Icom IC-701

SECTION 7 MAINTENANCE AND ADJUSTMENT
This set has been completely adjusted and checked at the
factory so no adjustment should be necessary. However,
during prolonged use, the preadjusted oscillating frequency,
etc. may need slight adjustment. If this becomes necessary,
the following procedures should be followed. As the
adjustments other than those specified herein require high
skill and expensive equipment, for best results the set
should be sent back to the dealer or ICOM distributor for
adjustment.
7-1 MEASURING INSTRUMENTS
REQUIRED FOR ADJUSTMENT
(1) FREQUENCY COUNTER
FREQUENCY RANGE _ 1 - 90MHz
ACCURACY BETTER THAN +1 ppm
SENSITIVITY 100mV or BETTER
(2) SIGNAL GENERATOR
FREQUENCY RANGE
OUTPUT VOLTAGE
(3) MULTIMETER
(4) AC MILLIVOLTMETER
1.8MHz - 30MHz
—20 - 90dB (0dB =1#V)
20KQ/Volt or better
MEASURING RANGE ~ 100-200mV
(5) RF VOLTMETER
FREQUENCY RANGE _ 1.8-30MHz
MEASURING RANGE _ 0.1-1V
(6) RFWATTMETER
MEASURING RANGE ~— 20-100 Watts
FREQUENCY RANGE _ 1.8-30MHz
IMPEDANCE 50 OHMS
SWR LESS THAN 1.1
(7) AF OSCILLATOR
OUTPUT FREQUENCY 200-3000Hz
OUTPUT VOLTAGE 0-100mV
DISTORTION LESS THAN 0.1%
(8) OSCILLOSCOPE SYNCROSCOPE
(9) DIGITAL VOLTMETER
MEASURING RANGE 0.001—10V 3-1/2 DIGITS
7-2 RECEIVER ADJUSTMENT
7-2-1 BFO FREQUENCY ADJUSTMENT
The BFO oscillator frequencies differ in accordance with
BFO Frequency Adjustment
aS R85
RTTY WIDE
NARROW
MARK MARK
: (transmit)
(transmit) Adj
Adj. :
C78
CW, RTTY SPACE
(transmit) Adj.
each mode and for transmitting and receiving operation.
Adjust corresponding trimmer capacitors and trimmer
resistors as shown in the table below. Connect the input
terminals of the frequency counter across the lead wire of
the BFO output D10, or D11, in the B unit, and ground.
Connect a digital Voltmeter to the cathode of D36 of the
“A” unit and check voltage for 8V DC +100mV. Adjust
R202 as necessary for 8V. This is a critical adjustment.
(a) Place the set in receive. Make frequency adjustments
as follows.
RECEIVE OPERATION
ADJUSTING BFO OUTPUT
POINT FREQUENCY
CW (CW-N) | C69 (B unit) 9.01320 MHz
i 9.014525MHz
(b) Turn ON the speech processor (COMP) but keep the
knob fully counterclockwise to supress RF power
from being transmitted. Then place the set in the
transmit mode.
ADJUSTING BFO OUTPUT
C78 (B unit) 9.01240MHz
R87 (B unit) 9.01223MHz (note 1)
(S3 in B unit to N)
R85 (B unit)
(S3 in B unit to W)
CW (CW-N)
RTTY
9.01155MHz (note 1)
NOTE 1:
S3 in the “B” unit is a change over switch (RTTY Switch)
for narrow modulation (170Hz shift width) and wide modu-
lation (850Hz shift width) RTTY transmission, which is
located under the access cover.
NOTE 2:
Fine adjustment for the SSB carrier point should be
performed in accordance with adjustment “4, CARRIER
POINT ADJUSTMENT, in the transmitter section adjust-
ment procedures.
C72 RTTY (receive) Adj.
C69 CW (receive) Adj.
C66 USB Adj.
C75 LSB Adj.
Connect frequency counter
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