Sanyo Vhr-757g User manual

FILE

NO.

SANYO

SERVICE

MANUAL

Video

Cassette

Recorder

VHR-757G

(Product

Code

:

143

171

65)

(Switzerland

&

Italy)

VHR-757EX

(Product

Code

:

143

171

64)

(Europe)

VHR-757NL

(Product

Code

:

143

171

66)

(Netherlands)

VHR-777EV

(Product

Code

:

143

171

67)

(Europe)

(VHR-757G,

VHR-757EX,

VHR-757NL)

VHS

V

H

R

777

EX

=

an

(Product

Code

:

143

171

23)

CONTENTS

(Europe)

SELF-DIAGNOSIS

DISPLAY

cssscscccscsssseccesssssssesenssesesnseseveneee

2

V

-

R-797

S

P

1.

DISASSEMBLY

.....ccccccccccsssccsecssescecsesessucssesecssuessessnessuseneeness

5

2.

ELECTRICAL

ADJUSTMENT

.....scssssssssssssssesscssssessessseeeesnes

9

(Product

Code

:

143

171

12)

3.

TEST

POINTS

FOR

TAPE

PATH

ADJUSTMENT

...........+.

13

(Spain

&

Portugal)

4.

PARTS

LIST

Please

see

other

materials

with

Reference

MECHANISM

PARTS

.....csscsscsseecsseecsescsvsesseceseessesssseesseesseens

14

number

given

in

table

below.

CABINET

&

CHASSIS

PARTS

...cccescccssscsscsesesseesseessecesseenes

16

ELECTRICAL

PARTS

..cccccessccoscsccusecsnscccssseccuccscneecsneecosecese

17

|

Materials

|

Model

No.

ACCESSORIES

....cccccsscesssescseccuscccconesueesuscuessasessesaseoneseeeene

27

V95

|

PACKING

MATERIALS

cccsssssssssssssssssssssscssssesescssescescssseseeeee

27

KiSchanicn'l'Mechanaml

ee

CIRCUIT

DIAGRAMS

(Refer

to

the

separate

volume)

Manual

|

V95

II

aaesaees

Mechanism

5315

PRODUCT

SAFETY

NOTICE

The

components

designated

by

a

symbol

(/\\)

in

this

schematic

diagram

designates

components

whose

value

are

of

special

significance

to

product

safety.

Should

any

component

designated

by

a

symbol

need

to

be

replaced,

use

only

the

part

designated

in

the

parts

List.

Do

not

deviate

from

the

resistance,

wattage,

and

voltage

ratings

shown.

NOTE:

1.

Parts

order

must

contain

model

number,

part

number,

and

description.

2.

Substitute

parts

may

be

supplied

as

the

service

parts.

3.

N.S.P.

:

Not

available

as

service

parts.

Design

and

specifications

are

subject

to

change

without

notice.

REFERENCE

No.SM531579

MP4H/G5,

EX5,

NL5,

EV3, EX3,

SP

SELF-DIAGNOSIS

DISPLAY

Mechanism

Mode

Display

/

Head

Output

Drop

Warning

Display

/

Cylinder

Rotation

Accumulated

Time

Display

This

unit

displays

the

diagnosis

contents

of

abnormalities

and

the

mechanism,

mode

on

its

display

panel

in

2-digit

numbers.

When

the

head

playback

output

has

dropped,

the

"L"

sign

will

be

blinked.

Some

models

(listed

later)

will

also

display

the

cylinder

rotation

accumulated

time.

FE

These

display

shows

the

outline

of

the

problems.

Use

it

as

a

reference

when

servicing

the

unit.

1.

Self-Diagnosis

Contentes

and

Mechanism

Mode

Display

*

When

the

STOP

button

on

the

remote

control

is

pressed

for

about

19

seconds

continuously,

the

self-diagnosis

number

will

be

displayed

on

the

reception

channel

display

of

the

display

panel

and

number

indicating

the

failed

mechanism

mode

(changed

mode

when

being

shifted)

on

the

tape

counter

"seconds"

display

for

10'seconds

each.

*

—

During

self-diagnosis

display,

displays

other

than

the

diagnosis

number/mechanism

mode

number

and

the

cylinder

accumulated

rotation

time

display

described

later

(some

models

only)

will

be

turned

off

and

when

displays

end,

the

normal

display

will

be

returned

automatically.

