JVC PC-V77 Manuel utilisateur

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JVC

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~

Free

service manuals

Gratis

schema'

s

Digitized

by

IA'WW.frceservicemanuals.info

An

instruction

booklet

(B

/E/G

version)

is

provided

with

this

manual.

Contents

Page

Safety

Precautions

....

........

..........

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

2

Location

of

Main

Parts 3

Removal

of

Main

Parts

......

...

......

....

..

........

..

.....

4

Adjustment

.......

..

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

..

.......

....

...

.. .

.........

7

Block Diagram

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

..

......

.....

12

Wiring

Connections

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

14

Standard

Schematic

Diagram

..

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

........

.

15

Location

of

P.C. Board Parts and Parts

List

Tuner

P.C. Board Parts ..

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

...........

20

DIN Board

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

..

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

...

23

Page

Main

P.C. Boad parts

....

..........

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

......

...

24

DTS P.C. Board parts

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

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

..... 2B

~

Exploded

View

of

Speaker

Box

and

Parts

List

....

29

[jQ]

Exploded

View

of

Mechanism

Assembly

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

30

Mechanism

Component

Parts

List

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

.. 31

[ill

Exploded

View

of

Enclosure

Assembly

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

..

32

Enclosure

Assembly

Parts

List

....

........

..

.........

33

Im

Packing

and

Packing Parts

List

..

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

....

35

rrn

Accessories

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

.

......

..

Back

Cover

No.

1740-1

October

1987

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A

/B/E/G/UN

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Safety Precautions

1.

The

design

of

this

product

contains

special

hardware.

Many

circuits

and

compo

n

ents

specially

for

safety

purposes.

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 per-

formed

by

qualified

personnel

only

.

2.

Alterations

of

the

design or

circuitry

of

the

product

should

not

be made.

Any

design

alterations

or additions

will

void

the

manufacturer's

warranty

and

will

further

relieve

the

manufacturer

of

responsibi

l

ity

for

personal injury or pro-

perty

damage

resulting

therefrom.

3.

Many

electrical and

mechanical

parts in the

product

have

special

safety

-related

characteristics.

These

characteri

-

stics

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. El

ectrical

components

hav

-

ing such features are

identified

by

(Lt)

on the schematics

and

parts

list

in

Service

manual.

The

use

of

a

substitute

replacement

which

does

not

have

the same

safety

characteristics

as

the

recommended

replacement

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/

or

the

like

to

be

separated

from

live

parts,

high

temperature

part,

mov

-

ing

parts

and/

or

sharp

edges

for

the

prevention

of

elec-

tric

shock

and

fire hazard.

When

service

is required,

the

original lead

routing

and

dress

should

be

observed,

and

they

should

be

confirm

-

ed

to

be

returned

to

normal

,

after

re-assembling.

5. Leakage

current

check

(Safety

for

electrical

shock

hazard)

A

fter

re-assembling

the

product

,

always

perform an isola-

tion

check

on

the

exposed

metal

parts

of

the

Products

(antenna

terminals

,

knobs

,

metal

cabinet,

screw

heads,

earphone

jack

,

control

shafts,

etc.)

to

be sure

the

pro

-

duct

is safe

to

operate

without

danger

of

electrical shock.

2 (No.

1740)

Do

not

use a line

isolation

transformer

du

ring

this

check.

• Plug

the

AC line

cord

directly

into

the

AC

outlet.

Us-

ing 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

(water

pipe,

etc.).

Any

l

eakage

current

must

not

ex

-

ceed

0.5

mA

AC

(r.m.s.).

•

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

1500

{l

10

W

resistor

paralleled

by

a

0.15

/LF

AC-

type

capacitor

between

an exposed metal part and a

known

good

earth

ground

(water

pipe,

etc.)

Measure

the

AC

voltage

across

the

resistor

with

the

AC

voltmeter.

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.).

AC

VOLTMETER

(HAVING

1000

ON

,

OR

MORE SENSITIVITYI

0.1

5

/LF

AC

-TYPE

GOOD EARTH GROUND

PLACE THIS PROBE

ON EACH EXPOSED

METAL

PART

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Location of Main Parts

Main Board

---

Ass

'V

Speaker

Term

inal

Switch

SEA

Cover

Power Transformer

Fig

. 2-1

AMP

/SEA Board

Ass'V CD

Jack

Ass'v

INo.

