Jvc PC-V77 Service Manual

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Contents

Safety Location Removal Adjustment Block Diagram Wiring Standard Location

Precautions

of

Main

of

Main

Connections

Schematic

of

P.C. Board Parts and Parts

Tuner

P.C. Board Parts ..

DIN Board

Parts 3 Parts

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

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

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

An

instruction

... .

.... ....

...... ... .

......

...

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

Diagram ..................

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

booklet

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

......

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

....

...

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

.. .

.........

......... 15

List

...........

(B

/E/G

.....

...

Page

12 14

20 23

version)

2

4 7

is

provided

Main DTS P.C. Board parts

~

Exploded

[jQ]

Exploded

Mechanism

[ill

Exploded

Enclosure

Im

Packing

rrn

Accessories

with

P.C. Boad parts

View View

View

and

~

IA'WW. frceservicemanuals.info

this

manual.

....

..........

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

of

Speaker

of

Mechanism

Component

of

Enclosure

Assembly

Packing Parts

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

Box

Parts

Assembly

Parts

List

List ......................

Digitized

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

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

and

Parts

Assembly

List

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

.. ..

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

by

......

List

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

..

Back

Page

...

24

..... 2B

....

29

30 .. 31 ..

32

33

....

35

Cover

No.

1740-1

October

1987

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1.

The

Many purposes. For the manufacturer. those formed

2.

Alterations

not

the manufacturer perty

3.

Many special stics the by voltage, wattage, these parts ing such features are and replacement characteristics shown shock,

4 . The leads in

ties, clamps, separated ing tric When dress ed

5. Leakage

(Safety

fter

A tion

(antenna

earphone duct

Safety Precautions

design

of

this

circuits

continued

original

used in

by

be made . manufacturer's

damage electrical and

safety

are protection using

special

list

parts

in fire ,

parts

shock

service

should

to

be

for

re-assembling

check

is safe

and

protection,

design

Replacement

the

original

qualified

of

the

design or

Any

design

of

responsibility

resulting

-related

often

not

evident

afforded

replacement

etc.

safety

of

Service

list

in

Service

which

as

the

parts

or

other

the

products

tubings,

from

live

and/

or

sharp

and

fire hazard .

is required,

be

observed,

returned

current

on

terminals, knobs, metal

jack, control

to

check

electrical

the

exposed

to

operate

the

product

unless

personnel

warranty

mechanical

characteristics

manual. El

list

parts,

contains

components

no

changes

authorized

parts

circuits.

only

circuitry

alterations

and

for

therefrom.

parts in the

characteristics.

from

visual

by

them

necessarily be

components

Replacement

ectrical

identified

does

recommended

hazards.

edges

normal, after

shock

product, always

shafts,

without

by

manual.

in

barriers and/

The

not

have

Service

are

routed

high

temperature

for

the

original lead

and

they

hazard)

metal

etc.)

danger

cabinet,

special

specially

should be made

must

Service should be per-

.

of

the

or additions

will

further

personal injury or pro-

inspection

parts

are

(Lt)

on the schematics

use

manual

or

prevention

should

re-assembling.

parts

to

of

hardware.

for

safety

in

writing

be identical

product

These

rated

identified

components

of a substitute the same replacement

and dressed

the

perform an isola-

of

be sure

electrical shock.

relieve

product

characteri

obtained

for

which

may

like

part,

routing

be

confirm

the

Products

screw

by

should

will

nor can

higher

safety

create

of

heads,

the

void

the

have

in

the

hav

part

with

to

mov

elec-

and

pro

to

be

Do

not

use a line

• Plug

•

-

GOOD EARTH GROUND

the

ing a " Leakage current particularly path

to

(water ceed

0.5 Alternate Plug

the

AC

voltmeter

an sensitivity

10 W resistor capacitor good

earth Measure AC

voltmeter.