*

Refer

to

"Self-Diagnosis

Contents"

for

the

self-diagnosis

numbers

and

the

"Mechanism

Mode

Display

Contents"

for

the

mechanism

mode

numbers.

e

When

the

"0"

button

on

the

remote

control

unit

is

pressed

during

display,

and

clearing

the

self-diagnosis

display

and

mechanism

&

mode

display.

Display

panel

Self-Diagnosis

number

Mechanism

mode

number

(Reception

channel

display)

(Tape

counter

"Seconds"

display)

Self-Diagnosis

Contents

Mechanism

Operations

and

State

After

Occurrence

Shifts

to

the

STOP

mode.

There

is

no

abnormality

in

the

mechanism.

The

cylinder

motor

does

not

rotate.

|

*

The

cylinder

motor

is

faulty.

*

The

control

of

the

cylinder

motor

is

faulty.

¢

The

tape

winds

around

the

cylinder.

¢

The

take-up

reel

is

caught.

*

The

reel

belt

is

faulty.

¢

The

take-up

torque

has

decreased.

¢

The

capstan

motor

is

faulty.

¢

The

control

of

the

capstan

motor

is

faulty.

¢

Error

in

the

operations

of

the

tape

loading

mechanism.

*

Foreign

particles

in

the

tape

load-

ing

mechanism.

¢

The

tape

end

sensor

is

faulty.

¢

The

reel

brake

of

the

tape

cassette

has

not

been

released.

¢

The

tape

guide

is

caught.

¢

The

loading

motor

is

faulty.

¢

The

control

of

the

loading

motor

is

faulty.

The

take-up

reel

does

not

rotate.

Shifts

to

the

STOP

mode.

The

capstan

motor

does

not

rotate.

Shifts

to

the

STOP

mode.

Unloads,

shifts

to

the

INITIAL

mode,

and

the

power

goes

off.

The

tape

cannot

be

loaded

with

the

cassette

inserted.

(But

unloading

can

be

performed.)

Tape

loading

and

unloading

cannot

be

performed

with

the

cassette

in-

serted.

The

power

is

forcibly

turned

off

with

the

mechanism

at

its

current

position.

Mechanism

Operations

and

State

After

Occurrence

Front

unloading

cannot

be

performed

|

*

The

cassette

drive

mechanism

is

|

Front

loads

and

shifts

to

the

STOP

or

when

ejecting

the

cassette.

faulty.

INITIAL

mode.

(Front

loading

can

be

performed.)

¢

The

front

door

is

caught.

¢

When

the

power

switch

is

turned

on

before

eject

operations:

Shifts

to

the

STOP

mode.

e

When

the

power

switch

is

turned

off

before

eject

operations:

Shifts

to

the

INITIAL

mode

and

the

power

goes

off.

Front

loading

and

front

unloading

can-

|

*

The

tape

cassette

is

caught

in

the

|

The

power

is

forcibly

turned

off

with

not

be

performed

when

ejecting

the

|

cassette

drive

mechanism.

the

mechanism

at

its

current

position.

cassette.

*

The

main

cam

and

front

rack

gear

of

the

front

loading

mechanism

have

not

engaged

properly.

¢

The

gears

of

the

front

loading

drive

mechanism

have

not

engaged

prop-

erly.

¢

The

mechanism

mode

switch

con-

tact

is

faulty.

No.

Problem

Main

Possible

Cause

06

07

The

power

is

forcibly

turned

off

with

the

mechanism

at

its

current

position.

The

mechanism

becomes

1

(RE-

VIEW)

while

moving

from

2

(IDLER),

3

(STILL),

4

(BRAKE),

and

to

5

(STOP).

ae

The

mechanism

becomes

7

(INITIAL)

while

moving

from

1

(REVIEW),

2

(IDLER),

3

(STILL),

4

(BRAKE),

and

to

5

(STOP).

Carries

out

tape

take-up

operations,

shifts

to

the

INITIAL

mode,

and

the

power

goes

off.

*

The

mechanism

mode

switch

con-

tact

is

faulty.

Note:

For

details

of

mechanism

operations

corresponding

to

the

mechanism

positions

of

the

self-diagnosis

numbers

08

and

09

above,

refer

to

the

separate

volume

on

the

V95

I

mechanism

manual.

