor is 22K.

If you look at V1 6au6 you will see the difference.  There the tube is being use as a pentode.  Notice the screen resistor is connected to the B+ before the plate load resistor.  Also notice the 1meg value for the screen resistor.  The screen draws only a few ma so your need a very high value resistor to bring the B+ down the normal screen voltage level.  This is not the case with V2 where the screen is being used as an added plate (like a triode).  The 22K resistor is just there to limit the screen current and to slightly reduce the screen voltage from the full plate voltage.  This helps to ensure that the plate draws most of the total plate and screen current.

V2 6au6 could have been 1/2 of a 12au7 (which is twin triodes)  Instead of a 12au7 V2 should have been a 6c4 triode.  Johnson probably used a 6au6 for V2 because they had a ton of them and maybe cheaper for some reason.

Fred

Signal tracer at the cathodes of both 807's sound was strong and clear and responded well to the Audio potentiometer.

This is great news! The only thing left are the 807s themselves and the mod transformer. Are all the voltages within spec on both 807's pins?

 Time fer an air check?

klc

ill load up on 7290

Well all, I guess its working ...I did some test calls on 7295, I had 2 come backs who reported my sound as loud and clear.  I will try and get on the bands tomorrow and we will see what the experts have to say.  I can not thank all of you enough who have helped me through all of this.  HAM's are the best !!!  yes a little gushie hahaha

I heard a little bit of that but the static was intense. Drop me an email if you'd like to set up a sched. It would be nice to hear the results...

I bought a VFO should be here any day. That should make it easier to get on another band instead of crystals. I will email. Thanks again for all your help

If you decide to do any upgrading, here are a few suggestions:


Phil

Added RF Filter Circuit and Clamp Circuit improvements.

Thank You

Think I have most of the bugs out of the Viking now. One thing that isn't quit right is on 80M everything works but it loads completely on the #1 position of the coupling and I can't get plate below 250ma. Any ideas? Could it be the capacitors on the coupling switch? All other parameters are in spec

A WAG, try measuring the meter shunt...  u never know.Maybe feed 200 mA through the meter and see.

While yer at it place some SS diodes across the meter.


KLC

Ok I know im lost but a WAG? and SS diode?  Is that a schottkey diode?  Also, When I load on 40m, it all works like a charm, just made me thingk when I loaded on 80m and i didnt have to couple the power, and then its a bit high. 

Sorry..... Wild  *ss Guess.
      SS diode = Solid State diode.
            Sometimes, writing a responce on the telly phone keyboard makes fer a poor
                 communication.


Klc

LOL,  Guess I should have asked my kid to translate hahaha.  I should have known :)

Well, at least no one started talking about Nazi diodes.........


klc

The lower the frequency (band) the more loading capacitance is needed, so problems with those caps will be more noticeable on 80 than 40, 20, etc.

Can you get any better dip at the top of the band around 4mc?  I'm also assuming that you're tuning up into a 50Z load. An antenna mismatch can do that as well.

Acts the same with dummy or antenna. I suspected the dipole, so I rubbed it dead on for 3885 and with a swr of 1.3 still loads right away

Sounds like a loading cap went bad.

I will check the caps next

See Figures 3 and 10B in the manual.

Most likely one or more of those 300 pF (C33 to C38) caps have decreased in value.

Also make sure the variable capacitor (C29 and C30) mounting screws are tight.



Phil - AC0OB

Phil, thanks for the reply, after reading a bit last night, I'm thinking I should just replace them all. I was going to order the silver mica dipped???  Also the 150pf 1200 volt I can't find. Was thinking on ordering 2 300pf 1000 volt and installing in series. Am I on the right track?

You may wish to consider getting some "high current, high voltage" doe knob caps.

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.X330+pf+doorknob+capacitor.TRS0&_nkw=330+pf+doorknob+capacitor&_sacat=0

The 'stuff' that Viking used are rated at ~500 Volts ( the c38 at 1200 V). Get some of these knobs and never have to worry(?) about them going bad. You could fit most of these, or just a few, into the available space.

Murphys law design, at least use them for the "160/80m positions";  your switching out capacitance when you go up in freq, so placing the physically large, higher voltage caps in the 'lower' positions can be of benefit. --- load up yer 25' 160 meter  vertical can produce some very, very interesting values.

More info than you wanted, but if your going in and replacing things......


klc


klc

I've purchased from this guy....    http://stores.ebay.com/valtek2005/  no problem,

That will work.

As far as the 300 puffs go, I would replace the silver micas with the ceramic types rated at > = 2kV.

AES has these 330 pF at 3kV for 0.45 a piece:

https://www.tubesandmore.com/products/capacitors?filters=Type%3DCeramic%20Disc

and Mouser at:

http://www.mouser.com/ProductDetail/Vishay-Cera-Mite/564R30GAT33/?qs=sGAEpiMZZMt1mVBmZSXTPI4RnmSwHRBuLinJuYdYBsM%3d


Phil

The ceramics are ok in place of MICA?

Yes they are. I find them to be more reliable in Pi-Net loading applications.

Now for frequency determining circuits such as VFO's, the lower voltage micas may have a slight edge.

And the nice thing about ceramics is you can get them at higher voltages than equivalent value mica's for a lower cost.


