[Hammarlund] SP-600 Tuning

Tue, 12 Aug 2003 09:51:11 -0500

Hi Dave,

        I think it is more likely that maybe you have some old resistors
that are drifting around due to possible humidity changes in their
environment.  I wouldn't do any realignment work until it ran constantly for
a few days to bake out any moisture that may have worked it's way into the
set.

Since it is that way equally on every band...I don't believe it is an
alignment problem...I would more likely believe that there has been a slight
voltage change in the output of the regulated power supply causing the VFO
or Local Osc. to move slightly off frequency from when aligned...

Whatever has caused it is common to all bands...I would think if it were
alignment as a result of a cap drifting it would only affect one band.

Just going through some thoughts here...haven't looked at a schematic...

Cecil Acuff

----- Original Message ----- 
From: "Dave Faria" <[email protected]>
To: "hammarlund" <[email protected]>
Sent: Tuesday, August 12, 2003 8:30 AM
Subject: [Hammarlund] SP-600 Tuning

> GM List.  I have a curiosity question.  I let my 600 sit for several
months
> and turned it on yesterday(other projects).  My tuning is now off a
pointer
> width, in the same direction, on all bands.  I spent a fair amount of time
> recapping and aligning the radio.  I originally aligned the radio after a
24
> hour warm-up.  My signal generator is an old hp 8640b and I check it
against
> WWV.  I can redo the alignment today unless someone can tell me that's
just
> the way they are and it will do it agn in a few months.  I'll just figure
> its the new cap.s aging if its not a typical change.
>
> Thanks
> Dave
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