[AMRadio] Questions on Johnson Ranger II

Sun Apr 29 11:48:18 EDT 2012

Geoff,
Thanks for all the help.
Well,
I guess I can meter the primary of the Mod XFMR...if it's open that 
should be obvious.

OK, I have a handle on a old Viking II...is the mod XFMR the same...if 
it is, I can get it cheap.

Maybe I should adj the resistor just to see if it helps?
If the resister is open...would that cause the high current?
73,
Lee

-----Original Message-----
From: Geoff <w5omr at att.net>
To: Discussion of AM Radio in the Amateur Service 
<amradio at mailman.qth.net>
Sent: Sun, Apr 29, 2012 10:51 am
Subject: Re: [AMRadio] Questions on Johnson Ranger II

On 4/28/2012 4:58 PM, kc9cdt at aol.com wrote:
> Helo fellow AM enthusiasts,
> I just picked up a old Johnson Ranger II.
> Looks completely original, as far as I can tell.
> Even all the caps look original! Hard to believe.
>
> So,
> 1) The VFO bezel has a 1/8" dia paint spot missing and I would like to
> either get a different one, have this painted, or fix it my 
self....any
> suggestions?
> The front panel is excellent except for this one area.

I, for one, am not big on cosmetics.  I can't help you with in this
area, but there are several knowledgeable folk on this list that are
well versed in the subject of paint matching and cosmetic restoration 
of
old Johnson rigs.

> 2) Brought it up over 8 hours on a Variac and nothing bad happened
> (even though I did hear 1 little arc). It is now at 115VAC. I do plan
> to put a 3 wire cord on it and fuse.

Good steps.

> 3) Followed the steps in the book to tune up...20 watts out on 80, and
> 12 out on 40??
> a) plate voltage is around 600. Grid drive set at 2 ma.
> b) dummy load
> c) key down

Where's the screen voltage?
a 6146 in a Ranger takes about 2.5mA of grid drive. 250~270v on the
screen, 500~600v on the plate for ~110mA of plate current.  60 to 65w 
DC
input is about all you'll see out of that right, with probably 35~40w 
of
carrier output.

> 4) When I checked modulation current it went all the way over to the
> right... I see a step to adj. that in the book, but wander why it is 
so
> far off?

Sad to say, but it sounds like the modulation transformer primary might
be open.  Current would swing wildly with no load on the tubes.
Hammon (the organ people) have a transformer that works well in that
situation and won't cost you an arm and a leg.  Sorry, I don't remember
the model number of it, right off.

> 5) I find the manual a little lacking..what is the plate voltage right
> on the plate cap supposed to be?

Probably somewhere right around 500~600v.

The little Rangers were called the 'Magic Box' because it was hard to
believe that all that signal and audio could come out of such a small
box.  The 7027's are getting hard to find, but 6L6's will work, in a 
pinch.

The ultra high modulator current concerns me.  Adjusting the 
sliding-tap
resistor sets the screen current, and therefore affects the bias of the
modulators.  As I recall, that should be somewhere around 40~50mA.  The
interstage modulator driving transformer was the weak spot in the
Rangers, as well as Viking II's.

Good luck on the project
73 = Best Regards,
-Geoff/W5OMR

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