Sony ST-S444ES User manual

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FM tuner section : : : —s]
Tuning
range
87.5
MHz
-
108
MHz
Signal-to-noise
ratio
5
is
el
ns
Gene
Antenna terminals Pe
75 ohms, unbalanced Harmonic distortion |Mono: 0.03 % (WIDE), 0.05 %
Intermediate frequency at 1 kHz (NARROW)
10.7 MHz Stereo: 0.04 % (WIDE), 0.06 %
(NARROW)
; IM distortion Mono: 0.03 % (WIDE), 0.05 %
AEP, UK model | US, Canadian, € Nesdon Re
(at 40 kHz model (at 75 kHz | Stereo: 0.04 % (WIDE), 0.06 %
deviation) deviation) | (NARROW)
| é
Sensitivity at 46 dB quieting |at50 dB quieting | Separation
17.3 dBf, 2 uV 16.8 dBf, 1.8 pV at 1 kHz 60 dB
(mono) (mono)
37.9 dBf, 22.5 yV| 37.9 dB, 22.5 pV Frequency response | 40 Hz - 12.5 kHz
(stereo) (stereo) +0.2 dB 30 Hz - 15 KHz
r 30 Hz - 15 kHz +0.2 dB
Usable sensitivity |10.3 dBf,0.9yV | 10.3 dBf, 0.94V +0.2 dB ve
(IHF) (IHF) ~0.5
0.8 pV (S/N = 26 dB) Selectivity at 300 kHz at 400 kHz
30 (WIDE)/57 60 (WIDEV90
_ (NARROW) dB (NARROW) dB
MICROFILM }
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY SHADING AND MARK
A ON THE SCHEMATIC DIAGRAMS AND IN THE
PARTS LIST ARE CRITICAL TO SAFE OPERATION.
REPLACE THESE COMPONENTS WITH SONY PARTS
WHOSE PART NUMBERS APPEAR AS SHOWN IN THIS
MANUAL OR IN SUPPLEMENTS PUBLISHED BY SONY.
ATTENTION AU COMPOSANT AYANT RAPPORT
A LA SECURITE!
LES COMPOSANTS IDENTIFIES PAR UNE TRAME ET
UNE MARQUE A SUR LES DIAGRAMMES SCHE-
MATIQUES ET LA LISTE DES PIECES SONT CRITIQUES
POUR LA SECURITE DE FONCTIONNEMENT. NE REM-
PLACER CES COMPOSANTS QUE PAR DES PIECES
SONY DONT LES NUMEROS SONT DONNES DANS CE
MANUEL OU DANS LES SUPPLEMENTS PUBLIES PAR
SONY.
US Model
Canadian Model
AEP Model
UK Model
E Model
Capture ratio 1.0 dB
AM suppression ratio 65 dB
Image response ratio 120 dB
IF response ratio 120 dB
— Continued on next page —
FM STEREO /FM-AM TUNER
ON
Y.

ST-S444ES
Spurious response ratio 120 dB
RF intermodulation 88 dB (IHF)
Muting threshold Approx. 29 dBf, 8uV
Auto tuning threshold Approx. 29 dBf, 8uV
Output level/impedance at 75 kHz deviation
750 mV, 620 ohms
Cal tone 400 Hz, 50 % mod
AM tuner section
Tuning range AEP, UK, E model:
531 - 1,602 kHz
US, Canadian, E model:
531 - 1,602 kHz (with the AM channel
plan selector set at 9 kHz)
530 - 1,610 kHz(with the AM channel
plan selector set at 10 kHz)
LAYOUT-FREE AM antenna
External antenna terminal
Intermediate frequency
450 kHz
Usable sensitivity
LAYOUT-FREE AM antenna
300 pV/m (at 999 or 1,000 kHz)
External antenna
30 uV (at 999 or 1,000 kHz)
Signal-to-noise-ratio
Antenna
54dB
Harmonic distortion
0.3 %
Selectivity AEP, UK model:
35 dB
US, Canadian, E model:
35 dB (9 kHz), 38 dB (10 kHz)
Image response ratio
42 dB (at 999 or 1,000 kHz)
Auto-tuning threshold
Approx. 1mV/m
General
System
PLL quartz-locked digital synthesizer
system
FM stereo, FM/AM super-heterodyne
tuner.
