Icom IC-701

7-3-3 COMPRESSOR CIRCUIT ADJUSTMENT
Place the set in the transmit mode in USB at 14MHz and
turn the compressor and mic gain knobs fully clockwise.
Then as shown in figure, connect the AF oscillator across
Pin 1, the input, and pin 4, ground, of the mic connector
and apply an input of 100mV, at 1000Hz. Turn R68 fully
in the direction as indicated by the arrow. (clockwise)
Connect an
AF oscillator
Ground side
Compressor circuit adjustment
7-3-4 CARRIER POINT ADJUSTMENT
Place the set in transmit in USB at 14MHz and turn the
compressor OFF with the mic gain knob turned fully
clockwise. Connect the AF oscillator across Pin 1 (input)
and Pin 4 (ground), of the mic connector.
(a) Set the frequency of the AF oscillator to 270Hz and
the output at a level that gives approximately 20
Watts output on the watt meter.
(b) Then vary the AF oscillator frequency to 2700Hz
a and adjust C66 in the “B” unit to obtain 20 Watts on
the meter.
(c) Performing the adjustments shown in (b) will affect
the adjustment done in (a). Repeat adjustments in
(a) and (b) until no difference is present.
(a) Place the meter switch to ALC and adjust R25 so
that the meter indicates 60% on the Po scale.
(b) Adjust R68 in the “A” unit so that the meter
indicates 50% on the Po scale.
(c) Place the meter switch to COMP and adjust R213 in
the “‘A’’ unit so that the meter indicates its full scale.
(d) Then turn the mic gain knob on the front panel fully
counter-clockwise and adjust R40 so that the meter
just begins to swing and set it in that position.
(e) Performing the adjustment shown in (d) will affect
the adjustments done in (c). Repeat adjustments in
(c) and (d) until no difference is present.
R68
Described in (b)
i R25
Described in (a)
R213
Described in (c)
tjanw,
KOS ABIL
AN;
/
SY
(d) Place the MODE switch to LSB and adjust C75 the
same as the adjustments done in (a), (b) and (c) using
C75.
7-3-5 SPEECH PROCESSOR ADJUSTMENT
When the compressor is turned ON, the SSB signal passes
through the crystal filters FL1 and FL2 in the “A” unit.
Since the rated center frequencies of these filters differ
from the actual center frequencies by a certain amount,
deterioration of audio quality results due to narrowing of
the SSB band width. To eliminate this problem, the VXO
frequency is shifted to cover the drift mentioned above in
the following adjustments. Place the set in the transmit
mode in USB at 14MHz with the mic gain and compressor
knobs turned fully clockwise and connect the AF oscillator
output across of the mic connector as before with the
frequency set at 2600Hz.
R40 Described in (d)
aanacie ntcne cates paeanQencseee eit GMs tab ht Lien abn ALAS maken