My Omni VI has recently started to have a slight warble in both TX and
RX frequency when on 30 meters. About the only thing unique to 30 meters
that would affect the frequency stability is the band select crystal and
associated components. My guess is that the crystal or other parts have
aged, requiring a minor adjustment to L19 in order to get the oscillator
to stay locked. By reading all the descriptions in my Omni VI manual, it
is apparent that the way to adjust these oscillators is to monitor the
DC voltage at connector 84, and adjust so that the oscillator is on the
right frequency AND the DC correction voltage on connector 84 is in the
middle of it's range. Nowhere in th manual can I find what is the ideal
voltage at connector 84. I want to fix it this weekend, and as long as I
have it opened up, I should probably adjust all of the bands. I probably
should not use the voltage on the other bands as an ideal to aim for,
since those parts have no doubt also aged. I suppose I could adjust one
of the inductors while watching the voltage in order to determine the
full correction voltage swing, and then set it right in the middle. I
would rather be aiming for a known specified voltage. I don't want to
wait until Ten-Tec is open next Monday. Have any of you on the reflector
made this adjustment? Can you tell me the correct voltage at connector
84? Is that even the right place to monitor the correction voltage? What
is the recommended instrument? Oscilloscope in DC coupled mode with 10X
probe? Digital multimeter?
Thanks in advance for any help,
Ken N6KB
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