JVC TD-V711 User manual

TD-V711

A/B/C/E/G/J/

_

SERVICE

MANUAL

Contents

Page

[1]

Safety

Precautions

....0..0.ccccccccceeseseteerreee

2

[10]

Location

of

P.C.

Board

Parts

and

Parts

List

Specifications

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3

Main:

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22

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16

[3]

Location

of

Main

Parts

.......

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¢

visas

oeseh

Cente

vase

4

Power

Supply/Mechanism

Control

...............5..

20

[4]

Location

of

Control

.........

saaggetagas

eee

ES

[14]

Exploded

View

of

Mechanism

Assembly

Parts

Removal

of

Main

Parts

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

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wu

and:

Parts:

Listisi

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Sui

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ts

22

[6]

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20...

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[12]

Exploded

View

of

Enclosure

Assembly

Parts

[7]

Block

Diagram

......ccccccccccccccssecesseseesecesevssecsvese

12

and

Parts

List

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

cece

Ledisaantet

totes:

24

[8]

Wiring

oo...

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‘ggasasanee

ges

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13

[13}

Packing”

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28

[9]

Standard

Schematic

Diagram

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

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4

[14]

ACCOSSONES

is.

sonic

Ai

Seis

sasseatieeaas

certian

ooadadasee

ed

No.

4294

March

1988

TD-V711

A/B/C/E/G/J/U

[1]

Safety

Precautions

1.

The

design

of

this

product

contains

special

hardware

and

may

circuits

and

components

specially

for

safety

pur-

poses.

For

continued

protection,

no

changes

should

be

made

to

the

original

design

unless

authorized

in

writing

by

the

manufacturer.

Replacement

parts

must

be

identical

to

those

used

in

the

original

circuits.

Service

should

be

performed

by

qualified

personnel

only.

2.

Alterations

of

the

design

or

circuitry

of

the

product

should

not

be

made.

Any

design

alterations

of

the

product

should

not

be

made.

Any

design

alterations

or

additions

will

void

the

manufacturer’s

warranty

and

will

further

relieve

the

manufacturer

or

responsibility

for

personal

injury

or

property

damage

resulting

therefrom.

3.

Many

electrical

and

mechanical

parts

in

the

product

have

special

safety-related

characteristics.

These

characteristics

are

often

not

evident

from

visual

inspection

nor

can

the

protection

afforded

by

them

necessarily

be

obtained

by

using

replacement

components

rated

for

higher

voltage,

wattage,

etc.

Replacement

parts

which

have

these

special

safety

characteristics

are

identified

in

the

Parts

List

of

Service

Manual.

Electrical

components

having

such

features

are

identified

by

(A\)

on

the

schematic

diagram

and

Parts

List

in

Service

Manual.

The

use

of

a

substitute

replacement

which

does

not

have

the

same

safety

characteristics

as

the

recommended

replace-

ment

part

shown

in

the

Parts

List

in

Service

Manual

may

create

shock,

fire,

or

other

hazards.

4.

The

leads

in

the

products

are

routed

and

dressed

with

ties,

clamps,

tubings,

barriers

and

the

like

to

be

separated

from

live

parts,

high

temperature

parts,

moving

parts

and/or

sharp

edges

for

the

prevention

of

electric

shock

and

fire

hazard.

When

service

is

required,

the

original

lead

routing

and

dress

should

be

observed,

and

it

should

be

confirmed

that

they

have

been

returned

to

normal,

after

re-assembling.

5.

Leakage

current

check

(Electrical

shock

hazard

testing)

After

re-assembling

the

product,

always

perform

an

isolation

check

on

the

exposed

metal

parts

of

the

product

(antenna

terminals,

knobs,

metal

cabinet,

screw

heads,

headphone

jack,

control

shafts,

etc.)

to

be

sure

the

pro-

duct

is

safe

to

operate

without

danger

of

electrical

shock.

Do

not

use

a

line

isolation

transformer

during

this

check.

©

Plug

the

AC

line

cord

directly

into

the

AC

outlet.

