Sony ST-S3000ES Service Manual ▷ View online
— 5 —
FM Discriminator ADJUSTMENT
(NULL and MONO Distortion Adjustment)
(NULL and MONO Distortion Adjustment)
Setting :
IF BAND : WIDE
ANT ATT : OFF
IF BAND : WIDE
ANT ATT : OFF
FM RF SSG
1 kHz
highpass
filter
highpass
filter
distortion meter
FM ANTENNA (75
Ω
)
LINE OUT
Modulation: Monaural Standard signal
Output level: 6mV (76dB) (at 75
Output level: 6mV (76dB) (at 75
Ω
open)
Procedure :
1. Tune the set to 98 MHz.
2. Adjust IFT252 for 0V reading on the digital voltmeter.
1. Tune the set to 98 MHz.
2. Adjust IFT252 for 0V reading on the digital voltmeter.
.................. NULL
3. Adjust IFT253 for a minimum reading on the distortion meter.
.................. MONO Distortion (THD)
4. Repeat the adjustments of 2 and 3 several times.
Note : When replacing the ceramic filter, perform this alignment.
TP251
NULL terminal
NULL terminal
Digital Voltmeter
(DC range)
(DC range)
set
Stereo Level Adjustment
Setting :
IF BAND : WIDE
ANT ATT : OFF
IF BAND : WIDE
ANT ATT : OFF
FM RF SSG
set
FM ANTENNA (75
Ω
)
Modulation: Stereo Standard signal
Output level: 18µV (25dB) (at 75
Output level: 18µV (25dB) (at 75
Ω
open)
Procedure :
1. Tune the set to 98 MHz.
2. Adjust RV251 to the point (moment) when the “STEREO”
1. Tune the set to 98 MHz.
2. Adjust RV251 to the point (moment) when the “STEREO”
indicator will change from going off to going on.
FM RF SSG
set
FM ANTENNA (75
Ω
)
Modulation: Stereo Standard signal
Output level: 18µV (25dB) (at 75
Output level: 18µV (25dB) (at 75
Ω
open)
Narrow Gain Adjustment
Setting :
IF BAND : NARROW
ANT ATT : OFF
IF BAND : NARROW
ANT ATT : OFF
Procedure :
1. Tune the set to 98 MHz.
2. Set “IF BAND : NARROW” according to the procedure of “How
1. Tune the set to 98 MHz.
2. Set “IF BAND : NARROW” according to the procedure of “How
to switch IF BAND WIDE/NARROW” on page 6.
3. Adjust RV231 to the point (moment) when the “STEREO” indi-
cator will change from going off to going on.
FM Meter Level Adjustment
Setting :
IF BAND : WIDE
ANT ATT : OFF
IF BAND : WIDE
ANT ATT : OFF
FM RF SSG
FM ANTENNA (75
Ω
)
Modulation: Stereo Standard signal
Output level: 3mV (76dB) (at 75
Output level: 3mV (76dB) (at 75
Ω
open)
Procedure :
1. Tune the set to 98 MHz.
2. Press DISPLAY button to display the digital signal, then adjust
1. Tune the set to 98 MHz.
2. Press DISPLAY button to display the digital signal, then adjust
RV221 to be displayed as “SIG 70dB”.
Stereo Separation Adjustment
Setting :
IF BAND : WIDE
IF BAND : WIDE
set
FM RF SSG
FM ANTENNA (75
Ω
)
set
LINE OUT
level meter
Modulation: Stereo Standard signal
Output level: 6mV (76dB) (at 75
Output level: 6mV (76dB) (at 75
Ω
open)
Procedure :
1. Refer to “How to switch IF BAND WIDE/NARROW” on page
1. Refer to “How to switch IF BAND WIDE/NARROW” on page
6.
FM stereo
Signal generator
Output channel
Level meter
connection
Level meter
reading (dB)
L-CH
L-CH
A
B
Adjust RV301 for minimum
reading on Level meter
reading on Level meter
R-CH
L-CH
R-CH
R-CH
C
D
Adjust RV301 for minimum
reading on Level meter
reading on Level meter
L-CH
R-CH
L-CH Stereo separation : A - B
R-CH Stereo separation : C - D
R-CH Stereo separation : C - D
The separations of both channels should be equal.
— 6 —
AM SECTION
AM Meter Level Adjustment
Setting :
BAND : LW
BAND : LW
loop antenna
AM RF SSG
AM antenna
terminal (TM1)
terminal (TM1)
loop antenna
(Supplied accessories)
(Supplied accessories)
Field strength dB (µV/m) = SSG output level dB (µV/m) –26dB.
