Pioneer SX-303 Service manual

(D

rrloNEEFl'

:-_ t

I

AM/FM

STEREO

RECETVER

sixr3Gl3

MODEL

Model

sx-303/KU sx-303/Kc

sx-303/s

SX-303L/HE sx-303L/HEZ

o

This

service manual

additional

o

manuel

Ge

o

Este

manual

SX-303

(SX-303L)

AC120V only

AC1 1 0V,

AC220V

'l2OV

only

is

service

manual.

d'instruction

de

servicio

COMES

Voltage

,22OV

applicable

se refdre

IN FIVE

and

24OV

to the

au mode

trata del m6todo

VERSIONS

(switchabte)

KU types.

de r6glage,

de

ajuste

For

servicing

en frangais.

escrito

en espafiol.

DISTINGUISHED

U.S.A. model

Canada model

General export

European

West

continent

germany

of the

AS FOLLOWS:

Remarks

model

with AM-LW

other types,

ORDER ARP-

with AM-LW

band tuner

please

232-0

band tuner

refer

NO.

to the

CONTENTS

1.

SPECIFICATIONS

2.

FRONT

3.

PARTS

4.

BLOCK

5,

CIRCUIT PACKING

6.

EXPLODED

7.

PICINEEFI FIC|NEEFI FfoNEEFI PI('NEEFf

PANEL

LOCATION

DIAGRAM

ELECTFICINI€9 ELEcrFloNlc ELECTFICINIGB

FACILITIES

DESCRIPTIONS

VIEW

AND PARTS

ELECTFICINIC

.

IUAAI

[EuFtoPEI

AUaTFIALIA

LIST

CclFlPClFIATIClN

lNC. 1925

N.v.

E.

Keerbengtean

FTY.

Dorninguez

t-lO.

lzA-le4

2 3 4 5 6 8 9

4-1,

St., Long

1,e74o

Boundany Ftoad,

8. P.C.

9.

10.

11. DIALCORDSTRINGING

12.

BOARDS SCHEMATIC DIAGRAM ELECTRICAL

ADJUSTMENTS...

CONNECTION

PARTS

LIST

DIAGRAM

. .

nEcucr

AJUSTE

Meguno

Bevenen,

1-chome,

Beech,

Catifonnia

Betgium

Bnaeside,

Mesuno-ku,

gOB1O

Victonier

YX O DEC.

Tokyo

U.S.A.

819F,

1F3,

1982

Japan

.Ausrnatia

Printed

......

... 24

in

lapan

12 15 17 19

20

22

1.

SPECIFICATIONS

Amplifier

Continuous watts* 40Hertz than

Total

ohms, from

I

continuous rated

22.5watts

I watt

Section

Average

per

channel,

to

20,000

0.3o/o total

Harmonic

per

Distortion

TAPE)

povrrcr

per

channel

Power

min.,

Output

at

Hertz with

harmonic

(40

output

power

output

distortion.

Hertz

output

. . . . No more than

is

45

ohms f rom

8

no

more

to

20,fi)0

No more than

Hertz,

0.3%

O.15yo

l*"r..irr"ii""oiri.r,i""it,i""r,rlrt,ill'iJir1"=t;?1,

from

ohms,

8

continuous rated

Damping Factor

(Sensitivity/l

I

nput

PHONO TAPE

Phono

PHONO

Output Level

TAPE REC SPEAKER A, B, A

Frequency

PHONO

TAPE PLAY

Tone

Control

BASS

TREBLE

Loudness

Hum and

PHONO

TAPEPLAY

Tuner

FM

UsableSensitivity..

50dB Ouieting

MONO STEREO

Signal-to-Noise

MONO

STEREO . . 70dB

Distortion

MONO

STEREO lkHz. ...O.6Yo

AUX)

PLAY

Overload

Level

Response

(RIAA

.

Contour

(lHF,

Noise

MM ..

Section**

Sensitivity

Ratio

(at

65dBf)

lkHz.

power

output

(1

kHz, 8 ohms)

mpedance)

(T.H.D.0.1%.