Using

a

‘‘Leakage

Current

Tester’’,

measure

the

leakage

current

from

each

exposed

metal

part

of

the

cabinet,

particularly

any

exposed

metal

part

having

a

return

path

to

the

chassis,

to

a

known

good

earth

ground.

Any

leakage

current

must

not

exceed

0.5

mA

AC

(r.m.s.).

e

Alternate

check

method

Plug

the

AC

line

cord

directly

into

the

AC

outlet.

Use

an

AC

voltmeter

having

1,000

ohms

per

volt

or

more

sensitivity

in

the

following

manner.

Connect

a

1,500

©

10

W

resistor

paralleled

by

a

0.15

»F

AC-type

capacitor

between

an

exposed

metal

part

and

a

known

good

earth

ground.

5

f

AC

VOLTMETER

Measure

the

AC

voltage

across

the

resistor

with

the

AC

Peary

(Having

1000

ohms/volt

voltmeter.

or

more

sensitivity.)

Move

the

resistor

connection

to

each

exposed

metal

part,

particularly

any

exposed

metal

part

having

a

return

path

to

the

chassis,

and

measure

the

AC

voltage

across

the

resistor.

Now,

reverse

the

plug

in

the

AC

outlet

and

repeat

each

measurement.

Any

voltage

measured

must

not

exceed

0.75

V

AC

(r.m.s.).

This

corresponds

to

0.5

mA

AC

(r.m.s.).

0.15

wF

AC

TYPE

Place

this

probe

c

on

each

exposed

1500

2

10

W

metal

part.

Good

earth

ground

Warning

.

This

equipment

has

been

designed

and

manufactured

to

meet

international

safety

standards.

.

It

is

the

legal

responsibility

of

the

repairer

to

ensure

that

these

safety

standards

are

mainteined.

.

Repairs

must

be

made

in

accordance

with

the

relevant

safety

standards.

.

It

is

essential

that

safety

critical

components

are

replaced

by

approved

parts.

.

If

mains

voltage

selector

is

provided,

check

setting

for

local

voltage.

ahWN

=

2

(No.

4294)

2)

Specifications

Type

Track

system

Tape

speed

Frequency

response

S/N

ratio

Improvement

of

MOL

Wow

and

flutter

Channel

separation

Crosstalk

Harmonic

distortion

Heads

Motors

:

Stereo

cassette

deck

:

4-track,

2-channel

:

1-7/8

inch/sec

(4.8

cm/sec)

:

(—

20 dB

recording)

Metal

tape;

10—22,000

Hz

15—20,000

Hz

(+3

dB)

Chrome

tape;

10—20,000

Hz

15—

18,000

Hz

(+3

dB)

Normal

tape;

10—20,000

Hz

15—18,000

Hz

(+3

dB)

:

59 dB

(S=1

kHz,

K3=3%

N=A-weighted,

Metal

tape)

The

S/N

is

improved

by

about

15

dB

at

500

Hz

and

by

max.

20

dB

at

1

kHz

~

10

kHz

with

Dolby

C

NR

on

and

improved

by

5

dB

at

1

kHz

and

by

10 dB

at

above

5

kHz

with

Dolby

B

NR

on.

:

4

dB

at

10

kHz

with

Dolby

C

NR

on.

:

0.022%

(WRMS)

:

40

dB

(1

kHz)

:

65

dB

(1

kHz)

:K3;

0.5%

THD;

1.0%

(metal

tape,

1

kHz

O

VU)

:

Erase

(2-Gap

Ferrite)

x

1,

Record

(Sen-Alloy)

x

1,

Playback

(Amorphous

Ferrite)

x

1

:

Pulse

servo

direct

drive

motor

for

capstan

x

1

DC

motor

for

reel

x

1

DC

motor

for

mechanism

drive

x

1

Fast

forward/Rewind

time

Imput

terminals

CD

DIRECT

(x

1

circuit)

DIRECT

(x

1

circuit)

LINE

IN

(x

1

circuit)

Output

terminals

LINE

OUT

(x

1

circuit)

PHONES

x

1

Other

terminals

Power

requirement

TD-V711A/B/E/G

TD-V711C/J

Power

consumpiton

Dimensions

(W

x

H

x

D)

Weight

Accessories

TD-V711

A/B/C/E/G/J/U

:

Approx.