30% amplitude
modulation by
400Hz signal
modulation by
400Hz signal
Carrier frequency: 216kHz
Modulation: AUDIO 400Hz, 30% modulation
Modulation: AUDIO 400Hz, 30% modulation
Procedure :
1. Set AM RF signal generator so that the AM antenna input level
1. Set AM RF signal generator so that the AM antenna input level
becomes 74dBµ/m.
2. Adjust RV402 so that 1 to 10 indication bars light up on the signal
meter.
Adjustment Location
[MAIN BOARD] — Component Side —
60cm
set
FE101
RV402
AM Meter Level
AM Meter Level
RV301
Stereo
Separation
Stereo
Separation
RV231
Narrow
Gain
Narrow
Gain
RV251
S t e r e o
Level
S t e r e o
Level
IFT253
(THD)
(THD)
IFT252
(NULL)
(NULL)
CNP701
IFT252, 253
FM Discriminator
FM Discriminator
RV221
FM Meter Level
FM Meter Level
— 7 —
4-1. WAVEFORMS
THIS NOTE IS COMMON FOR PRINTED WIRING BOARDS
AND SCHEMATIC DIAGRAMS.
(In addition to this, the necessary note is printed in each
block.)
AND SCHEMATIC DIAGRAMS.
(In addition to this, the necessary note is printed in each
block.)
NOTE
•
: parts extracted from the component side.
•
: parts extracted from the conductor side.
•
: Pattern from the side which enable seeing.
NOTE
• All capacitors are in
µ
F unless otherwise noted. pF :
µµ
F 50WV
or less are not indicated except for electrolytics and tantalums.
• All resistors are in
Ω
and 1/4W or less unless otherwise speci-
fied.
•
¢
: Internal component.
•
: nonflammable resistor.
•
: panel designation.
SECTION 4
DIAGRAMS
IC801
!£
4.332MHz
MAIN SECTION
1
3.2Vp-p
IC701
!¡
X2
4.2MHz
DISPLAY SECTION
1
5.2Vp-p
•
B+
: B+ Line
•
B–
: B– Line
•
: adjustment for repalf
• Voltage and waveforms are dc with respect to ground under no-
signal conditions.
no mark : FM
MW
no mark : FM
MW
: ( )
LW
: < >
*
: Can not be measu
• Voltages are taken with a VOM (Input impedance 10M
Ω
).
Voltage variations may be noted due to normal production toler-
ances.
ances.
• Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal production toler-
ances.
ances.
• Circled numbers refer to waveforms.
• Signal path.
• Signal path.
: FM
: AM
: AM
Note: The components identified by mark
!
or dotted
line with mark
!
are critical for safety.
Replace only with part number specified.
— 8 —
4-2. IC BLOCK DIAGRAMS
3
6
11
2
5
8
1
4
14
15
12
9
10
16
13
7
FM IF AMP
LIMITER
AF/NULL
METER
QUADRATURE
DET
AF AMP
IF OFF
NULL METER
SHORTING
LEVEL
DET
METER
DRIVE
MUTING
CIRCUIT
CIRCUIT
DETUNE
DET
GND
B+
IC401 LA1245
3
6
9
2
5
8
1
4
7
10
18
15
12
19
16
13
20
17
14
11
AM RF AMP
AM IF AMP
AM
MIXING
AGC
AM
OSC
GND
B+
(RF)
AM DET
METER
DRIVE
B+
(IF)
1
FM/AM SELECT
MUTING
FM/AM SELECT CONTROL
LOGIC / MUTE ON/OFF
MUTING
OUT
LAMP
DRIVE
PLL
VCC
GND
MPX
22
21 20 19 18 17 16
15
14
13
12
2
3
4
5
6
7
8
9
10
11
IC301 LA3401
IC221, 251 LA1235
1
2
3
4
REG
GND
CONTROL
REG
5
6
7
IC901 LA5667
TEST LOGIC AND OUTPUT
SELECTOR SWITCH
QUALITY BIT
GENERATOR
OSCILLATOR
AND
DIVIDER
RECONSTRUCTION
FILTER
57KHz
BANDPASS
(8th ORDER)
ANTI-
ALIASING
FILTER
COSTAS LOOP
VARIABLE AND
FIXED DIVIDER
FIXED DIVIDER
CLOCKED
COMPARATOR
CLOCK REGENERATION
AND SYNC
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
REFERENCE
VOLTAGE
DIFFERENTIAL
DECODER
BIPHASE
SYMBOL
SYMBOL
DECODER
Vp1
QUAL
RDDA
VREF
MUX
VDDA
VSSA
CIN
SCOUT
RDCL
T57
OSCO
OSCI
VDDD
VSSD
TEST
TSTLD
IC801 SAA6579
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