Pioneer SX-303 User manual

YQ) PIONEER
CIRCUIT
DESCRIPTIONS
le
ae
REPAIR
&
ADJUSTMENTS
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4
ce
AM/FM STEREO RECEIVER _
MODEL SX-303 (SX-303L) COMES IN FIVE VERSIONS DISTINGUISHED AS FOLLOWS:
Model | Voltage : Remarks |
SX-303/KU | = AC120V only - oats Fe | ou S.A. model
SX-303/KC AC120V only | | ¥ = a Ee | . fF Canada model
SX-303/S Pe ACT 10V,120V, 220V and 240V (switchable) General export model |
: a SSiSSaRcnL: ETT aidan acienaaemeatae r i nt treet ee a yee ee et Or
SX-303L/HE | AGC2Z2Z0V Oaly 4 he ow BS European continent model with AM-LW band tuner |
| SxX-303L/HEZ | AC220V Only OE os pee toe! aS ay | - =: West germany model with AM-LW band tuner |
@ This service manual is applicable to the Ku types. For servicing of the thier types, please refer to the
additional service manual. cae eae
® Ce manuel d’instruction se ice au faode. ite réglage, en frangais:
@ Este manual ae | servicio trata del metodo de ajuste escrito en n espaol.
CONTENTS
_ SPECIFICATIONS .............0000002. 2 8. P.C. BOARDS CONNECTION DIAGRAM rae
1
2. FRONT PANEL FACILITIES. .0..00..0.000.. 3 9. SCHEMATIC DIAGRAM ... ae eee ee
3. PARTSLOCATION ....... Sf ade ned: 4 10, ELECTRICAL PARTS LIST.......... ae
4 BLOCK DIAGRAM so ocds acide, 5 11, DIAL CORD STRINGING .. ne Ae
5. CIRCUIT DESCRIPTIONS . he eae ie 6 12. ADJUSTMENTS ae eee ata gia cane 20
6.
PACKING........0.-.
0.
-
Lees.
—
REGLAGE
........0...,
—-
aie
tee
7 EXPLODED VIEW AND PARTS List eee SO _AJUSTE ae cewtewua sete tuk, sates. Oe
RBPIONEER ELECTRONIC CORPORATION 4-1. Meguro 1-Chome, Meguro-ku, Tokyo 153, Japan
PIONEER ELECTRONICS (USA) INC. 1S25 £. Dominguez St., Long Beach, California 90810 UW. S.A.
PIONEER ELECTRONIC [EUROPE] N.V. Keetbergiaan 1, 2740 Severen, Belgium
PIONEER ELECTRONICS AUSTRALIA PTY. LTD. 173-184 Boundary Road, Braeside, Victoria 3195, GSE
YX © DEC. 1982 Primte d in | ea Ut

1. SPECIFICATIONS
Amplifier Section
Continuous Average Power Output is 45
watts* per channel, min., at 8ohms from
40Hertz to 20,000 Hertz with no more
than 0.3% total harmonic distortion.
Total Harmonic Distortion (40 Hertz to 20,000 Hertz,
8 ohms, from TAPE)
continuous rated power output
ot ta ite; Morahan rir ule Ae ee ee ance No more than 0.3%
22.5 watts per channel power output
Sie Ge Rcaree bani wee BL Le No more than 0.15%
| watt per channel power output
ee eee ee ee eee are eae No more than 0.2%
intermodulation Distortion (50 Hertz: 7,000 Hertz =4: 1,
8 ohms, from AUX)
continuous rated power output
ao oh fie ais Wns fs Beane ek ee No more than 0.3%
Damping Factor (1 kHz, 8o0hms)...... 6a Sena ne tie 22
Input (Sensitivity/Impedance)
PHONO ................ 2.5 mV/50 kilohms
TAPE PLAY 66.0% 3044454 4% 150 mV/50 kilohms
Phono Overload Level (T.H.D.0.1%, 1,000Hz)
PHONG) se sak ea eo eee eae ewes 150 mV
Output Level
"PAPE REG cise erie ei bcec dale tim eae ele, 4 150 mV
SPEAKER............... A, B, A series B, off
Frequency Response
PHONO (RIAA Equalization)
bs kasi WOM exes: Mee eee 30Hz to 20,000Hz+0.5dB
TAPE PLAY.......... 15Hz to 50,000Hz *3dB
Tone Control
BASS, cei ery dee seat +9dB (100Hz)
PPG BEE ery, eis hows aarp aie +9dB (10kHz)
Loudness Contour (Volum control set at- 40dB position)
Rr a ee eee +8dB (100Hz), +6dB (10,000H2z)
Hum and Noise (IHF, short circuited, A network)
PHONO MM..............00c ee eee 71dB
"ARP PLAY ot se cw ee me “es eR ede 97dB
FM Tuner Section**
Usable Sensitivity ............0. 10.7dBf (0.9nV)
50dB Quieting Sensitivity
MONO: 4 occcda ee ace Be Bans &4 15.3dBf (1.6uV)
STEREO <4 4054 eed was 37 .6dBf (21uV)
Signal-to-Noise Ratio
MON Os. oie ees 6-228 ee a ed 75dB (at 85dBf)
STEREO «6-35. hie k Chase 4 SS3 70dB (at 85dBf)
Distortion (at 65dBf)
MONO TKAZ cee sc bt ee es 0.3%
STEREO kHz ...........0 000 eens 0.6%
Capture Rate 24 Bee cS GEESE EO NS , 2.5dB
Alternate Channel Selectivity (400kHz) ....... 50dB
Stereo Separation (1kHz)................. 35dB
Frequency Response ....... 30Hz to 15kHz, 76 dB
Spurious Response Ratio .............,... 70dB
Image Response Ratio ............... 0005 45dB
IF Response Ratio .................204. 100dB
AM Suppression Ratio .............-...0. 45dB
Subcarrier Product Ratio........ 2.0002 ee eae 31dB
Muting Threshold .............-. 27d Bf (6.3uV)
AM Tuner Section
Sensitivity
IHF, Loop antenna................ 3202 /m
IHF, Ext.antenna........... Beaty ab-werds tele 30uV
Selectivity ....... hae aceste a ah e Aine es 25dB
Signal-to-Noise Ratio... 2... 0.0... ee ee 43dB
Image Response Ratio .............00008- 40dB
IF Response Ratio ............. 0000 bees 45dB
Antenna ............000008 AM Loop Antenna
Miscellaneous
Power Requirements ............ AC 120 V, 5OHz
Power
Consumption
...
190
Watts(UL),
225
VA(CSA)
Dimensions ........ 420 (W) x 98 (H) x 214(D) mm
16-9/16(W) X 3-7/8(H) X 8-7/16(D) in
Weight (without package)............. 5 kg (11 Ib)
Furnished Parts
FM T-type Antenna ...........0000 2 eee, |
AM Loop Antenna ............ 0.0.00 cee . 1
Operating Instructions ............0 2.008 ee el
*Measured pursuant to the Federal Trade Commission’s Trade
Regulation rule on Power Output Claims for Amplifier.
**FM muting functions with this unit when the signals are veak.
The unit’s internal wires are therefore treated so that the sirrals
are not muted when the sensitivity is measured.
NOTE:
Specifications and design subject to possible modification wih out.
notice.