Move

the part, particularly return voltage the

AC voltage (r.m.s.) This

corresponds

isolation

AC line

from

the

pipe,

AC line

the

path

across

outlet

measured

.

cord

Current

each

exposed

any

exposed

chassis,

etc.).

mA

AC

(r.m.s.).

check

method.

cord

having

in

the

following paralleled

between

resistor

0.1 5 /LF AC-TYPE

an exposed metal part and a

ground

AC

voltage

connection any

to

the the and

to

transformer during

directly

to a known

Any leakage

directly

(water

exposed

chassis,

resistor.

repeat

must

0.5

into

Tester",

metal

into

1,000

ohms

manner. Connect a 1500

by a 0.15

pipe,

across

to

and measure

Now, each not

mA

AC (r.m .s.).

AC

VOLTMETER

(HAVING

OR

MORE SENSITIVITY I

this

check.

the

AC

outlet.

measure

part

good

current

etc.)

the

each

metal

measurement.

exceed

PLACE THIS PROBE ON EACH EXPOSED METAL

of

having a

earth

must

the

AC

per

resistor

exposed

part

reverse

1000

ON

PART

the

leakage

the

cabinet,

return ground not

outlet.

Use

volt

or

more

/LF

AC-

type

known

with

metal

having

the

plug

Any

0.75 V AC

,

Us-

ex

the

AC

in

-

{l

a

2 (No.

1740)

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Location of Main Parts

SEA

Cover

AMP

/SEA Board

Ass'V CD

Jack

Ass'v

Main Board

Ass

'V

---

Speaker

Term

inal

Switch

Power Transformer

Fig

. 2-1

INo.

1740)

3

PC-V77

A/B/E/G/

UN

Removal of Main Parts

Cabinet Section

• Replacing

Remove

the

fuse

the

telescopic antenna.

the

rear

screw

cabinet

®

the

replace fuse

at

rear

of

the cabinet

to

replace

the

T. antenna.

• Rear

1) Remove

2) Remove eight

3)

•

1)

2) Remove

3) Remove

4)

5)

6)

cover

the

cabinet . Disconnect

(GN

version)

Amp.

Board/SEA

Remove

ass'y

Pull and remove Remove

ass'y Pull motor

the

.

the the

the

and 3D speaker

the

entire

tuner,

battery

the

two

volume Function/Tape

five

screws

connector

Board/3D

screws

the

screws

ass'y

etc.

cover.

G), @ and @ retaining the rear

knob

SEA

ass'y.

slightly, then

(CND

1)

on Din

speaker

@ securing

.

switch

volume

cover.

Jack

ass'y

the

knob.

® and ® securing

remove

the

Board.

CD

in-jack

the

board

head wire ,

Fig. 3-1

• Tuner board ass'y

1)

Remove

2) Pull

•

Mechanism

1)

Remove

2) Open

• For reassembly,

• LeD

1)

Remove

2) Remove

the

out

the

cassette

assembly

indicator

the the

wire

board ass'y.

ass'y

six

screws

of

the

ass'y

two

connector

(j) .

door

to

lift

the

cabinet

button

screws screws

for

the

remove .

rear

and

button

securing

securing the

tuner

slightly

lever.

the

board.

for

lamp LCD

easier

ass'y

board.

Fig.

3-2

Fig. 3-3

7

.

7

4 (No.

1740)

Fig.

3-4

• Cassette door

1)

Pull

the

lid up

2)

Remove the door spring.

3)

Close

the

hj

::0

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(j)

M

::0

<

H

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~

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(j)

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o

outer

• SEA board

1)

Remove board.

2) Remove

(For reassembly , i slider hole.)

• The parts on the

the

Mechanism Section

(Top

View)

to

remove.

door and remove the center

shaft

and pull

ass'y

two

four

screws

nsert

power

out

toward

@ securing

the

rec spring

amp board can still be replaced.

shaft

. Then remove

the

front

the

into

the

panel.

pre-amp

SEA board.

switch

's

(Bottom

View)

Free

se

e manuals

schema

Gralis

.