Power requirements
AEP model: 220 V ac (or 240 V ac
adjustable by authorized Sony
personnel),
50/60 Hz
UK model: 240 V ac (or 220 V ac
adjustable by authorized Sony
personnel),
50 Hz
US, Canadian model: 120 V ac, 60 Hz
E model: 120, 220 or 240 V ac
adjustable, 50/60 Hz
Power consumption
18 watts
Dimensions Approx. 430 x 80 x 340 mm (w/h/d)
(17 x 34/4 x 134/2 inches)
including projecting parts and controls
Weight Approx. 4.4 kg (12 Ibs 21 02) net
While the information given is true at the time of print-
ing, small production changes in the course of our com-
pany’s policy of improvement through research and
design might not necessarily be indicated in the
specifications. We would ask you to check with your ap-
pointed Sony dealer if clarification on any point is
required.
PDP PL PL LL LLL LL DL LDL DL DL DL DOLL DLL LLL LL LDL PDO DOLL DL DL LLLP DL LDS LDL DL LL POLL DLL LOL LLL ODL OEP DO OE OL OE OOD LOL OCOCOOOR OOD
~ MODEL IDENTIFICATION —
(Specification Label)
SONY:
FM STEREO/FM-AM TUNER
MODEL NO, ST-S444ES
US model: AC120V 60Hz 18W
Canadian model: AC120V 60Hz 18W
AEP model: AC 220V~ 50/60Hz 18W
UK model: AC 240V~ 50/60Hz 18W
E model: AC 120/220/240V ~ 50/60Hz 18W

SAFETY CHECK-OUT (US Model)
After correcting the original service problem,
perform the following safety check before releasing
the set to the customer:
Check the antenna terminals, metal trim, ‘“‘metallized”
knobs, screws, and all other exposed metal parts for
AC leakage. Check leakage as described below.
LEAKAGE TEST
The AC leakage from any exposed metal part to
earth ground and from all exposed metal parts to any
exposed metal part having a return to chassis, must
not exceed 0.5mA (500 microamperes). Leakage
current can be measured by any one of three
methods.
1.
N
Fig. A. Using an AC voltmeter to check AC leakage.
A commercial leakage tester, such as the
Simpson 229 or RCA WT-540A. Follow the
manufacturers’ instructions to use these instru-
ments.
A battery-operated AC milliammeter. The Data
Precision 245 digital multimeter is suitable for
this job.
Measuring the voltage drop across a resistor by
means of a VOM or battery-operated AC volt-
meter. The “limit” indication is 0.75 V, so
analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa
SH-63Trd are examples of a passive VOM that
is suitable. Nearly all battery operated digital
multimeters that have a 2V AC range are
(See Fig. A)
suitable.
To Exposed Metal
Parts on Set
AC
voltmeter
0.15 uF
° (0.75 V)
ie 5kQ ae
+ Earth Ground
ST-S444ES
FEATURES
PLL-CIRCUIT EMPLOYING DIRECT
COMPARATOR TECHNOLOGY
The ST-S444ES with its refined Phase Locked Loop
(PLL) circuit can tune to a frequency with extraordinary
precision.
An IC developed by Sony allows the comparison fre-
quency to be as high as the 50 kHz channel spacing fre-
quency, thus eliminating the tendency of a low com-
parison frequency, which was formerly generally em-
ployed, to slip into the audio range and degrade the
signal-to-noise ratio. The local oscillator output can
therefore be directly supplied to the programmable
divider section without an additional pre-scaler. We call
this PLL-circuit technology the Direct Comparator meth-
od.
The result is almost rippleless local oscillation, greatly
reduced spurious radiation, and an extremely high
signal-to-noise ratio.
