Advertisement
= ADJUSTMENTS
OF VFO-5S
1. Adjustment of crystal oscillation
(Refer to Fig. 14)
When
the device
does
not
oscillate
with
a crystal
oscillator
having
a frequency
characteristic
of 5.5~4.9
MHz, the ceramic trimmer T1 must be adjusted.
If it does
not still start oscillation
owing
to defect
of the crystal
oscillator or inherent unsuitable matching to the circuit, a
new
crystal
oscillator
must
be
purchased
with
circuit
designation.
Oscillating condition must be judged by the deflection
of the RF
meter
after putting TS-515
into the state of
transmitting.
In this case,
a dummy load must be cannect-
ed to ANT without fail.
2.
Matching of frequency
(1) Purpose:
To perform frequency tracking of VFO unit.
(2) Measuring instrument:
Frequency counter.
(3) Adjusting procedures:
1)
Connect the main body and the unit VFO-5S
by the attached VFO cable.
2)
Throw
down
the VFO
crystal change over
switch to VFO side.
3)
Set the function
switch
to REC
or REC/
XMIT.
4)
Set the RIT knob to the RIT off position.
5)
Turn on the power switch on the main body.
6)
Connect the frequency counter to the output
terminal of the VFO unit.
7}
Tune
to 5.5MHz
by rotating
the tracking
variable capacitor in the VFO
unit at ''0" in
calibration,
8)
At this stage, tune to 4.9MHz by rotating the
core of coil in the unit at "600°
in calibra-
tion.
9)
Obtain
the output
of 5.5MHz
+1.7kHz
and
4.9MHz
+1.7kHz
at the calibration
'"O" and
"600", respectively, by repeating the adjust-
ment specified hy ttems 7) and 8) for several
times.
3.
RIT
(1) Purpose:
To adjust the transmitting frequency to the center
(zero point) of the RIT knob.
(2) Measuring instruments:
1)
AF generator
2)
Oscilloscope
(3) Adjusting procedures:
1)
Remove
the case of the unit VFO-5S
in ac-
cordance with Item 4, relative to maintenance.
2)
Connect the main body and the unit VFO-5S
by the attached VFO cable.
3)
Turn on the power switch on the main body.
4)
Throw
down
the
VFO-crystal
change
over
switch to VFO side.
5)
Set the function
switch
to REC
or REC/
XMIT.
6)
Adjust the RIT knob of the unit VFO-5S to
the ''0" position exactly.
7)
Set the AGC/CAL
switch in the main body to
25kHz,
8)
Receive
the marker
at 14.2MHz
by turning
the dial in the unit VFO-5S
and obtain a
beat sound of about 1000Hz.
In this case, receive a signal at its maximum
sensitivity by adjusting the knob at each stage.
9)
Set the function
of the oscilloscope
to EXT
HORIZONTAL
and introduce the AF genera-
tor output (1000Hz, 1V) to the H terminal.
10)
Introduce
the
received
output
to
the
V
terminal
of the oscilloscope
and
adjust the
VFO
dial
finely
until
the
Lissajous' figure
stops.
In this case, the figure should
be a
circle.
11)
Set the RIT
knob
of the unit VFO-5S
to
OFF
and adjust the RIT VR
10k
(VR2)
with
in the chassis of VFO-5S
so that the
Lissajous'
figure of the oscilloscope
will be-
come a circle again.
[Note]
Adjustment specified by Item 11) must
be finish-
ed
within
one
minute.
If it cannot
be made
within
this period, readjustment
must
be made
from item 10).
4.
Maintenance
(1) Remove the case
Remove
two screws on the surface of the upper
panel and four screws on the bottom surface. The
front panel must be quietly pulled outof place.
The removal of leg portion of leg porton is not
required.
Be
careful
since
it often
results
in 'requency
deviation
and
the
cause
of drift
if the
case
is
dissolved unnecessary .
(2) Lubrication to gear portion
A small quantity
of machine
oil must te applied
once a year to dial gears.
(3) Pilot lamp
The pilot lamp must be provided with 4 wvan base
of 12V/1.5W.
31
Advertisement
