The AM Forum

OK, checked out the voltages and solder joints on this EFJ V1 that I purchased at the Peoria Hamfest.

It didn't come with any crystals.

I was going to order some crystals for it before I shot the DVFO (Homebrew) juice to it.

Q1: What is the crystal holder type? The crystal socket pin spacing is 0.5" The manual doesn't specify the type.

Q2: The V6 6au6 Pierce osc. tube was running hot so I removed the tube temporarily. I assume this is due to no self biasing because of no RF?

Thanks

Phil - AC0OB

Phil,

The crystal type is a standard FT-243 type.  The "fake" FT-243 crystals with a small crystal soldered inside the FT-243 case will probably work OK for phone.  I haven't tried one in a Viking 1 but in a Ranger and Viking 500 there is a slight frequency drift during the first couple of seconds of the oscillator circuit starting that would sound very bad on CW.

The Viking 1 uses a shorting style CW key jack so if you have it in CW mode with no key plugged in then the 6AU6 cathode will be shorted to ground and the tube will generate some heat.  As long as you have a CW key plugged in (and open) it shouldn't be a problem.

Carefully check the 5R4 tube bases and sockets and clean as necessary to avoid carbon tracks from forming, these tubes are prone to this problem.  I had to replace one of the sockets in my Viking 1 because of this issue.  Also, the switch that is used to add the extra 160 meter components (activated by 160 in switch) tends to seize if not used so add some lubrication to the bushing or the drive wheel will shear off (the voice of sad experience).

I think I remember seeing your Viking 1 at Peoria.  It was a good hamfest last year and I found a Millen transmitter and 500 watt amplifier there.  Hopefully 2012 will also be a good year!

If you need a manual you can find it here;

 Viking 1  (http://bama.edebris.com/manuals/johnson/viking1/operatn)

Thanks Roger and BIL,

Roger

This unit has all SS rectifiers except for the 6AL5 bias rectifier. I will be ordering crystals from Bry (AF4K) for testing and for backup if ever the Digital VFO dies.

Besides, I haven't had a crystal controlled rig since my Novice days when I had an EICO 720, so nostalgia is setting in already, albeit on a slightly larger (and heavier) scale.  8)

Does it seem these boatanchors get heavier each week just by sitting?  :o

Thanks for pointing out that part of the schematic (6AU6 cathode circuit for osc. V6) that I had not observed. The lines were so light I guess I neglected to look more closely. I went back to the orginal manual and it was more readable.

BIL,

The V1 came with the original manual (brown and tattered) and a copy from BAMA.

Once the rig is up and running, I plan to do the 6AQ5 audio mod driver upgrade.

Phil - AC0OB

Good deal, Phil.
Good luck with the 'ol girl!

I do have another question.

After receiving the crystals I found no oscillator (6AU6 stage) or buffer (6AQ5 stage) current metering. Some rf is leaking through to the grid of the final as shown by the final's grid current metering.

I found a 5.2 ohm resistor from ground to the cathode of the 6AU6 osc. , but the output of the osc. output was going to the grid (pin 1) AND cathode (pin 2) of the buffer amp.   ???  Undoubtedly, the buffer has no current flowing through it, save for maybe through the 47k grid resistor.  

Can anyone tell me the proper values of the cathode/metering/shunt resistances for these two stages? The manual/schematic gives no values.

 Thanks for all the help.

Phil - AC0OB
 

Phil,

Go to the BAMA link I posted. There's a full schematic and parts list included.

Being typical BAMA submitted scans, page 2 of the parts list is missing. Schematic doesn't show the values for the meter resistors.

I'll post'em when I get home.

If the Viking 1 is the same metering as a Viking II, here are the meter shunt values:

Oscillator cathode and Final Grid current:  5.1 ohm (regular resistors)

Buffer Cathode:   2.2 ohm (regular resistor)

Final and Modulator Cathodes:  200 Milli-ohm (these are pieces of resistance wires in the rig but can be replaced with 2 watt 1% resistors)

1% resistors are available from Mouser and DigiKey. 

 

I have the original manual and no value was given, or maybe page was missing?

It does appear the meter is a 5mA meter with 20 ohm resistance, so I'll try to estimate the tube currents and calculate the proper cathode/shunt resistances.

Was just trying to take the easy way out.  

Further investigation shows this person used 5.2 ohm shunt resistances in other places as well.

Fun and games.   :D

Phil - AC0OB

Page 2 is missing.  In my purchased manual, it lists SH 3 @ 100 mv for 25 ma and SH 5 @ 100 mv for 50 ma.  On page 3 the meter is a 5 ma @ 20 ohms meter.  The rest is Ohm's law.

I have included a quality schematic which is suitable for a 11 x 14 printout for everyone's benefit

One more thing: if the shunts opened up the meter would peg.  I doubt that the resistances on these shunts went down.  I'd look somewhere else.

Outside of the 4D32, the Viking I schematic is virtually identical to the Viking II.

I believe the shunt values I gave earlier will work on the Viking I.

I agree.  I only wished to point out that the non-reading switch settings was probably not due to the shunts.  Should they open up (the only way I think they could fail) the meter would peg not have no reading. The shunts can be easily checked but I'm betting that there is another problem on those switch positions.

Al

Thanks for all the pointers and component values and the big schemat Al. So far, it's been like going down a dark country road with a new girlfriend; never know what to expect.  ;)


I think you're right. I think maybe the shunt return(s) or the meter switch wiring may have been mucked with. So far, the high-side shunt metering wiring checks out, color code and continuity wise. Haven't checked all the low side wiring and continuity as yet.  I did locate the plate current shunt SH1 and Modulator shunt SH2; they are both 0.2 ohm 1% 2W resistors.