STATE OF THE ART
Every element of the ST-S444ES is chosen with an eye to
optimum reception. Dual-gate MOS FETs in the RF
amplifier, and five varactors in the front-end block in-
sure high sensitivity and an excellent spurious response
ratio. Four uni-phase filters in the IF amplifier provide
high selectivity. The PLL multiplex decoder with a pilot
canceler insures a flat frequency response, clear sepa-
ration and very low distortion.
EFFORTLESS TUNING
Tuning is easy using the digital frequency readout in the
frequency display window.
Three methods of tuning are available :
Automatic tuning, in which the entire AM or FM band is
scanned automatically until a signal is received.
Manual tuning, in which the AM or FM band can be
scanned either rapidly or step-by-step.
Memory preset tuning, in which the frequencies of up to
eight stations can be stored. In this mode, this infor-
mation will be retained when the power is turned off
so that you can tune in your favorite station with the
push of a button. Various conditions can also be
memorized for each individual station to permit
one-touch reception. All the memorized settings are
displayed in the FL display window.
The SCAN/READ button allows you to scan automa-
tically the preset stations only, listening to each one for
a few seconds to check if there is anything you would
like to listen to.

ST-S444ES
A.C.T. (AUDIO CURRENT TRANSFER) CIRCUIT
This tuner employs the A.C.T. technique developed for
Sony integrated amplifiers. The A.C.T. circuit design vir-
tually eliminates the problems which the conventional
voltage transfer design had: electrical interference be-
tween the left and right channels, decreased sound
quality, distortion, noise, etc. caused by the fact that
both the signal source current and the power supply cur-
rent flow through the same ground.
This technique insures the tuner’s high-quality recep-
tion performance.
PROGRAM FUNCTION
Using the Program Function, you can automatically
tune in to up to four stations which have been memoriz-
ed in any sequence you want. Stations will be received
one by one as the power is turned on and off by an op-
tional timer. This Program Function enables timer-
activated reception or recording of a number of stations
as compared to the single station capability of conven-
tional tuners.
OTHER REFINEMENTS
The HI-BLEND switch reduces noise in FM stereo rece-
tion.
The ten-step SIGNAL indicator shows the strength of
the tuned signal.
The CAL (CALibration) TONE button produces a 400 Hz,
50 % mod. signal (equivalent to 37.5 kHz deviation), which
is useful for calibrating the recording level on a tape deck.
The two-pole beat-cut filter is positioned before the multi-
plex circuit to assure better FM stereo reception.
OPERATING VOLTAGE
Before connecting the unit to the power source, check
that the operating voltage of your unit is the same as the
local power line voltage.
AEP mode! operates on 220 V ac (or 240 V ac adjustable
by authorized Sony personnel). .
UK model operates on 240 V ac (or 220 V ac adjustable by
authorized Sony personnel).
The USA and Canada models operate only on 120 V ac.
The E model operates on either 120, 220 or 240 V ac. The
voltage selector is located on the rear panel. If the
selector must be reset, disconnect the ac power cord
and turn the selector with a coin so that the arrow
mark of the selector points to the proper voltage
figure.
PRECAUTIONS
On safety
eBefore operating the unit, be sure that the operating
voltage of your unit is identical with that of your local
power supply.
eShould any liquid or soild object fall into the cabinet,
unplug the unit and have it checked by qualified person-
nel before operating it any further.
e Unplug the unit from the wall outlet if it is not to be
used for an extended period of time. To disconnect the
cord, pull it out by grasping the plug. Never pull it out by
the cord.
On installation
eDo not install the unit in a location near heat sources
such as radiators or air ducts, or in a place subject to
direct sunlight, excessive dust, mechanical vibration or
shock.
eGood air circulation is essential to prevent internal
heat build-up in the unit. Place the unit in a location with
adequate air circulation.
On operation
eWhen the unit is not in use, turn the power off to con-
serve energy and to extend the useful life of your unit.
eSet the PROGRAM switch to OFF when the Program
Function is not being used. If this is not done, you can-
not tune with the TUNING or station preset buttons.
