Sony ST-JX44L User manual

MICROFILM
SPECIFICATIONS
FM tuner section
Tuning range
Antenna terminals
87.5 MHz - 108 MHz
300 ohms, balanced
75 ohms, unbalanced
Intermediate frequency
10.7 MHz
(at 40 kHz deviation)
at 46 dB quieting
17.3 dBf, 4 pV (mono)
Sensitivity
38.3 dBf, 45 pV
(stereo)
10.3 dBf, 1.8 uV (IHF)
1.6 pV (S/N = 26 dB)
Usable sensitivity
76 dB (mono)
71 dB (stereo)
Signal-to-noise ratio
Harmonic distortion
at 1 kHz 0.08% (mono)
0.15% (stereo)
IM distortion 0.08% (mono)
0.15% (stereo)
Separation
at 1 kHz 50 dB
40 Hz — 12.5 kHz +0.5 dB
30 Hz - 15 kHz +95 dB
Frequency response
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY SHADING AND MARK
A ON THE SCHEMATIC DIAGRAMS, EXPLODED
VIEWS 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.
Selectivity
Capture ratio
AM suppression ratio
at 300 kHz
80 dB
60 dB
Image response ratio 50 dB
IF response ratio 90 dB
Spurious response ratio | 70 dB
RF intermodulation 60 dB (IHF)
Muting threshold
approx. 25.2 dBf, 10 pV
Output level/
impedance
at 75 kHz deviation
750 mV, 4.7 k ohms
— Continued on page 2 —
ATTENTION AU COMPOSANT AYANT RAPPORT
ALA SECURITE!
LES COMPOSANTS IDENTIFIES PAR UNE TRAME ET
UNE MARQUE /\ SUR LES DIAGRAMMES SCHE-
MATIQUES, LES VUES EXPLOSEES ET LA LISTE
DES PIECES SONT CRITIQUES POUR LA SECURITE
DE FONCTIONNEMENT. NE REMPLACER CES
COMPOSANTS QUE PAR DES PIECES SONY DONT
LES NUMEROS SONT DONNES DANS CE MANUEL
OU DANS LES SUPPLEMENTS PUBLIES PAR SONY.
®)
SERVICE MANUAL

ST-JX44L
MWILW tuner section
MW LW
Tuning range §22 kHz — 1,602 kHz 153 KHz - 344 kHz
ferrite-bar provided provided
antenna
Antenna
external
antenna provided provided
terminal
Intermediate 450 kHz 450 kHz
frequency
ferrite-bar 200 pV/im 500 pV/m
Usable antenna (at 1,000 kHz) (at 230 kHz)
Seren uIty external 30 uV 50 pV
antenna (at 1,000 kHz) (at 230 kHz)
Signal-to-noise ratio 55 dB 55 dB
Harmonic distortion 0.3% 0.3%
ao 35 dB 35 dB
Selectivity (@ kHz) Q kHz)
Image response ratio 45 dB 45 dB
(at 999 kHz) (at 230 kHz)
General
System PLL quartz-locked digital synthesizer
system
System FM stereo, FM/AM superheterodyne 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), 50/60 Hz
Memory back-up power: 3 V dc, two bat-
teries, IEC designation R6 (size AA)
Battery life: approx. 1 year with Sony
SUM-3(NS) New Super Batteries
Power consumption 8 watts
Dimensions Approx. 430 x 55 x 300 mm (w/h/d)
(17 x 2!/4 x 117/s inches)
including projecting parts and controls
Weight Approx. 2.9 kg (6 Ibs 7 oz) net
Approx. 3.4 kg (7 Ibs 8 oz) in shipping carton
MODEL IDENTIFICATION
— Specification Label —
SONY
FM STEREO/FM-AM TUNER
FREQUENCY RANGE : FM87.5 —1O8MHz
LW 153-344kHz ==MW522—1602kHz
50/60Hz
=
MODEL NO ST—JUX44L
IF [FMIO.7MHz AM450kHz
- Ae tg e 8W
1
SERIAL _NO,
FEATURES
The quartz-locked digital frequency-synthesizer system allows ac-
curate and stabie tuning that is not affected by temperature varia-
tions or long period usage.
Quick and accurate station selection is possible with an electronic
digital readout on the frequency display window. Tuning can be
done either by changing frequency display reading rapidly, or step
by step.
The MEMORY SCAN button allows you to scan automatically the
preset stations only, listening to each one for a few seconds to
check if there is anything you would like to listen to.
FM muting circuit is incorporated to eliminate any interstation
noise. The setting of the S{ERE° switch can also be memorized for
each station, and permits one-touch reception with a suitable
mode/FM muting setting.
A beat-cut filter for eliminating 114 kHz beats is provided prior to
the multiplex circuit to assure better FM stereo reception.
Circuit highlights
Excellent reception characteristics are assured by employing
carefully selected parts: a MOS FET in the RF amp. for high sen-
sitivity and excellent spurious response ratio, three uni-phase
filters and an IC in the IF amplifier for high selectivity, and a phase-
locked loop IC for excellent separation and low-distortion
characteristics.
The memory contents are retained by two memory back-up bat:
teries when the power is turned off. These memory back-up bat-
teries also aliow the last station tuned in to be held in the memory.
With the RM-44 system remote controller, you can remotely control
power on/off and prememorized station selection.
AEP model: 220V ~
UK model: 240V ~
AEP-W. Germany model:

