JVC AV-14F71/VT Service Manual

A

SER VICE MANUAL

COLOUR TELEVISION

V-14F71

BASIC CHASSIS

AV-14F71

/VT

CG

CONTENTS

SPECIFICATIONS

!

SAFETY PRECAUTIONS

!

FEATURES

!

FUNCTIONS

!

SPECIFIC SERVICE INSTRUCTIONS

!

SERVICE ADJUSTMENTS

!

PARTS LIST

!

★

OPERATING INSTRUCTIONS

★

STANDARD CIRCUIT DIAGRAM

1

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COPYRIGHT © 2001 VICTOR COMPANY OF JAPAN, LTD.

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2-1

2
3
4
5
6

No. 51918
Nov. 2001

A

V-14F71

SPECIFICATIONS

ITEM

Dimensions(W×H×D)
Mass

TV RF System

Colour System

Picture Tube
High Voltage

Receiving Frequency

Intermediate
Frequency

Colour Sub Carrier Frequency

RF Mode PAL / SECAM / NTSC3.58 / NTSC4.43
VIDEO Mode PAL / SECAM / NTSC3.58 / NTSC4.43

VHF (VL) 46.25MHz～168.25MHz
VHF (VH) 175.25MHz～463.25MHz
UHF 471.28MHz～863.25MHz

CA TV

VIF Carrier 38.0MHz

SIF Carrier

CONTENT

462mm×340.5mm×375mm
10kg

B/G, I, D/K, K1,M

Visible size: 34cm measured diagona lly

22.5kV±1.5kV(at zero beam current)

Cable TVs of Mid (X-Z, S1-S10)
Super (S11-S20) & Hyper (S21-S41) bands receivable

32.5MHz(5.5MHz) / 33.5MHz (4.5MHz )

31.5MHz (6.5MHz)

32.0MHz (6.0MHz)
PAL (4.43MHz),

SECAM (4.40625MHz / 4.25MHz)
NTSC (3.58MHz / 4.43MHz)

Power Input

Power Consumption
Speaker
Audio Output
Aerial Input Terminal
Input

Output

Headphone jack
Remote Control Unit

Operating Voltage AC90～260V, 50 / 60Hz
Rated Voltage AC110～240V, 50 / 60Hz

70W (Max) / 47W(Avg.)
5cm×9 cm, Oval type×2
3W (monaural)
75Ω Unbalanced

Video 1V(p-p), 75Ω, RCA×2 (Front / Rear)

Audio

Video 1V(p-p), 75Ω, RCA×1

Audio

500mV(rms) (-4dBs), High impe dance ,
RCA×2 (Front / Rear)

500mV(rms) (-4dBs), Low impedance,
RCA×1

3.5mm min i jack
RM-C367GY

(Battery size : AA / R06 / UM-3×2)

Design and specificat ions ar e s ubjec t to change without notice.

2

No. 51918

A

SAFETY PRECAUTIONS

V-14F71

1. The design of this product contains special hardware, many
circuits and components 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 performed by qualified personnel
only.

2. Alterations of the design or circuitry of the products should not be
made. Any design alterations or additions will void the
manuf act urer's warran t y and wil l fur t h er reli ev e t h e manufacturer
of responsi bility f or person al injury or pr operty dam age res ulting
therefrom.

3. Many electrical and mechanical parts in the products have
special s afety-relat ed charact eristics. T hese char acteristics are
often not evident f rom visual i nspection nor can t he protect ion
afford ed by them n ecess arily be obt ained by using rep lacem ent
compon ents rated f or higher voltag e, watt ag e, etc. R epl acem ent
parts which have these special safety characteristics are
identified in the parts list of Service manual.

compon ents hav in g su ch feat ures are id entif ied by s hadin g
on the sche matics and by (

The us e of a subst itute replacement whic h does n ot

manual.

have the same safety characteristics as the recommended
replac ement part shown i n the p arts list of S ervic e manu al may
cause shock, fire, or other hazards.

) on the parts list in Service

!!!!

Electrical

4.

Don't short b etween the LIV E side groun d and ISOLATED
(NEUTRAL) side ground or EARTH side ground when
repairing.

Some model's power circuit is partly different in the GND. The
difference of the GND is sh ow n b y the LIVE : (") side GND, the
ISOLATED(NEUTRAL ) : (#) side GND and EARTH : ($) side
GND. Don't short between the LIVE side GND and
ISOLATED(NEUTRAL) side GND or EARTH side GND and
never meas ure with a measuri ng apparatus (osc illoscope etc .)
the LIVE side GND and ISOLATED(NEUTRAL) side GND or
EARTH side GND at the same time.
If above not e wi ll n ot be kept, a fus e or any par ts will be broken.

5. If any repair has been made to the chassis, it is recommended
that the B1 setting should be checked or adjusted (See
ADJUSTMENT OF B1 POWER SUPPLY).

