Sanyo M7700l User manual

SERV.

8423

SERVICE

MANUAL

MINI

FM/MW/SW/LW

STEREO

RADIO

CASSETTE

RECORDER

M77OOLE

EUROPE

141

888

07

SPECIFICATIONS

Recording

System.

.............

AC

Bias

DIN

OUTPUT

202

ves

doe

etd

Dees

2.2k-ohm

Erasing

System.

...............

AC

Erasing

EXT.Speaker

..............

3.2

—

Gohm

Tape

Speed

..................

1-7/8ips

+3%

Headphone

................

8o0hm

Fast

ForwardTime.............

140sec.

(C-60

cassette)

Current

Consumption

(at

Min.

VR)

Rewind

Time...............0-.

‘140sec.

(C-60

cassette)

RECORD

mode

.............

210mMA

Wow

&

Flutter...

..0.....000.0.

0.25%

RMS

PLAY

mode

...............

160mA

Frequency

Response

F.FWD

mode

..............

180mA

NORMAL

.................

70

—

10,000Hz

REW

mode

................

180mA

Signal

to

Noise

Ratio

Output

Power

...........00...

2.0/chW

(maximum)

without

DOLBY

.............

Better

than

48dB

Power

Source

Hum

&

Noise.......

Less

than

—55dBs

(Min.

Vol.

and

Tone)

AC

BS

ta

eee

Bae

AC

Adaptor

(120/240V

50/60Hz)

Crosstalk

Bo)

iteersrerreg

ete

7.5V

(UM-2,C

Cell,

HP

11,R14,

Babyzellen

x

5)

Track

to

Track...

2...

Better

than

50dB

Channel!

Separation.

.........

~

Better

than

50dB

Frequency

Range

Distortion

(3rd

harmonic)

LEW

>

vegetal,

erat

Loe

he

2

te

a

Ns

150

—

350kHz

NORMAL

ALS

ase

eden

ce

fie

5%

IAW

ts

oS

SN

Sect

ence

a

AE

ci

AS

525

—

1,605kHz

Terminal

Impedance

SW

ena

e

Ma

kG

ee

ea

Bowes

ett

d

5.8

—

18MHz

MEE

cS

aint

one

Oh

kA

fo

At

3.3k-ohm

EM

seve

Bunce

oehce

tease

al

koh

dao

87.5

—

108MHz

DIN

INPUT...

00.2

0000000..

3.3k-ohm

—Specifications

subject

to

change

without

notice.—

WM-4529.

DISASSEMBLY

INSTRUCTIONS

CABINET

BOTTOM

ASSEMBLY

REMOVAL

AMPLIFIER

P.C.BOARD

ASSEMBLY

REMOVAL

1.

Take

out

the

cassette

tape

from

the

compartment

by

1.

Follow

the

instructions

for

the

Cabinet

Bottom

Assembly

pressing

the

STOP/EJECT

button.

Removal.

2.

Turn

over

the

unit

on

a

soft

surface

and

remove

the

battery

2.

Unscrew

the

two

screws

(6

&

7)

fastening

the

P.C

Board.

compartment

lid.

Then,

take

out

the

five

batteries

from

the

unit.

3.

Unscrew

the

five

screws

(1

—5)

fastening

the

Cabinet

Bottom

and

lift

the

Cabinet

Bottom

as

illustrated.

3.

Pull

out

the

connector

(CN1)

from

the

P.C.Board.

4.

Carefully

remove

the

P.C.

Board

by

lifting

it

in

the

numerical

order

as

illustrated.

Cabinet

Bottom

Connector

(CN1)

4.

Pull

out

the

two

connectors

of

the

dipole

antenna

from

the

Radio

Tuner

P.C.Board.

Then,

remove

the

Cabinet

Bottom.

Cabinet

Bottom

5.

Reassembie

in

the

reverser

order.

RADIO

TUNER

P.C.BOARD

REMOVAL

1.

Follow

the

instructions

for

the

Cabinet

Bottom

Assembly

Removal.

2.

Turn

the

Tuning

Knob

fully

in

an

arbitrary

direction.