ST-JX44L
SERVICING NOTES
@ THE CERAMIC CAPACITORS |
This set uses tube-type ceramic capacitors whose
shape is identical with the carbon resistors. Be careful
not to use resistors instead of capacitors in repairing.
Disc-type ceramic capacitors can be used for
replacing those originally used in the set.
Two kinds of drilled holes are provided in some
patterns for mounting the tube-type and disc-type
ceramic capacitors. Use appropriate holes where
applicable.
Silvering on inside
of tube formin envelope{ green
second electrode.
AUAVUVRALBEVanerene ss
nS ay
\ ANRRTED Ven vewnnnn. | 1D,
Silvering deposited on outside
of tube forming one electrode.
COLOR CODE (in pF)
Temperature
Tolerance charac-
teristic
Ist or 2nd
olor Digit
Peown | a ef Cd
are ae a
RH
orange
SIO] Ol AINA] Nn! lw] wp
10!
103
10° |
ue 10°
10°
silver 107?
multiplier
temperature
characteristic
tolerance
2nd digit
7K
yellow violet : gold white
7 10'°+5% SL @® 470pF +5% SL

ST-JX44L
® Circuit Connections Depending on the Ceramic Filter
(CF101 ~ 103)
This set employs five types of ceramic filter which
have different center frequency. The pattern connec-
tions will be different to match the center frequency
with the intermediate frequency. That is, the pattern
connections will be different depending on the color
mark on the ceramic filter.
color mark
AN
Jumper wire connection
(e) (e)
xX
x
x
[e)
x
10)
Xx
[@)
x
O : connected
FM intermediate
frequency (MHz)
X : not connected
FM intermediate frequency is determined by five
types as shown above with specifing the state at
terminal 24, 25 and 26 of IC402 by Jumper wire
connection.
* CF101, 102 and 103 should be used the ceramic
filters of same center frequency.
*Jumper wires (J1-J3) are located in the section
“FE-4” of the mounting diagram on page 21 or 29.