95

sec.

with

C-60

cassette

:

Min.

input

level;

80

mV

Input

impedance;

50

kQ

:

Min.

input

level;

80

mV

Input

impedance;

50

kQ

:

Min.

input

level;

80

mV

Input

impedance;

50

kQ

:

Output

level;

300

mV

Output

impedance;

600

2

:

Output

level;

O~

1

mW/8

Q

Matching

impedance

82

—

1k2

:

COMPU

LINK-1/SYNCHRO

x

2

:

AC240/220/120

V,

50/60

Hz

:

AC

120

V,

60

Hz

:18W

>475

x

132

x

336mm

(18-3/4""

x

5-1/4"

x

13-1/4’’)

:

8.3

kg

(18.4

Ibs)

:

plug

cord

.............:.c08

2

Remote

cable

...............06

1

Design

and

specifications

are

subject

to

change

without

notice.

(No.

4294)

3

TD-V711

A/B/C/E/G/J/U

4

3)

Location

of

Main

Parts

Main

Board

Ass’y

Power

Switch

Power

Supply/

Power

Cord

Mechanism

Control

Board

Ass’y

input

Select

Switch

Main

Board

Ass’‘y

Power

Transformer

=

A

ae

I

>

i, ss

mn.

Volume

(Input)

q

Power

Switch—e

/

Remote

Bar

“EE

Leaf

Switch

Board

Ass’y

BIAS/BALANCE

Mechanism

Ass’‘y

Volume

Board

Ass’y

'

H.

Phones

Board

Ass’y

H.

Phones

Board

Ass‘y

Power

Supply/

Mechanism

Control

Board

Assy

Cam

Motor

Reel

Motor

Cam

Switch

Board

Cam

Motor

Ass’y

Reel

Motor

Ass’y

PB

Head

REC

Head

Pinch

Roller

E.

Head

DD

Motor

Ass’y

Pinch

roller

Fig.

3-1

(No.

4294)

4)

Location

of

Controls

TO-V711

STEREO

CASSETTIIDECK

@

TIMER

switch

When

an

optional

timer

is

used,

recording

and

playback

can

be

performed

at

any

desired

time.

@

POWER

switch

©

Cassette

holder

@

MULTI

MODE

display

(See

Fig.

4-2)

Tape

remaining

time

display

MEMORY

indicator

PEAK

LEVEL

METER

Recording

guide

indicator

Digital

peak

indicator

Tape

indicator

Digital

counter

Tape

length

indicator

Mechansim

mode

indicator

HX

PRO

indicator

NR

DEFEAT

indicator

MPX

Filter

indicator

DOLBY

NR

mode

indicator

Monitor

indicator

@

INPUT

LEVEL

control

Adjust

the

recording

level

with

this

control.

@

EJECT

button

Press

to

open

the

cassette

holder.

@

PHONES

jack

connect

headphones

(with

an

impedance

of

8

ohms

to

1

kohm).

@

PHONES

LEVEL

control

@

DOLBY

NR

switches

Set

to

ON

for

recording

using

the

Dolby

NR

SYSTEM

or

for

playback

using

the

Dolby

NR

system.

Set

to

OFF/DEFEAT

when

the

Dolby

NR

system

is

not

used.

@

Dolby

HX

PRO

switch

POWOQVOMWOOOONWO)

Fig.

4-1

@

MPxX

FILTER

siwtch

The

MPX

filter

functions

when

the

tape

is

recorded

using

the

Dolby

NR

system.

Normally,

set

this

switch

to

OFF.

When

an

FM

stereo

broadcast

is

to

be

recorded

using

Dolby

NR,

set

this

to

ON

to

prevent

the

Dolby

NR

circuit

from

malfunctioning

(otherwise

the

sound

quali-

ty

could

deteriorate).

