Sanyo MW731L Schematic

s~

o

Service Manual

.-

Cassette Recorder

M W731'_ (SPAIN)

-. Specifications

Recording system .. AC bias, 4-track

stereo
Erasing system Magnet erase, 2-track
Tape speed 4.75 cm/seco

(1-7/8 i.p.s.)
Rewind and fast

forward time 110 seco (C-60)

Frequency range LW: 150 - 285 kHz

MW: 525 - 1,605 kHz
SW: 5.95 - 18.0 MHz
FM: 87.5 - 108 MHz

Terminal impedance . HEADPHONES:

320hms

CD/LlNE IN:

47 kohms

___ Specifications subject to change without notice.

Frequency response . 80 ~ 12,000 Hz
Output power 11W (P.M.P.O.)

3.5 + 3.5W

(MUSIC POWER)

Power source DC: 9V, "D" type x 6

AC: 120/220V,

50/60Hz

Dimensions 575x136x131 mm

(WxHxDI

Weight Approx. 3.4 kg

including batteries

PRODUCT CODE NO.
142 809 62 (Gray)
142 809 63 (Red)

REFERENCE No. WM-580187

DISASSEMBLY _

REMOVAL OF CABINET

!(~

flEMOV

Al

OF MECHANISM

-1-

·

,.

-- DISASSEMBLY _

REMOVAL OF P.C. BOARD

¡

-

-

o o

O.3~x717mm

<ID

3

Turns

~

'-...

-2-

lO'

I

HEAO REPLACEMENT ANO AZIMUTH

After replaeement, demagnetize the heads by using

•

a head eraser.
Be sure to dean the head assembly before making

•

the adjustrnent.

TAPE "B"

R/P HEAD

=~

R~E

AOJUSTMENT--------------

REMOVAL OF TOP LID

TAPE "A"

PLAY HEAD

SCOPE

~-, m~

ITJ=,¡~[J] O ~ ~

'--------132Ql------..-J ---

t.

TAPE DECK A AZIMUTH ADJUSTMENT

(1) Insert the test tape

azimuth adjustment into tape deek A.
(2) Press tape deek A's play button.
(3) Usecross-tip serewdriver to turn the serew

ment of the tape deek A azimuth so that the left/right

outputs are maximized while tape deek A is playing

baek.

2.

TAPE DECK B AZIMUTH ADJUSTMENT

(1) Insert the test tape for azimuth adjustment into tape

deek B.
(2) Press tape deek B's play button.
(3) Use eross-tip serewdriver to turn the serew for adjust-

ment of the tape deek B azimuth so that the left/right

outputs are maximized while tape deek S is playing

baek.

(VTT-703,

ete.; 10 kHz) for

tor

adjust-

TAPE "A"

-3-

-- HOW TO REPLACE THE MOTOR ANO AOJUST THE

MOTOR REPLACEMENT

SPEEO,-------------

-

MOTOR SPEED ADJUSTMENT

• DUBBING SWITCH : NORMAL
(1) Insert the test tape (MTT-111 N, ete. 3,000 Hz) into

tape deek A.
(2) Press tape deek A's play button.
(3) Adjust SVR901 (on the ampoboard) sothat the

freqency eounter shows a readinq of 3,000 Hz.

~==--==-=FJ]k3J

o

MOTOR SPEED

SVR901

-4-

I----I~ -:

o ~~l

1--- __

ADJUSTMENT OF MECHANISM ------------------------

• Clean the head, capstan and pinch roller before measurement.

• Check the torque and tension.

Measuring itern Tape-up torqus

Cassette for
measurement

PLAY
F. FWD/REW

PLAY:TW-2111
F. FWD/REW:TW2231

30~60gr·cm
55~120gr·cm

Back 1ension

PLAY:TW-2111

1.5~4.5gr·cm (TAPE"B")

-

TUNERADJUSTMENT------------------------------

• Use a plastic screwdirver for adjustment.

• Adjust the intermediate frequency of MW and FM to the frequency of ceramic filter.
Supply voltage DC 9.0V
Speaker impedance 2.7 ohm
Standard Ouptput 50mW (0.36V)
Function selector RADIO
Fine Tuning CENTER

CT-3@

TPl

~

L106

o

SANO SW

L107 vc~-k9 V~~-1

Ll08 h

~@

CT-4 VCT-2

Tape tension

Drive power cassette

TW-2412
60gr or more

-

CT-l

@

CT-2

111 I 111111

e

O

fF>2 L101

VCT_14~

U-1-

El

rd

e ~

~

Ll02

L104-1

~~;M~;IQf

º ~

T301

MW

Step

~

f---

Step

-

Adjusting

Circuit Input Output

Closed the output

1 IF

2 Tuning

Coverage to Test Loop speaker terminals

4

Tracking

5

6 Repeat adjustments

LW BAND SELECT SWITCH: LW

Adjusting

Circuit Input Output

1 Tuning Connect AM SG

Coverage to Test Loop speaker terminals

2
3

Tracking

4
5 Repeat adjustments

terminal by sweep
generator, it place
to L104-2

Connect AM SG Connect VTVM to 515kHz

Connect AM SG Connect VTVM to 600kHz 600kHz L104-2
to Test Loop speaker terminals

Connect AM SG Connect VTVM to 160kHz 160kHz L104-1

to Test Loop speaker terminals

BAND SELECT SWITCH : MW

Connections

Connect sweep
generator to C305,
C301 (GND)

Connections

Connect VTVM to 140kHz

P

rol ~~ ~~~

R106 ~ ~

+B T303 ~

C30! ~ SVR501 TP3

lFGNO o

SG Frequency

460kHz

1640kHz High End VCT-4

1400kHz·

SG Frequency Position of tuning dial

290kHz High End CT-3

280kHz

Position of tuning dial

ti

(il

Low

Lowend L107

1400kHz VCT-3

Lowend L106

280kHz CT-l

T302

I

~

D

Adjustment

Adjustment

r

CS07

FM S.V

VTVM

Oscilloscope

T303 MAX.