ST-JX44L
@
Handling
Precautions
for
MOS
ICs
(1C402:
TCP4621BP,
1C601:
LC4001B,
1C701:
»
PD4011BC)
Generally, the insulation resistance of the oxide
layer in MOS IC structures is very high, and the oxide
layer is very thin. Because of this, it is possible that
the static voltages usually present on clothes and the
human body will be enough to generate a potential
difference across the insulator, high enough to cause
a breakdown of the insulating layer.
The following precautions should be taken while
handling these ICs.
(Particular care should be taken under conditions
of low humidity.)
Precautions in Replacing MOS ICs
1. Store new ICs by inserting them into a urethane-
polyester cushion (which is somewhat conduc-
tive), or wrapping it in aluminum foil, so that
all the pins are at the same potential.
(The ICs should be stored in that manner until
mounted on the circuit board.)
Fig.
A
partially
conductive
unrethane-polyester
cushion
Ic
Fig. B aluminum foil
2. Check the soldering iron for possible power-line
leakage current. Make sure that there is no
leakage path by connecting an ohmmeter to the
tip of the soldering iron and the plug as shown
in Fig. C. If there is a leakage path, use some
other soldering iron.
VOM
(Q x 10,000 range)
3. Equalize any potential difference between the
clothes, the tools in use, the work bench, the
set being worked on, and the packaged IC by
touching them ail in succession with the hands
or a conductive wire or tool.
4. The following are effective methods for handl-
ing ICs that remove the potential difference
across the oxide layer.
@ Use a paper clip modified by soldering in a
wire braid insert.
wire braid
soldered soldered
. Make sure that there is
Fig. D no solder on the inside.
clip
partially conductive
£ urethane-polyester
Fig. E queen or aluminum
oll
wire braid
clip
Make sure that all the pins are in
contact with the wire braid (all
; the pins will then be at the same
Fig. F __ potential.).

ST-JX44L
® Take a short length of fine bare wire and Precaution while Checking C-MOS ICs
wind it around the IC so that it shorts alli the
pins of the IC, while it is still in the urethane- The C-MOS ICs (Complementary MOS) are MOS
polyester
cushion
or
aluminum
foil.
This
ICs
that
have
their
output
sections
made
up
of
ensures
that
all
the
pins
are
at
the
same
N-channel
and
P-channel
push-pull
stages
to
increase
their
speed
of
operation.
If
the
output
terminal
of
potential.
these ICs comes into contact with B+ or B- voltage,
fine
bare
wire
then
the
FET
which
is
ON
at
that
time
will
either
(stripped solid hookup
wire, etc.) become shorted or open.
This is valid for all the output sections that are
connected together by the interconnections. Even
the circuits that are physically separated (and not on
the same board) can be destroyed simultaneously.
Example:
partially conductive
urethane-polyester
If this line is grounded, or touches
8+ or B- bus..., the output stage
of this IC will be destroyed.
Fig. 1
Fig. G
@ When it is necessary to handle the IC with
the fingers, do not touch any pin, and hold
the IC at the ends of its plastic-package case
as shown in Fig. H.
SP,
Fig. H
5, Method of Mounting
Insert the IC while holding it with the modified
clip, and solder all the pins with the clip still
shorting the pins. (Similarly, solder all the pins
while the bare shorting wire is still wound
around them.). Remove the clip or the bare
shorting wire only after all the pins have been
soldered.