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3

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•

Motor

bracket

1) Remove

2) Remove the chassis and M. Then remove the

synchro

(The Return the pause per position.)

• Head

1) Remove the record/playback head's

2)

• Pinch roller

1) Remove

section

and loosen

Remove

(Recording/playback deck)

the

three

screws

bracket

arm can be

lock

screw

®.

the

erase head

the

pinch roller arm

G).

bracket

arm (panel).

removed

after

mounting

it

is removed

stopper

from

the

from

the

mounting

screw

E.

Fig.

button

side.

pause

lock

.

from

the

pro-

screw

®

3-6

Fig.

3-7

• Flywheel

1)

Remove

2) Pull

out

ass'y

the C washer

the

flywheel

® securing

ass'y

.

the

capstan

shaft.

R~(.

PlilY

R~w

FF Stop Pausf'

Fig.

Ej~ct

3-8

(No.

1740)

5

PC-V77

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• Removal

• Leaf

hJ

::0

M M

(j)

M

::0

<

H

n

M

~

t-<

(j)

H

Z

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o

• Gear

• Lock arm

• Chassis removal

of

the

chassis.

switch

Press

the

switch's

remove.

IBelow

Remove For reassembly,

the ®

Press remove .

1)

Remove

2)

Remove

3)

Remove metal.

4)

Gently

the

the C washer

section

the

arm

the the the

remove

button

ass'y

lock

panel and raise from

flywheel)

@ securing

insert

the

.

stopper

three two

two screws

screws

the

from

0,

button

from

the

mechanical

the

left

the

gear.

Sensing Lever arm stand

window

®, and

®, and pull

Cl)

spring

s.

0.

® securing

ass'y

from

the

capstan

chassi

to

into

to

s.

Fig.

3-9

Flywh

eel

Fig. 3-

10

Fig. 3-11

6 INo.

1740)

Fig.

3-12

PC-V77

A/B

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UN

~

Main Adjustment

• Amplifier adjustments

Conditions

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Power

Input Output

supply

levels

Item

Head azimuth adjustment

Tape speed adjustment

Checking &

flutter

Playback output

Confirming playback frequency response

Recording bias frequency

Rec/Play frequency response

Rec/play output adjustment

wow

level

voltages

: DC 1 2

(from AUX Speaker 0 dBm /6

Headphones 0 dBm/

Tape used

VTT703

(10kHz)

VTT712

(3 kHz)

VTT712

(3 kHz)

VTT724

(1

kHz)

VTT739

(TS

-8)

Normal tape

(TS-8) Normal tape

(TS

-8)

Normal tape

V,

Timer

1.5

V SEA controls

battery)

8 dBm, MIC

48

dBm

Tape select Tapes used

n

32

n

Adjustment/check

Maximize minimize phase difference

channels.

To

After

compound.

[ Fine adjustment after assembly should

with

After speed

1.

Adjust with

2. Check To

3.

cru,

Deck Deck

Adjust VR202 TP251 and

With puts at

63

Set just

1 kHz

series Deck

so

20

-

1 kHz

Deck

Measure

Adjust the AUX

reference level is - 0 dBm ± 1 dB.

outputs

adjust deck

adjustment,

the

normal speed

adjustment

the

VR851 .

if

confirm

then

B : 0.35% A :

0.40%

VR10l, VR102

(deck

respect

at TP151 and TP251 should

Hz, and - 1 ± 3

beat

cut

the

oscillating

with L 721.

when

A:

Adjust

that

the

dB

with

is

- 0 dB ± 1 dB at

B : Same as

outputs

VR

121

level

when

(CD)

IN

of

decks A and

A,

adjust FWD

head

cover

adjustment

normal

Deck

high

set

B)

TP751

to

switch

measuring .)

rec /

respect

signal -

speed

cru

speed mode, play back Deck

Deck

(JIS RMS) or less

so

that

are -

their

outputs

S 7

frequency

(Connect a

VR

122

play

output

deck

from

(L

ch) and VR221

recording and playing back an

method

between

apply

removed

of

is

at

3000

lA]

to

record mode.