@

INPUT

SELECT

switches

and

indicators

Press

these

to

set

to

the

inpujt

you

want

to

record.

The

corresponding

indicator

will

ight:

CD

DIRECT:

When

recording

directly

from

a

CD

player.

DIRECT:

When

recording

directly

from

other

equipment.

LINE:

When

recording

from

a

stereo

amplifier.

@®

MONITOR

button

When

recording,

set

to

SOURCE

to

monitor

the

sound

just

before

it

is

recorded.

Set

to

TAPE

to

monitor

the

sound

recorded

on

the

tape.

@®

BIAS

adjust

control

Adjust

recording

bias

according

to

the

characteristics

of

the

tape

used

for

recording.

@®

BALANCE

control

Adjusts

the

balance

between

the

signals

input

via

the

left

and

right

LINE

IN

jacks.

@

RESET

button

Press

to

reset

the

tape

counter

to

‘‘O0000’’.

@

DISPLAY

button

Select

the

mode

of

the

digital

counter.

The

tape

counter

will

be

indicated

when

the

power

is

first

switched

on.

Press

this

button

to

select

the

tape

remaining

time

display.

dis

-—30

20]

15

12

10

TD-V711

A/B/C/E/G/J/A

LEFY

Sie

It

RIGH}

C300

C

@®

TAPE

LENGTH

button

use

this

button

when

you

want

to

check

the

remaining

tape

time.

The

remaining

time

must

be

displayed

in

the

digital

counter

before

setting

the

tape

length

(e.g.,

C-60).

@®

MEMORY

button

Use

this

button

to

specify

the

position

at

which

you

want

the

tape

to

stop

in

rewind,

etc.

@)

CALL

button

(Digital

peak)

Press

to

call

up

the

stored

peakm

level

or

reset

the

memory.

@

Cassette

operation

buttons

<<

(Rewind):

Press

to

rewind

the

tape.

PLAY:

Press

to

start

recording/playback.

Press

this

but-

ton

with

either

the

<<

or

®®

button

for

music

scanning.

bP

(fast

forward):

Press

to

fast

forward

the

tape.

@

(stop):

Press

to

stop

the

tape.

©

REC/REC

MUTE:

Press

the

PLAY

button

while

pressing

this

button

to

start

recording,

and

press

to

leave

an

ap-

propriate

non-recorded

section.

Hi

(pause):

Press

to

stop

the

tape

temporarily.

Press

the

PLAY

button

to

release

the

pause

mode.

Press

this

together

with

O

REC/REC

MUTE

button

before

starting

recording

to

enter

the

record-pause

mode.

Fig.

4-2

(No.

4294)

5

TD-V711

A/B/C/E/G/J/U

[5]

Removal

of

Main

Parts

Cabinet

Section

@

Top

Cover

1)

Remove

four

screws

on

both

sides.

2)

Remove

two

screws

fixing

the

back.

@

Bottom

Cover

1)

Remove

six

screws

@)

and

a).

[Main/power

source

base

parts

can

be

replaced

in

this

condition]

@

Front

Plate

1}

Remove

INPUT

LEVEL

voiume

knob

and

BIAS/BALANCE

knob.

2)

Remove

five

screws

(2)

fixing

the

front

panel.

@

Front

Panel

Ass‘y

1)

Remove

power

switch

knob.

2)

Remove

switch

side

of

input

switch

remote

bar

and

remove

knob.

3)

Pull

input

volume

remote

bar

inside

and

remove

from

front

panel.

4)

Remove

two

screws

(3)

fixing

the

center

chassis

from

the

front.

5)

Remove

four

screws

(4)

on

both

sides.

6)

Remove

wires

if

necessary.

@

Removal

from

Front

Panel

Mechanism

Ass‘y

1)

Remove

two

screws

fixing

mechansim

ass’y

top.

2)

Remove

LED

lead

soldering

on

leaf

switch

base.

3)

Remove

two

screws

6)

fixing

mechanism

ass’y

bottom.