2.FRONT PANEL FACILITIES
)
a AM sa ec
@) POWER SWITCH
Push this to switch on and off the unit’s power. Power is
supplied at the depressed (=) switch position (ON) and
turned off at the released (IL) position (OFF).
(2) HEADPHONE JACK
Connect the plug on the stereo headphones to this jack
when listening to sound through headphones.
(3) TONE CONTROLS
BASS : The bass is increased when this control is rotated
clockwise from the center position and reduced
when rotated counterclockwise.
TREBLE :The treble is increased when this control Is
rotated clockwise from the center position and
reduced when rotated counterclockwise.
(4) BALANCE CONTROL
This is normally kept at its center position. It is rotated
when the volume of sound delivered through the left and
right channels of the speakers or headphones differs.
The right channel volume is reduced when the control is
rotated toward the LEFT from the center position while
the left channel volume is reduced when it is rotated
toward the RIGHT.
(S) FUNCTION SWITCHES
PHONO : Press when listening to records.
FM : Press when listening to FM broadcasts.
AM : Press when listening to AM broadcasts.
(6) TAPE (ADPT) SWITCH
This is depressed when using a tape deck or adaptor unit
connected to the rear panel TAPE/ADAPTOR jacks.
@ LOUDNESS SWITCH
Depress this switch to the ON position when Sistening to
sound at a low level of volume. This will enhance the bass
and treble and give more life to the sound even at a low
volume.
EO ASCEVER $x-3903
i 3h so a2 aa 36
i 4 1a Ud bos ties it al '
pperregerrege
@rrna + | }e fe
® @ @
OF
Jere
100 caf
1 bea
VOLUME CONTROL
Use this to adjust the volume of the sound delivered
through the speakers or headphones.
The volume is increased when this control is rotated
clockwise from the minimum “0” position.
@Q) TUNING INDICATOR (TUNING)
This lights up to indicate that an FM, AM station has been
tuned in.
STEREO INDICATOR (STEREO)
This lights up automatically when an FM station broad-
casting in stereo has been tuned in.
d) SPEAKERS SWITCHES
These are used to select the speakers through which you
will listen to the sound.
The selected speakers are now working.
A: The sound is heard from the speakers connected to
the speaker A terminals on the rear panel.
B: The sound is heard from the speakers connected to
the speaker B terminals on the rear panel.
No sound will be heard when SPEAKERS A and B switches
are both released. This is the position at which the sound
can be heard through the headphones.
NOTE:
No sound will be heard through the speakers when both the A
and B switches are depressed if only one set of speakers has been
connected to either the A or B SPEAKERS terminals.
(2 FREQUENCY SCALE
This indicates the frequency of the broadcasting station
(FM, AM).
The top level figures (88 ~ 108) indicate the FM band.
The bottom level figures (55 ~ 160) indicate the AM band.
(3) TUNING KNOB
Rotate this knob to pick up stations (FM, AM).
POWER INDICATOR

3. PARTS LOCATION
NOTES:
e Parts without part number cannot be supplied.
e The A, mark found on some component parts indicates the importance of the
safety factor of the part. Therefore, when replacing, be sure to use parts of identical
designation.
e For your Parts Stock Control, the fast moving items are indicated with the marks
kx and x,
**x GENERALLY MOVES FASTER THAN kx.
This classification shall be adjusted by each distributor because it depends on model
number, temperature, humidity, etc.
Front Panel View
Speaker knob —--———-—__--—____-- Bonnet
AAD-608 ANE 410
Front pane! assembly
ANM-293 = ; SOF ee om . ee i. r oes _ ce ores | owe é | eCo--— Tuning knob
6g EE ; | on AAA084
Power knob-————~—--__-_—_—___-.-__# : cae y ry os : € 2 Fe sa 7 : ‘
AAD-605
ace
tf
to
nae
ioc
[Moe
:
cra
pee
Phone jack —-—————---—___—___ Function knob A
AKN-045 (TAPE, LOUDNESS)
AAD-606
Knob B a - ——-___ | ————_—_———. Function knob B
(BASS, TREBLE, BALANCE) (PHONO, FM, AM)
AAB-317 AAD-607
Rear Panel View
~——— —_______-__-——- /\ aCsocket
Lv AKP-039
Earth terminal
Rear panel
Complex
terminal
—-_-————
(eee
A
AC
power
cord
AKX-073 ADG-073
Top View
Complex asermrbly
GWM-265
/\i%* Fuse (T2.5A) -
AEK-123
[\* Power transformer (120V) FM Front-end
ATT-944 AWB-O14
kk fC
NSt 53L
/\ we Push switch
(POWER)
ASG-541
*k* Functionsw itch
ASG-412
Switch assembly 7777