(deck

the

output

21

dBm

at

d8

at

10kHz.

21

to

position 1 and ad-

of

(L

ch) and

of

to

the

reference level at

10kHz

A.

TP151 and

20

dB

with

first

screw

.

, perform double

deck A to

A)

1 kHz,

be

C724

100

an input signal

respect

B;

adjust

left

and right

, then

REV

locking

be

done

3000

Hz +

10Hz

and VR201 ,

of

TP151 ,

the

out-

- 5 ± 3

to

68

{)

resistor in

VR222

(R

.

TP251.

ch) so

(R

to

ch)

that

the

Center Normal Recording chrome tape TS-6 metal tape TS-7

Switch

to

Tape /normal speed

.

Tape /Normal

speed

.

High speed

Tape/Normal

speed Tape/Normal

speed

Tape /Normal speed

dB

S721

(Beat

±

2 :

3 :

66

68

setting

cut)

kHz kHz

normal

tape

TS-8 (UR)

Adjustment

Deck

A:

Adjust

then

REV

Deck

B

VR851

Deck

A

L

ch: VR10l

R ch : VR201

Deck

B

L

ch:

VR102

R

ch:

VR202

L721

L ch : VR R

ch : VR222

L ch : VR 121 R

ch:

122

VR221

location

FWD

(No.

1740)

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Location of Adjustment

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VR

222

VR1

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REC/

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5c;

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Fig. 4-1

LEVE

RESPONSE

I22 L

VR1

21

~RE

VR221

Ad

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L

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B 0 BIAS FREOUEN

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VR851

CY

Adj

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SPEED

Adj

• Tuner Alignment

BASIC CONDITIONS

POWER SOURCE

LOAD RESISTANCE

MODULA

1. 1 -1 Conditions

(1

(2) (3) (4) (5) (6)

1-2 Connection

( (2)

1-3 Aligning 1-4 Alignme

TION

AM

IF

ALIGNMENT

)

Power

Function Band select Volume SEA control: Variable

1)

Tuner input: Tuner

OF

of

source:

switch

control

capacitor

of

output:

position

nt

(Waveform)

OF

SSG

switch

THE RECEIVER

OF

THE RECEIVER

Item

the

receiver.

position:

:

Sweeper and

:

the

receiver

D

DC

12V

, AC

120V

50

mW (0.55 V)/6

400 Hz. 30%

DC

7 V

the

minimum

T2

AM

450

power

I.F.T. (above

(When the receiver, wh

ich shall be requir ed by the RADIO AM Minimum gain Center position Near

Positive side Positive side Negative side to TP7 CFT, Adjust maximum and In

this case,

marker (

11

is supplied

voltage

to to

the kHz) on

should

position

capacity

TP3 TP6

1

symmet

wavehead should be appeared

the

Description

directly

be

position where no signal come in.

mentioned

rical

wave

scope

to

the

tuner

adjusted

tuner

of

to

the

proper level

.)

aligning

form can be obtained.

Sweeper.

posit

at

in the

ion) so

the

that

center

B

(No_

1740)

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Item

2. FM

IF

ALIGNMENT

2-1

Conditions

(1

)

P

ower

(2)

Function

(3)

Band select

(4)

Volume

(5)

SEA

(6)

Variable

2-2

Connection

( 1 )

Tuner

(2)

Tuner

NOTE

a)

Attach a capacitor Sweeper

b)

Attach a resistor

2-3

Aligning

2-4

Alignment

NO

TE

The discrimi Do

not

AM

3. 3-1

3-2

3-3 3-4

RF

Conditions

(1

)

Power

(2)

Function

(3)

Volume

(4)

SEA

(5)

Variable capacitor: Refer Conditions

(1)

Modulation

(2)

Frequency : Refer

(3)

Outp Power Alignment

Ba

Sw

itc 1 2

3

of

the

receiver

source:

switch

contro

control

capacitor:

input output:

input.

position:

use one

ALIGNMENT

source :

switch

contro

control

ut level

output

nd Select

h Posi

AM

or

MW

posit

ion: RADIO

switch:

l:

:

of

Sweeper

:

(Waveform

nator

that

of

the

l:

:

of

SSG.