5.

Reassemble

in

the

reverse

order.

DISASSEMBLY

3.

Unscrew

a

screw

(8)

fastening

the

P.C.Board.

4.

Remove

the

P.C.Board

by

lifting

the

tuning

knob

side

of

it.

NOTE:

Do

not

turn

the

Tuning

Knob

before

the

Tuner

P.C.Board

is

re-mounted

to

the

unit.

5.

Reassembie

in

the

reverse

order.

RADIO

CHASSIS

ASSEMBLY

REMOVAL

1.

Remove

the

Cabinet

Bottom

Assembly,

Amplifier

P.C.Board

Assembly,

and

Tuner

P.C.Board

Assembly

by

following

the

instructions

for

them.

2.

Pull

out

the

Volume

Control

Knob,

Tone

Control!

Knob,

Balance

Control

Knob,

Mixing

Control

Knob,

and

Tuning

Knob

from

the

unit

as

illustrated.

Volume

Control

Knob

TanaContrerKnes

Mixing

Control!

Knob

Balance

Control

Knob

»

cca@)

S)

Ve

iC

Connector

(CN

1)

Radio

Chassis

Tuning

Knob

3,

Unsolder

the

three

leads

from

the

Radio

Tuner

P.C.Board

and

remove

the

connector

(CN1)

from

the

Amplifier

P.C.Board

as

illustrated.

INSTRUCTIONS

(Continued)

4.

Unscrew

the

two

screws

(9

&10}

fastening

the

Radio

Chassis

and

remove

the

Radio

Chassis

by

tilting

it

as

illustrated.

NOTE:

*

The

Radio

Chassis

may

be

removed

without

unsoldering

the

leads.

Remove

the

Radio

Chassis

noting

the

leads.

*

If

the

Radio

Chassis

from

the

Cabinet

Top

is

completely

removed,

unsolder

the

lead

wires

of

the

Sound

Level

L.E.D.

and

Built-in

Microphone

from

the

Amplifier

P.C.Board.

5.

Reassemble

in

the

reverse

order.

CHASSIS

ASSEMBLY

REMOVAL

1.

After

removing

the

Cabinet

Bottom

and

Radio

Chassis,

unscrew

the

screw

(6)

fastening

the

Amplifier

P.C.Board.

Then,

turn

over

the

Radio

Chassis.

See

the

illustration

below.

2.

Unscrew

the

screw

(11)

fastening

the

Jack

Bracket,

the

screw

(12)

fastening

the

Governor

Circuit

P.C.Board,

and

the

screws

(13

—

16)

fastening

the

Chassis

as

illustrated.

DISASSEMBLY

INSTRUCTIONS

(continuea)

3.

After

removing

the

Jack

Bracket

and

the

Governor

Circuit

CASSETTE

COMPARTMENT

LID

REMOVAL

P.C.Board,

remove

the

Chassis

as

illustrated.

1.

Open

the

cassette

compartment

lid

by

pressing

the

STOP/EJECT

button.

2.

To

remove

the

cassette

compartment

lid,

unlock

the

click

of

the

cassette

compartment

lid

from

the

Cabinet

Top

by

Chassis

pressing

the

counter

side

of

the

lid

as

illustrated.

Cassette

Compartment

Lid

Radio

Chassis

4.

Reassemblie

in

the

reverse

order.

NOTICE

ON

REASSEMBLY

1.

When

the

unit

is

re-assembled,

check

to

see

that

the

lead

wires

do

not

touch

the

driving

mechanism

(Example:

Flywheel,

Pulley,

and

Belts

etc.,).

2.

When

you

solder

the

removed

lead

wires,

please

refer

to

the

Wiring

Diagram.

MECHANICAL

ADJUSTMENTS

GENERAL

REMARK

@

Before

adjusting

the

mechanism

of

this

unit,

wipe

the

tape

contacting

surfaces

clean

as

well

as

the

contact

surfaces

of

the

driving

parts

with

a

soft

cloth

soaked

in

alcohol.

Trouble

may

occur

because

of

oil

and

grease

stains.