4.BLOCK DIAGRAM
FM FRONT END (173) FM.IF AMP
—
| soon
BAL
FM
| 750
UNBAL
[ GND
AM
LOOP
ANT
LED DRIVER
Re AaRaeey
FM FRONT END L mm |
(2/3) FM FRONT END
(373)
AM FRONT END
FM (Uch)
FM(Rch) | |
S1-|
Si-2
|
SI-3
S1-4
Si-5
POWER
ON/OFF
MUTING
PLAY
—
ie
a
Heer:
SOE
e)
ae
TONE
CONTROL
“igy.
“Se
Pes.
VR2-2,
2-3
EQUALIZER
AMP
0
°
eee
+82
(1/4)
i
ie
Se
;
g
USOmv|
Qi7|
poi7
06
+B2 AM +BI
18.9V| PHONES
+B2
FM
2
6
|
!
|
|
|
!
{
!
O : VR I
0)
+B2
:
O
:
O
2
ii
(3/4,4/4) (2/2)} (2/4)
POWER AMP
=
$1-4 $1-5
peene
(2/2)
(2/2)
Rch REC
PLAY
ia
ae
TO
POWER
SUPPLY
&
PROTECTOR
Reh
SPEAKERS
+B1(35V)
SP B
S101
°
POINTER
AC
120V
cS
ne
oe
e;
a8
08
1)
N
SP
A
“oy
z
;
SI-|
;
FUNCTION
(PHONO)
ON-OFF
|
9
bLanenmne
S1-2 : FUNCTION (FM)
Si-3.: FUNCTION (AM) |
$1-4 : TAPE MONITOR ON - OFF S2-1: SPEAKERS A (ON — OFF SIO : POWER ON — OFF
S!-5 : LOUDNESS ON - OFF S2-2: SPEAKERS 8 ON — OFF

5. CIRCUIT DESCRIPTIONS
FM Front End
A unitized variable capacitor type front end
unit 1s used consisting of an FET RF single stage
amp, local oscillator/mixer IC and an IF trans-
former.
FM IF Amp, Detector and MPX Circuit
A 2-transistor IF amp with ceramic filter is used
and the next stage has an IC (M51533L) contain-
ing the FM IF detector and MPX circuit. The block
diagram of IC M51588L is shown in Fig. 5-1. This
IC uses a peak detection method which can be
adjusted with a single coil. The PLL method is
employed to reconstitute the 38kHz sub-carrier
for the MPX circuit.
The IF signal is input at pin 1 and the detection
output is obtained from pin 5. The detection out-
put passes through the muting Q4, goes to pin 9,
passes through the MPX circuit and the stereo
signals are obtained from pins 11 and 12. In
addition, this unit detects the presence or absence
TUNING y)
| Z T.P 6
TP |
at ©
ms 3rd
1F
AM oO FM
S1-3 f ai L OUT
Fig. 5-1
paar, f
(6)
PHASE
\/2
\/2
ile Shan COMPARATOR| | “°° DIVIDER DIVIDER
1
! nes
L
LEVEL INPUT
@) alae BUFFER
CIRCUIT
STEREO (13)
: SWITCH Fiancee J IND 7
MPX
On
of a pilot signal to automatically switch between
stereo and mono reception by R14 which is con-
nected to pin 14. When a stereo signal is received, —
pin 13 drops to the low level to light the stereo
indicator.
When
pin
2
is
grounded,
the
PLL
VCO
and
FM
IF
operation
stop
(for
AM).
FM Muting and LED Driver
With
this
unit,
muting
is
automatically
activated
when
the
antenna
input
drops
below
10uV.
As
the
antenna
input
decreases,
the
voltage
at
pin
3
drops,
Q5
is
turned
off
and
Q6
is
turned
on.
As
a
result,
the
gate
voltage
of
Q4
drops,
Q4
is
turned
off
and
the
detector
output
circuit
is
blocked
(Fig.
5-1).
When
an
FM
or
AM
station
is
tuned
in,
the
base
potential
of
Q5
is
raised,
Q5
is
turned
on
and
the
tuning
indicator
lights.
A RI4
LL]
M5i533L
(10)
:
+B2
1/2
STEREO PHASE
FM 1F, Detector and MPX circuit

AM Tuner
This’ uses a variable capacitor type tuning
circuit composed of three transistors, a 2-tran-
sistor front end and a single transistor AM IF
detector.
AF Section
The equalizer circuit has a low-noise operation
amp (2 channel) M5218P.
The power amp has a 45; watt output power IC
STK4141-2S (See Fig. 5-4). |
The tone control circuit is placed in the negative
feedback loop of the power amp.
Protective Circuits
This unit has a circuit to detect DC voltages at
the power amp outputs and a muting circuit that
operates when power is turned on and off.
Fig. 5-2 shows the construction of the DC
voltage protection circuit. When a DC voltage
VOLUME
BALANCE
VOLUME
TO POWER AMP
appears at the power amp output, either Q13
(plus) or Q14 (minus) is activated depending on
the polarity of the DC voltage and a trigger is
applied to D15. This turns on D15, +B1 is shorted,
the fuse on the primary side is cut and the power
supply circuit is shut off.
Fig. 5-3 shows the power on/off muting circuit.
Time constant t, is longer than t, so that imme-
diately after the power is turned on, the emitter
potential of Q15 exceeds its base potential, Q15 is
turned on to activate Q16 and Q17 and ground the
signal. A few seconds later, the base potential of
@15 rises to turn off Q15 along with Q16 and Q17.
When the power is turned off, the charge of
C161 passes through D18; it is almost completely
discharged in an instant to make the base potential
of Q15 zero. However, because the charge of C160
remains, Q15 is turned on and muting is activated
in the same manner as when power is turned on.
TO
SPEAKER
SWITCHES
+B3
tr,t2 * time constant
Fig. 5-3. Power ON/OFF muting circuit

f--------
=
12 11 Vee
t
|
!
I
|
|
IN 1(+)0
|
21
INi(-) ©
|
1
I
!
Pe ie
l
|
[ |
I
I
70
|
;
|
|
;
{
eee
OO
Oe
HO
—
—O-
3 5 6 8 9 10 13 14
GND
MUTING
Vee
OUT!
OUT2
VEE
6. PACKING
4
Fig.5-4
Equivalent
circuit
of
power
IC
Mark
No.
von °
=
Part No.
AHA-335
ARB-526
ATB-076
ADH-005
AHE-107
iT
[5
GND
@
IN 2(+)
=
IN2(-)
=
|
|
|
|
|
O
{
|
O
i
|
|
|
|
|
|
|
|
|
|
|
pieces
Description
Side pad
Operating instructions
(English)
Loop antenna ssembly
T-type antenna
Packing case