Equalization)

(Volum

control

+8dB

. .

short circuited, A

more

No

.....2.smV/S0kilohms

. . .

150

1,000H2)

.

to

30Hz

15Hz to SO,OOOHz+]OA

setat-40d8

(100H2),

+6dB

.10.7d8f(O.9pV)

...15.3dBf

..37.6d8f

...75d8(at85dBf)

than

0.3% 22

mV/50

20,000H2t0.5d8

network)

kilohms

. . 150mV

. 150 mV

B, off

series

(100H2)

i9dB

(10kHz)

19dB

position)

(10,000H2)

71dB

......97d8

(1.6pV) (211ty1

(at

85dBf)

...0.3Yo

AMI-oopAntenna Operating

'Measured

Regulation

**FM

The

are not muted when the sensitivity is measured.

NOTE: Specifications notice.

CaptureRatio . Alternate

Stereo

Frequency Response

SpuriousResponseRatio.

lmageResponseRatio lF ResponseRatio. AMSuppressionRatio

SubcarrierProductRatio.

Muting Threshold Antenna Input

AM

Sensitivity

Selectivity Signal-to-Noise Ratio lmage Response lF Antenna AM

Miscellaneous Power

Power Dimensions

Weight

Channel Selectivity

Separation

Tuner

f HF,

Loop Ext.

lHF,

ResponseRatio.

Requirements Consumption .

(without

(lkHz)

. . . 300 ohms

Section

antenna

Ratio

. . . 42O

16-9/16(W) X

package)

(400kHzl

..

30Hzto lSkHz,1ffOt

balanced, 75 ohms

AC

.

. . 190 Watts(UL),

(W)

x

98

lHl

3-718(H)

Furnished Parts

FMT-typeAntenna

Instructions

pursuant

rule

functions

muting

unit's internal

and design subject

Povver

on

wires are therefore treated so that the signals

Federal

to the

Output

with this unit when the signals are weak.

Claims

possible

to

Trade

Commission's Trade

for

Amplifier.

modification

..2.5d8

. .

50dB

. .

35dB

......7ft8

....45d8

....100d8

...45d8

......31d8

(6.3pV)

27dBf

unbalanced

32O1N

30gV

.

2ft8

. . . ..43d8

....40d8

.....45d8

Loop Antenna

120 V,

60Hz

22S VA(CSA)

(D)

x

214

X

8-7116(D)

. .5 kS

........1

mm

(11

......1

without

lm

in

tO)

1

2

2.

FRONT

PANEL FACILITIES

powen

O

Push

this to supplied at the turned

off at the released

HenopHoNE

@

Connect the when listening to

rorue

@

BASS

TREBLE

eeLeNcE

@

This

is normally when

the volume

right

channels of The right rotatd the left toward

@

PHONO : FM : Press AM :

@

This connected

o

Depress sound at a low level and treble volume.

the RIGHT.

rurucrroN

rape

is depressed

LouorrrEss

swrrcH

wrritch

depressed

plug

on the stereo headphones

sound through

coNTRoLs

:

Thebass

clockwise from the when rotated

:

The treble is increased rotated reduced

channel volume is reduced

toward

channel

clockwise

when rotated

coNTRoL

kept at its center

of

the speakers or

the LEFT

volume

swrrcHEs

Press when listening

when listening to FM

Press when listening

(ADPT)

when using a tape

rear

to the

this

svrritch to the

give

and

on

and off

(r)

(I)

the

switch

position

unit's

position

(OFF).

power.

(ON)

JAcK

to this

headphones.

is increased

sound delivered through the left

whenthiscontrol

position

center

counterclockwise.

when

from

the center

counterclockwise.

position.

headphones

when the control is

from

the

center

is reduced

to records.

to AM broadcasts.

when it is rotated

broadcasts.

isrotated

and reduced

this

control is

position

lt is

differs.

position

swrrcH

or

panel

TAPE/ADAPTOR

deck

adaptor

jacks.

swtTcH

position

ON of volume. This more life

to the sound

when listening to

enhance the bass

will

even at a low

Power

and

jack

and

rotated

and

while

unit

voluruE

@

is

Use this to through The clockwise from

@

This lights up tuned in.