These

manual

reference

numbers

are

shown

in

the

cover.

Mechanism

Mode

Display

Contents

Mechanism

Mode

Mechanism

Mode

No.

Mechanism

Mode

No.

CASSETTE

OUT

PLAY

16

VIDEO

INSERT

01

STANDBY

REC

VIDEO

INSERT-PAUSE

02

STOP

10

AUDIO

DUBBING

AUDIO/VIDEO

INSERT

03

STILL

11

X2

SPEED

PLAY

REVERSE

X2

SPEED

PLAY

04

REC-PAUSE

12

CUE

05

AUDIO

DUBBING-PAUSE

13

REVIEW

FAST

FORWARD

REWIND

FRAME

ADVANCE

14

SLOW

OTHERS

2.

Head

Output

Drop

Warning

Display

*

When

the

STOP

button

on

the

remote

control

is

pressed

for

10

seconds

continuously

10

seconds

after

play

starts,

"L"

will

be

displayed

blinking

at

the

first

digit

of

the

minutes

position

on

the

tape

counter

when

the

head

output

is

lower

than

the

specified

value

to

indicate

an

abnormality.

*

The

cause

of

the

abnormality

may

be

due

to

drop

in

the

playback

output

caused

by

drop

in

the

efficiency

of

the

cassette

used

or

head

clogging.

Refer

to

"Head

Playback

Output

Voltage

Check"

as

a

means

to

judge

the

abnormality.

Display

panel

Head

output

drop

warning

display

(Tape

counter

“1st

digit

of

Minutes."

position)

=36

Head

playback

output

voltage

check

Cassette

Used

Cassette

with

normal

playback

output

Recorded

cassette

(with

tabs)

Rental

cassette

(without

tabs)

Warning

Display

Envelope

Detection

Output

Voltage

Envelope

detec-

tion

output

(IC301

25

or

R3032

Mark

side:

see

Fig.

2-1-1)

Switching

pulse

(TP

183:

see

Fig.

2-1-2)

Envelope

detec-

tion

output

(iC301

25

or

R3032

Mark

side:

see

Fig.

2-1-1)

Switching

pulse

(TP183:

see

Fig.

2-1-2)

av

Envelope

detec-

tion

output

,

(IC301

25

or

R3032

Mark

side:

see

Fig.

2-1-1)

Switching

pulse

(TP183:

see

Fig.

2-1-2)

Envelope

detec-

tion

output

(IC301

25

or

R3032

Mark

side:

see

Fig.

2-1-1)

Switching

pulse

(TP

183:

see

Fig.

2-1-2)

t

f__

0.5~0.95V

t

=¥

More

than

0.95V

+

Less

than

4

0.5V

Main

Cause

When

the

output

voltage

differ-

ence

of

the

two

channels

is

0.5

to

0.95V

¢

The

video

heads

of

both

are

normal

When

the

output

voltage

differ-

ence

of

the

two

channels

is

more

than

0.95V

¢

Tracking

adjustment

has

not

been

performed

accurately

‘e

One

video

head

is

clogged

¢

One

video

head

has

worn

out

When

the

average

output

volt-

age

of

the

two

channels

is

less

than

0.5V

¢

Tracking

adjustment

has

not

been

performed

accurately

¢

Both

video

heads

are

clogged

¢

Both

video

heads

have

worn

out

When

the

output

voitage

dif-

ference

of

the

two

channels

is

more

than

0.95V

¢

Tracking

adjustment

has

not

been

performed

accurately

¢

One

video

head

is

clogged

¢

One

video

head

has

worn

out

¢

Some

rental

cassettes

may

have

extremely

low

video

playback

outputs

even

when

both

video

heads

are

normal.

As

the

average

output

voltage

of

the

two

heads

may

be

less

than

0.5V

for

some,

no

warning

displays

will

be

shown.

.

Cylinder

rotation

accumulated

time

display

@

*

Press

the

STOP

button

on

the

remote

control

for

approximately

10

seconds

and

the

cylinder

rotation

accumulated

time

excluding

the

cassette

out

and

standby

operation

time

will

be

displayed

on

the

"Hours"

display

in

units

of

100

hours.

("33"

will

be

displayed

for

10

seconds

for

3,200

to

3,299

hours.)