1740)

3

PC-V77

A/B/E/G/

UN

Removal of Main Parts

Cabinet Section

• Replacing

the

fuse

Remove

the

rear

cabinet

the

replace fuse

• Replacing

the

telescopic antenna.

Remove

the

screw

®

at

rear

of

the cabinet

to

replace

the

T. antenna.

• Rear

cover

1) Remove

the

battery

cover.

2) Remove eight

screws

G), @ and @ retaining the rear

cabinet.

3)

Disconnect

the

connector

(CND

1)

on Din

Jack

Board.

(GN

version)

•

Amp.

Board/SEA

Board/3D

speaker

ass'y

1)

Remove

the

two

screws

@ securing

the

CD

in-jack

ass'y

.

2) Remove

the

volume

knob

.

3) Remove

the

Function/Tape

switch

knob.

4)

Pull and remove

the

SEA

volume

cover.

5)

Remove

the

five

screws

® and ® securing

the

board

ass'y

and 3D speaker

ass'y.

6)

Pull

the

entire

ass'y

slightly

,

then

remove

the

head wire,

motor

tuner,

etc.

• Tuner board ass'y

1)

Remove

the

wire

connector

for

the

tuner

board.

2) Pull

out

the

board ass'y.

•

Mechanism

ass'y

1)

Remove

the

six

screws

(j) .

2) Open

the

cassette

door

to

remove.

• For reassembly,

lift

the

cabinet

rear

slightly

for

easier

assembly

of

the

button

and

button

lever.

• LeD

indicator

ass'y

1)

Remove

the

two

screws

2) Remove

the

two

screws

4 (No.

1740)

securing

the

lamp

ass'y

.

securing the

LCD

board.

7

Fig. 3-1

Fig.

3-2

Fig. 3-3

7 7

Fig.

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• Cassette door

1)

Pull

the

lid up

to

remove.

2)

Remove the door spring.

3)

Close

the

door and remove the center

shaft

. Then remove

the

outer

shaft

and pull

out

toward

the

front

panel.

• SEA board

ass'y

1)

Remove

the

two

screws

@ securing

the

pre-amp

board.

2) Remove

the

four

screws

@ securing

the

SEA board.

(For reassembly, i

nsert

the

rec spring

into

the

switch

's

slider hole.)

• The parts on the

power

amp board can still be replaced.

Mechanism Section

(Top

View)

(Bottom

View)

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Free

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Fig.

3-6

•

Motor

bracket

(Recording/playback deck)

1) Remove

the

three

screws

G).

2) Remove the chassis and M.

bracket

from

the

button

side.

Then remove the

bracket

arm (panel).

(The

synchro

arm can be

removed

from

the

pause

lock

.

Return the pause

lock

after

it

is removed

from

the

pro-

per position.)

• Head

section

1) Remove the record/playback head's

mounting

screw

®

and loosen

screw

®.

2)

Remove

the

erase head

mounting

screw

• Pinch roller

1) Remove

the

pinch roller arm

stopper

E.

• Flywheel

ass'y

1)

Remove

the

C

washer

® securing

the

capstan

shaft.

2) Pull

out

the

flywheel

ass'y

.

Fig.

3-7

R~(.

PlilY

R

~

w

FF Stop

Pa

usf'

E

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~ct

Fig.

3-8

(No.

1740)

5

PC

-

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A/B/E/G/

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• Removal

of

the

button

ass'y

from

the

mechanical

chassis.

• Leaf

switch

Press

the

switch's

lock

panel and raise from

the

left

to

remove.

• Gear

IBelow

the

flywheel)

Remove

the

C

washer

@ securing

the

gear.

For reassembly,

insert

the

Sensing Lever arm stand

into

the ®

section

.

• Lock arm

Press

the

arm

stopper

from

window

®, and pull

to

remove.

• Chassis removal

1)

Remove

the

three

0,

®, and

Cl)

spring

s.

2)

Remove

the

two

screws

0.

3)

Remove

the

two

s

crews

® securing

the

capstan

metal.

4)

Gently

remove

the

button

ass'y

from

the

chassi

s.

6 INo.

1740)

Fig.

3-9

Fl

y

wh

eel

Fig. 3-

10

Fig. 3-11

Fig.