@

This lights up casting in

@

These are used to

will listen

The selected A: The

B: The

No sound are both released. can

and B

@

This indicates

(FM,

The The

@

Rotate this knob

@

the

volume

ruruIruG

sreneo rNDrcAToR

stereo

speerERs

to the sound.

sound

the

speaker

sound is heard

the

speaker B terminals

heard

be

NOTE:

No

rcund will

switches are depressed

connected

FREoUENcY

AM).

level figures

top

bottom level

TUNTNG

POWER

coNTRoL

adjust the volume

speakers or headphones.

is

increased

the minimum

when this

"0"

tNDIcAToR

to indicate

automatically when

has been

that

an

tuned in.

swrrcHEs

the

select

speakers are now working.

is heard from

A terminals on the rear

heard

will be

This is the

through

to either

the headphones.

heard

be

the A or

frequency

the

(88

figures

KNoB

pick

to

|ND|CATOR

speakers through which

the speakers connected to

from

the speakers connected to

on the rear

when

SPEAKERS

position

through

the spakers when

if

only one

I SPEAKE RS terminals.

scALE

of the broadcasting

-

108)

-

(55

160)

up

stations

of

the

sound delivered

control

position.

(TUNING)

FM,

AM station has

(srEREo)

FM

an

indicate

(FM,

station broad-

panel.

A and B switches

at which the sound

set of speakers has

the FM band.

the AM band.

AM).

is rotated

been

you

both

the

been

station

A

PARTS

3.

LOCATION

NOTES: .

Parts

.

The b morh sofety designation.

.

your

For ta

and

''

GENERALLY

Thb claesificotion numbe

l.

part

found

of

the

Potts

Stock Control, the

without

factor

f , te mperature,

nu

ber connot be

on

aome component

port-

Thereforc,

MOWS FASTER

be

shall

odjusted by eoch di;tributor

humidity, e tc.

supplied.

ports

uhen replocing,

fost

THAN '.

mot)ing

items are

indicates

be

6ure

becouse

the importonce

ports

to

use

indicated u)ith

it deDends

of the

of id.enticol

the moths

on model

Front Panel

Speaker knob AAD60A

panel

Front

ANM-293

AAD$O5

jack

Phone AKN-(X5

Knob B

(BASS,

TREBLE, BALANCE)

AAB3I7

View

assembly

Rear Panel View

Earth

terminal

Complex terminal AKX{73

..-":.n

f\,-

Bonnet

ANE4lO

Knob A

AAB316

Function knob A {TAPE, AAD€06

(vo

LU1M E)

LOUDNESS)

Function knob B (PHONO,

AAD607

FM,

A ac socket

AKP.O39

AM)

Top View

(T2.5A)

Fuse

l\r*t

AEK-123

Push swirch

A**

(POWER'

ASG-541

Switch assembly

AWB{44

**

tc

M5153L

BLOCK DIAGRAM

4.

T

3OOO

|

.

FM

I

L r rrupar

l-

AM

LOOP

I L

BAL

cND

ANT

AM

FM

FRONT

ENO

END

FM(Rch)

(1/3)

rcr

r-;1-l

i Itfr

(Lch)

FM

lrJ

i I

MIX AMP

LED

DRIVER FM

FM.IF AMP

MUTE

+82

AM

04

IF

FT.I IF,/OET MPX

RE6ULA.

rfrR

METER

OETECTOR

AMP

tx

crav

l-

Lch REC

,"o"o

i-

eiror,ro

f

Rch

REC

".o"

l-

ac

r20v

60

Hr

[5dtl

lzsmrl

EQUALIZER AMP

sr-l

PHONO

r_-

134,4/41

sr-4

sr-5

TAPE

LO

(t/4)

lt/2) |

POWER SUPPLY A PROTECTOR

(t/?

sr-4

| 2/2 t

U ON ESS

)

sr-5 (2/2

(?/2)

)

POWER

ON,/OFF MUTING

ffi--D"t

TONE CONTROL vR2-2,2-3

o='""o'

POWER AMP

s2-2

+92

SP- B

15.4V

07

(vzl

s2-l

SP-A

lt/2)

(

t'Ery I

pHoNEs

TO

Rch

SPEAKE RS

l

I"o

],,

^

: FUt{CTION

SI-l SI-2: FUNCTION sr-5 : FUt{cTroN ( AM)

:

TAPE MONITOR

SI-4

(PHOtlO) {FM)

sr-5: LouoNEss

9!L-

oN oN ON or

oFF

-.9!E

-.g_Eq

--qEE

-_q!!