On cleaning
Clean the cabinet, front and rear panels periodically
with a soft dry cloth. If the stains are difficult to remove,
use a cloth moistened with a mild detergent solution.
Do not use solvents such as alcohol, benzine or thinner,
since they will damage the finish.
On repacking
Do not throw away the carton and the packing material.
It makes an ideal container to transport the unit in.
When shipping the unit for repair work or to another
location, repack it as illustrated on the carton box.
For the customers in the USA
For detailed safety precautions, see the leaflet “IMPOR-
TANT SAFEGUARDS”.
Note about the AM channel! plan selector
This tuner has a two-position AM channel plan selector
underneath the right front corner. To tune in AM sta-
tions correctly, the selector should be correctly set ac-
cording to the AM frequency allocation system of your
country.
9kHz: for countries where the frequencies are allo-
cated at intervals of 9 kHz.
10 kHz: for countries where the frequencies are allo-
cated at intervals of 10 kHz, for example, the USA
and Canada.
This selector is factory preset. If the AM frequencies are
not allocated at intervals in your country, the selector
setting should be changed. Be sure to turn off the power
before changing the position of the selector.

SECTION 1
ST-S444ES
OUTLINE
1-1. FUNCTION OF CONTROLS
Each number in the text is keyed to that of the photo above.
@ POWER switch
Depress to turn on the power. To turn the power off,
press the switch again.
@ TUNE MODE button
To tune in a station with the automatic tuning system,
press this button so that the TUNING AUTO indicator
lights up.
When you want to tune with manual tuning system,
press the button again so that the TUNING MANUAL in-
dicator lights up.
AM (FY EI TT) kHz
FM Li Li, | MHz STEREO
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© MUTING/MODE button
This button serves a dual purpose: it is a muting switch
and FM mode selector.
To tune in a strong FM station, press the button so that
the MUTING ON and MODE STEREO indicators light up.
In this mode, the muting circuit will pe activated to
eliminate interstation noise while tuning and the FM
station will be received in stereo mode.
When you want to tune in a very weak FM staion, press
the button again so that the MUTING OFF and MODE
MONO indicators light up. The muting circuit will be
deactivated and the FM station is received in monaural
mode. In this mode, keep the amplifier volume down to
avoid speaker damage caused by interstation noise dur-
ing tuning.
—5—
ST-S444ES
© FM/AM selector button
Selects the desired band: FM or AM. The selected
band wili be indicated in the display window.
© !F BAND button
Normally press this button so that the IF BAND WIDE in-
dicator lights up. Low-distortion, hi-fi FM broadcasting
sound can be obtained. When there is interference by
adjacent stations, press the button so that the IF BAND
NARROW indicator lights up. The higher selectivity will
improve the reception.
@ HI-BLEND button
When FM stereo signals are weak and noisy, press this
button so that the HI-BLEND ON indicator lights up.
This will provide better reception, although the stereo
effect at high frequencies is slightly reduced.
To deactivate the high-biend circuit, press the button
again. The HI-BLEND OFF indicator will light up.
@ CAL TONE button
Normally press this button so that the CAL TONE in-
dicator is not lit.
To obtain a 400 Hz, 50 % modulated signal for adjusting
the recording level on a cassette deck, press the button.
The CAL TONE indicator will light up.
Generally, on cassette decks, adjust the recording level
so that the peak meters to —4dB, and on reel-to-reel
tape decks the peak level meters deflect as close as
possible to 0dB. However, depending on the broadcast
programs or the tapes you use, some further ad-
justments may be necessary. You can determine the
most appropriate recording level for your tape deck
after several trials, using the suggested levels as a star-
ting point.
To deactivate the cal tone circuit, press the CAL TONE
button again.
@ TUNING button
Press either side of this button to change the frequency.
Press the left side ( - ) to go to a lower frequency and the
right side ( + ) to go to a higher.
During automatic tuning: Press to start automatic fre-
quency scanning. The frequencies below or above that
shown on the display window will be scanned automa-
tically until a signal is received. To resume scanning,
press the button again.