@

Carefully

handle

the

belt

because

grease

easily

attaches

to

it.

FLYWHEEL

THRUST

ADJUSTMENT

The

clearance

between

the

Flywheel

Thrust

and

the

Flywheel

should

be

0.03

—

0.35mm

with

the

Chassis

turned

over.

\f

necessary

,

adjust

the

clearance

by

the

following

procedure.

1.

While

moving

the

Capstan

up

and

down,

slowly

turn

the

Flywheel

Thrust

clockwise

to

obtain

the

clearance

of

O

between

the

Thrust

and

Flywheel.

NOTE:

Do

not

turn

the

Flywheel

Thrust

forcibly.

Adjustment

Flywheel

Support

S

+

Flywheel

Thrust

'

0.03

—

0.35

mm

Flywheel

Capstan

_—

2.

Turn

the

Thrust

counter-clockwise

by

45°

from

the

position.

3.

After

the

adjustment,

secure

the

Thrust

with

paint

or

glue.

POWER

SWITCH

POSITION

ADJUSTMENT

1.

Check

to

see

that

the

Power

Switch

is

positioned

over

the

center

of

the

chassis

adjusting

hole

as

illustrated.

Mounting

Screw

Power

Switch

Position

the

leaf

over

the

center

of

the

hole.

Take-up

Gear

2.

|f

necessary,

loosen

the

screw

fastening

the

Switch

and

adjust

the

switch

position

by

moving

the

Switch.

3.

After

tightening

the

screw,

check

the

switch

movement

as

follows:

*

Set the

unit

in

the

playback

mode

and

slowly

push

the

F.FWD

button.

Then,

check

that

the

Power

Switch

is

changed

over

from

‘'Close’’

to

"Open",

and

that

it

is

changed

to

‘’Close’’

again

after

the

Take-up

Gear

meshes

with

the

FF

Gear.

4.

Check

that

the

Power

Switch

functions

properly.

Then,

secure

the

screw

with

paint

or

glue.

ELECTRICAL

ADJUSTMENTS

REQUIRED

EQUIPMENTS

VTVM

(two

sets)

Frequency

Counter

Dummy

Load

(470

k-ohm)

Dualtrace

Synchroscope

Test

Tapes

*

3kHz

test

Tape

(TEAC

MTT-111)

for

Tape

Speed

Adjustment

*

8kHz

Test

Tape

(TEAC

MTT113C)

for

Head

Azimuth

Adjustment

*

1kHz

Test

Tape

(TEAC

MTT-112B)

for

Playback

Gain

Adjustment

DC

Constant-Voltage

Regulator

Alignment

Tool

Prior

to

the

Electrical

Adjustments,

set

the

unit

and

the

measuring

instruments

as

follows:

Function

Switch

2.2...

0.0...

00

ees

TAPE

Mode

Switch.............

0000s

STEREO

Input

Select

Switch

.............

to

REC/PB

terminal

Beat

Cancel

Switch

..........

0.0000

eee

ee

es

1

DC

Constant-Voltage

Regulator

Output

.......

7.5V

DC

NOTE:

1.

Perform

each

adjustment

in

the

described

order.

2.

Obtain

the

output

from

the

R/P

DIN

socket.

3.

Supply

7.5

V

DC

from

the

constant-voltage

regulator

to

the

unit.

4.

When

obtaining

the

output

from

the

R/P

DIN

socket,

connect

the

leads

noting

the

terminal

numbers

as

illustrated.

Ground

Right

Channel

Output

Right

Channel

Input

Left

Channel

Input

Left

Channel

Output

TAPE

SPEED

ADJUSTMENT

1.

2

Remove

the

battery

compartment

lid

and

connect

the

frequency

counter

to

the

left

or

right

channel

output

terminals

of

the

R/P

DIN

socket

as

illustrated.

Frequency

Counter

3,000Hz

(+3%)

Dummy

Load

470

k-ohm

Insert

the

3

kHz

test

tape

(Example:

TEAC

MTT-111)

into

the

compartment

and

play

it

back.

