Table of Contents
Advertisement
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
cin totic
ON
or
Aa ns 8s IE
cnet
Re
2 Leos ca ns inieintat He ahh lnm na MANN
Advertisement
Table of Contents