During manual tuning: Press and keep the TUNING
button depressed to change the frequency continuously
until the figures in the frequency display window ap-
proach the desired frequency. The frequency figures will
change rapidly. To change the frequency slowly (in
0.05 MHz steps) to tune in a station accurately, press
the button and release immediately.
When the frequency figures reach the end of the tuning
range, the frequency will then be scanned from the op-
posite end of the tuning range.
© Station preset buttons and station identification
windows
To call up a memorized station, press the appropriate
button.
Station labels (supplied) identifying memorized stations
can be placed in the station identification windows
above the buttons.
@ SCAN/READ button
This button has a dual purpose. With the PROGRAM
switch set to OFF, it works as a memory SCAN button
and with the PROGRAM switch set to ON, as a program
READ button.
SCAN button: Press to automatically scan the sta-
tions memorized on the station preset buttons.
READ button: By pushing this button, the programmed
station order can be checked.
@ MEMORY/SET button
This button has a dual purpose. With the PROGRAM
switch set to OFF, it works as a MEMORY button and
with the PROGRAM switch set to ON, as a program SET
button.
MEMORY button: Press to memorize the tuned station
to a station preset button. The MEMORY indicator will
appear in the frequency display window for a few
seconds indicating that the preset memory circuit is
standing by.
SET button: Press to program the preset stations in
the desired order. The MEMORY indicator will appear in-
dicating that the program circuit is standing by.
@® PROGRAM switch
To use the program function, set this switch to ON. For
ordinary use, be sure to keep the switch in the OFF
position.
Display window
® IF BAND indicator
Indicates the setting of the IF BAND button.
@® HI-BLEND indicator
Indicates the setting of the HI-BLEND button.
® MUTING indicator
Indicates the setting of the MUTING/MODE button.
@ MODE indicator
Indicates the setting of the MUTING/MODE button.
@ TUNING indicator
The AUTO indicator shows the automatic tuning mode,
and the MANUAL indicator, the manual tuning mode set
with the TUNE MODE button.
® CAL TONE indicator
Lights up to show that a 400 Hz calibrating tone signal
is provided by the CAL TONE button.
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© FM/AM selector button
Selects the desired band: FM or AM. The selected
band will be indicated in the display window.
@ IF BAND button
Normally press this button so that the IF BAND WIDE in-
dicator lights up. Low-distortion, hi-fi FM broadcasting
sound can be obtained. When there is interference by
adjacent stations, press the button so that the IF BAND
NARROW indicator lights up. The higher selectivity will
improve the reception.
© HI-BLEND button
When FM stereo signals are weak and noisy, press this
button so that the HI-BLEND ON indicator lights up.
This will provide better reception, although the stereo
effect at high frequencies is slightly reduced.
To deactivate the high-blend circuit, press the button
again. The HI-BLEND OFF indicator will tight up.
@ CAL TONE button
Normally press this button so that the CAL TONE in-
dicator is not lit.
To obtain a 400 Hz, 50 % modulated signal for adjusting
the recording levei on a cassette deck, press the button.
The CAL TONE indicator will light up.
Generally, on cassette decks, adjust the recording level
so that the peak meters to —4dB, and on reel-to-reel
tape decks the peak level meters deflect as close as
possible to 0 dB. However, depending on the broadcast
programs or the tapes you use, some further ad-
justments may be necessary. You can determine the
most appropriate recording level for your tape deck
after several trials, using the suggested levels as a star-
ting point.
To deactivate the cal tone circuit, press the CAL TONE
button again.
© TUNING button
Press either side of this button to change the frequency.
Press the left side ( - ) to go to a lower frequency and the
right side ( + ) to go to a higher.
During automatic tuning: Press to start automatic fre-
quency scanning. The frequencies below or above that
shown on the display window will be scanned automa-
tically until a signal is received. To resume scanning,
press the button again.
During manual tuning: Press and keep the TUNING
button depressed to change the frequency continuously
until the figures in the frequency display window ap-
proach the desired frequency. The frequency figures will
change rapidly. To change the frequency slowly (in
0.05 MHz steps) to tune in a station accurately, press
the button and release immediately.
