[Johnson] Re: [Boatanchors] Johnson-Viking 122 VFO Freq. Jump

[Sherrill Watkins]

Gentlemen: On any key that is old it would be normal for oxidation to occur
on any piviot or contact. The keys made back in the 1940's and earlier may
especially be prone to oxidation of the points because silver was used and it
is prone to oxidation. Cleaning the contacts without removing the silver is a
problem. A friend has a circa 1925 Vibroplex and the contact points are so
oxidized that no current will flow through an ohmmeter. I suspect the
contacts are silver and he is reluctant to try to clean them. Some of the
older bugs had a little jumper wire around the piviot points because of the
tendency of oxidation to occur in the pivots. I think some of the WW2, J-36
bugs were made like that. That may have been part of the requirement of the
J-36 military specification? - 73- Sherrill W. k4own.  

-----Original Message-----
From: Ed Swynar [mailto:gswynar at durham.net] 
Sent: Thursday, February 24, 2005 2:18 PM
To: Bill Stewart; johnson at mailman.qth.net
Cc: boatanchors at mailman.qth.net
Subject: [Johnson] Re: [Boatanchors] Johnson-Viking 122 VFO Freq. Jump


Hi Bill,

Good point you make there!

I've had similar experiences with the old 1929-style rigs I use for the
different AWA events here, & my Vibroplex...when I get "jumpiness" in the
signal, sure enough, the contacts on the bug are BLACK!

I guess there remains some residual sparking/arcing there, despite
precautions taken by yours truly...

Again, your point is very well taken, and well worth remembering...!

~73!~ Eddy VE3CUI - VE3XZ





----- Original Message -----
From: "Bill Stewart" <bstewart at ipass.net>
To: <johnson at mailman.qth.net>
Cc: <boatanchors at mailman.qth.net>
Sent: Thursday, February 24, 2005 2:08 PM
Subject: [Boatanchors] Johnson-Viking 122 VFO Freq. Jump


> For the past month or so I have been using the Viking 2/122 VFO quite 
> a
bit on 40 & 80 mtr. CW. For a key, I primarily use a J-44 (also by EFJ).
Several weeks ago I noticed in my monitoring rx. that there was an occasional
freq. jump of anywhere from a few cycles to a hundred or so. It only occurred
on key closure....no jump while the carrier was on. I opened up the VFO and
sprayed the band switch, cked tubes, tightened hardware, etc....it still had
the jump. I did find the dropping res. at the vr tube to be out of tol. and
replaced it...still had the jump. One night while listening to the jumping
osc. in the rx., in a very small fit of frustration I mashed the key down
sort of hard and moved it from side to side....noticing that the jump was
occurring as I put pressure on the key and moved it around. Long story short,
I found that there was anywhere from 1.6 ohms to over 700 ohms ( that's
right, 700 ) across the key plug. This type of key uses a piece of flat
spring steel for tension instead of the coiled spring like the J-38. This
flat spring steel also acts as a connection between the top contact (part
with the knob) and a terminal. The tension screw makes the connection between
the top contact and the spring steel tensioner. I cleaned and polished the
point of contact between the tension screw and spring but still had some
occasional jump so I jumped around the the tension screw. So far, the problem
has cleared up.
>
> I thought this was an oddity that you guys might be interested in...it
sure stumped me for a while...
> 73 de Bill K4JYS _______________________________________________
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>


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