Problem with 144 Transverter Oscillator - New Information

[K8RS]

Gurus,
          I am in the Alignment Procedure Part I on the 144 MHz Transverter (page 59).  After the unit has been on for an hour or more, the voltage reading on TP1--testing the local oscillator voltage--varies between 0.002 and 1.642 vdc.
        When I first turn the unit on using the K2, the voltage is a steady 1.642 vdc and the RF output of the Transverter can be set to a steady 20 watts.  But after the unit has been on for a while the voltage on the oscillator begins to vary and the RF output of the Transverter varies with it.
         The oscillator seems to be going in and out of oscillation.  What would be causing this?  A failed crystal?  A part in the oscillator circuit?  Will it settle down when I tune the inductors?  Clearly I need some help and suggestion.  The crystal is in a crystal oven and the jumper on JP9 is over pins 4-5.
                                  Thanks,
                                               Roger K8RS K2/100 #3478
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[Robert Friess]

Hi Roger,

It is very unusual that an oscillator would behave the way you describe,
however, strange things do happen.  There are not any adjustments on the
oscillator so it may be that you have a marginal oscillator transistor or
crystal or a combination of both.  It is just possible that as the XV warms
up, the gain of the oscillator transistor drops just enough to stop
oscillating.  Please ask Scott at Elecraft to send you a new crystal and
transistor.

73,
Bob, N6CM
XV Designer
----- Original Message -----
From: "RCStimson" <[hidden email]>
To: "Elecraft" <[hidden email]>
Sent: Monday, June 28, 2004 8:40 AM
Subject: [Elecraft] Problem with 144 Transverter Oscillator - New
Information


Gurus,
          I am in the Alignment Procedure Part I on the 144 MHz Transverter
(page 59).  After the unit has been on for an hour or more, the voltage
reading on TP1--testing the local oscillator voltage--varies between 0.002
and 1.642 vdc.
        When I first turn the unit on using the K2, the voltage is a steady
1.642 vdc and the RF output of the Transverter can be set to a steady 20
watts.  But after the unit has been on for a while the voltage on the
oscillator begins to vary and the RF output of the Transverter varies with
it.
         The oscillator seems to be going in and out of oscillation.  What
would be causing this?  A failed crystal?  A part in the oscillator circuit?
Will it settle down when I tune the inductors?  Clearly I need some help and
suggestion.  The crystal is in a crystal oven and the jumper on JP9 is over
pins 4-5.
                                  Thanks,
                                               Roger K8RS K2/100 #3478
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