When the frequency figures reach the end of the tuning
range, the frequency will then be scanned from the op-
posite end of the tuning range.
@ Station preset buttons and station identification
windows
To call up a memorized station, press the appropriate
button.
Station labels (supplied) identifying memorized stations
can be placed in the station identification windows
above the buttons.
@ SCAN/READ button
This button has a dual purpose. With the PROGRAM
switch set to OFF, it works as a memory SCAN button
and with the PROGRAM switch set to ON, as a program
READ button.
SCAN button: Press to automatically scan the sta-
tions memorized on the station preset buttons.
READ button: By pushing this button, the programmed
station order can be checked.
@ MEMORYISET button
This button has a dual purpose. With the PROGRAM
switch set to OFF, it works as a MEMORY button and
with the PROGRAM switch set to ON, as a program SET
button.
MEMORY button: Press to memorize the tuned station
to a station preset button. The MEMORY indicator will
appear in the frequency display window for a few
seconds indicating that the preset memory circuit is
standing by.
SET button: Press to program the preset stations in
the desired order. The MEMORY indicator will appear in-
dicating that the program circuit is standing by.
@ PROGRAM switch
To use the program function, set this switch to ON. For
ordinary use, be sure to keep the switch in the OFF
position.
Display window
@® IF BAND indicator
Indicates the setting of the IF BAND button.
@ HI-BLEND indicator
Indicates the setting of the HI-BLEND button.
® MUTING indicator
Indicates the setting of the MUTING/MODE button.
@ MODE indicator
Indicates the setting of the MUTING/MODE button.
@® TUNING indicator
The AUTO indicator shows the automatic tuning mode,
and the MANUAL indicator, the manual tuning mode set
with the TUNE MODE button.
® CAL TONE indicator
Lights up to show that a 400 Hz calibrating tone signal
is provided by the CAL TONE button. :
@® MEMORY indicator
When the MEMORY/SET button is pressed, “MEMORY”
will appear for a few seconds indicating that the.memo-
ry circuit is standing by..
@ Band/frequency display
The band and frequency being received is displayed
here.
@ STEREO indicator
This indicator will light when an FM stereo program of
sufficient signal strength is tuned in with the
MUTING/MODE button set to STEREO.
@® SIGNAL indicator
Indicates the strength of the tuned signal by the amo-
unt of indicator illumination. The fullest illumination
means the antenna input signal is strong. When the in-
dicator illuminates only at the low end, it means the
antenna input signal is weak.
The lines tracing the upper and lower ends of the ver-
tical bars indicate the signal-to-noise ratio curves.
@® PROGRAM indicator
With the PROGRAM switch set to ON, the order in the
programmed sequence of the station being received is
displayed here.
ST-S444ES

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FLUORESCENT
FL DRIVE
DISPLAY TUBE
1C604 FL8OI
LED ORIVE
C603
DISPLAY DRIVE
Q623 , 0625 , 2627, 0628 , 063!
Q633,, 0635, 0642 , 0644, 0646
0648 , 650, Q652 , Q654
7- 13,17, 18, 71,72 -—X_ 24-28, 4, 42-44 IO =52 , 54~60,62—68,70 -X 19-21, 23-29, 31-34, 40
i} ny
PT9OI
0-@
VOL REG
Q501 ,Q502
RECT
D501 ,0502
B+2
15.7V
SWITCHING
Q62I
RECT
0503 ,0504
VOL REG
8+3
STATIC 6.4V
DRIVE
'c8ol
0505, D506
iC50}
6V
RESET
B+!
29.5 RECT
0507 ,0508
a gta J

ST-S444ES ST-S444ES
SECTION 2
DISASSEMBLY
PANEL ASSY DISPLAY BOARD
CASE REMOVAL
Remove four case
screws.
+BVTT3 x 6 (6 pes)
BVTT3 x 6 (2 pes)
BOTTOM PLATE
Remove screws at both top and bottom sides.