: Refer

of

the

measuring

:

tion

and

the

receiver

(30

pF) and

(100

km

):

's

CF

is

of

receiver.

position:

attenuator

Sort of Antenna to be

att

ached

in series

yellow

another

in SSG:

position

to

resistor

to

.

color .

:

SSG

Same

FM Minimum

Center

Near

Positive side Positive Negative

(30

kO)

to

the

positive

Discriminate ("S" curve Adjust may

Adjust

waveform

Same

RAD

50mW

Center

Approx. 50 Speaker terminals

equenc

Fr

520

Turn

L5

as

mentioned

gain

position

the

minimum

to

side

to

side

the

posi

tive

side cable

Waveform

waveform)

the

discriminate

be changed

the

discriminate

may

as

mentioned

IO

position

the

follow

the

basic

the

following

mW

y of SSG

kHz

until

the

voltage

in

position

capacity

TP5 TP6

to

TP7

side cable

which

to

IF

be changed

in

ing li

st

condition

list

of

Description

item

1-1

position

which

shall be led

:

T1

coil (T1) so

waveform

from

that "S"

as

~

T2

so

that

above

to

balanced " S"

item

1-1.

shown

Preset

TP9

in

item

in

item

Memory No.

M5

becomes

where

Sweeper

shown

3-4 .

4.4±

no signal

from

output

curve

waveform

in

following

symmetrical

curve

waveform

0.05

v.

come

.

figure.

IF

Al

igning

Posi

L5

in.

.

tion

4 5

Adjustments

(

tion

6

7 281 8 9

10 11

12

circuit

ing. (See page

LW

(B

/E/GIV

Version)

after

replacement

AM(MW) oscilla-)

10)

Loop

initial

Antenn

sett

-

a

Adjust the

tuner

Turn

Adjust that

1,400

L6

the

600

kHz kHz

the

above aligning position (L3 & TC3) repeatedly so

can be obtained

MHz

until

the

164

kHz

272

kHz

the

above

tuner

can be obtained t he best

to

voltage

to to

aligning

be received

the

best sensitivity.

of

TP9

becomes

be received be received

position

600

kHz

1,400

kHz (M4)

M5

4.4

164

kHz (M 1)

272

kHz (M

(L4 & TC -4)

sensitivity

±0 .

(M2)

02

V.

5)

repeatedly

.

L3

TC3

that

L6

L4

TC-4

so

(No.

1740)

9

PC-V77

tJ

.....

A/B/E/G/

13 14

15

UN

Band Select

Switch

SW

Position

Sort

attached

of

Antenna

Dummy

Antenna

to

SSG

be

Frequency

Turn L6 until

of

17.9MHz

SSG Preset

the

voltage

of

TP9 becomes 4.

Memory

M5

No.

4±0.02

Aligning Position

L6

V.

16 17

18

4. 4-1 Conditions

4-3 Connection

4-4

(A/U Version)

Adjust that

the tuner can be obtained

Item

FM

RF

ALIGNMENT

of

the

receiver .