S2.I : SPEAKERS S2.2: SPEAXERS

-

oFF

_9_l!-

-

!-!L

oFF

I

sror

i

PoWER

oil - oFF

5

CIRCUIT DESCRIPTIONS

5.

FM Front End

A unitized variable capacitor

unit is used consisting of an

type front end

FET

single stage

RF amp, local oscillator/mixer IC and an IF transformer.

FM

lF Amp,

2-transistor IF amp with

A and the next ing the FM IF detdctor and diagram IC uses adjusted with a single employed to for

the

The IF signal output is obtained put passes passes signals addition,

Detector and MPX Circuit

ceramic filter is used

stage

has an IC

(M51533L)

MPX circuit. The block

of IC M51533L is shown

peak

a

detection method

coil. The

reconstitute the 38kHz sub-carrier

MPX

circuit.

is input

through

the MPX circuit and

are obtained

from

the muting

at pin

frorn

5. The detection out-

pins

this unit detects the

in Fig. 5-1.

which can be

PLL

method

1 and the

goes

Q4,

the

11 and 1'2. In

presence

or absence

contain-

This

detection

to

9,

stereo

pilot

of a stereo nected pin

13 indicator. and FM IF

FM Muting

With when antenna input

drops,

is

result, off

and the detector (Fig. in,

the base

on and the

signal

to automatically

and mono reception

to

drops to

14. the low level

When

operation

When a

2

is

stop

and LED Driver

this unit,

the antenna

muting is

input drops

decreases,

is turned

Q5

the

gate

off

voltage

and

of

output

5-1).

When

potential

an

FM of

tuning indicator

switch between

by

R14 which is

stereo signal is received,

to light

grounded,

(for

AM).

automatically

below

the

voltage at is turned

Q6

drops,

Q4

circuit is

or

AM station

is raised,

Q5

the stereo

PLL

the

VCO

activated

10pV. As the

on.

As a

is turned

Q4

blocked

is tuned

is

turned

Q5

lights.

con-

3

OETECTOR

LEVE L METE R CIRCUIT

Fig.5-1

nrtr F?? |

INPUT

BU FFER

TER

S

EO

rTC

H

5W

R OUT

I

L OUT

FM lF,

Detector and

MPX

circuit

AM Tuner

This uses a

circuit

composed sistor front detector.

AF Section

The equalizer

(2

amp

The

channel)

power

STK4141-2S

The tone

feedback Protective

This the operates

Fig. voltage

unit

power

when

5-2

protection

loop

Circuits

amp

variable capacitor

end

of three

and

transistors, a

a single

circuit has a low-noise

M5218P.

amp has

(See

control

of the

has a

outputs

power

shows

a

Fig.

5-4).

circuit is

power

circuit

is

turned

the

circuit.

watt output

45

placed

amp.

to

detect DC

and construction

When

type tuning

transistor AM

in the negative

voltages

a

muting circuit

on and

off.

of

a DC

2-fuan-

IF

operation power

IC

that

the DC

voltage

at

appears

(plus) the applied the fuse supply

Fig.

at

or

Q14

polarity

to D15.

on circuit 5-3

the

shows Time constant diately potential turned signal.

Q15 C161

discharged of

remains, in

after the

of

on to activate

A few

rises

to turn

When

the

passes

zero.