3-12

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Main Adjustment

• Amplifier adjustments

Conditions

Power

supply

voltages

: DC 12

V,

Timer

1.5

V SEA controls

Tape select

Tapes used

Input

levels

Output

levels

Item

Head azimuth

adjustment

Tape speed

adjustment

Checking

wow

&

flutter

Playback

output

level

Confirming

playback

frequency

response

Recording bias

frequency

Rec/Play

frequency

response

Rec/play

output

adjustment

(from

battery)

AUX

8 dBm, MIC

48

dBm

Speaker 0 dBm/6 n

Headphones 0 dBm/

32

n

Tape used

Adjustment/check

method

VTT703

Maximize

outputs

of

decks A and

B;

adjust

to

(10kHz)

minimize phase difference

between

left

and right

channels.

To

adjust deck

A,

adjust FWD

first

, then

REV

.

After

adjustment,

apply

screw

locking

compound.

[ Fine adjustment after assembly should

be

done

with

the

head

cover

removed

.

VTT712

After

normal speed

adjustment

, perform double

(3 kHz) speed

adjustment

1.

Adjust

the

normal

speed

of

deck

A

to

3000

with

VR851 .

2. Check

if

Deck

cru

is

at

3000

Hz +

10Hz

.

3.

To

confirm

high

speed mode, play back Deck

cru,

then

set

Deck

lA]

to

record mode.

VTT712

Deck

B : 0.

35

%

(3 kHz)

Deck

A :

0.40%

(JIS RMS) or less

VTT724

Adjust

VR10l

,

VR102

(deck

A)

and VR201 ,

(1

kHz)

VR202

(deck

B)

so

that

the

output

of

TP151 ,

TP251 and

TP751

are -

21

dBm

VTT739

With

respect

to

their

outputs

at

1 kHz,

the

out-

puts

at TP151 and TP251 should

be

- 5 ± 3

dB

at

63

Hz, and - 1 ± 3

d8

at

10kHz.

(TS

-8)

Set

beat

cut

switch

S7

21

to

position 1 and

ad

-

Normal tape

just

the

oscillating

frequency

of

C724

to

68

±

1 kHz

with

L

721.

(Connect a

100

{)

resistor in

series

when

measuring.)

(TS-8)

Deck

A:

Adjust

VR

122

(L

ch) and

VR222

(R

ch)

Normal tape so

that

the

rec/

play

output

of

an input signal

-

20

dB

with

respect

to

the

reference level at

1 kHz

is

- 0 dB ± 1 dB at

10kHz

.

Deck

B : Same as

deck

A.

Measure

outputs

from

TP151 and

TP251.

(TS

-8)

Adjust

VR

121

(L

ch) and VR221

(R

ch) so

that

Normal tape

the

level

when

recording and playing back an

AUX

(CD)

IN

signal -

20

dB

with

respect

to

the

reference level is - 0 dBm ± 1 dB.

Center

Normal

PC

-

V77

A/B

/E/G/

UN

Recording

normal

tape

TS-8 (UR)

chrome tape TS-6

metal tape TS-7

Switch

setting

Adjustment

location

Tape/normal

Deck

A:

Adjust

FWD

speed

then

REV

Deck

B

Tape/Normal

VR851

speed

High speed

Tape/Normal

speed

Tape/Normal

Deck

A

speed L

ch

:

VR10l

R ch : VR201

Deck

B

L

ch:

VR102

R

ch:

VR202

Tape/Normal

speed

S721

L721

(Beat

cut)

2 :

66

kHz

3 :

68

kHz L ch : VR

122

R

ch

:

VR222

L ch : VR 121

R

ch:

VR221

(No.

1740)

7

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A/B

/E/G/

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Location of Adjustment

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TP151

VR1

21

~RE

C

ORDING

GAIN

Ad

j.

VR221

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102

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__________________________

______

~I~DECK

IA]

SPEED

Adj

• Tuner Alignment

BASIC CONDITIONS

REC/

PLA

Y

POWER SOURCE

OF

THE RECEIVER

LOAD RESISTANCE

OF

THE RECEIVER

MODULA

TION

OF

SSG

Item

1.

AM

IF

ALIGNMENT

1-1 Conditions

of

the

receiver.

