JRC JHS-7 - Simple Adjustment

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6.3 Simple Adjustment
This subparagraph describes simple adjustment
procedure that can be followed without use of
special measuring instruments.
Before simple adjustment, perform the following
initial settings:
(1) SQ control Turned fully counter
clockwise
(2) Channel number: CH16
(3) PWR/VOL switch: Upon adjustment,
turned clockwise to
switch on the power.
6.3.1 Checking of Voltages
The power supply voltage should be 7.2V.
step signal
Check
point
Measuring
equipment
Measurement
(standard)
1 7.2V J201
pin 8
Circuit tester
or digital
voltmeter
7.2V
2 5V J202
pin 8
Circuit tester
or digital
voltmeter
5V
3 R5 J201
pin 1
Circuit tester
or digital
voltmeter
5V during Rx
0V during Tx
4 S5 J202
pin 10
Circuit tester
or digital
voltmeter
5V
5 T7 J202
pin 1
Circuit tester
or digital
voltmeter
0V during Rx
7V during Tx
6.3.2 Adjustment of the Synthesizer
Connect a digital voltmeter to the check point ③
on the CMN-241 main unit.
step control Check point Procedure
1 CV2 CMN-241
③
Set the voltage at
2.5V DC ±0.1V
for reception.
2 CV3 CMN-241
③
Set the voltage at
2.5V DC ±0.1V
for transmission.
6.3.3 Frequency Adjustment
(1) Connect a simple whip antenna to the
input terminal of the frequency counter.
(2) Bring the antenna of the radiotelephone
near the antenna of the frequency counter,
and put the radiotelephone in
transmission mode.
(3) Adjust CV3 on the CMN-241 main unit so
that the frequency may be set at 156.8MHz
±100Hz
6.3.4 Transmit Output Adjustment
(1) Remove the antenna using the exclusive
wrench.
(2) Connect a power meter (50Ω) to the
antenna terminal.
(3) Adjust RV1 on the CMN-241 main unit so
that the transmit output may be 0.8W±
20%
6.3.5 Tuning of the Receiver
(1) Connect a standard signal generator (50Ω)
to the antenna terminal.
(2) Set the frequency and output level of the
standard signal generator at 156.8MHz
and 0dBμ, respectively.
(3) Adjust L5 through L8, T1, and T2 on the
CMN-241 main unit so that the noise from
the speaker may be minimized.