4)

Open

cassette

door

and

remove.

Timer

Switch

Remove

four

pawls

(A)

fixisng

the

switch

base.

Headphone

jack

Base

1)

Pull

out

output

volume

knob.

2)

Remove

nut

fixing

the

jack.

3)

Remove

volume

bracket,

push

up

volume

shaft

and

remove

from

groove.

Volume

Base

1)

Remove

two

pawls

fixing

the

BIAS

adjustment

volume/BALANCE

volume

base.

Display,

DOLBY

B/C NR,

HX,

MPX

Switch

Base

1)

Remove

two

scrws.

@)

fixing

the

switch.

2)

Remove

six

pawls

©)

fixing

the

base.

Inside

view

Fig.

5-4

Switch

Base

Ass’y

Remove

pawl

©)

,

then

remove

five

pawls

©

pawls

from

(©)

side

in

order.

Push

base

from

front

panel

hole

for

easier

removal.

(No.

4294)

6

Mechansim

Section

@

Head

parts

1)

To

remove

head

block,

remove

three

screws

@)

3)

.

2)

To

remove

erasing

head,

remove

one

screw

3)

To

remove

playback

head,

remove

three

special

nuts

(5)

;

then

remove

playback

head

base

and

remove

two

screws

Caution:

A

spring

will

come

off

when

removing

playback

head.

4)

To

remove

record/playback

head.

(1)

Remove

playback

head.

(2)

Remove

three

screws

M®Ee

fixing

record/playback

head.

Caution:

Springs

@@)

are

the

same

and

@)

is

different.

(Springs

Q)

and

6)

are

the

same)

@

DD

Motor

Ass’y

1)

Remove

two

screws

;

2)

Remove

two

screws

from

both

sides

of

the

chassis.

3)

Slide

idler

to

right

and

lift

chassis

to

remove.

@

Cam

Motor

Remove

two

screws

a2

a3

‘

@

Reel

Motor

Remove

two

screws

(5)

:

@

Cam

Switch

1)

Remove

one

screw

:

2)

Slide

brake

and

pull

out.

(Cautions

for

assembling)

(1)

Align

car

gear

and

cam

switch

holes.

(2)

Head

base

arm

stud

must

match

cam

switch

gear

groove.

@

Pinch

Roller

1)

Remove

left

hexagon

nut

a?

,

2)

Remove

arm

hooked

on

chassis

on

right.

(Only

push

arm

as

required

to

remove)

®

is

playback

head

in-

Stalling

position

adjusting

.

screw.

(to

move

playback

Fig.

5-5

head back

and

forth)

Brake

(Slide

position)

Push

arm

to

remove

(Only

push

as

required

to

remove)

Fig.

5-8

TD-V711

A/B/C/E/G/J/U

16]

Main

Adjustment

1.

Measuring

instruments

required

for

adjustment

(1)

Audio

frequency

oscilloator

(5)

Recording

standard

tape

(range:

50~20

kHz

and

output

OdB

with

6000

TS-9(UDI),

TS-6(SA),

TS-7(ME)

or

the

like.

impedance)

(use

standard

tape

specified

by

Victor)

(2)

Attenuator

(impedance

600

)

(6)

Resistors

600

Q

(attenuator

matching)

(3)

Electronic

voltmeter

(7)

Distortion

gauge

(band

pass

filter)

(4)

Standard

tape

(8)

Torque

gauge

(cassette)

CTG-N

mechanical

adjusting.

VTT712

(Tape

speed,

wow

and

flutter

check)

(9)

Wow

and

flutter

gauge

VTT724

(reference

level)

(10)

Frequency

counter

VTT739

(for

playback

frequency

characteristics)

(11)

M300

gauge

VMT6447

(music

scanning)

TMT6448

(music

scanning)

TMT702

(14

kHz)

2.

Mechanical

Adjustment

When

replacing

head,

check

the

height,

direction

and

tilt

(rough

adjustment)

of

each head

as

follows.

Tape

travel

adjustment

Use

tool

M300.

Be

careful

not

to

damage

head.

