[TenTec] Rebuilding VFO

[Mike Hyder -N4NT-]

Ron, I had hoped that you would get some advice more in response to what
I think was your question.  First, rebuilding the PTO is not an
insurmountable task.  As someone else said, usually the trouble is just
that the grease which lubricates its mechanism has become sticky with
age.  This requires removing and dismantling the PTO then thoroughly
cleaning the old grease out and replacing it with new.

It is right much bother to remove the PTO from the rig.  The job is made
much easier with the instructions Ten-Tec will provide you.  Note that I
echoed the 'usually' above.  Sometimes the PTO will have gone so long
without proper lubrication that the bearing race is scored.  For these
reasons, I suggest that prior to commencing the job, one have a 'PTO
rebuild kit' from Ten-Tec on hand to facilitate the replacement of
parts.  The kit comes with instructions for the disassembly of the PTO,
itself.

A PTO with the sticky grease problem will behave in a peculiar way:
when tuning CW signals, it will seem that they warble and it is
increasingly difficult to get on a frequency.  But that does not seem to
be what you asked about.

If you don't experience the 'warble', and you do experience drift in the
PTO from turn-on then you have a different problem to tackle.  If you
examine the PTO case, you will see that either the top or the bottom
cover is held in place with a screw.  Removing that cover gives access
to the foil side of the circuit board.  I cannot tell you this for sure
but believe you will find an NPO capacitor soldered to the foil side.
Changing this to a different value may change thermal drift in the PTO,
so experimentation with different values is called for.  Another thing
you can try is removing the fish paper under that cover and replacing
the cover without the paper -- that may work for you.

Please let me know what you do and what you are able to accomplish.

73, Mike -N4NT-

----- Original Message -----
From: "Ron Wicker" <ronwick@flash.net>
To: <tentec@qth.net>
Sent: Sunday, September 23, 2001 12:55
Subject: [TenTec] Rebuilding VFO


I have a Triton 544 transceiver that is drifting a lot on turn on.  Is
there
a procedure for recapping the VFO?  If there is a source of info,
regarding
this procedure and what caps to use, please direct me to it.  I have
some
other older Ten Tec rigs and they seem to be similar in construction.
Any
advise?
Ron, AA5NI.......

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