LOCATION AND FUNCTION OF CONTROLS
Before plugging in or attempting to operate this tuner,
ST-JX44L
ST-JX44L
it is suggested that you familiarize yourself with all its switches and the purpose of each.
Each number in the photo is keyed to the descriptive text.
i POWER switch
Band/frequency-display window
and indicators (See the next page)
Yap Band selector
KD TUNING button
STEREO gyi
iMUTINGSWiteh
3 MEMORY SCAN button
@ POWER switch
Depress to turn on the power. To turn the power off, press the
switch again.
@ Band selector
Selects the desired band: FM, MW or LW. Each time the selector
is
pressed,
the
band
will
change
and
the
selected
band
wil!
be
indicated in the band/frequency-display window.
© 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. To change the frequency continuously until the desired
frequency is received, keep the button depressed. The frequency
figures will change rapidly. To change the frequency slowly (in
0.05 MHz steps for FM, 9 kHz steps for AM and MW and 1 kHz steps
for LW), press and immediately release the button.
@ Station identification windows
Station labels (supplied) identifying pre-memorized stations can be
placed in these windows.
@ Station preset buttons
To call up a pre-memorized station, press the appropriate button.
@ MEMORY switch
Press to operate memory circuit. The MEMORY indicator will ap-
pear on the band/frequency-display window for a few seconds in-
dicating that the memory circuit is standing by.
1® Station identification
windows
he Station preset buttons
(a MEMORY switch
@ STEREO switch
This switch serves the dual purpose of a mode and FM muting
switch.
Normally keep this switch engaged (the MUTING indicator il-
luminates) to eliminate FM interstation noise while tuning from sta-
tion to station. The tuner operates in stereo mode for stereo sound
sources and will be automatically switched to mono mode for
monaural sound sources.
When you want to tune in a very weak station, or when an FM pro-
gram is too noisy, press the switch to disengage it. (The MUTING in-
dicator illumination will go out.) This will enable the tuner to receive
weak stations, although the stereo feature is sacrificed. in this
case, keep the amplifier volume down to avoid speaker damage
caused by the interstation noise.
@ MEMORY SCAN button
Press for automatic scanning of the stations pre-memorized on the
station preset buttons.
BAND/FREQUENCY-DISPLAY WINDOW AND INDICATORS
B® MEMORY indicator
MEMORY,
© MEMORY indicator
When
the
MEMORY
switch
is
pressed,
“MEMORY”
will
appear
for
a
few
seconds
indicating
that
the
memory
circuit
is
standing
by.
@ Band/frequency-disptay
Permits
reading
the
received
frequency
at
a
glance
from
the
figures.
@ STEREO indicator
This indicator will light when an FM stereo program of sufficient
signal strength is tuned in with the STEREO switch engaged.
@® PRESET button indicator
When the station preset button is pressed, a figure from 1 to 8 cor-
responding to the pressed button will appear.
When the MEMORY SCAN button is pressed, the figures will
change in sequence.
@® MUTING indicator
This indicator illuminates when the STEREO switch is engaged.
@® LOCKED indicator
This indicator illuminates when a signal stronger than the tuner’s
muting level is tuned in and locked.
Band/frequency-display
[E} LOCKED indicator
1b} STEREO indicator
STEREO
[¥) PRESET button indicator
MUTING
MHz LOCKED
[K) MUTING indicator

