[Johnson] Viking Ranger VFO Problems/Access

[ashley40 at aol.com]

 What WE do to every Johnson VFO that passes through our shop:
1) Replace mica caps (4) (2 ea 500pf 1%, 2 ea 1000pf 1% dipped mica)
2) Replace ( if needed) burned phenolic main board, some arrive burned.
3) Remove VR tube, socket, series resistor , vfo tube and socket4) Replace VFO tube socket with mil-grade ceramic5) Replace all resistors 
6) Modify shroud to allow for easy removal without having to fuss with the side plate7) Rebuild flex coupler8) Disassemble, clean, polish ball races, relube and reassembly ball drive9) Add Ball Drive panel snubber assembly10) Install solid state +150V regulator. 
11) If R5 is burned or open, this means the rotary contacts on SW1, (9&10) are "make before break" and the rotating contact needs to be modified to change to "break before make". ( Make before break means R4 is temporarily shorted and the entire IP is dropped across R4)
   Patience, a couple of jewelers needle files and you are in business.12) Lubricate the shaft of SW 1 ( they often show up with the switch frozen from lack of lube). This lube process may take some time as the oil has to work its way into the space between the switch shaft and the threaded bushing)13) Remove C4 ( 6 meter trimmer) and associated wiring14 Remove and discard alignment pins ( we furnish a new alignment tool), install plastic hole plugs in open alignment pin holes) 


Thank You 

 (johnson at mailman.qth.net)
 
 
  Thank YouKiss-ElectronicsMs Ashley Hall183 N 5th PL.Cornelius, Oregon97113  W7DUZ  www.kiss-electronics.com 
 
-----Original Message-----
From: Glen Zook via Johnson <johnson at mailman.qth.net>
To: Mark Donaldson <wa1qhq at yahoo.com>; Bill Cromwell <wrcromwell at gmail.com>
Cc: johnson <johnson at mailman.qth.net>
Sent: Mon, Jul 22, 2019 9:14 am
Subject: Re: [Johnson] Viking Ranger VFO Problems/Access

Moving the resistor outside of the box is not a good idea.  Doing so increases, by a substantial amount, the time it takes for the VFO temperature to stabilize.  The frequency stabilizing capacitors are designed to be operated at the temperature level that is generated by the resistor being located within the VFO box.
Basically, the VFO is going to drift for much longer if the resistor is not within the VFO box.  However, it is certainly proper to increase the wattage of the replacement resistor.
Glen, K9STH 
Website: https://k9sth.net 

    On Monday, July 22, 2019, 10:51:24 AM CDT, Bill Cromwell <wrcromwell at gmail.com> wrote:  
 
 Hi,

There is a mod that moves the Chernobyl resistor outside the VFO box.
Upsize the wattage rating too.

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