Electrical Adjustments; Base Unit Section - Sony SPP-M100 Service Manual

5-1. BASE UNIT SECTION

• Apply 9V dc from regulated DC power supply.
• Set to baseunit manual test mode. (Refer to page 11.)
• Switch position :
DIAL MODE : P (Pulse)
TX Section Adjustment
• Perform the adjustments at 25CH (46.970MHz) as a rule.
1. TX VCO Adjustment
Setting :
digital
voltmeter
Procedure :
1 The digital voltmeter connected TP9 (TX VCO) to GND.
2 Adjust the L102 for 0.9 to 1.1V reading on the digital volt-
meter.
Adjustment Location : Base main board (see page 21)
2. RX VCO Adjustment
Setting :
digital
voltmeter
Procedure :
1 The digital voltmeter connected TP8 (RX VCO) to GND.
2 Adjust the L2 for 0.9 to 1.1V reading on the digital voltme-
ter.
Adjustment Location : Base main board (see page 21)
RX Section Adjustment
• Perform the adjustment at T1CH (RX : 48.970MHz) as a rule.
1. DET Adjustment
Setting :
level meter
TP402
TEL LINE
FM rf signal
generator
SECTION 5

ELECTRICAL ADJUSTMENTS

TP9 (TX VCO)
TP8 (RX VCO)
TP402
PBX tester
TP401
or
FB
DC48V
TP401
TP17 (ANT)
TP12 (GND)
Procedure :
1 FM rf signal generator condition :
Carrier frequency
Modulation frequency : 1kHz
Deviation
Output level
2 Adjust the L4 for the maximum reading on the level meter.
Adjustment Location :
2. IF Adjustment
Setting :
level meter
FM rf signal
generator
Procedure :
1 FM rf signal generator condition :
Carrier frequency
Modulation frequency
Deviation
Output level
2 Adjust the L3 for the noise level to minimum reading on
the level meter.
Adjustment Location :
3. SQ SENSITIVITY Adjustment
Setting :
oscilloscope
(DC range)
FM rf signal
generator
Procedure :
1 FM rf signal generator condition :
Carrier frequency
Modulation frequency
Deviation
Output level
2 Adjust the RV601 so that the waveform appearing on the
oscilloscope has a duty of 50%.
(Since the waveform is not accurately observed, adjust so
that the top and bottom retrace lines are in the same condi-
tion.)
– 19 –
: 48.970MHz
: 3kHz
: 60dBµV (1mV) (EMF)
Base main board (see page 21)
TP29 (IF)
TP17 (ANT)
TP12 (GND)
: 48.970MHz
: 1kHz
: 3kHz
: –6dBµV (0.501µV) (EMF)
Base main board (see page 21)
TP10 (SQ)
TP17 (ANT)
TP12 (GND)
: 48.970MHz
: 1kHz
: 3kHz
: –6dBµ V (0.501µV) (EMF)