¢

To

erase

the

cylinder

rotation

accumulated

time

display,

press

the

RESET

button

on

the

remote

control

during

the

accumulated

time

display.

Display

panel

Cylinder

rotation

accumulated

display

(Tape

counter

"Hours"

display)

|g

1

DISASSEMBLY

:

1-1.

REMOVAL

OF

CABINET,

MECHANISM

UNIT,

AND

MAIN

BOARD

3S

REMOVING

THE

CABINET

PARTS

(Fig.

1-1-1)

1.

Remove

the

cabinet

and

bottom

cover

by

removing

the

four

screws

(1)

and

four

screws

@).

Remove

the

front

panel

by

removing

the

locks

of

the

clamps

(A)

using

a

screwdriver,

etc.

and

slightly

rotating

the

bottom

part

in

the

direction

of

the

arrow.

Notes:

«

Electrical

adjustments

for

the

this

model

can

be

performed

with

only

the

cabinet

removed.

¢

When

replacing

the

bottom

cover,

do

not

tighten

the

screws

@

too

much.

Excess

tightness

may

damage

the

screws

taps

on

the

chassis.

REMOVING

THE

MECHANISM

MAIN

UNIT

AND

THE

CP-1

PWB

ASSEMBLY

(Fig.

1-1-2

and

1-1-3)

After

removing

the

cabinet

parts,

remove.the

mechanism

unit

and

the

CP-1

PWB

assembly

connected

as

follows.

_

M-MP2N/G-1

®

@s

Pe

Clamps(A)

Front

Panel

Spread

out

the

lock

clamps

(C)

in

the

arrow

direction

slightly

and

remove

the

TM-1

PWB

as

shown

in

Fig.

1-1-2.

Remove

the

screw

@

at

the

chassis.

Remove

the

screw

©)

in

the

chassis,

the

screw

©,

and

the

holder

in

this

order.

Remove

the

two

screws

(2

and

two

screws

®

of

the

mechanism

unit.

The

two

screws

(8)

of

the

cassette

tray

can

be

removed

easily

by

pushing

the

tray

lock

lever

in

the

arrow

direction

to

remove

the

lock

as

shown

in

the

enlarge

view

A

and

by

pushing

the

lid

opener

lever

in

the

arrow

direction

to

remove

the

lock

as

shown

in

the

enlarge

view

B.

Lift

up

the

whole

mechanism

unit

and

main

board

(CP-1

PWB

assembly),

and

as

shown

in

Fig.

1-1-3,

push

the

two

lock

clamps

(D)

of

the

chassis

in

the

arrow

direction

so

that

they

can

be

removed

from

the

chassis.

Cabinet

Main

Unit

Bottom

Cover

Fig,

1-1-1

Fig.

1-1-2

ao

9

1-2.

TEMPORARILY

SETTING

UP

AND

CONNECTING

CP-1

PWB

ASSEMBLY

The

following

is

an

example

of

how

to

place

and

connect

the

main

board

without

a

jig,

when

repairing

the

CP-1

PWB

assembly.

1.

Place

the

mechanism

unit

and

main

board

up

side

down

as

2.

Operete

the

unit

using

the

buttons

on

TM-1

PWB

or

the

a

whole

on

a

flat

surface

with

foil

side

of

the

main

board

remote

control.

facing

up.

M-PF2LN/TA-4

CP-1

PWB

Assembly

(Foil

side)

Terminal

Boord

TM-1

PWB

Cassette

Compartment

Mechanism

Main

Unit

1-3.

INSTALLATION

OF

THE

FRONT

PANEL

When

installing

the

front

panel

to

the

chassis

after

repaires

and

adjustments.

1.

Pressing

down

the

door

opener

lever

of

the

mechanism

Note:

Opened

cassette

door

position

does

not

install

the

front

main

unit.

panel

to

the

chassis.

2.

Set

the

cassette

door

to

half-opened

state

as

shown

in

Fig.

1-1-5,

and

install

the

front

panel

to

the

chassis.

M-MA4/U-5

Jutted

part

of

Cassette

Holder

Front

Panel

Cassette

Door

(Position

A)

Cassette

Door

(Position

B)

Fig.

1-1-5

1-4.

CIRCUIT

BOARD

LOCATIONS

L-MP4H/G3,

SP2

VHR-757G,

VHR-757EX,

VHR-757NL

3

in

1

Tuner

(Tuner/IF/RF

Conv.)