Phil - AC0OB

Hello all,  sorry it has taken me this long to get things done.  Ok, so I have the Caps replaced in the Coupling.  This had no effect on it at all, transmitter on 80M still is more then fully coupled at the first (#1) coupling position (Grid 6ma, Plate 250ma).  I have checked my antenna, SWR 1.3 on 80M and I use a tuner to tweak that down to 1.1.  The Viking loads exactly the same whether I use a 50 ohm dummy, or the Dipole antenna. I have checked all the hardware tight, I loosened and then re tightened them all.  Looking for the next direction to take now.

73
Dave KC3GMQ

The next step is to see if the Coupling control is actually switching in the proper capacitor combinations. You can do this with a capacitance checker or even a simple ohmmeter. Be sure the rotary contacts are clean (pencil erasers make excellent contact cleaners).

Also, does the loading change at all in the first few positions of the Coupling switch?

Ok so I made a video and you can see how I am loading it, and that the capacitance just makes the plate rise and I cant get it below 250ma.  Going to work on the switch now with my eraser, Hope the video link to youtube works

https://youtu.be/R5iQEN0IroE

Is the 160 meter switch in the Out position? Can't tell from the video. You should verify that the actual switch is in the "out" position.
For final amplifier tuning (the big knob) the scale should be somewhere between 15 to 25 for 80 meters. Anything higher and you could be trying to dip on a harmonic frequency.
With the final amplifier tuning window set to roughly zero, you can tune the oscillator and buffer up, then drop the grid down so the plate current maybe reads 50 to 75 ma. (or some low value) and start cranking the "big knob" for a pronounced dip as you move up the scale. I think on my Viking II I had at least two dips but only one was a pronounced dip.

I think I found my Coupling issue,  As I was digging in to clean the switches lol, they are pretty bad,  I found that one of the contacts is burned off.  I am going to remove the switch, clean it, and try and make a makeshift contact.  I have done this once before.  I bent a small piece of hookup wire and soldered it on.  If there is a better method, I would love to know about it :)

I would NOT  be switching between the loading positions with the plate on.  Good way to prematurely kill that switch.  Where you are getting too much current and not a very pronounced dip you have either the condition that Pete indicated or you have a position on that stepped loading control already burned out.  Or maybe one of the fixed loading caps is no longer working.  You should be able to get a good pronounced dip with light loading (all the loading caps switched in).  Unless you are trying to tune for the second harmonic as Pete has indicated which will not produce as pronounced dip + you might get one of those coveted pink ticket if you're hooked up to an antenna.  The instruction is pretty good about that section in the manual.  At those current levels, you are really beating the he!! out of those 6146's

a

Thanks for the last two posts. So I made a repair to the switch. Still loaded the same. I have no issues on 40m and higher. I did play a bit and is I destine the antenna, I can load more to the antenna...  So I am tuning to the first dip, it was at about 25 on the big knob like mentioned previously. All switches are. Lean now too. I will add, The Transmitter is how I received it. I will admit, I am also learning as I go. So far it has been fix one issue and find another. The loading switch will need a better repair, or replacement. And FYI, I replaced all the loading caps.

You didn't answer whether the 160 switch is in or out. Should be out for all bands except 160. Check/verify that switch since it's on a pulley system.

It is out, checked and cleaned that switch also

If you are still not getting much of a dip, I'd start replacing the fixed loading caps.  I believe these caps have a history of failure.  If any of these caps open up, the final could be over coupled and that would result in high dip which will damage the 6146's (due to high plate current) and will result in flattopping on the modulation peaks which will in turn result in buckshotting or splatter.  So, that problem needs to be addressed

One point I want to verify is that you are tuning up with full grid drive (4 to 6 ma).  I thought I saw you turn the drive back to zero after checking the driver peak that it would give the required drive.  I cannot imagine turning the drive down and then trying to do the plate circuit tune up.  

The final point is that if you have a "healthy" tank circuit, you will get a pronounced dip going to a relatively quite low plate current.  If you cannot achieve this pronounced dip then the tank circuit needs to be fixed.  That's assuming a grid current of 4 to 6 ma.

a

PS: I just took another look at that loading switch.  That's the worse corrosion I have EVER seen.  That switch needs to be shiny. If it cannot be make to be shiny then it should be replaced. That could be your problem

Alan, when you saw me return the drive back to zero, that is right after I set the buffer and the book says to go to zero before turning the plate on. After the plates on, I go up to 100ma, dip, then check grid. This is the point where the issue is. Once I've done the initial plate dip, and checked grid at 6 you start loading the antenna. My problem is, on 80m, at position #1, after the first dip I'm at 250ma on plate with 6ma of grid. That's fine for CW, but phone says max 230ma of plate. All loading caps have been replaced with new. Coupling switch is repaired and shiny clean.

Dave KC3GMQ

Makes me wonder if you have a CDC coil set installed instead of the normal Viking II coil set.

Try these settings for 75M:

FREQ Sw - 3.3 - 4.5,
Drive 2,
MinMax coupling - 4
Coupling Sw. - 2.3 to 3.5.


Phil - AC0OB

Well I am calling the Viking II complete.  I do not have a smoking gun cause of the coupling, But it is working now.  I was able to get on 3873 the other night and rag chew a bit.  Been leaving the transmitter running to keep it warm lol,  but it is loading and transmitting good now.  Hoping it is not something more intermittant and it will be good and reliable now.  I am thinking the new caps, switching cleaning and repair did the trick. 

73
Dave
KC3GMQ