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Setting :
AF signal
generator
Telescopic
antenna
Frequency counter
Transmission Frequency Check
1. Set the noise filter SW to OFF.
2. Input a signal of 1 kHz, 40 mVrms to only the L-CH (J402).
3. Connect a telescopic antenna to the frequency counter input
and extend the antenna to a length of approximately 8 cm.
4. Place TX-BASE board close to the frequency counter, then mea-
sure the frequencies of CH1, CH2 and CH3 and make sure the
values are as follows:
TE
CH1 : 863.5 MHz ± 40 kHz
L 13942296513
CH2 : 864.0 MHz ± 40 kHz
CH3 : 864.5 MHz ± 40 kHz
When the frequency does not satisfy the specified value, ex-
change the vco unit. When completed with replacement, recheck
the frequecies of CH1, CH2 and CH3.
Compresser Output Check
1. Set the channel to CH2.
2. Input a signal of 1 kHz, 316 mVrms to L-CH and R-CH of J402.
3. Measure IC 601 pin 7 and IC 602 pin 7 on the CHG-NR board
using a digital voltmeter (AC range) and confirm the value is
100 mVrms ± 5mV (Fig.1).
4. Input a signal of 1 kHz, 31.6 mVtms to L-CH and R-CH of J402.
5. Measure IC 601 pin 7 and IC 602 pin 7 on the CHG-NR board
using a digital voltmeter (AC range) and confirm the value is
31.6 mVrms ± 5 mV (Fig.1).
6. When the frequency is not satisfied the specified value, exchange
TX- BASE board or CHG-NR board.
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SECTION 3
ELECTRICAL ADJUSTMENTS
set
TMR-RF875R
L-CH / R-CH (J402)
set
8 cm
TMR-RF875R
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Pilot Signal and MPX Signal Modulation Check and
Adjustment
1. Set the channel to CH2.
2. No signal input (The operating time in this case is limited to 4
or 5 minutes.)
3. See the RV402 and RV403 to max. (clockwise)
4. Connect a digital voltmeter (AC range) to the movable terminal
of RV403 (Fig.2).
5. Adjust the value of the digital voltmeter to minimum by RV401.
6. See the RV402 to minimum. (counter clock wise)
7. Adjust the value of the digital voltmeter to max by L407.
8. Adjust the value of the digital voltmerter to 1.7 mVrms ± 0.1
mV by RV403.
9. Connect a digital voltmeter (AC range) with LPF to movable
terminal of RV403 (Fig.2).
10. Input a signal of 1 kHz, 316 mVrms to only the L-CH.
11. Adjust the value of the digital voltmeter to 2.5 mVrms ± 0.2
mV by RV402.
Connection points and Adjustment Location :
CH3 ← CH2 ← CH1
(L-CH) (R-CH)
J402
S402
RV402
RV403
Q Q
3
6 7
1 3
1 5
VCO UNIT
R464
L407
RV401
RV401-403,
L407
digital
Modulation
voltmeter
check and
(AC range)
adjustment.
digital
voltmeter
(AC range)
R464
+
–
(Fig. 2)
co
.
9 4
2 8
CHG-NR board
0 5
8
2 9
9 4
2 8
IC 602
1
8
8
1
4
5
4
5
IC 601
7 pin
+
–
(Fig. 1)
m
9 9
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