[Kenwood] TS-940S: AF Tune control operation unstable (oscillation at some points) - advice?

[David Feldman]

As it turns out, that WAS the problem! 

The original owner since new was a phone op, I never used it before, and after rotating the control through range about 20 times, the problem disappeared.

Thanks!

Dave

--------------------------------------------
On Sun, 12/2/18,  <k3ac at aol.com> wrote:

 Subject: Re: [Kenwood] TS-940S: AF Tune control operation unstable (oscillation at some points) - advice?
 To: wb0gaz at yahoo.com, kenwood at mailman.qth.net
 Date: Sunday, December 2, 2018, 10:52 PM
 
 
 
 Dave - well, the
 AF Tune pot on the 940 is not used very often (at least I
 don't recall using it much when I had my 940 on
 CW)  so I suspect (at least an initial step) that it
 may have developed some corrosion internally. Are you able
 to get to it at all without removing front panel? If so,
 might be worth shooting a little Caig FaderLube (not DeOxit)
 inside and working the control to see if that improves the
 instablity/oscillation. Getting to the opening of the case
 under the solder terminals can be difficult but you may be
 able to get a thin straw-like applicator close enough to get
 some of the lube inside.
 
 
 Bob,
 K3AC
 
 
 
 In a message dated 12/2/2018 10:35:40 PM Eastern Standard
 Time, kenwood at mailman.qth.net writes:
 
 
 
 
 Have TS-940 S/N 7M range. In CW mode, with AF
 Tune button active, adjusting the AF Tune control results in
 some apparent oscillation or similar instability. There is a
 tunable gain/level peak (I think normal operation; I'd
 not ever tried that control before on a TS-940), however,
 rotating the control across the range also produces
 unstable, sharp (and fairly loud) audio tone artifacts at
 some points.
 
 
 Advice request - does this sound familiar to
 anyone? I'll have to open it up anyway for another issue
 (the backup battery is also now dead), but would like avoid
 reinventing the troubleshooting wheel if this is otherwise a
 known type of issue.
 
 
 Thanks,
 
 
 Dave
 wb0gaz at yahoo.com
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