Mees co et pee
Neca an
NSisepane”
7. EXPLODED
Mark
[> [> >
[>
x
No.
sda ade
=
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
Part No.
ANE-410
BBZ30PO80F ZK
ATT-944
PMZ30PO60F MC
AAD-608
VMZ30PO60F MC
NK9SOFUC
AAB-317
NK7OFUC
AAA-084
AAB-316
ANM-293
AAD-607
AAD-606
ASG-541
AAD-605
AEC-784
AXA-373
AEC-471
MTZ30P100FZK
AEK-123
AKP-039
ADG-073
GWM-265
AKN-045
SUJ8LY XSF
ACG-017
BBT3SOPO80FZK
VIEW AND PARTS LIST
NOTES:
e Parts without part number cannot be supplied.
e The A mark found on some component parts indicates the importance of the
safety factor of the part. Therefore, when replacing, be sure to use parts of identical
designation.
e For your Parts Stock Control, the fast moving items are indicated with the marks
ke and x.
tke GENERALLY MOVES FASTER THAN x.
This classification shall be adjusted by each distributor because it depends on model
number, temperature, humidity, etc.
Description Mark No. Part No. Descriptions
Bonnet 50. Speaker switch assembly
Screw (3 x 8) 51. Switch holder
Power transformer (120V) 52. Pully assembly
Screw (3 x 6) 53: LED assembly
Speaker knob 54. Earth
Screw ( 3 x 6) 55. Mounting plate
Nut 56. Pully assembly
Knob B (BASS, TREBLE, 57. Pully assembly
BALANCE) 58. Pully holder
Nut 59. Headphone jack assembly
Tuning knob
60. Chassis
Knob A (VOLUME) 61. Bottom Plate
Front panel assembly 62. Binder
Function knob B (PHONO, 63. Earth terminal
FM, AM) 64. Rear panel
Function knob A (TAPE,
LOUDNESS) 65. Tuning drum
Push switch (POWER) 66. Smoother
67. Pointer holder
Power knob 68. Pointer assembly
Cabinet bumper 69. Heat sink
Tuning shaft
Nylon rivet 70. Wire holder
Screw (3 x 10)
Fuse (T2.5A)
AC socket
AC power cord
Complex assembly
Phone Jack (PHONES)
Speaker switch
Ceramic (0.01)
Screw (3 x 8)
A

AY],
A
|
|
|
|
|
ince of the
: of identical
the marks
is on model
assembly
kK assembly
y

8.P.C. BOARDS CONNECTION
External Appearances of Transistors and IC's
2SA 726S 2SC1923
N
Lot No My PE NOE a
Type No
hre hee @
B
Cc
2SC 461
Lot No
Lot No r ‘
Type No ree
loss Nee
S
G
2SD 880
28D 313
2SA1115
2SC2603 File
Lot No
Nee
m
JA101 STK4171-2S
2SA 992
Lot No
Type No 1
Are
E
S B
2SK 246 M5218P
og
NJM4558DX
ie
eh
me
|
|
i
Type
No
Lot
No
aay
|
7
loss
Index
:
\
M51533L
DIAGRAM
LED
=—y0OS AEL-4
~“
06
COMPLEX Ass*y GWM- 265
Q3
Q2
VRi
Q4 ai
Q6 Q5
Q9 Q8 Q10 Q14 Q13
Q7 Q16
Qt2 Qi5 Qil QI7
150, C157: CI56
0022 0
Q1;2,7,9 25C461_ Q3 M51533L
Q4 28K 246. Q1iO0 M5218P
Q5,6,13,16,17 Jvc501 Qii STK4171-25
Q8 2SA992
Qi2 250880
Q14,15 JAIO1
APE.
MONITOR
VRe-1
BALANCE

4
D
6
/
. g
NOTE:
:
The
indicated
semiconductors
are
representative
ones
:
only.
Other
alternative
semiconductors
may
be
used
and
are listed in the parts list.
HEADPHONE
JACK Ass’y
KX Ass’y GWM-265
Q7
Qi6
2
Q4
ai
Q6
@Q5
Qg9
Q8
Qto
Qi4
Q13
Qi2
Qi5
Qii
Q17
SWITCH
Ass’y
1Ol &: C1a2z
Cio3 :
Q 2.2/50. 2.2//50
RIO!
t
‘4
C501
0.01 /AC125
ACG-017
FUIOL 2.54
Si0!: POWER
ASG- 541
1101 ATT - 944
cr ae
Sa aad means |
AC t20V
A 60Hz
GUO)
: : |
SWITCHED
—_
UNSWITCHED
IOOW
MAX.
100W
MAX.
Nase a seeded ee ed
Q1;2,7,9
2890461:
Q3
M51533L
Qs 25K 246 Q1IO0 M5218P
Q5,6,13,16,17
ycsor
Qil_
STK4171-25
Qs
2SA992
SZ-027
Qi2
Q14,15
~GI3O C128... RI38
0 35
APE
MONITOR
AEL-405
-
3%
(OIAL
POINTER)
BALANCE
TREBLE
100k
BASS
POINTER Ass’y