Q15

the

same

Q15

in

power

(minus)

of the

This

primary

is shut

the

t1 is longer

power exceeds

seconds

off

power

through

an

instant

However,

is

turned

manner

amp

is activated

DC voltage

turns

on D15,

side

is

off.

power

on/off

than

is

turned

its base

and

Q16

later,

the base

along

Q15

is

turned

D18;

it is

to

make the

because

on

and

as when

output,

depending

and a

+81

cut and

muting

t2

so that imme-

on, the

potential,

and

Q17

with

Q16

off, the

almost

base

the

charge

muting is

power

is

either

Q13

trigger

is

shorted,

power

the

circuit.

emitter

Q15

ground

potential

and

e1Z.

charge

completely

potential

of C160

activated

turned

on.

on

is

the

of of

Fig.

5-2

Fig. 5-3

Voltage

DC

Power

POWER AMP

protection

TO POWER AMP

ON/OFF

muting

(

L

circuit

tr,r2

circuit

ch )

TO SPEAKE

R

SWITCHES

ont

const

I

rN r(+)l

2

rN

l(-

)

fi

r8

tN2(+)

t7

rN2(-)

I

PACKING

6.

GND

68

MUTING

Fis.5-4

9

VEE

to

OUT

Equivalent

ta

I

OUT 2

circuit

Mark No. Part

power

of

1.

2.

3.

4.

5.

.J

t6

GN

lC

No. Doscription

AHA.335 AR8526

ATB{76 ADH.OOS AHE-107

pad

Side Operating

(English Loop antenna assembly

T-type antenna

Packing

instructions

)

case

a

T.EXPLODED VIEW

AND

PARTS

LIST

Mark

A

No. Part

1.

2.

*

3.

4. 5, AAD€O8 Speaker

6.

7.

8. AAB-317

9.

10. AAAO84 Tuning knob

11. A48-316 Knob A

12.

13. AAD€07

14. AAD€06

**

ts. ASG-541

16. AAD€05 Power knob

17. AEC-784

18. AXA-373 Tuning

19. AEC471 Nylon rivet

20.

No.

ANE410 BBZ30P080FZK

ATT-944 Power

PMZ30PO60FMC

VMZ30P06OFMC NK9OFUC

NKT0FUC Nut

ANM-293

MTZ3OPIOOFZK

Description

Bonnet Screw

Screw

Screw(3x6)

Nut Knob BALANCE}

Front

Function FM, Function LOUDNESS}

Pushswitch

Cabinet

Screw

NO?ES: o

Parts without

o

The

S

safety

designotion.

your

o

For t* ond *T GENERALLY

This classification shall

number,

(3

x

8)

transformer (3

x

6l

knob

B

{BASS,

(VOLUME)

panel

assembly

knob B

AM)

knob A

(POWER)

bumper

shaft

(3

x

1O)

part

marh

of the

factor

Parts

*.

temperaturc,

{120V}

TREBLE,

(PHONO,

(TAPE.

found

number cannot

on

some

part.

Therefore, when

Stoch Control,

MOWS

TASTER THAN ).

be

adjusted

humidity, e tc.

lVlark

be

supplied.

component

the

mouing items are indicated with the morhs

fast

each

by

No. Part

50. 51 .

52.

53.

54.

55.

56.

57.

58.

59.

60.

61.

62.

63.

64.

65.

66.

67.

68.

69.

parts

replacing,

indicates the importance

be

sure

distributor because it depends on model

No. Decriptions

parts

to use

Speaker switch assembly

holder

Switch Pully

assembly

LED assembly

Earth

Mounting Pully Pully Pully holder

Headphone

Chassis Bottom Binder Earth Rear

Tuning drum Smoother

Pointer Pointer Heat

Wire holder

plate

assembly assembly

Plate

terminal

panel

holder

assembly

sink

of identicol

jack

assembly

of the

a A A

A

**

z't. AEK-123

22. AKP-039 AC

23. ADG-073 Ac GWM-265

24. AKN-045 Phone

25,

**

26. SUJSLYXSF

27.

ACGO17 Ceramic BBT30P080FZK

24.

(T2.5A)

Fuse

socket power

cord

Complex assembly

Speaker

Screw

(PHONES)

Jack

switch

(0.01

(3

x

8)

)

I