[Johnson] Ranger VFO Access Question

Wed Dec 19 10:01:56 EST 2012

Thanks Bill and others for the advice.  Dern, I was hoping there would be an 'easy button' to push and I could take off the VFO shield and have unfettered access to those circuits.  From my 1996 adventure in the Valiant VFO, I seem to recall side access  being cramped and difficult to work with.  

Yes this Ranger has the keying circuit, so some disassembly will be required just to get access to the side panel.  And I vaguely remember my Valiant cover removal process.  I am going to look close at the vfo shield and just see if there's any way to remove the whole thing without removing the front panel.    The only thing coming out of the front of the shield would be the main tuning isolated shaft.  If that's going to a hole in the shield rather than a slot , then the only way to remove the entire shield is to remove the front panel, which I have no desire to do.  Then it's side access and be happy with it :) 

That's a good reminder about all the shield screws and nuts being put back in.   I also heard other experts say that they go through their BA and loosen and retighten every single screw and nut to try and re-establish ground connections that may be intermittent or lost due to corrosion or lose parts.  This Ranger hasn't been used in 39 years so no one knows the status of any of the ground connections. 

Yes I'll check the OA2 regulator in the VFO, that's one of the reasons I need to get in there.  I wasn't observing drift in the vfo signal, but a wobble once or twice a  second, random, maybe 100-200  hz.  And yes that under rated power resistor will be changed for sure.  On my Valiant, that thing changed value downward until it drew so much current, it burned up and took the 6AU6 oscillator tube and OA2 regulator with it.  In that case I replace the tubes and relocated a new higher power series current limit resistor outside of the vfo shield, and under the chassis.  It was easy to do. There is a chassis grommet right next to the solder lug where the old power resistor was, so I just passed two short wires through that grommet to a new lug directly under the vfo.  Don't know if having the power resistor outside the vfo shield makes any difference.  Yes it will reduce heat dissipated by that resistor but don't know if it really affects vfo performance.  I remember many years ago a ham on one of the BA lists did a detailed study of drift with the power resistor in versus out of the shield.  From what I recall, it was an impressive study.  At the same time there was a big hub bub discussion on whether the heat from the power resistor helps stabilize the oscillator or is bad for it.  Lots of arguing and opinions.  My genius conclusion at the time was either would work just fine . hi hi   I chose to relocate the power resistor just to reduce heat trapped in there.  I once talked on the phone for several hours with  Manley Youngberg, designer of the Ranger 1.  I do recall asking him about that resistor. It was just an error, that's all.  I do have it recorded on tape somewhere though.  I'll have to find that.    I'm thinking that I"ll just replace the resistor with an appropriately rated one and leave it in the VFO.  I did want unfettered VFO access so I could inspect all the solder joints, maybe put some DeOxit on the variable capacitor. 

This is my last Ranger.  At one time I had two Ranger 1's and two Ranger 2's.  Sold all of them, then this one was given to me last year by a local Old Timer who was in his 90's.  Told me that his family was planning to just throw all his radio stuff out when he passed away.  He was almost frantic to find someone to take his HBR-17 receiver that he built in the 60's. It meant so much to him.  I got the Ranger along with the HBR-17.  The Ranger was terribly grimy. It has literally sat on the floor next to his desk for 39 years.  There was a mouse problem in the shack so I figured the discoloration and grime on the cabinet was corrosion and rust due to mouse pee. The knobs were filthy. I was afraid to look inside.  I took GOJO to the cabinet top and was shocked when it cleaned up and looked like new.  Knobs now look like new.  Front panel is gorgeous with the only distraction being where the OT engraved his callsign under the bandswitch knob.  The inside was dusty but under the dust it looks like it was built yesterday. 

I  have a Johnson Courier amplifier that I used with my earlier Ranger and a Pacemaker.   What a fabulous amp!!  Runs a pair of 811's, and this one was refurbished by a good friend, has a newly rewound power transformer, and is recapped.  Looks like a million bucks and runs like a million bucks.  

73, Scott WA9WFA 

----- Original Message -----

From: "Bill Cromwell" <wrcromwell at gmail.com> 
To: whitebear1122 at comcast.net 
Cc: johnson at mailman.qth.net 
Sent: Tuesday, December 18, 2012 8:31:26 PM 
Subject: Re: [Johnson] Ranger VFO Access Question 

Hi Scott, 

You are right that access is through that side plate. If yours has the 
keying circuit you have to move that out of the way first. Three screws 
on top and lift it up and move it over. Let it dangle on the wires. On 
mine there is a short terminal strip that holds a wire to the dial lamp 
in that side. The screw that holds that strip is one of the screws that 
holds the side cover on. Unplug that dial lamp and move it aside and out 
of your way, too. I remove the tubes on that side for easier access to 
the screws. 

You will also have to remove the nuts from two spade bolts that extend 
under the chassis from that side plate. Take your time - they can be 
hard to get to with other parts crowded around them. When you reassemble 
the VFO cage do NOT be tempted to leave those off. They are *required* 
for RF isolation from the power amp! Somebody had been tempted with the 
Ranger I have and the VFO was really flaky on 40 meters. 
Replacing/retightening *ALL* screws and nuts cured all of that. 

Todays standards are not the same as when the Ranger was marketed. The 
VFOs are a little drifty. Mine is worse on 40 meters so I only use it on 
160, 80, and 40 but with the VFO switch locked on  160. The bandswitch 
still operates everything else as designed. I get 40 meter output at 
slightly lower output. I am building up a heterodyne VFO system 
patterned after the Hallicrafters HA-5. Documents for that are available 
on BAMA. The VFO and an xtal oscillator run all the time and a mixer and 
output buffer are keyed. Doing that resolves several issues with keyed, 
free running VFOs. 

You might want to replace the 6AU6 wih a 6AH6. Make sure the gas 
regulator tube is working ok. The series resistor for the regulator was 
marginal and may be out of spec in yours. The one in mine was replaced 
by a heavier (higher wattage) resistor before I acquired it. Some people 
suggest relocating that resistor and it's heat outside the VFO cage. 
Others have suggested it's presence inside the cage helps stabilize the 
the VFO temp sooner. Mine is inside. I haven't tried it outside. 

Good luck with your project. 

73, 

Bill KU8H 

On Tue, 2012-12-18 at 21:54 +0000, whitebear1122 at comcast.net wrote: 
> 
> I powered up a Johnson Ranger 1 over the weekend.  It had not been powered since 1973 according to the previous owner.  I brought it up slowly over a 5 minute period using a variac so as not to just slam HV on the original electrolytics.  It powered up fine.  6146 was dead so I replaced it and was getting full power output.  I did notice the oscillator is moving around some.  The transmitter signal sounds good and clean on the receiver, just the frequency is moving a little bit here and there.   
> 
> 
> I would like to peruse the VFO compartment but it looks nearly impossible to get into without major disassembly.  I'm trying to remember back in the mid 90's I accessed my Valiant VFO compartment from the left side, to replace the 6AU6, OA2, and burnt series current limit resistor.  Even then access was limited from the side, cramped space, difficult.     
> 
> 
> 
> I see the side screws that affix the lid go all the way around the top edge, including two screws facing the VFO dial.  Can't get at them.  Has anyone here gotten good access to the VFO compartment other than coming in on the side?  I fear the answer is something like total vfo disassembly... 
> 
> 
> 
> 73, Scott WA9WFA 
> ______________________________________________________________ 