1 2 3 4
NOTE:
9 . S C Hi E Mi ATI C D AG RAM The indicated semiconductors are representative ones
only. Other alternative semiconductors may be used and
are listed in the parts list.
COMPLEX Ass’y (1/3) GWM-265 | ¥
. RESISTORS:
(3/3)
[Furor AEK- "123
RI87 ACN+140
R
13.4
A
R12
Le
|
:
: :
‘
.
:
6
180
:
22
Indicated
in
2,
%W,
YW,
+5%
tolerance
unless
otherwise
noted
k
:k&,
Qi,2
M:
MQ,
(F)
:
£1%,
(G)
:
22%,
(K)
:+10%
(M);
£20%
tolerance
FM
IF
AMP
c2
FM
FRONT
END
(1/73)
AWB-044
ra
201
RII
186
i
eee
ee
wae
a
CONOR
TG
ee
Ge
pe
Te
WOT
yg
eh
as
ee
ae
OTN
gay
He
aN)
Pare
7
470
R?
C5
ie
on
2.
CAPACITORS:
R2
10k
ae
rd
aed
Indicated
in
capacity
(uF)/voltage
(V)
unless otherwise
noted
p
:
pF
!
5.6k
3
001
eC
aa
'
Indication
without
voltage
is
50V
except
electrolytic
capacitor.
ae
|
Fi
Ql
Ly
lpg
iN
+
470
3.
VOLTAGE,
CURRENT:
30090
BAL
=
(6)
we
/
\
KC)
[237
Q3
[___}:
Signal
voltage
at(
4OW+
40
W
8Q)output
(1kHz)
[
=
'
fo.ar
FM
IF/ODET
& MPX
L_]
:
DC
vettage
(V}
at
no
input
signal
FM
rae
C6
|
(s)
.
a
Ae
‘
Value
in{
—_)
is
OC
voltage
at
rated
power.
R3
L750
UNBAL
Aa
470
an
Sol
4,
OTHERS:
[
|
2]
il
mp
:
Signal
route.
GND
(5)
ie
:
@
:
Adjusting
point.
(7)
001
T
ee
r)
The
A
mark
found
on
some
component
parts
indicates
the
im-
AM
portance
of
the
safety
factor
of
the
part.
Therefore,
when
replacing,
(10)
R56
be
sure to
use
parts
of identical
designation.
180
D
C2!
This
is
the
basic
schematic
diagram,
but
the
actual
circuit
may
vary
TCT?
®
Jae
0.22/50
a
due
to
improvements
in
design.
$1-3-3
SI-3-4
SI-1+3
Si-1-4
at
aa
sae
ae
a
es
ei
ma
res
Sve +
LED
Ass’y
[8
Qi2
REGULATOR
pric
a
|
c
—
D8
AEL-406
|
27
‘s
'
02
1/80
Md
i
D6
AEL
407
C28
R46
ek
eee
sn
Anes
3.4
|
baw
sr
10/50
180
42h
f
Mes
eee
&2)
Ja-
J ae
,
SWITCHES:
a
2
I
RI74
i
a-2
!
STEREO
;
+
me
es ee I
S
a
|
ae
2.2k
O O
|
COMPLEX
Ass’y
T2
R38
O
S
5 A
4
_
’
ere
NOk
cos
BR
mea
ak:
Rive
ik
>
S1-1
:
FUNCTION
(PHONO)
ON
-
OFF
=
0.01)02
|
“
‘f
J
|rap}
css
tyes
Ba
vR3:
VCO
aby
pg
‘
S1-2
;
FUNCTION
(FM)
ON
—
OFF
=
-———
T
wl.
=
73
C34
ark} 19/80
47/
OB
ae
t
wi, PATUNEDI
23
S1-3
:
FUNCTION
(AM)
ON
—
OFF
O
con
«4510p
Ps
25
ee
Lind
K)
Sten
$ >
a2
wie
S1-4
:
TAPE
MONITOR
ON
—
OFF
:
ea
|
pen
is
=a
98
cao
is
$!-5
:
LOUDNESS
ON
~
OFF
oe
Tier
EIS
ae
At
POINTER
Ass'y
47/0
SSS
i
aeons
=
-
;
+p
-
aay
r
a
[2h
aya
RSS
sos
ee
.
O07
AEL-405
!
SWITCH
Ass'y
:
y
‘
«-
.
—
!
c31
Z
Ral
AM
FRONT
ENO
i
cas
R53,
0.022
w—{47)-—(4)
S2-1
:
SPEAKERS
(A)
(ON
—
OFF
:
10/50
Sk
He
i
Oe
8)
:
‘
Ree
a8
$2-2
:
SPEAKERS
(8B)
ON
~—
OFF
!
ads
FMERONT
END
|S3E,ce
$99B
2)
cag
ae
:
ae
aos
i
DIAL
POINTER
:
(3/3)
/28
aor]
MUTING
‘
.
{
$
so
OUTSIDE
OF
PC
BOARD
area
a
TE(6)d
S101
:
POWER
ON
—
OFF
:
FM
FRONT
END
QQ.
AM
IF
AMP
|
oe
(2/3)
AM
ae
FM
L
(1)
The
underlined
indicates
the
switch
position.
eat
:
]
Qi5~17
FM
R
L
92,
on
ow
38
SS
ase
!
saat
azov10
07
O16
330
[os]
Newel
PROTECTOR
2
7
1
z
28)
R170
COMPLEX
Ass'y
A
si01
:
:
PLAY ©&
TIOt ATT-944
-
TAPE A
+ R POWER AMP
Lcce BB gies f70e ‘
2.2k i‘) A AC POWER CORD
ex ais MUTING Vee OUT! Vee ADG-073
Q1id0 R19 CHS or
EQUALIZER AMP 150k
100p RIS4
[i3.41
Rt2t
Ri23
47k
AC
120V
PHONO
(©
ss
=
aww
SWITCHED
UNSWITCHED
rior + SD) 1ooW MAX 10OW MAX
PALL an
C103
_RI25
er
220p
OFF OFF ,
Si-3-1 St-4-1 — St- 8-1 cuz eae HEADPHONE JACK Assy
AM TAPE | LOUDNESS fOOp SOL [ . - is
NITOR
t
RI76 —-RI7B
Leh | (8) 150 180
Sat
TG
OnE
eee
ee
eee
Reh VR2-1: BALANCE Culé eee, |
R a ()
ens Bes cne theo RI77 —-RIT9 t
$1-3-2 Si-4-2 $1-5-2 12k 100p 69 150 180
2 ©
VRI-2
cio4 250k ~PHONES
220 a ae :
e ate C120 seem RI3I R132 i i S7mv/ 80 } a
Rio2 10/50 5. seem tOOk fue ge Be AT SPEAKERS iW
ik + eh tg ee
PHONO O 2
R133 ci2t R134
Put 180k fie at 180k
RUS Ik RNG Ik
Ci57
0.022 RI35 Hl C24 R136 a
a +| ee 730 fon COMPLEX Ass'y (2/3)
RU4
0.033
es
-
=
-
i REG: 2.2k Gi)
; VR2-2-2 R138
TAPE ot ' t
a
TAPE
56k
40)
ec Rect. tines
RI39 R140 | Sy
27k 2.7 G8) Lch Reh
’ be tn elo beeing '
: 2 pies Pisa wane VR2-2: BASS VR2-3 : TREBLE gps ae pee fee | $P 8
T3 ATB-084 C145,146 ACH-252 | OOO ® | '[iav/aa]
ci48
ACG-019
Q1,2,7,9
25C461
|
:
!
Fi,2 ATF-083 Q4 25K246 1 | OO © isp a :
'’ F3 ATF-084 RI66 ACN-131 Q5,.6.13,16,17 JC5O1 01,3,12.17.18 ! SS —_ (plane
garueesiae “St meres as 2SA992 Q3 M51533L 1N4148 08 KZL140 013.14 tOE2FO :
VR2 ACT -602 Qt2 25D880 Q1i0 MS5218P D2 = WZ-075 09 RB402 DI5 BCREAM-4
VR3 RHBSAVS5O2 Q14,15 JAIOI Qii STK4171-2S 04 2-1K261 Off WZ-130 D16 $Z-027
'
| _|
4 5 6
NO
OO