Adjust

the

tape

speed

by

turning

the

potentiometer

(P801)

on

the

Governor

Circuit

P.C.Board

with

an

alignment

tool

to

obtain

3,000

Hz

(43%)

on

the

frequency

counter.

See

the

illustration

below.

Tape

Speed

Adjusting

Hole

HEAD

AZIMUTH

ADJUSTMENT

ile

Remove

the

cassette

compartment

lid.

Connect

a

VTVM

and

{

a

dualtrace

synchroscope

to

the

R/P

DIN

socket

as

illustrated.

Synchroscope

x.)

dc)

Dummy

Load

470

k-ohm

Dummy

Load

470

k-ohm

Set

the

synchroscope

as

follows:

*S

MODE.

2

fang

tp

Dust

i

Be

©

tat

hk

dat

2

a,

CHOP

Po

SOURCE

chsh

Setok

a

ines

setlist

INT

(CH1

of

CH2}

*™“SWEEPIMODES

os.

2

oct

hb

oat

See

Nera

Bee

AUTO

Insert

the

8

kHz

test

tape

(Example:

TEAC

MTT-113)

into

the

compartment

and

play

it

back.

Slowly

turn

the

azimuth

adjusting

screw

until

the

amplitudes

of

both

channel

output

wave

forms

become

maximum

and

the

wave

forms

overlap

as

well

as

possible

in

the

maximum

condition

of

the

VT

VM

as

illustrated.

R/P

Head

ELECTRICAL

ADJUSTMENTS

(continua)

Adjustment

4.

After

the

adjustment,

secure

the

screw

with

paint

or

glue.

PLAYBACK

GAIN

ADJUSTMENT

1.

Connect

the

two

sets

of

VTVM

to

the

R/P

DIN

socket

as

illustrated

and

insert

the

1

kHz

test

tape

(Example:

TEAC

MTT-112B)

into

the

compartment.

REC

VTVM

B

Dummy

Load

470

k-ohm

470

k-ohm

RIGHT

CHANNEL

2.

Check

to

see

that

the

output

of

the

right

channel

is

0.65

V

(£0.1

V)

with

the

unit

in

the

playback

mode.

3.

If

necessary,

ground

the

resistor

R108

and/or

R109

by

soldering

the

pattern

to

obtain

the

specified

output

as

illustrated.

Q303

LEFT

CHANNEL

4.

Adjust

the

output

by

grounding

or

separating

the

resistor

R208

and/or

R209

with

the

same

method

as

RIGHT

CHANNEL.

5.

After

the

adjustment,

check

that

the

output

difference

between

the

right

channel

and

the

left

channel

is

within

2

dB.

a,

c205

R205

ote

:

aed

owe

“Se

]

ow

C206

e4}+-6C207

C2

Die

eite

pec

eae

a

od

*

R207

fee

x

oes

oc:

na

Gee

ee

‘emia

ts

om

«

C2108

be

am

ae

HE

tc2

zeit

c2097*"

c20stia709

0%

owe

ae

R202

dus

R210

O

=

oft

R208

&

rset

2

oO.

Teed

R203

|

OSCILLATOR

FREQUENCY

AND

RECORDING

BIAS

ADJUSTMENT

RIGHT

CHANNEL

1.

Connect

the

VTVM

across

R103,

and

the

frequency

counter

to

the

output

terminal

of

the

VTVM

as

illustrated.

VTVM

3.8mV

—

4.3mV

Frequency

Counter

48.85kHz

—

48.95kHz

ote

6

TS)

Os

dae

Q303

2.

Set

the

unit

in

the

recording

mode.

Then,

adjust

the

frequency

by

turning

the

core

of

the

oscillator

transformer

(T301)

with

an

alignment

tool

until

the

frequency

counter

reads

48.85

kHz

—

48.95

kHz.

3.

Adjust

the

potentiometer

(P101)

with

the

unit

in

the

recording

mode

until

the

VTVM

reads

3.8mMV

—43

mV

(380

nA

—

430

pA).

LEFT

CHANNEL

Connect

the

VTVM_~

across

R203.