TERMINAL BOARD
jack plate
+BVTP3 x 8, tapping
BVTTS3 x 6 (7 pes)
Tuner board can be checked by removing the bottom plate.

SECTION 3
ADJUSTMENTS
FM SECTION
Setting:
Band: FM 1
CAL TONE Level Adjustment
Setting:
VTVM (dc range)
button.
OV reading on VOM.
OUTPUT
should be made.
Procedure:
1. Press CAL TONE switch. RT603
2. Adjust RT603 for —6dB (0.39V) reading on
VTVM.
STANDARD SIGNALS FOR ADJUSTMENT:
FM rf Monaural Signal
Carrier frequency: 98MHz
Modulation: 400Hz, 75kHz deviation
(100%)
US, Canadian, E Model
FM rf Stereo Signal
Carrier frequency: 98MHz
Modulation: Audio 400Hz,
33.75kHz deviation (45%)
Subchannel
33.75kHz deviation (45%)
Pilot 19kHz
7,5kHz deviation (10%)
AEP, UK Model
FM
rf
Stereo
Signal
FM
rf
Monaural
Signal
Carrier
frequency:
98MHz
Carrier
frequency:
98MHz
Modulation:
Audio
400Hz
Modulation:
400Hz,
40kHz
deviation
(100%)
16.25kHz
deviation
(40%)
Subchannel
16.25kHz
deviation
(40%)
Pilot
19kHz
7,5kHz
deviation
(19%)
Discriminator Adjustment
A) Primary Side (NULL)
@ Procedure VOM {dc range) @ Procedure:
-Detune
the
set
by
pushing
the
TUNING
(+,
—)
Turn
the
core
(secondary
side:
Red)
of
IFT102
for
3.
Turn
the
core
(primary
side:
Black)
of
IFT103
for
Note:
Repeat
both
secondary
and
primary
sides
adjustments
Note: When the ceramic filter is replaced, these adjustments
ST-S444ES ST-S444ES
Muting Width Adjustment
Setting:
MUTING/MODE switch: ON
B) Secondary Side (DISTORTION)
IF BAND: WIDE
MODE: MONO
FM
rf
signal
distortion
generator
meter
Procedure:
FM rf signal
generator
VTVM
o.o1uF LL
aS page SR
lL set | j
test
point
SS
4
1 FM ANTENNA terminal OUTPUT
FM rf Monaural signal FM ANTENNA ouTPUT pee rmina
R145 Output level: 1mV (60dB) terminal (752)
Carrier frequency: Q98MHz (US, Canadian) +40 — +65kHz
*(AEP, G-AEP, UK, E) +25 —+40kHz
ImV (60dB)
minimum
distortion
reading
on
the
distortion
meter.
Output
level:
. Receive 98MHz signal.
2. With a carrier frequency of 98MHz '+40 to.
+6 5kHz + adjust IFT101 so that output signal is
os — -
several times.
Confirm minimum distortion for NARROW IF BAND.
IFT101
IFT102
. When necessary, repeat above steps so that output
signal is obtained at same frequency detuning
point
to
both
plus
and
minus
directions
within
10kHz.
FM Muting Level Adjustment
Setting:
IF BAND: WIDE
FM
rf
signal
generator
oscilloscope
FM ANTENNA terminal OUTPUT
(75Q)
FM rf Monaural signal
Output level: 12.6uV (220B)
Procedure:
1. Mode: MUTING ON
2.
Tune
the
set
to
98MHz
by
pressing
the
TUNING
button
(+,
—)
and
adjust
the
output
level
of
signal
generator
at
22dB
(12.6uV).
3.
Turn
RT101
(WIDE)
at
the
position
where
the
waveform
suddenly
appears
on
the
oscilloscope.
4, Mode: MUTING OFF
5.
Turn
RT102
(NARROW)
at
the
position
where
the
waveform
suddenly
appears
on
the
oscillo-
scope.
test point
Gate Voltage Adjustment VTVM (dc range)
Adjust RT601 so that gate voltage
of Q601 is 1.8V (+0.1V) at
87.5MHz.