Selected band FM/MW/LW \
i
e
|
|
MANUAL TUNING
(1
eae
(Q
setectinedesieavang
==
SSS~*S
|
|
|
i
|
POWER
|
|
|
f
i
|
} 4 Adjust the volume and tone.
i
=
ere
ee
ee
a
ibis
sscat
j
Amplifier
—) Proyvrrg
° foes Ss ee SSs5
(
3
For
FM
reception,
press.
yt
4
Tune
in
the
desired
station,
observing
the
\
|
LOCKED
indicator
and
the
band/frequency
i
display.
i
for lower frequencies for higher frequencies i
r
TUNING
+
-
TUNING
+
|
STEREO
|
i
|
STEREO
| cle
To tune in a very weak station, see below.
MUTNG
When
the
frequency
figures
reach
the
end
of
the
tuning
range
of
each
band,
the
frequency
will
then
be
scanned
from
the
opposite
end
of
the
tuning
range.
se eee
To tune in a weak or noisy station
@When
FM
stereo
signals
are
noisy,
or
to
tune
in
a
very
weak
FM
Station,
lower
the
volume
and
disengage
the
MUR
Switch
by
pressing
it
again.
The
MUTING
indicator
illumination
will
go
out.
he
will
result
in
better
reception,
at
the
sacrifice
of
the
stereo
ef-
ect.
ST-JX44L ST-JX44L
MEMORY PRESET TUNING
This tuner’s electronic tuning system (utilizing a PLL—Phase Lock-
ed Loop— synthesizer) and a memory circuit make tuning very easy.
Once the frequencies of the stations you want to tune in are
memorized, all you have to do is push a button.
TO MEMORIZE STATION FREQUENCIES
Preparation: A total of eight station preset buttons can be preset
for either FM or AM (MW and LW) in any desired sequence. Arrange
the order of stations for each station preset button and note the
band and the frequency of each in advance.
Follow the numbered sequence.
1 2
Tune in the desired station,
following the procedure
described in “MANUAL
TUNING”. Illuminates for a few seconds.
Note that the settings of
the muting Switch for atetis
reception of “ LOCKED
this station are memorized.
STEREO
Repeat these steps for each station preset button.
Replace the station labels to conform to the selected pre-
memorized stations.
Notes
e@The MEMORY indicator will go off automatically after a few
seconds. When the indicator is out, the memory circuit does not
operate to memorize the station.
e@The previous memory will be erased when a new frequency is
committed to the memory of the same button. An erasure cannot
be made without a new input.
TO CHECK A PRE-MEMORIZED FREQUENCY
After the memory procedure is completed, confirm the pre-
memorized frequency. Press the TUNING button and change the
frequency display indication. Press the station preset button to be
checked. The frequency which had been pre-memorized should
then be indicated in the band/frequency-display window.
TO RECEIVE A PRE-MEMORIZED STATION
Turn the POWER switch on and simply press the desired station
preset button.
Memory of the last received station
This tuner includes a memory circuit to remember the station
which had been received for more than one second just
before the power was turned off. This station will be
automatically tuned in when the power is turned on again.
This memory system enables you to make a timer-activated
recording from the tuner.
10
= =a
3 While the MEMORY indicator is illuminated,
press the desired staticn preset button.
STEREO
MEMORY
MUTING fam
vocken LAG
The MEMORY indicator will go out, and the band,
frequency and settings of the ucie. switch will
be memorized.
MEMORY SCANNING
The MEMORY SCAN button allows you to quickly hear what kind of
programs are being broadcast by the pre-memorized stations.
When you press the MEMORY SCAN button, the pre-memorized
stations are automatically received in order from the pre-
memorized station to the immediate right of the station being
received for about 4 seconds each.
Pushing a particular station preset button stops the scanning.
The scanning sequence will be shown by the flickering of the figure
in the band/frequency display window.
After the station preset button on the far
Pg ah a ice Ol cst right has been activated, the button on the
, L -! ! far left will be activated and the sequence
repeated.
Press to start Press to stop memory
memory scanning. scanning.
When you press the MEMORY SCAN button during manual tuning,
scanning will start from the station memorized on the leftmost sta-
tion preset button.
—10—

ST-JX441
SECTION 1
OUTLINE
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ST-JX44L
@ CONTROLLER IC TCP4621BP-6504/-6505
1C402
(TCP4621BP-6504/-6505)
is
a
microcomputer
IC.
The terminal functions are as follows:
Main Functions:
e Key input detection
e Fluorescent indicator tube (FL401) indication
output
¢ Data transmission to PLL frequency synthesizer
IC (IC401: CX778A) (16 bit serial data)
1C402 Terminal Functions
FL tube... Fluorescent Indicator Tube
+B
CLOCK Signal input for “STEREO” indication
ee ners aera
LATCH © Signal input for external remote controller
Muting control signal output MUT. 1
(L: mute)
Signal output for FM mode switch MUT. 0
(L: “STE REO/MUTING” on)
Signal input for “LOCKED” indication
(H: “LOCKED”)
Digit
signal
for
MW/LW
switchi
ignal
;
Grid
6
switching
signal
output
eg
grid
(H:
MW,
L:
LW)
iv
FM/AM switching signal output
(H: FM, L: AM)
CPU operation stop signal input
(H: CPU operation stop)
Signal output for
FL
tube
segment
drive
Reset
signal
input
CLOCK (1700Hz}
g
h Microcomputer clock input (360k Hz)
Grid 5
Digit
signal
output
Grid
4
ee
: ey inpu
tor FL tube grid Grid 3
drive
Grid 2
Grid 1 Digit signal output
for FL tube grid drive
—12—