The AM Forum
March 28, 2024, 06:50:03 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: 1 ... 3 [4] 5 ... 9   Go Down
  Print  
Author Topic: Johnson Viking II sending carrier with plate off  (Read 89541 times)
0 Members and 1 Guest are viewing this topic.
N1BCG
Member

Offline Offline

Posts: 836


« Reply #75 on: March 26, 2017, 11:10:41 PM »

Quite a tour of the rig, eh?
Logged
KC3GMQ
Member

Offline Offline

Posts: 173


« Reply #76 on: March 26, 2017, 11:12:17 PM »

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


* IMG_2775.JPG (710.58 KB, 1512x2016 - viewed 326 times.)
Logged
KA2DZT
Member

Offline Offline

Posts: 2192


« Reply #77 on: March 26, 2017, 11:14:09 PM »

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
Logged
N1BCG
Member

Offline Offline

Posts: 836


« Reply #78 on: March 26, 2017, 11:23:09 PM »

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

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.
Logged
KC3GMQ
Member

Offline Offline

Posts: 173


« Reply #79 on: March 26, 2017, 11:32:34 PM »

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


* IMG_2776.JPG (745.51 KB, 1512x2016 - viewed 340 times.)
Logged
KB2WIG
Contributing
Member
*
Offline Offline

Posts: 4484



« Reply #80 on: March 26, 2017, 11:37:33 PM »

  In case you don't have it.


* vikingiiptt.gif (12.7 KB, 700x700 - viewed 330 times.)
Logged

What? Me worry?
KC3GMQ
Member

Offline Offline

Posts: 173


« Reply #81 on: March 26, 2017, 11:40:10 PM »

I did not, thank you
Logged
DMOD
AC0OB - A Place where Thermionic Emitters Rule!
Contributing
Member
*
Offline Offline

Posts: 1768


« Reply #82 on: March 26, 2017, 11:49:39 PM »

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


Phil - AC0OB



* Viking II - CDC Control Relay.pdf (24.03 KB - downloaded 149 times.)
Logged

Charlie Eppes: Dad would be so happy if we married a doctor.
Don Eppes: Yeah, well, Dad would be happy if I married someone with a pulse.NUMB3RS   Smiley
KC3GMQ
Member

Offline Offline

Posts: 173


« Reply #83 on: March 26, 2017, 11:57:48 PM »

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 Smiley
Logged
KA2DZT
Member

Offline Offline

Posts: 2192


« Reply #84 on: March 27, 2017, 12:17:19 AM »

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.
Logged
N1BCG
Member

Offline Offline

Posts: 836


« Reply #85 on: March 27, 2017, 12:54:56 PM »

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!


* IMG_2775.JPG (692.42 KB, 1146x910 - viewed 339 times.)
Logged
KC3GMQ
Member

Offline Offline

Posts: 173


« Reply #86 on: March 27, 2017, 01:14:10 PM »

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
Logged
N1BCG
Member

Offline Offline

Posts: 836


« Reply #87 on: March 27, 2017, 01:48:39 PM »

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.
Logged
KB5MD
Contributing
Member
*
Offline Offline

Posts: 614


« Reply #88 on: March 27, 2017, 03:17:44 PM »

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.
Logged
KC3GMQ
Member

Offline Offline

Posts: 173


« Reply #89 on: March 27, 2017, 03:56:17 PM »

Ok,  I put the piece of paper in, loaded it up in CW,  cant in phone now because the carrier is gone Smiley  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?


* IMG_2777.JPG (1077.29 KB, 2016x1512 - viewed 318 times.)

* IMG_2778.JPG (1104.05 KB, 2016x1512 - viewed 319 times.)

* IMG_2779.JPG (1108.71 KB, 2016x1512 - viewed 318 times.)
Logged
KC3GMQ
Member

Offline Offline

Posts: 173


« Reply #90 on: March 27, 2017, 04:05:40 PM »

more pics


* IMG_2780.JPG (1337.78 KB, 2016x1512 - viewed 306 times.)

* IMG_2781.JPG (1052.12 KB, 2016x1512 - viewed 296 times.)

* IMG_2782.JPG (981.62 KB, 2016x1512 - viewed 326 times.)
Logged
KC3GMQ
Member

Offline Offline

Posts: 173


« Reply #91 on: March 27, 2017, 04:06:04 PM »

and one more


* IMG_2783.JPG (969.82 KB, 2016x1512 - viewed 319 times.)
Logged
N1BCG
Member

Offline Offline

Posts: 836


« Reply #92 on: March 27, 2017, 04:39:20 PM »

Ok,  I put the piece of paper in, loaded it up in CW,  cant in phone now because the carrier is gone Smiley  then switched over to phone, plate on, buffed up the finals, adjusted the modulation, all seems to work..... which is GREAT.

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.
Logged
KC3GMQ
Member

Offline Offline

Posts: 173


« Reply #93 on: March 27, 2017, 04:45:47 PM »

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?
Logged
N1BCG
Member

Offline Offline

Posts: 836


« Reply #94 on: March 27, 2017, 04:54:36 PM »

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!
Logged
KC3GMQ
Member

Offline Offline

Posts: 173


« Reply #95 on: March 27, 2017, 05:01:22 PM »

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


* IMG_2784.JPG (1786.39 KB, 2016x1512 - viewed 282 times.)

* IMG_2785.JPG (1054.38 KB, 2016x1512 - viewed 289 times.)

* IMG_2786.JPG (1109.97 KB, 2016x1512 - viewed 287 times.)
Logged
N1BCG
Member

Offline Offline

Posts: 836


« Reply #96 on: March 27, 2017, 05:07:58 PM »

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?
Logged
KC3GMQ
Member

Offline Offline

Posts: 173


« Reply #97 on: March 27, 2017, 05:20:04 PM »

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.


* InkedIMG_2788_LI.jpg (2051.61 KB, 1512x2016 - viewed 288 times.)

* IMG_2790.JPG (876.19 KB, 2016x1512 - viewed 316 times.)
Logged
N1BCG
Member

Offline Offline

Posts: 836


« Reply #98 on: March 27, 2017, 05:28:28 PM »

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...
Logged
N1BCG
Member

Offline Offline

Posts: 836


« Reply #99 on: March 27, 2017, 05:43:19 PM »

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...
Logged
Pages: 1 ... 3 [4] 5 ... 9   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone © 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.068 seconds with 19 queries.