5 . = eds g, Pe iegierig 18 a Aa
Sa A aM a a a EI ie otha anata i aC sii nant Rt hea Ra et “matte
or 6 mtn A aa athe
a eter A mh
con edaldstn ais neonate asin amh Amt evan AM LL in Ab fa eabph annual a Dyna abvceunbedAcicpipeneenst.an ne Peter. ae
i
10.ELECTRICAL PARTS LIST
NOTES:
e
When
ordering
resistors,
first
convert
resistance
values
into
code
form
as
shown
in
the following examples.
Ex.1
When
there
are
2
effective
digits
(any
digit
apart
from
0),
such
as
560
ohm
and
47k
ohm
(tolerance
is
shown
by
J
=
5%,
and
K
=
10%).
5602 56 x 10! O68 see ke RD4“PS BEM
47RQ 47x 10° IB) 228 Be oe es a RD“*PS AMG
0.52 OF Org etc cee eas oe Sk es RN2H K
12 LG oo patent gee a eh era Bs oe A RSIPOMO K
Ex.2
When
there
are
3
effective
digits
(such
as
in
high
precision
metal
film
resis-
tors).
§.62k2 562x100 5621......... RN%*SR FEAF
e
The
A,
mark
found
on
some
component
parts
indicates
the
importance
of
the
safety
factor
of
the
part.
Therefore,
when
replacing,
be
sure
to
use
parts
of
identical
designation.
e
For
your
Parts
Stock
Control,
the
fast
moving
items
are
indicated
with
the
marks
xw and x.
tke GENERALLY MOVES FASTER THAN x.
This
classification
shall
be
adjusted
by
each
distributor
because
it
depends
on
model
number , temperature, humidity, etc.
Miscellaneous Parts List
P.C. BOARD ASSEMBLIES
Mark Part No.
GWM-265
OTHERS
Mark Part No.
L\ * ATT-944
wk ASG-541
ACG-017
kk AEK-123
ADG-073
AKP-039
SPP PS
Symbol & Description
Complex assembly
Headphone jack assembly
LED assembly
Pointer assembly
Switch assembly
Symbol & Description
T101 Power transformer (120V)
$101 Push switch (POWER)
C501 Ceramic (0.01/AC125V)
FU101 Fuse (T2.5A)
AC power cord
AC socket
Complex Assembly (GWM-265)
CAPACITORS
Mark Part No.
ACH-252
CEA 101M SOL
CEA R22M SOL
CEA OR1M SOL
CEA R47M SOL
CEA 010M SOL
CEA 100M 50L.
CEA 220M 25L
CEA 470M 10L
CEA 470M 25L
CEA 101M 25L
17
Symbol & Description
- €145, C146 Electrolytic (4700/50V)
C139
C11,C21, C22
C12
C10
C14, C17, C27, Ct11, C112,
C123, C124
C16, C28, C31, C38, C119,
C120, C138, C154, C155, C161
C33, C121, C122
C26, C105, C106
C135, C136, C137, C151, C153
C9, C37, C140
Mark
Part No.
CEA 101M 35L
CEA 221M 10L
CEA 471M 6L.
CEANL 2R2M 50
CQMA 122K 50
CQMA 562K 50
CQMA 153K 50
CQMA 333K 50
CQMA 2425 50
CQMA 822J 50
COMLA 124K 50
COSA 1825 50
COSA 511J50
CCDUJ 050C 50
CCDSL 270J 50
CCDSL 121J 50
CCDSL 101J 50
CCDSL 221J 50
CCDCH 150J 50
CCDCH 220J 50
CKDYF 103Z 50
CKDYF 223Z 50
CKDYX 473M 25
CKDYB 222K 50
ACG-019
Symbol & Description
C150
C147, C160
C143
C101, C102
C131, C132
C15, C133, C134
C19, C20
C127, Ci28
C107, C108
C109, C110
C129, C130
C18
C34
C7
C125, C126
C30
C113, C114, C117, C118
C103, C104
C24
C36
C2—C5, C23, C29, C32, C40, C42
C6, C8, C13, C43, C115, C116,
C144, C152, C156, C157
C39, C141, C142
C41
C148 ceramic (0.01/150V)
COILS AND TRANSFORMERS
RESISTORS
Note: When ordering resistors, convert the resistance value Mark Part No. Symbol & Description
into code form, and then rewrite the part no. as before. ATH-053 L1,L2 AF choke coil
| ATH L3 Micro induct
Mark _— Part No. Symbol & Description wes ENG en
*® ACT-162 VR1 ~—- Volume (250k) ATE-058 T1 FM detector transformer
& ACT-602 VR2 Volume assembly (100kx2, 1M) ATB-085 T2 AM antenna coil
* RHB8AVS502 VR3 Semi-fixed (5k) ATB-084 T3 AM oscillator coil
A\ ACN-131 R166 Wire-wound (0.22x2,2W) ATF-083 F1,F2 FM ceramic filter
fi ACN-140 R187 Carbon composition ATF 084 F3 AM ceramic filter
{2.2M, 1/2W)
A\ RD%PMFL OOO R12, R155—R159, R173
RD%PM OOO R35, R36, R115, R116, R147—R154, OTHERS
R160—R165, R167, R168, R172, R174,
R175, R180 Mark Part No. Symbol & Description
ooo ;
RD1/8PM J Other resistors kk ASG-412 51 Sees
(FUNCTION, TAPE,
LOUDNESS)
SEMICONDUCTORS AWB -044 FM Front-end
ace AKX-073 Complex terminal
Mark Part No. Symbol & Description
we 2S8C461 Q1,Q2,Q7,a9 AEC-940 Rivet
(2501923) PBZ30ZPO60FMC Screw (3 x 6)
wk §TK4171-2S Q11 ABA-271 Screw
*&k M51533L-B Q3
&k M5218 P Q10
(NJIM4558DX) Headphone Jack Assembly
&* 2SK246 Q4 Mark Part No. Symbol! & Description a
rare (2SK34) Q12 AKN-045 Phone jack (PHONES)
2SD680 RD%PM OOO J R176—R179
(2$D313)
wk 2SA992 Os
(2SA726S)
[\ *&*® JC501 Q5, 06, 013, Q16, Q17 LEDA
mia ssembl
(282603) Y
A wk JA101 Q14,Q15
L\ ; a
P F {
| (2SA1115) Mark art No Symbol & Description
*® AEL-406 D5 (Red STEREO)
* 1N4148 D1, 03, D12, D17, D1i8 *& AEL-407 D6 (Green TUNING)
{US1035)
(12076)
(1$1555)
Pointer
Assembly
Ay RB402 D9 Mark Part No. Symboi & Description
AY ® 10E2FD D13,014 ace |
t, %® BCR6AM-4 D15 * AEL-405 D7 (Red)
AAF-118 Pointer
*® 2-1K261 D4
* KZL140 D8
*® SZ-027 D16 .
* WZ-130 D11 Switch Assem bly
(M2Z-130) woe
* WZ-075 D2 Mark Part No. Symbol & Description
eure wk SUJBLYXSF S2 Push switch (SPEAKERS)