Then,

adjust

the

potentiometer

(P201)

until

the

VTVM

reads

3.8

mV

—

43

mV

(380

pA

~—

430

pA).

VTVM

3.8mV

—

4.3mV

TUNER

ADJUSTMENT

Measuring

Instruments

Required

at

FM/SW

alignment

(Tuning

Range

and

Tracking)

@

AM

Standard-signal

Generator

@

FM

Standard-signal

Generator

®@

Generator

Scope

:

@

Stereo

Signal

Generator

Scope

atte

eS

re

®

Loop

Antenna

‘3

ped

le

@

Dummy

Antenna

(300

ohm,

balanced

type)

sl

Eid

ab

ie!

$

te

e

VTVM

nie

¢

@

Frequency

Counter

7

Orerg@rre

aig

@

Distortion

Meter

"9

P|

GTP

10

®

Oscilloscope

ry

s

ee

@

Dummy

Load

(3.2

ohm)

+

ee

t

Te

osz-5

®

Alignment

Tool

¥

fod

rzsiew

rag

pot

°C

%

TQ,

|

es

1

6

oe

0ed

NOTE:

opie

F009}

gsre_°

°

87%8

Set

the

Function

Switch

to

RADIO

(ON).

Then,

perform

each

alignment

following

the

chart

below.

(Input

Side)

(Output

Side)

Measuring

Instrument

Connections

at

MW/LW

alignment

;

FM

Signal

Generator

Loop

Antenna

?

AM

Standard

Signal

Generator

Dummy

Antenna

VTVM

Oscilloscope

[

;

Bama

Load

|

Dummy

Load

EXT.

SP

32-60

3.2

ohm

fee

ee

3.2

ohm

iO}

Pe

MW

ALIGNMENT

Standard

test

frequency

400

kHz

and

modulation

30%

at

AM

Connections

Frequency

Alignment

of

Signal

OUTPUT

Generator

Tuning

Dial

Setting

Adjustment

Remarks

Calibration

Connect

standard

Obtain

symmetrical

curve

of

IF

for

loop

antenna

to

Connect

input

and

maximum

amplitude,

T5,76

and

T7

|

output

terminal

of

terminal

of

gene-scope.

gene-scope

to

460

kHz

T5,T6

and

T7

Adjustment

Place

bar

antenna

detector

output.

of

60

cm

away

from

IF

Gain

loop

antenna.

Calibration

Connect

standard

505

kHz

T10

Obtain

sine

wave

of

400

Hz

of

loop

antenna

to

Connect

VTVM

with

+

and

maximum

amplitude.

Tuning

Range

|

output

of

signal

3.2

ohm

dummy

load;

1670

kHz

High

End

TC3

generator.

and

oscilloscope

to

Adjustment

Place

bar

antenna

Ext.

speaker

terminal.|

600

kHz

600

kHz

L5-1

(bar

ant.

coil)

of

60

cm

away

from

Tracking

loop

antenna.

1400

kHz

1400

kHz

TC4

L

Repeat

the

above

adjustments.

*

Use

a

screwdriver

with

plastic

grip

for

all

adjustments.

FM

ALIGNMENT

Connections

TUNER

ADJUSTMENT

(continue)

Standard

test

frequency

400

Hz

and

deviation

22.5

kHz

Frequency

Alignment

Calibration

Place

output

of

gene-scope

on

Trap

Coil

(L2).

of

Signal

OUTPUT

Generator

Connect

input

terminal

of

gene-

scope

to

detector

output.

Calibration

of

Tuning

Range

Adjustment

of

Tracking

Connect

signal

generator

to

antenna

terminal

through

dummy

antenna.

Tuning

Dial

Setting

Low

End

Adjustments

Turn

T4

(blue

core}

fully

counter-

clockwise.

T2

and

T3

Obtain

symmetrical

curve

and

maximum

amplitude.

T4

(blue

core)

Obtain

S

curve

and

maximum

amplitude.

Connect

VTVM

with

3.2

ohm

dummy

load

and

oscilloscope

to

4

High

End

Ext.

speaker

terminal.

