Tuning the "cal." signal and monitoring a transmitted carrier reveals a slight 
frequency "warble" of sorts.  PTO is clean and has the ground strap 
modification, and this issue seems unrelated to the PTO, in that physical 
movement or position of the PTO has no effect.  This is some type of minor 
instability seemingly not related to anything mechanical.  Improves as rig 
warms, but takes about an hour to clear.   Any suggestions on how to narrow 
this to the (presumably) offending oscillator?  Seems like it would not show up 
on a counter, but perhaps as "jiggle" on a scope?  I believe I read somewhere 
about an analog switch IC that can cause frequency jumping.  The frequency 
deviation is minor, but enough to roughen up received and transmitted signals.  
Rig is very early SR#.  General VFO stability is acceptable.  Could this be 
normal for the old rig?  Thanks!
Leon (N5LAZ).
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