Pes Te Syn reer :
11. DIAL CORD STRINGING
. Remove the bonnet.
. Remove the tuning drum from the shaft of the
tuning capacitor.
. Tie one end of the cord to the stud A located
inside the tuning drum.
. Rotate the tuning capacitor right around until
the rotor blades are fully intermeshed.
. Secure the tuning drum back onto the tuning
capacitor shaft, making sure that the securing
screw B faces directly upward.
. Pass the cord out through the small opening in
the circumference of the tuning drum (see
diagram), and then take it over pulleys C and D
in that sequence.
. Wind the cord around the tuning shaft 3 times.
. Pass it over pulley E, wind it around the tuning
drum 1 time, and finally tie it to the spring
hook F so that it is tensioned.
cQ-
Tuning drum
10.
11.
12.
13.
14,
. Turn the tuning shaft, and check that the cord
moves smoothly.
Cut off any excess cord.
Turn the tuning shaft counter-clockwise
as far as it will go.
Align the dial pointer with the starting point
of the dial scale, and then pass the cord over
it.
Check that the dial pointer is in line with the
starting point of the dial scale.
Finally apply the locking paint to the cord
securing positions (stud A and spring hook F)
and the dial pointer connection.
Starting point
88 90
Pf] AM
acian on EES
Dial pointer
1

12. ADJUSTMENTS
FM Tuner Section
Check that the dial pointer indicates a starting point.
Connect the SIGNAL meter between terminal no. 1 of complex assembly and the ground.
In principle, no adjustment should be made on FM tracking. (See page 21, if necessary.)
Set the FM switch to ON and connect terminal no. 6 to the ground.
om 3G Positi f Adjustment
Step
(400Hz,
+75kHz
deviation)
leila
ctiae
eee
Adjustment
procedure
- dial pointer point
Frequency Level
a: 98MHz 66dB 98MHz T1
Set the output of the REC OUT terminal to the maximum
value.
rl I AU tt
2.
98MHz
46dB
S8MHz
T6
Set
the
SIGNAL
meter
to
the
maximum
value.
3. 98MHz2 66dB 98MHz TM Adjust the output of the REC OUT terminal distortion to
the minimum tevel.
Disconnect terminal no. 6 from the ground.
98MHz | 66dB
Not modulated
VR3
T6
98MHz 66dB (within Minimize the distortion of the REC OUT terminal signal.
* Stereo modulation +90° )
NOTE:
Connect the MPX SG to the FM SG external modulator terminal and set the modulation of Main (1kHz, L+R) +67.5kHz
deviation, Pilot (19kHz) £7.5kHz deviation.
Adjustment points in brackets are
for SX-303L (Low Wave) only.
Fig. 11-1 Adjustment points
2O