It appears the ocs. plate current should be about 8 mils (for 40mV across the cathode resistor for metering) and the buffer current should be about 35 mils (for about 77 mV for metering). I know the oscillator was working because I put it in CW mode with a 3.885 crystal in it, hit the floor switch and my receiver quieted. And I could zero beat it. The osc does have a 5.2 ohm 1/2 Watt cathode/shunt resistor. Awaitng some 2.2 ohm resistors for the buffer cathode shunt. The final's grid shunt is also a 5.2 ohm 1/2 watt resistor.

I was working on it last night and doing some wiring color code tracing and I did a double take:   :o   discovered the builder liked purple hookup wire. The 650 volt B+ line AND the modulator cathode are both wired with purple wire, same guage stranded. Fortunately, they are separate circuits, as further tracing and continuity checks confirmed.

The Johnson audio mods of April 22, '53 have been made but I have seen no evidence of any W7IIP mods, which I intend to do once I am sure this girl is workin properly.

regards,

Phil - AC0OB

OK Phil

The good, bad and the ugly was that this was a kit.  The good is that it is easy to work on (as compared to a 32v which was never intended to be worked on by the user).  The bad is that the kit builder got to muck around with it and there certainly could have been mistakes done on it.  The ugly is that sometimes, more often than we wish, Hammy Hambone would get in there and take a commercially wired unit and put his territorial marks on it much as a dog would check out every fire hydrant in the area.  I have a perfectly good V1 that has had the plate connection soldered to.  Apparently, the cap came off and instead of putting a new 4D32 in or trying to resolder the cap, he just soldered the plate connection directly onto the tube

GL es 73, Al

As a side note, and not to derail the thread or anything... but looking at both schematics, the V1 looks essentially the same as the V2, minus all of the TVI stuff, but one big thing is missing - the clamp tube... What gives here?

Just curious... ;D

I'm guessing from looking at the handbooks of the era that clampers were not in vogue in '49, the date for the V1.  Besides, since I work for Raytheon, I have a bias for the 4D32 - it's one he!! of a rugged tube.  There really wasn't a need to have a clamper on the screens

The 6146's?  it's my understanding that the screens on that tube are a bit wimpy and need the TLC that a clamper offers.  That's my story and I'm sticken to it  ;D  I'm just glad I have one each of the Vikers and am looking forward to putting both of them on the air

Al

Speaking of Raytheon, I have a spare NOS 4D32 tube I bought from a Kaleeforna business and the lit that came with it says it was tested on April 7th, 1952. It even has the curves printed out.

Phil

That's the way we do things here, Phil (I work for Mother Ray)  ;D

Heh... in the back of my head, I was considering swapping out the tired 6146's in my V2 for a 4D32 - I have a couple on hand, and a socket somewhere around here... Hmmm...

Since I didnt know what I was doing in 57 I constantly fried 6146's in a DX-100 I built. Of course it was screen burn-out from trying to load strange excuses for antennas. Dumped that and got a used V-1 which never burped no matter what dumbass thing I tried.

The 4D32 has been high on my favorite tube list ever since.

Carl

In my checking the biases and metering, I applied HV for a second or two and the plate cherried up right away.

What I found out was that Hammy Hambone decided that the Osc. Cath, Buffer Cath. , and PA grids all needed to be grounded somehow when the metering switch was set to those respective meterings. Of course, this meant no bias on the grid of the PA (-75 volts to ground instead) which meant I am pretty sure that the final tube is now fully gettered,  ::) but still checks out fine on the Hickock 800.

Hammy apparently didn't get the concept of "floating" metering.   ;D

So I have to trace down the wiring to and from the meter switch and find out why Hammy favors grounds so much.  :D :

I thought about eventually converting this from the 4D32 to the 6146 (I have a stash of those for the Kenwoody TS-820S), but I decided I am having too much fun with this rig as it is.   :P

Phil - AC0OB

Don't change over to 6146's They are wimps of toobs.  Just check out

http://www.surplussales.com/Tubes-Sock-Acc/TubeSpecials.html

Scroll down to find the 4D32's  Buy the pack of 3 and you'll never have to buy another 4D32.  Looks like they sell the sockets too

It sounds like it was a kit that was miswired and never used.  When you get it rewired, you should have cherry iron

Al

4D32's are available for $24.50 each at Fair Radio.

Good price.  Looks like they have a quantity of 'em

Those ARE good tube prices. Surplus Sales did say they were 1977 manf. tubes.

I found the problem to the "Case-of-the-Grounded PA-Grid-Bias,"  etc.

I shouldn't have gotten on Hammy's case too much but when Hammy updated the meter to the VikingII config (with ckoke coil , etc) he "globbed" solder on the + terminal (red wire) and the glob was touching the copper coating of the meter shield. It was almost impossible see; I finally took a magnifying glass and mirror and started looking at the metering connections and the meter switch. All metering now appears to be normal.

I scoped the Osc and Buffer and PA grid and they are showing very nice sine waves to the final's grid with a 7.160 Mhz crystal.

And oh yes, the PA grid bias is a solid -76 Volts.

Tonight I will check output power and modulation and hopefully find a QSO to join. I have 3.705, 3.725, 3.880, 3.885, and 3.890 75m crystals.


Phil - AC0OB