Sony SPP-69, Service Manual

Page: 12 / 32

– 12 –
0 V
Adjust so that they
synchronize at 0 V.
RSSI output waveform AF oscillator
EXT signal
20 Hz
RSSI WAVEFORM
+
–
oscilloscope
(DC range)
TP9 (SIG OUT)
TP19 (GND)
FM RF
signal generator
TP2
TP3 (RX GND)
AF oscillator
Output: 20 Hz
level meter
+
–
PBX tester
TP104
600
Ω
TP105
F.B.
DC 48V
or
FM RF
signal generator
TP2
TP3 (RX GND)
+
–
digital voltmeter
TP5 (RX VT)
TP3 (RX GND)
+
–
digital voltmeter
TP6 (TX VT)
TP19 (GND)
SECTION 4
ELECTRICAL ADJUSTMENTS
BASE UNIT SECTION
Note:
• Apply 9V dc from regurated DC power supply.
• Perform the adjustment at TEST3CH (28CH : 49.910 MHz) as a
rule.
• Set to base unit manual test mode. (Refer to page 7)
• Switch position :
S302 (DIAL MODE) : P (pulse)
TX SECTION ADJUSTMENT
• The electrolytic capacitor (10 µF/10 V) connected TP23 (DET
OUT) to TP19 (GND). (Only TX section adjustment)
TX VT Adjustment
Setting :
Procedure :
1. The digital voltmeter connected TP6 (TX VT) to TP19 (GND).
2. Adjust the L52 for 2.2 ± 0.05 V reading on the digital voltmeter.
RX VT Adjustment
Setting :
Procedure :
1. Adjust the FL101 for the maximam reading on the level meter.
Also check that the output level is the specified values.
Specified Value : –1.4 to –9.6 dBV
RSSI Hi Adjustment
Note:
• Perform the adjustment at TEST3CH (28CH : 49.910 MHz) as a
rule.
Setting :
Procedure :
1. The digital voltmeter connected TP5 (RX VT) to TP3
(RX GND).
2. Adjust the L101 for 2.4 ± 0.05 V reading on the digital voltmeter.
Procedure :
1. Use the oscilloscope to confirm the FM RF signal generator
input (AF) signal waveform and RSSI signal, and use the RV101
so that they are synchronized (duty is synchronized).
Carrier frequency : 49.910 MHz
Modulation
: 1 kHz
Deviation : FM 3 kHz
Output level : 60 dBµV (1 mV) (EMF)
RX SECTION ADJUSTMENT
RX LEVEL Adjustment
Note:
• Perform the adjustment at TEST3CH (28CH : 49.910 MHz) as a
rule.
Setting :
Carrier frequency : 49.910 MHz
Modulation
: 20 Hz (EXT)
Deviation : AM 50%
Output level : 17 dBµV (7.1 µV) (EMF)
Adjustment Location : base main board (See page 13)