+
i
!
FM tracking
FM SG
(400Hz, +75kHz deviation)
jm | on dial pointer point
es
106MHz 10dB 106MHz
4 | Confirm that the dial pointer does not get out of position at 106MHz and 98MHz.
Position of Adjustment
Adjustment procedure
“Set the SIGNAL meter to the maximum value.
NOTE: (For $X-303L/HEZ)
@
When
87.6MHz
can
not
be
received
with
this
unit,
adjust
the
oscillator
(TC7)
and
then
it
can
be
received.
It
is
prohibited
to
receive
87,.2MHz
or
below
and
so
after
having
adjusted
the
oscillator,
make
sure
that
it
does
not
receive
87.2MHz
or
below.
AM Tuner Section
e Check that the dial pointer indicates a starting point.
e Turn ON the MW switch.
¢
Connect
the
SIGNAL
meter
between
the
terminal
no.
1
of
complex
assembly
and
the
ground.
AM
SG
Positi
f
Adjust
t
(400Hz,
30%
modulation)
cade
iy
sees
Adjustment
procedure
dial pointer point
Set the SIGNAL meter to the maximum value.
603kHz 603kHz T3
1395kHz
Set the SIGNAL meter to the maximum value.
Repeat
steps
4
to
5
until
maximum
sensitivity
is
attained.
Long Wave Section (SX-303L/HE, HEZ only)
@ Set the AM BAND switch to the LW position.
AM SG
(400Hz, 30% modulation)
Le
164kHz
100dB
164kHz
2.
Set
the
AM
SG
to
30dB
output
level,
repeat
steps
1
to
2
above.
254kHz
50d8
254kHz
TC1
4
|
Set
the
SIGNAL
meter
to
the
maximum
value.
164kHz
50dB
164kHz
T4
pk.
|
Repeat
steps
4
to
5
until
maximum
sensitivity
ts
attained.
Position of
dial pointer
Adjustment
point
Adjustment procedure
Set the SIGNAL meter to the maximum value.
271

12. REGLAGE
Section Tuner MF
Vérifier que l’aiguille du cadran indique un point de départ.
e Brancher le mesureur de signal sur la borne n° 1 et la masse du montage de l’ensemble.
e En principe, aucun réglage ne devrait étre fait sur l’accord MF (Voir page 23 si nécessaire).
e
Positionner
le
commutateur
de
MF
sur
ON
et
raccorder
la
borne
n°
6
a
la
masse
du
montage.
FM SG
ane Position de Point de
+75kHz ‘
Etape (400Hz, déviation +75kHz) aiguille réglage Procédure de réglage
11 Positionner la sortie sur la borne de REC OUT 4a Ja valeur
maximum.
T6 Positionner le mesureur de signa! a Ja valeur maximum.
66dB 98MHz TI Regler la sortie de la borne REC OUT au niveau minimum
de distorsion.
Déconnecter ja borne n° 6 de ja masse du montage.
98MHz 66dB
. . ‘ oO x
Nonaneduld 98MHz VRS Positionner le signal de la borne n° 4 a 76kHz (+200Hz).
98MHz 66dB bs !
nae 98MHz (entre Abaisser ja distorsion du signal sur la borne REC OUT.
* Stereo de modulation +90°)
* REMARQUE:
Brancher
le
MPX
SG
sur
la
borne
du
modulateur
extérieur
du
MF
SG
et
régler
la
modulation
sur
le
fil
principal
(1kHz,
L+R)
£67,5kHz de déviation, sur le Pilote (19kHz) +7,5kHz de déviation.
Les points de réglage entre parenthéses ne
os concernent que le SX-303L (onde inférieure).
Fig. 11-1 Points de réglage
ao

ACCORD MF
FM SG
Etape (400Hz, déviation +75kHz) |
“Fréquence | Niveau
Vérifier que l'aiguille du cadran ne change pas de position 4 106MHz ni 4 98MHz.
Section Tuner AM
e Verifier que l’aiguille du cadran indique un point de départ.
e Branche le commutateur de MW (PO) sur ON.
e Brancher le mesureur de signal entre la borne n° 1 du récepteur et la masse.
| AM SG Sosiond
Etape (400Hz, modulation de 30%) Teale
Fréquence Niveau
Position de
lVaiguille
Point de
: Procédure de réglage
réglage
Positionner le mesureur de signal sur la valeur maximum.
Point de
réglage
Procédure
de
réglage
1395kHz 100dB 1395kHz
Positionner le mesureur de signal a la valeur maximum,
2. 603kHz 100d8 603kHz T3
3: Positionner le AM SG 4a un niveau de sortie de 30dB, répéter les positions 1 et 2 ci-dessus.
ae 1395kHz 30dB 1395kHz TC4 |
: Positionner le mesureur de signal a Ja valeur maximum.
i
ee
Positionner
je
AM
SG
a
un
niveau
de
sortie
de
30dB,
répéter
les
positions
1
et
2
ci-dessus.
Section Grandes Ondes (SX-303L/HE, HEZ uniquement)
® Mettre le commutateur de gamme d’ondes sur LW (GO).
AM
SG
a
.
(400Hz,
modulation
de
30%)
aie
Sry
Procédure
de
réglage
Fréquence
Niveau
|
254kHz
Positionner le mesureur de signal a la valeur maximum.
23

12. AJUSTE
SecciOn del sintonizador de FM
@e Comprobar que el indicador del cuadrante indica un punto de inicio.
e Conectar el medidor de senal (SIGNAL) entre el terminal no 1 del ensamble complejo y masa.
e
En
principio,
no
debera
efectuarse
ningun
ajuste
en
el
seguimiento
de
FM.
(Ver
la
pagina
25
si
es
necesario).
3
Poner el selector de FM én ON y conectar el terminal no 6 a masa.
FM SG Posicién del Puntad
(400Hz, +75kHz de desviacién) | indicador del eid Procedimientos de ajuste
ajuste
cuadrante
T1 Ajustar la salida del terminal REC PUT al valor maximo.
T6 Ajustar el medidor SIGNAL al valor maximo.
TI Ajustar la salida del terminal REC OUT con distorsion
__| al nivel minimo. |
Desconectar e! terminal no 6 de masa.
(dentro de | Minimizar ta distorsion de la sefal del terminal REC OUT.
+90°)
* NOTA:
Conectar
el
generador
de
sefiales
de
multiplex
(MPX
SG)
al
terminal
de
modulador
exterior
del
generador
de
senalesde
FM
(FM
SG)
y
ajustar
la
modulacién
a
Principal
(1kHz.
L+R)
+67,5kHz
de
desviacion,
Piloto
(19kHz)
+7,5kHz
de
desviacion.
Los puntos de ajuste entre paréntesis son sélo
as para el modelo SX-303L (onda larga).
Fig. 11 Puntos de ajuste
24