Top Vievy; Bottom View - Icom ic-751a Instruction Manual

(2)
SIMPLE
FREQUENCY ADJUSTMENT A
very accurate frequency counter
is
required to
align the frequency
of the IC-751A.
However,
a
simple check
may
be performed by
receiving radio station
WWV,
WWVH
or other standard
frequency
signals.
1)
Select the
AM
mode
and
GENERAL COVERAGE
mode.
NOTE:
This adjustment
calibrates
the reference
oscillator,
therefore
it
is
unnecessary
to
calibrate
on any
other frequency.
2)
Use
the
TUNING
CONTROL
to
set
the frequency
display to the
exact
frequency
of the standard
frequency
station
(10.000.0MHz
for
WWV/WWVH).
Check
for
a
strong
receiver
signal.
3)
Turn
ON
the
MARKER
SWITCH
on
the top
panel.
4)
Adjust the
MARKER
CALIBRATOR
on
the
top
panel
for
zero
beat.
Zero
beat
exists
when two
signals are
on
exactly the
same
frequency
resulting
in
no
audible tone.
5)
Turn
OFF
the
MARKER
SWITCH.
(3)
ELECTRONIC KEYER WEIGHT
CONTROL
Features designed
into
the
custom
microprocessor
include contact
debouncing,
RF
immunity,
self-completing character generation,
dot
memory
and weight
control.
The
keying speed can be
varied continuously from
5 to
45 words
per
minute.
The R8
WEIGHT CONTROL
is
set fully counterclockwise
at
the
factory
which
sets
the
DOT;SPACE:DASH
ratio at
1:1:3.
DOTS
and
DASHES
increase
in
length
if
R8
is
turned
clockwise.
(4)
CW
SIDETONE
FREQUENCY
ADJUSTMENT
1
)
This control
is
factory
set
for
a
700Hz
tone.
2)
Connect
a
CW
key
to the
KEY JACK
on
the rear panel
and
select
the
CW
mode.
(5)
SCAN SPEED ADJUSTMENT
(6)
BFO ADJUSTMENT
(7)
TRANSMIT AUDIO ADJUSTMENT
3)
Close the
CW
key and
adjust
R374
for
a
suitable tone. Refer to
SECTION 13-2 BOTTOM VIEW
for
the adjustment
location.
1)
Activate the
PROGRAMMED
SCAN.
Refer to
SECTION
8
for
information
on
the scanning functions.
2)
Adjust
R14
for a suitable scanning speed. Refer to
SECTION
13-2
BOTTOM
VIEW
for the
adjustment
location.
1
)
Connect
a
frequency counter
to
CPI on
the
MAIN
unit. Refer to
SECTION 13-1 TOP VIEW
for
the
CPI
location.
MODE
FREQUENCY
(MHz)
ADJUSTMENT
RECEIVE TRANSMIT
USB
9.01300 9.01300 C202
LSB
9.01000 9.01000 L33
CW
9.00990
NO SIGNAL
L34
RTTY
9.008475 9.008475 L35
AM
NO
SIGNAL
9.01000 L33
FM NO
SIGNAL
NO
SIGNAL
The
bass
and
treble
response of your transmitted
signal
may
be
altered
with the
R155
adjustment
on
the
MAIN
unit.
Refer to
SECTION 13-1 TOP VIEW
for the
R155
location.
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