[Johnson] Kit wiring instructions for Johnson Valiant

[Dave Harmon]

+1 on THAT!
Relocating that resistor outside the VFO box should not be considered.

Dave Harmon
K6XYZ[at]sbcglobal[dot]net
Sperry, Ok.

-----Original Message-----
From: johnson-bounces at mailman.qth.net
[mailto:johnson-bounces at mailman.qth.net] On Behalf Of Glen Zook
Sent: Thursday, January 19, 2012 12:01 PM
To: Jerry K; johnson at mailman.qth.net
Subject: Re: [Johnson] Kit wiring instructions for Johnson Valiant

There have been a number of experiments concerning the placement of this
resistor.  Most have found that putting it outside of the VFO compartment
actually affects the stability of the VFO in a negative manner.  The VFO
temperature compensating capacitors were chosen to include the effect of the
heating caused by the 18K ohm resistor.  When the resistor is put outside of
the compartment it takes longer, in some situations never, for the
temperature to reach the conditions at which the compensation capacitors
were calibrated.

Of course, the choice of where to locate this resistor can only be made by
the person doing the modification.  However, the previous experience of
others should be considered.
 
Glen, K9STH


Website:  http://k9sth.com


________________________________
 From: Jerry K <w5kp at hughes.net>
To: johnson at mailman.qth.net
Sent: Thursday, January 19, 2012 11:07 AM
Subject: Re: [Johnson] Kit wiring instructions for Johnson Valiant
 
While you're in there, don't forget to replace the famous 18K "Chernobyl"
dropping resistor with a 5 or 10 watt power resistor mounted OUTSIDE the VFO
box. Mouser sells nice compact power resistors for replacements.

Stu is right about the front panel, so unless you just HAVE to pull the
front panel for other reasons, on most of the half dozen or so I've
overhauled I've been able to get away with just removing the side plate--a
little tougher access and requires some extra finger gymnastics during
component replacements, but not all that bad, and far less dangerous to the
one irreplaceable part on the Ranger--the ultra-fragile and brittle "flex"
(ha!) insulated tuning shaft coupler behind the front dial. Also, mount a
couple of fuses inside the rear wall of the chassis (Radio Shack sells a
little plastic 3AG dual-fuse mount that fits
nicely) and replace that Rube Goldberg fused power plug and cord with a
standard three-wire grounded plug and cord. Easy to do while you have the
little beast upside down on the bench during recapping.

I believe the little Ranger is the best small boatanchor ever built... 
Have fun!
73 Jerry W5KP


On 1/19/2012 8:42 AM, Jim wrote:
> I second the use of AD5X's very useful documents.
> While you have the VFO exposed, replace the mica capacitors and check 
> the resistors.
>
> Jim
>
>> Suggestion:
>>
>> Don't skip getting the .pdf on front panel removal, read it a few 
>> times, and then be VERY careful not to put any side pressure on the 
>> flex coupling during the r&  r process.  It sooooo easy to destroy 
>> the phenolic wafer in that coupling, as it has been severely 
>> cooked/dried out over the last 45 years and will now be quite 
>> brittle.
>>
>> Finding a suitable replacement is a chore.  I even tried to 
>> repair/rebuild one from one of my Rangers, but  the material I used 
>> wasn't really thin enough, so it wasn't really a 'flex' coupling any 
>> more when I finished.  I was a lot more careful with the Pacemaker 
>> and the Valiant and managed to keep the couplings intact..
>>
>> 73 de Stu W7FE
>> Henderson, NV
>>

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