90

MHz

90

MHz

106

MHz

106

MHz

Obtain

sine-curve

and

maximum

amplitude.

Repeat

the

above

adjustments.

’

Use

a

screwdriver

with

plastic

grip

for

all

adjustments.

SW

ALIGNMENT

Alignment

Calibration

of

Tuning

Range

Adjustment

of

Tracking

Connections

Frequency

Connect

signal

generator

to

antenna

terminal

through

dummy

antenna.

of

Signal

OUTPUT

Generator

5.7

MHz

Connect

VTVM

with

Tuning

Dial

Setting

Low

End

Adjustment

3.2

ohm

dummy

load;

18.7

MHz

High

End

4

|

and

oscilloscope

to

Ext.

speaker

terminal.

6.5

MHz

6.5

MHz

17

MHz

17

MHz

Remarks

Obtain

sine-wave

of

400

Hz

and

maximum

amplitude.

Repeat

the

above

adjustments.

*

Use

a

screwdriver

with

plastic

grip

for

all

adjustments.

LW

ALIGNMENT

Alignment

Calibration

of

Tuning

Range

Adjustment

of

Connections

Frequency

Tracking

Connect

standard

loop

antenna

to

output

of

signal

generator.

Place

bar

antenna

60

cm

away

from

loop

antenna.

+

of

Signal

OUTPUT

Generator

147

kHz

Tuning

Dial

Setting

Low

End

Adjustment

T11

Connect

VTVM

with

3.2

ohm

dummy

load

365

Hz

High

End

TC8

and

oscilloscope

to

Ext.

speaker

terminal.

170

Hz

170

Hz

L5-2

(bar

ant.

coil)

310

Hz

310

Hz

TCS

+

Remarks

Obtain

sine-wave

of

400

Hz

and

maximum

amplitude,

Repeat

the

above

adjustments.

TUNER

ADJUSTMENT

(continued)

FM

MULTIPLEX

ADJUSTMENT

Prior

to

the

adjustment,

set

the

unit

as

follows:

2.

Connect

the

VTVM

with

3.2

ohm

dummy

load,

distortion

@®

FunctionSwitch

..........00ce0e

ae

RADIO

(ON)

meter,

and

oscilloscope

to

the

external

speaker

jack

of

the

@

Band

Select

Switch

........

00000

cee

eee

FM

left

channel

as

illustrated.

@

Mode

Switch.......

2.20.00.

es

STEREO

@

ToneControl

2.0.0...

ee

eee

MAXIMUM

VTVM

@

VolumeControl

.......

2.2...

200

ee

eee

Center

@

L

EXT.

SP

3.2

~

60

©:

Oscilloscope

19

kHz

(V.C.0.)

ADJUSTMENT

1.

Connect

the

frequency

counter

to

the

twelfth

in

IC2

as

illustrated.

»

Dummy

Load

3.2

ohm

Frequency

Counter

Distortion

Meter

3.

Adjust

the

input

measuring

instruments

as

follows:

@

Stereo

Signal

Generator

2.

Adjust

the

potentiometer

(P1)

until

the

oscillation

*

Pilot

Signal...

....

7.5

kHz

dev.

{modulation

10%)

frequency

of

IC2

becomes

19

kHz

(£20

Hz).

*

Stereo

Signal........

67.5

kHz

dev.

for

main

signal

(modulation

90%)

*

Modulation

Frequency

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

400

Hz

@

FM

Standard-signal

Generator

CHANNEL

SEPARATION

ADJUSTMENT

*

Signal

Generator

Frequency

............

98

MHz

1.

Insert

the

3000hm

dummy

antenna

(balanced

type)

*

Signal

Generator

Output

...........0...

66

dB

through

the

FM

antenna

terminals

(TP1

and

TP2)

in

the

Radio

Tuner

P.C.Board

as

illustrated.

4.

Perform

the

alignment

following

the

chart

on

the

Stereo

Signal

Generator

Dummy

Antenna

300

2.

—~10—

Sanyo M7700L User manual

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