(1

)

Power

source:

(2) Function

switch

pos

it

ion:

(3) Band select

switch

:

(4)

Volume

control

:

(5) SEA control:

(6) Variable

capacitor

:

VR851

FR

EOU

ENCY

RESPONSE

Adj

VR

222

5c;

o

B0 BIAS FREOUEN

CY

Adj

VR

I22 L

721

Fig. 4-1

DC

12V

, AC

120V

50

mW

(0

.5

5

V)/6

11

400

Hz

.

30

%

Description

DC

7 V

(When the

power

is supplied

directly

to

the

tuner

in the

receiver,

the

voltage

should

be

adjusted

to

the

proper level

wh

ich shall be required by

th

e

tuner

.)

RADIO

AM

Minimum gain

position

Center position

Near

the

minimum

capacity

position where no signal come in.

1-2 Connection

of

Sweeper and

the

receiver

(

1)

Tuner input: Positive side

to

TP3

(2) Tuner

output:

Positive side

to

TP6 1

Negative side to TP7

1-3 Aligning

position

: CFT,

T2

1-4

Al

ignme

nt

(Waveform)

:

Adjust

AM

I.F.T. (above

mentioned

aligning

posit

ion) so

that

D maximum and

symmet

rical

wave

form can be obtained.

In

this case,

the

wavehead should be appeared

at

the

center

marker (

450

kHz) on

the

scope

of

Sweeper.

B

(No_

1740)

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PC-V77

A/B/E/G/UIV

Item

Description

2. FM

IF

ALIGNMENT

2-1

Conditions

of

the

receiver

(1

) P

ower

source:

Same

as

mentioned

in

item

1-1

(2)

Function

switch

posit

ion: RADIO

(3) Band select

switch:

FM

(4)

Volume

contro

l:

Minimum

gain

position

(5) SEA

control

:

Center

position

(6) Variable

capacitor:

Near

the

minimum

capacity

position

where

no signal

come

in.

2-2 Connection

of

Sweeper

and

the

receiver

(1) Tuner

input

: Positive side

to

TP5

(2) Tuner

output:

Positive

side

to

TP6

Negative

side

to

TP7

NOTE

a)

Attach

a

capacitor

(30

pF) and

resistor

(30

kO)

to

the

posi

tive

side cable

which

shall be led

from

Sweeper

input.

b)

Attach

a

resistor

(100

km

in series

to

the

positive

side cable

which

shall be led

from

Sweeper

output

.

2-3

Aligning

position:

Discriminate

Waveform

:

T1

("S

"

curve

waveform)

2-4

Alignment

(Waveform

):

Adjust

the

discriminate

coil (T1) so

that

"

S"

curve

waveform

may

be changed

to

IF

waveform

as

shown

in

following

figure.

~

NO

TE

The discrimi

nator

's

CF

is

yellow

.

Adjust

the

discriminate

T2

so

that

above

symmetrical

IF

Do

not

use one

that

is

of

another

color.

waveform

may

be changed

to

balanced " S"

curve

waveform

.

3.

AM

RF

ALIGNMENT

3-1

Conditions

of

the

receiver.

(1

)

Power

source:

Same

as

mentioned

in

item

1-1.

(2)

Function

switch

position:

RAD

IO

(3)

Volume

contro

l:

50mW

(4) SEA

control

:

Center

position

(5) Variable capacitor: Refer

the

follow

ing li

st

shown

in

item

3-4.

3-2

Conditions

of

SSG.

(1)

Modulation

: Refer

the

basic

condition

(2) Frequency: Refer

the

following

list

shown

in

item

3-4.

(3)

Outp

ut level

of

the

attenuator

in SSG:

Approx

.

50

mW

3-3

Power

output

measuring

position

: Speaker terminals

3-4

Alignment

:

Ba

nd

Se

lect

Sort of

An

tenna to be Fr

equenc

y of SSG

Pr

es

et

Memory

No

.

Al

igning

Sw

itc

h Posi

tion

att

ached

to

SSG Posi

tion

1

520

kHz

M5

L5

2

AM

Turn

L5

until

the

voltage

of

TP9

becomes

4.4±

0.05

v.

