Electrical Adjustments; Base Unit Section - Sony SPP-114 Service Manual

BASE UNIT SECTION

Note:
• Apply 9V dc from regurated DC power supply.
• Perform the adjustment at T3CH (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 :
digital voltmeter
+
–
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 :
digital voltmeter
+
–
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.
12
SECTION 4

ELECTRICAL ADJUSTMENTS

TP6 (TX VT)
TP19 (GND)
TP5 (RX VT)
TP3 (RX GND)
RX SECTION ADJUSTMENT
RX LEVEL Adjustment
Note:
• Perform the adjustment at T3CH (28CH : 49.910 MHz) as a rule.
Setting :
FM RF
signal generator
Carrier frequency : 49.910 MHz
Modulation
Deviation
Output level
level meter
+
–
600 Ω
PBX tester
or
DC 48V
F.B.
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 T3CH (28CH : 49.910 MHz) as a rule.
Setting :
FM RF
AF oscillator
signal generator
Output: 20 Hz
Carrier frequency : 49.910 MHz
Modulation
Deviation
Output level
oscilloscope
(DC range)
+
TP9 (SIG OUT)
–
TP19 (GND)
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).
RSSI output waveform
0 V
Adjust so that they
synchronize at 0 V.
RSSI WAVEFORM
Adjustment Location : base main board (See page 13.)
TP2
TP3 (RX GND)
: 1 kHz
: FM 3 kHz
: 60 dBµV (1 mV) (EMF)
TP105
TP104
TP2
TP3 (RX GND)
: 20 Hz (EXT)
: AM 50%
: 17 dBµV (7.1 µV) (EMF)
AF oscillator
EXT signal
20 Hz