Tape

guide

adjustment

Tilt

adjustment

Reflector

position

(guide

post)

Reflector

position

(guide

post)

Guage

moving

direction

Le

Fig.

6-1

Fig.

6-2

(No.

4294)

7

TD-V711

A/B/C/E/G/J/U

\

Fly

wheel

and

thrust

check

Check

by

feeling

Back

tension

rubber

position

check

At

PLAY,

back

tension

rubber

should

touch

supply

wheel

to

stop

wheel.

At

MS/Stop,

back

tension

rubber

should

not

touch

supply

wheel.

Supply

disk

Back

tension

rubber

3

|

Pinch

roller

fastening

Right

pinch

roller

should

fasten

to

capstan

shaft

order

check

before

left

pinch

roller.

4

|

Pinch

roller

guide

Use

M300

gauge

and

adjust

@

so

that

3.8

mm

height

adjustment

gauge

can

pass.

5

|

Playback

head

height

1)

Use

M300

gauge

and

adjust

playback

head

Pinch

roller

and

tilt

adjustment

tape

guide

with

screw

so

that

3.8

mm

guide

height

gauge

can

pass.

Head

guide

adjustment

2)

Adjust

©

screw

so

that

playback

head

is

not

height

j

db

tilted

and

that

there

is

no

gap

between

the

~~

i

gauge

and

head.

3)

Gaugbe

will

touch

gap

face,

adjust

carefully.

Hold

a

flash

light

from

the

opposite

side

and

check

for

light

leakage.

4)

Re-check

guide

height.

If

gauge

touches,

re-adjsut

upper

1),

2).

Playback

head

tilt

adjustment

Playback

TMT7008

(14

khz)

and

adjust

screw

(0)

to

maximum

output

position

with

no

phase

difference.

Playback

azimuth

adjustment

Tape

travel

check

Recording

head

height,

tilt.

Azimuth

adjustment

Use

C-90

padded

tape

and

check

that

tape

head

is

not

curled

at

beginning

of

wind.

Use

mirror

tape

to

check

tape

travel.

1)

Record

and

playback

10

kHz

and

adjust

screw

to

maximum

output

position

with

no

phase

difference.

(azimuth

adjustment)

2)

Record

and

playback

10

kHz

and

adjust

screw

to

maximum

output

position

with

no

phase

difference.

(height

adjustment)

3)

use

M300

gauge

and

adjust

recording

head

tilt

with

screw

@)

following

the

procedure

for

adjusting

playback

head

tilt.

4)

Record

and

playback

10

kHz

and

re-adjust

Recording

head

azimuth

adjusting

screw

(E)

to

maximum

out-

nitadjustnent

put

position.

Match

L/R

phases.

8

(No.

4294)

TD-V711

A/B/C/E/G/J/U

Head

position

Use

M300

gauge

and

adjust

so

that

playback

head

is

in

front

of

recording

head.

Other

standards

are

as

follows.

The

measurements

are

as

against

guide

post

(H).

a=3.1~4.0

Playback

{¢7

3149

Guide

Post

MS

a=4.4~5.1mm

b=0.05~0.35

d=0.2~0.3

mm

9=0°

E

Head

R

Head}ip

B

Head

d

Bend

and

adjust

head

base

so

that

a

is

within

4.4~5.1

mm

at

MS.

al

Adjusting

part

-|

=

Head

position

adjustment

Adjust

screw

®)

so

that

playback

head

is

“‘b’’

measurement

in

front

of

recording

head.

[re-adjust

playback,

recording

azimuth

after

adjusting

@).1

Excessive

Insufficient

Bend

in

#

direction

("]

Bend

in

$

direction

Ht

After

this

adjustment,

check

Item

.

Controls

clearance

between

head

base

and

door

safety

when

door

safety

is

pulled

in

the

direction

of

the

arrow

at

STOP.

Checkling

door

safety

Head

base

Door

safety

lever

3.