3

or

MW

4

600

kHz

to

be received

600

kHz

(M2)

L3

5 (

Adjustments

after

AM(MW) oscilla- )

1,400

kHz

to

be received

1,400

kHz (M4)

TC3

6

tion

circuit

replacement

initial

sett

-

Adjust

the

above aligning position (L3 & TC3) repeatedly so

that

ing. (See page

10)

the

tuner

can be obtained

the

best sensitivity.

7 281

MHz

M5

L6

8 Loop

Antenn

a

Turn

L6

until

the

voltage

of

TP9

becomes

4.4

±0 .

02

V.

9

10

LW

164

kHz

to

be received

164

kHz (M1)

L4

11

272

kHz

to

be received

272

kHz (M

5)

TC-4

12

(B

/E/GIV

Adjust

the

above

aligning

position

(L4 & TC-4)

repeatedly

so

Version)

that

the

tuner

can be obtained the best

sensitivity

.

(No.

1740)

9

tJ

PC

-

V77

A/B/E/G/

UN

.....

Band Select

Switch

Position

13

14

15

SW

16

17

(A/U Version)

Sort

of

Antenna

to

be

attached

to

SSG

Dummy

Antenna

Frequency

of

SSG Preset

Memory

No. Aligning

Position

17.9MHz

M5

L6

Turn L6 until

the

voltage

of

TP9 becomes 4.

4±0.02

V.

6 MHz

to

be received 6

MHz

L4

17

MHz

to

be received 1

7 MHz

TC

-4

18

Adjust

the above aligning position (L4 & TP-4) repeatedly so

that

the tuner can be obtained

the

best sensitivity.

Item

Description

4.

FM

RF

ALIGNMENT

4-1 Conditions

of

the

receiver.

(1)

Power

source: Same

as

mentioned in

item

1-1.

(2) Function

switch

position: RADIO

(3) 8and select

switch:

FM

(4) Volume

control:

50

mW

(5) S

EA

control: Center position

(6) Variable capacitor: Refer the

following

list

shown

in item 4-3.

4-2

Condition

of

FM SSG.

(1

) Modulation: Refer the basic

condition

(2) Frequency: Refer the

following

list

shown

in

item

4-3.

(3)

Output

level

of

the

attenuator

in FM

SSG: The level shall

be

decided by

the

load resistance

of

the

receiver mentioned in

the

basic conditions.

4-3 Connection

of

sweeper

and

the

receiver.

(1

) Tuner

input

Positive side

to

TP

1.

Negative side

to

TP2.

(2) Tuner

output

Positive side

to

4-4

Alignment:

Band Select

Sort

of

Antenna

to

be Frequency

of

SSG Aligning

Switch

Position

attached

to

SSG Preset

Memory

No. Position

1

108

MHz

M5

L1

2

FM

Dummy

Adjust

L1 until

the

voltage

of

TP9 becomes

4.4±0.05

V.

3

Antenna

4

88

MHz

to

be received

90

MHz

(M2) L2

5

108

MHz

to

be received

108

MHz (M4)

TC

-2

6 Adjust the above aligning position (L2 &

TC

-2) repeatedly so that

the tuner can

be

obtained the best sensitivity.

Adjustments

after

AM

oscillation circuit replacement

Initial setting

• Set L5

to

VOM7U02

-

402.

(Seal

is

402

.)

• Position

TC

5 (trimmer) in

the

center.

1) Do tracking adjustment

of

L3

and TC3.

2) Measure the maximum sensitivity for every

100

kHz from

600

kHz (or

603

kHz)

to

1000

kHz (or

999

kHz). Then

do the following:

a)

If better than the threshold value (52

dB

/

m)

of

the max-

imum sensitivity at each frequency,

it

is

okay.

b)

If

it

becomes worse than the threshold value at around

700

kHz

to

800

kHz, set

TC

5

to

MAX

and readjust the

RF

tracking.

c)

If

it

becomes worse than the threshold value at around

900

kHz

to

1000

kHz, set

TC5

to

MIN and readjust

the

RF

tracking.

10

(No.

1740)

Reference OSC circuit parts

06

KV

1250

C25

OFS

41HJ

-391

TC5

OAT

3720

-

600M

L5

VOM7002

-401

IC2

LA1810

C260CT3OCH

-5R6Y

03

2SC2839(E) (Except for C/J version.)

JVC PC-V77 Manuel utilisateur

Manuels Système de haut-parleurs populaires d'autres marques