TN-3

PWB

for

VHR-757G

&

VHR-757NL

TN-5

PWB

for

VHR-757EX

TM-1

PWB

VHR-777EV,

VHR-777EX,

VHR-797SP

3

in

1

Tuner

(Tuner/IF/RF

Conv.)

AD-5

PWB

for

VHR-797SP

TN-3

PWB

for

VHR-777EV

TN-5

PWB

for

VHR-777EX

TN-6

PWB

for

VHR-797SP

TB-2

PWB

-

for

VHR-797SP

VP-1

PWB

Assembly

A

CP-1

PWB

Assembly

TM-8

PWB

for

VHR-757G

TM-9

PWB

for

VHR-757EX

&

VHR-757NL

VP-1

PWB

Assembly

A

CP-1

PWB

Assembly

x

)

2.

ELECTRICAL

ADJUSTMENT

VCR

PRESETTING

This

VCR

need

three

basic

presetting

by

using

the

menus

displayed

on-screen.

After

all

connection

have

been

made,

then

follow

steps

1

to

3

to

preset

the

VCR.

The

three

presetting

steps

will

be

displayed

in

sequence

on

TV

screen.

The

setting

are

entered

with

the

remote

control.

Turn

on

the

VCR

1.

Adjusting

the

TV

receiver

to

the

video

channel:

The

AUTO

SETUP

screen

will

appear.

When

the

video

channel

has

been

preset,

press

the

OK

button

on

the

remote

control.

2.

Country

selection:

Using

the

numeric

button,

select

the

country

of

use.

3.

Language

selection:

When

the

desired

language

has

been

select,

press

the

MENU/TV

button

directly

before

prevent

auto

tuning

will

start.

When

steps

1

to

3

have

been

finish,

ready

to

operate

the

all

operating

mode.

2-1.

SERVO

CIRCUIT

ADJUSTMENT

*

These

adjustments

should

be

done

upon

completion

of

the

tape

transport

adjustments.

e

If

the

tape

transport

adjustments

(except

the

tilt

adjustment)

are

done

after

these

adjustments,

follow

the

procedures

again

in

X

section

2-1-3,

"Switching

position

adj."

*

When

a

cassette

tape

is

loaded,

auto-tracking

will

be

set

immediately

after

starting

the

first

playback.

As

this

will

daviate

the

tracking

center

set,

be

sure

to

press

the

channel

buttons

(++)

and

(—)

once

directly

after

starting

playback

to

prevent

auto-tracking

from

being

set.

2-1-1.

TEST

EQUIPMENT

AND

STANDARDS

REQUIRED

Oscilloscope

Vertical

sensitivity

:

5

mV/DIV,

external

trigger

Bandwidth

:

more

than

10

MHz

Alignment

Tape

VHJ-0009

or

VHJ-0023

=:

SP

mode,

monoscope,

6

KHz

Blank

Tape

VHS-type

cassette

tape

Monitor

TV

2-1-2.

LOCATION

OF

ADJUSTMENT

POINTS

P12000B

A)

E

CP-1

PWB

(Foil

side)

Fig.

2-1-1

P66300D

TP183.-

TP182

(SW-P)

(ENV.

©®

=

a

VP-1

PWB

Assembly

Fig.

2-1-2

2-1-3.

SWITCHING

POSITION

ADJ.

[Measuring

Point

|

Measuring

Equipment

|

Adj.

Condition

TP101

PLAY

(SP)

mode

(VIDEO

OUT)

Alignment

tape

TP183

(SW-P)

(VHJ-0009

or

VHJ-0023)

Adj.

Value

|

6.5H+0.5H

1.

Play

back

the

alignment

tape.

2.

Set

the

tracking

control

position

to

the

center

by

pressing

CHANNEL

buttons

(++)

and

(—)

simultaneously.

3.

Adjust

VR351

(SW-P)

so

that

the

width

of

"T”

becomes

6.5

H

+

0.5

H

as

shown

in

Fig.

2-1-3.

Oscilloscope

Adj.

Location

VR351

(SW-P)

WS-SWP

T=6.5H

£0.5H

TL

nine

Front

edge

of

vertical

sync

signal

\

t

Rise

RF.SW.PULSE

Fig.

2-1-3

~10-

Sanyo VHR-757G User manual

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