( 1)

Power (2) (3) (4) (5) (6)

4-2 (1

) (2) (3)

(1

) (2)

1 2

3

source: Same

Function

8and select

Volume

EA

S Variable capacitor: Condition

Modulation: Refer the basic Frequency: Output SSG: The level shall

Tuner

Tuner Alignment:

Switch

switch

control:

control: Center position

level

input

output

Band Select

Position

FM

switch:

of

FM SSG .

of

sweeper

position:

the

attenuator

Sort

attached

and

of

Antenna

Dummy

Antenna

in FM

the

to

receiver.

to

be

SSG

RADIO FM 50

Refer the

receiver mentioned in

Positive side Negative side

Positive side

Frequency

108

Adjust

to

6 MHz

17

MHz

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

as

mentioned in

mW

following

condition

following

be

to

TP

to

TP2 .

to

of

SSG

MHz

L 1 until

the

voltage

be received 6

to

be received 1

the

Description

item

list

shown

list

shown

decided by

the

basic conditions.

1 .

Preset

of

TP9 becomes

best sensitivity.

1-1.

in item 4-3.

in

the

Memory

M5

MHz

7 MHz

item

4-3.

load resistance

No.

4.4±0.05

of

the

V.

Aligning Position

TC

L4

-4

L1

10

4 5

6

Adjustments Initial setting

• Set L5

• Position

1) Do tracking adjustment

2) Measure the maximum sensitivity for every 600

do the following: a)

If better than the threshold value (52 imum sensitivity at each frequency,

b)

If 700 RF

c)

If 900

the

(No.

1740)

after

AM

oscillation circuit replacement

to

VOM7U02-402.

TC

5 (trimmer) in

kHz (or

it

603

kHz)

to

becomes worse than the threshold value at around

kHz

to

800

to

1000

kHz, set

tracking.

becomes worse than the threshold value at around

kHz

RF

tracking.

of

1000

(Seal

the

L3

and TC3.

kHz (or

TC 5 to

TC5

center.

is

402

.)

100

999

kHz). Then

of

dB/m)

it

is

okay.

MAX

and readjust the

to

MIN and readjust

88

MHz

108

MHz

Adjust the above aligning position (L2 the tuner can

kHz from

the max-

be

Reference OSC circuit parts

06 C25 TC5 L5

IC2 C260CT3OCH 03

to

be received

to

be received

obtained the best sensitivity.

KV

1250

OFS

41HJ

-391

OAT

3720-600M

VOM7002

LA1810

2SC2839(E) (Except for

-401

-5R6Y

90

MHz

(M2) L2

108

MHz (M4)

&

TC

-2) repeatedly so that

version.)

C/J

TC

-2

o

f-'-

.Q

f-'-

et

f-'-

N

(\)

jl

• FM Stereo Separation Adjustment

'<

t!

'-r]

::0

trI trI

(f)

trI

::0

<

H

()

Receive a modulated

1.

2.

Modulate

3.

Check

If

the

l ch

separation

stereo

only, then

adjust

is

signal

35

Parts Arrangement for Alignment

DTS

Board

of

VR 1 until

dB

or

60

above

dBIL

FM

the R ch

(after

MHz.

98

output

passing

is

at

through

the

minimum.

DOlBY

t'1,;

r

lter

~l

rree service manuals

Gratis schema's

~

Digitized

www .rrcc!lcrviccmanuals.info

-V

//

oy

A /

t!>

/t/lJ/U/

V

I

t-<

(f)

H

Z

'-r]

o

(Pattern

@]

BAND

side)

@J

DOWN

@]

MI

SELECT

L

@]

M2

C

1

0

FM' FM2

FM3 AM

CNI

Fig.

~

CN2

0

4-2

I

TP8

0

VRI (FM

L3(MWl

T2

D

IC 2

MPXI

Tuner

lAM

5

BAR ANT.

Board

IF

I

CN3

T I IFM

o

IFM

L1

D

LS

(MW

TC3

IMW

10

IC

I

OSCI

DSC:

RF

I

~

IFI

L21FM

D

o

TC21FM

D

L

6(LW T

C'I

TP9

L4

~

W

TP

o

RF

TP

RrP

/SW

LW/

0

/

SW

2

I

OSC

I

SW

RFI

I

Fig.

4-3

(No.

1740)

11