MAX.

MAX.

VTVM

Oscilloscope

MAX.

MAX.

-5-

TUNERADJUSTMENT-----------------------------------------------------

SW

Step

1

r--

2

3
4

5

FM

Step

1 IF

2
3

-

4
5

-

6
7

Adjusting

Circuit

Tuning
Coverage

Tracking

Repeat adjustments

Adjusting

Circuit

------.------

Detector

Tuning
Coverage

Tracking

Repeat adjustments

Connect AM SG
to ANT terminal
through dummy

Connect AM SG

to

through dummy

Connect sweep
generator to
output line to
IC10l
and TP-2 (GND)

Connect FM SG
to TP-l (H),
TP-2 (GND)

Connect FM SG
toTP-l (H),
TP-2 (GND)

BANO SELECT SWITCH: SW

Connections

Input Output

Connect VTVM to
speaker terminals

ANT terminal

BANO SELECT SWITCH: FM FM OUMMY ANTENNA: 75Qunbalance

Input

CD

(H)

Connect VTVM to
speaker terminals

Connections

Connect sweep
generator of input
line to C507,
C301 (GND)

Connect VTVM to
speaker terminals

Connect VTVM to

speaker terminals

Output

SG Frequency Positio n of tuning dial Adjustment

5.8MHz

19.0kHz High End CT-4

7.0MHz 7.0MHz Ll05

16.0MHz 16.0MHz

SG Frequency Position01tuning dial

10.7MHz Low

87.35MHz Lowend Ll02

108.3MHz High End

90.0MHz

106.0MHz 106.0MHz VCT-l

Lowend L108

CT-2

Adjustment

T301

T302

VCT-2

90.0MHz

Ll0l

VTVM

Oscilloscope

MAX.

MAX.

VTVM

Oscilloscope

17?

17?

MAX.

MAX.

~--

FM VCO

1) INPUT
SIGNAL
CONNECTION
PILOT SIGNAL

2) ADJUSTMENT
ADJUST
FREQUENCY

3) INSTALLATION OF FREQUENCY COUNTER AND BUFFERAMP.

Turn SVR501 until the frequency counter reads 76.0 kHz

±200 Hz

BANO SELECT SWITCH: FM

FM MOOE SWITCH: FM STEREO

60dB 22.5kHz DEV. AT 98MHz
HOTTOT~l GROUNDTOT~2
OFF

SVR501
76kHz±200Hz

R504

MONO

STEREOI~

S2

1

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Vcc

FET:2SK44or2SK222

+

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FREQUENCY
COUNTER

Vcc

-6-

IF GROUND

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EXPLODED VIEW (MECHANISM) _

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-

--

-

SCHEMATIC DIAGRAM (AMP.) _

L-CH

TAPE"A"
PLAY
L-CH

TAPE"B"
R/P
R-CH

TAPE"A"

~:~

TAPE·B"

E.H

D

LIIIE IN

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D1-703.801-803.901-904 ••••• RECORD/PLAY SWITCH
21 .821 .921 .922 ••••••••••••• FUNCTION SWITCH
~1. 792.891.892.991 ••••••••• SURROUNDSWITCH
~1 ••••••••••••••••••••••••• TAPE"A"POWER SWITCH
kl. •••••••••••••••••••••••• TAPE"B"POWER SWITCH

~;¡•......•...•.•.•..•.•..•.

2 ••••••••••••••••••••••••• BEAT CANea SW

1••••••••••••••••••••••••• TAPE" A'PLAY SWITCH
1••••••••••••••••••••••••• ACIDC SWITCH

2 ••••••••••••••••••••••••• VOLTAGE 5aECT SWITCH

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2 R-CH SIGNAL
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1C901 M51166P PRE-AMP

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7;--:;;-"---IM.--t-::::::lt:::::7'------(

le902 LA4558 POWER AMP.

INPUT

AMP

SMALL
RIPPLE
FILTER

I

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POWER AMP
GNO

POWER AMP
GNO

OUTPUT

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A'AlC CONTROl

R/P

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.-

PRODUCT SAFETY NOTICE

Each percaution in this manual should be followed during servicing. Components identifled with the lEC svrnbolzb in the parts list and
the schematic diagram designate components in which safety can be of special significance. When replacing a component identified
with&,use only the replacement parts designated, or parts with the same ratings of resistance, wattage or voltage thatare designated
in the parts list in this manual.
Leakage-current or resistance measurements must be made to determine that exposed parts are acceptably insulated from the supply
circuit before erturning the product to the customer.

- 13-

;

---~--

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-

.-

WIRING DIAGRAM

(AMP.)---------------------------

LEO

P.C.B

UNE IN

L-CH R-CH

0701.702,801 }

0002,901. 903 ... .2SC18 15

0904

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POWER SUPPLY

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IC902 LA4558

7

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5901-904

5721.821JFUNCTION 5WITCH

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5892,991 ..

5931. TAPE "A" POWER SWITCH

5941........•.. TAPE ..B..POWER 5WITCH

5951. ....•....• DUBBING 5PEED 5WITCH

5952 BEAT CANCEL 5WITCH

5961 .•.....•.. TAPE "A" PLAY 5WITCH

5971 AC I DC 5WITCH

5972 VOLTAGE 5ELECT 5WITCH

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5931

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5961

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WIRING DIAGRAM (TUNER)

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TUNING

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Mar./'89/500 KM

P.C.S

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