Section 3 Electrical Adjustments; Tuner Section - Sony SRF-R405 Service Manual

TUNER SECTION

[FM]
Setting
ENT/BAND switch : FM
Signal generator
FM RF signal
generator
0.01 µ F
22.5 kHz frequency
deviation by
400 Hz signal 30%
Output level : as low as possible
[AM]
Setting
ENT/BAND switch : AM
Put the lead-wire
AM RF signal
generator antenna close
to the set.
30% amplitude
modulation by
400 Hz signal
Output level : as low as possible
MAIN board
TP3(LPF)
• Repeat the procedures in each adjustment several times for a
maximum reading on level meter, and the frequency coverage
and tracking adjustments should be finally done by the trimmer
capacitors.
Adjustment Location :
– MAIN board (side A) –
ELECTRICAL ADJUSTMENTS
0 dB = 1 µV
Level meter
16 Ω
Set
Headphones jack
(J401)
TP1(ANT)
MAIN board
Level meter
16 Ω
Set
Headphones jack
(J401)
Digital
Volt meter
TP4
(76kHz)
TP3 (LPF) TP1 (ANT)
SECTION 3
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L202
CT202
Adjust so that the voltage at TP3(LPF) becomes 2.60 ±0.05V.
L205
Adjust for a maximum reading on level meter.
T201
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L201
CT201
FM STEREO (76kHz) ADJUSTMENT
Adjustment point
RV301
FM STEREO (76kHz)
Procedure :
FM RF SSG
Carrier frequency : 76MHz
Modulation : no modulation
Output level : 0.1V (100dB)
1. Connect frequency counter to the positions shown below.
2. Tune the set to 76MHz.
TP4(76kHz)
– MAIN board (side B) –
T201
AM IF
Adjustment
L202, CT202
FM Tracking Adjustment
— 4 —
76.0MHz
108.0MHz
AM VCO ADJUSTMENT
531kHz
AM IF ADJUSTMENT
450kHz
585kHz
1,485kHz
Frequency Indication Frequency counter Reading
FM76MHz 76kHz ±200Hz
0.01 µ F
to TP1(ANT)
Frequency counter
0.01 µ F
+
–
Use a frequency counter
having input impedance
of 10M Ω or higher.
RV301
FM STEREO (76kHz)
Adjustment
L205
AM VCO Adjustment
L201, CT201
AM Tracking Adjustment