Electric

Circuit

Adjustment

Location

Main

Amplifier

Base

(parts

side)

Playuback

F

special

adjustment

O

VRI01

Playback

level

[vrioz

adjustment

'

'Record/Playback

bias

Playback

F

’

frequency

Sdjustment

special

adjustment

Dyvrz02

Playback

level

(yvrzo1

VR903

adjustment

Note:

The

record

a

1

kHz,

—

20

dB

signal

is

reference

VR401

level

(—

8

dBs)

level,

so

oO

Rech

|

Record/Playback

—

20

dB

is

fow

level.

Ctch

sensitivity

adjustment

i

Ref.

Record/

level

20

dB

Papecial

H

t

—

20

dB

wo

a

(oom

&

O

z

o

6

F

'

i)

{901

C35!

Meter

adjustment

AMP

P.C.

Board

Fig.

6-3

(No.

4294)

9

TD-V711

A/B/C/E/G/J/U

|

4.

Electrical

Circuit

Adjustment

Conduct

following

adjustments

after

adjusting

tape

travel

and

head

angle.

¢

Adjust

in

the

following

order.

¢

*

marks

must

be

adjusted

when

replacing

head.

Notice:

0

dBs

=

0.775V

Adjustment

and

checking

methods

;

Dolby

fee

=

eee

|

Frequency

level

Output

value

and

deviation

recording

sored

(=Cal.

Level)

;

Adjusting

Standard

Playback

level

|

1)

Playback

VTT724

(1

kHz)

and

adjust

|VR102,

Adjust

playback

level

when

VR102,

202

so

that

LINE

OUT

out-

202

replacing

head.

put

is

—

8

dBs.

(L—R

channel

output

Electronic

voltmeter

impedance

difference

should

be

within

0.5

dBs)

should

be

over

100

kQ.

2)

Check

headphone

output

(headphone

10

kHz

VR

...

maximum)

—

15

dBs+3

dB,

L—R

difference

VR101,

201

0.5+0.5

dB

L901

95

kHz

+1

kHz

within

2

dB.

Playback

test

tape

VTT739

(1

kHz,

L304,

404

Playback

equalizer

With

1

kHz

as

reference

NR

:

OFF

63

Hz

:

+2

dB+3

dB

(Check)

10

kHz)

and

adjust

VR101,

201

so

that

1

kHz,

10

kHz

output

is

at

standard

value.

TAPE

:

METAL

(fix

needle

to

gaugbe

lead

end

and

plug

to

connector

socket)

Connect

1

MQ

to

F.

counter

and

adjust

L901

so

that

CN

3 5

output

is

95

kHz.

At

METAL

poisiton

recording

mode,

ad-

just

L304,

L404

so

that

R354

and

R454

end

voltages

are

minimum.

Record

1

kHz

at

ref

—

20

dBs

input

and

then

record

50

Hz,

12.5

kHz.

Playback

and

adjust

302,

VR402

so

that

a

deviation

of

50

Hz,

12.5

kHz

against

1

kHz

is

at

standard

value.

(Basically,

adjust

so

that

1

kHz

and

12.5

kHz

out-

put

is

at

standard

value)

Bias

frequency

adjustment

HX

PRO

coil

adjustment

DC

voltmeter

Record/

Playback

frequency

characteristics

VR302,

402)With

1

kHz

bias

as

(VR904)

reference,

should

be

at/at

12.5

kHz

the

center.

|0.5+0.5

dB

(front

volume)

Ref

~—

20

dB:

—

20

GB

lowered

from

reference

input

value

=

—

28

dB

Adjust

normal,

left,

right

channels.

¢Bias

value

of

chrome

and

metal

tape

against

normal

tape

is

set

by

voltage

shift.

elf

bias

electric

current

is

not

adjusted

correctly

the

recor-

ding

characteristic

will

be

as

the

left

diagram.

High

frequency

rise

High

frequency

lowering

Response

(dB)

Excessive

bias

Insufficient

bias

electric

current

electric

current

-~~

Correct

value

of

bias

electric

current

Freqeuncy

t2.5kHz

10

(No.

4294)

JVC TD-V711 User manual

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