Reggie wrote:
Chuck, I followed you procedure and was able to pull it back to within
11 Khz, then the knob quit turning (was turning to the left). I had
the radio on 15,000 Khz. Turn the cal knob all the way to the left and
all the way to the right and was not able to hear the tone. Then I
turned the cal knob back to 14,089 and could hear it, but that's when
the knob quit turning. What does this mean?

Hi Reggie,

There are a couple of possibilities, the voltage source for the varicap
that is adjusted by the calibrate knob could have drifted, or the shaft
coupling that goes between the tuning cap and the counter shaft could have
been set incorrectly. To check for proper fine tuning operation, it should
shift the receiver frequency a total of 8KHz when you turn it from one end
to the other.

It is easy to adjust the shaft coupling. It has two set screws, one goes into
a brass shaft, and the other presses on a phenolic sleeve that goes around
the capacitor shaft.

Here is the proceedu

1) measure the RF voltage out of the 2nd VFO output on rear panel, is should
be 250mv
2) connect a frequency counter to the 2nd VFO output on rear panel. Set the
KHz dial to 1000KHz (up at the high end) The counter should read 3.6MHz

3) set the 2nd VFO to 0000KHz, and the counter should read 4.6MHz+/- 500Hz.
If it doesn't, adjust trimmer C4 for correct frequency.
4) set the 2nd VFO to 1000KHz, and adjust the mechanical coupling for 3.6MHz.

5) repeat steps 2-4 until the ends match. When they do, check each 100KHz
point for correctness. If they are wrong, the tabs on the main tuning
cap will need tweaking (DON'T DO THIS UNLESS YOU ARE REALLY SERIOUS!!).

6) check that the VFO varies from 0 to 8KHz when you adjust the fine tuning
control.


OK, that is the official factory sanctioned alignment instruction for the
VFO. Before you do any of it, check with a freq. counter to see what the 2nd VFO
frequencies are at 1000KHz, and 0000KHz. If you are lucky, they will both be
off by the same amount in the the same direction. If this is true, you just
need to slip the capacitor's shaft coupling. Don't go nuts on tightening the
set screw, it only needs to be snug.

Just out of curiosity, have you tried the BFO check position to see if your
BFO tuning knob is really at zero when its pointer shows zero? The BFO can
tune +/-15KHz.

-Chuck