6. The hig h voltage app lied t o the picture t ube must c onform wit h
that specified in Service manual. Excessive high voltage can
cause an increase in X-Ray emission, arcing and possible
component damage, therefore operation under excessive high
voltag e conditions s hould b e kept to a mi nimum, or sh ould be
prevented. If severe arcing occurs, remove the AC power
immediately and determine the cause by visual inspection
(incorrect installation, crac ked or melted high v oltage harn ess,
poor solderi ng, etc.). To maintain the prop er minimum level of
soft X-Ray emission, components in the high voltage circuitry
including the picture tube must be the exact replacements or
alternatives approved by the manufacturer of the complete
product.

7. Do not check high voltage by drawing an arc. Use a high voltage
meter or a high voltage probe with a VTVM. Discharge the
picture tube before attempting meter connection, by connecting
a clip l ead to th e g roun d fr am e and c on necti ng t h e oth er end of
the lead through a 10k! 2W resistor t o the an ode button.

8. W hen servic e is requir ed, obser ve the origin al lead dress . Extr a
precaut ion shou ld be gi ven to assure c orrect l ead dr ess in t he
high voltage circuit area. Where a short circuit has occurred,
those comp onents that in dicat e evidenc e of over heating should
be replaced. Always use the manufacturer's replacement
components.

9.

Isolation Check
(Saf ety for El ectrical Shock Hazard)

After re-assembling the product, always perform an isolation
check on the exposed metal parts of the cabinet (antenna
termin als , vid eo/ au dio input an d out put t erm in als , Con t r ol knobs,
metal c abinet, s crewhead s, earph one j ack, contr ol shafts, etc.)
to be sure the product is safe to operate without danger of
electrical shock.

(1)

Dielectric Strength Test

The isol ation b etween th e AC pr imar y circuit and all metal parts
expos ed t o th e user, p ar tic u larly any exposed metal part having a
return p ath to the chassis should withst and a voltage of 3000V
AC (r.m.s .) for a period of on e s ec on d.

(. . . . W ithstand a voltag e of 1100 V AC ( r.m.s.) to an applianc e

rated up t o 120V, and 3000V AC (r. m.s.) t o an appl iance rat ed
200V or mor e, f or a peri od of on e s ec on d.)
This method of test requires a test equipment not generally found
in the service trade.

(2)

Leak age Current Check

Plug the AC lin e c or d dir ec t l y int o t he AC outlet (d o not use a line
isolation transformer during this check.). 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 ( water pipe, etc. ). An y leak age c urr ent mus t not exceed

0.5mA AC (r.m.s.).
However, in tropical area, this must not exceed 0.2mA AC
(r.m.s.).

Alternate Check Method

""""

Plug the AC lin e c or d dir ec t l y int o t he AC outlet (d o not use a line
isolati on transform er during t his check. ). Use an AC voltmet er
having 1000 ohms per volt or more sensitivity in the following
manner. Connect a 1 500! 10W resistor paralleled by a 0.15"F
AC-typ e capacitor betw een an expos ed metal part and a know n
good earth ground (water pipe, etc.). Measure the AC voltage
across the resistor with the AC voltmeter. Move the resistor
connect ion t o each exp os ed met al p art, part icul arl y any exp osed
metal part h avin g a return p ath to th e chassis , and meas ure th e
AC voltag e across the res istor. N ow, re vers e the plug in the AC
outlet and repeat each measurement. Any voltage measured
must not exceed 0.75V AC (r.m.s.). This corresponds to 0.5mA
AC (r.m.s.).
However , i n t ropical area, this m us t n ot exceed 0.3 V A C (r.m.s.) .
This corresponds to 0.2mA AC (r.m.s.).

AC VOLTMETER

0.15μF AC-TYPE

1500

GOOD EARTH GROUND

!

(HAVING 1000
OR MORE SENSITIVITY)

10W

/V,

!

PLACE THIS PROBE
ON EACH EXPOSED
METAL PART

No.51918

3

A

V-14F71

FEATURES

New chassis desi gn enables use of an int eractive on-s c r een control.

"

Wide range voltage (110V～240V) AC p ow er input

"

With AUDIO / VIDEO INPUT & OUTPUT terminal.

"

MUTING button can reduce the audio level to zero instantly.

"

Functional remote control to operate TV set (for channel select, volume control, power ON/OFF, etc.) from a distance.

"

2

C bus control utilizes single chip ICs for IF, V/C, DEF. VSM PRESET, PRESET & TURBO TIMER.

I

"

By means of AUTO PROGRAM, the TV stations can be selected automatically and the TV channels can also be rearranged automatically.

"

Built-in ECO MODE (ECONOMY, ECOLOGY)

"

In accord ance with t he bright ness in a room , the brig htness and / of contras t of the pictur e can be ad justed aut omatically t o make t he
optimu m pic tu re which is eas y on th e eye.

Built-in ON TIMER, RETURN + & CHILD LOCK.

"

SYSTEM BLOCK DIAGRAM

IC702

MEMORY

SCL2/SDA2

IC701

MICRO

COMPUTER

IC301

VIDEO/CHROMA

DECORDER

SCL1/SDA1

TU001

TUNER

4

No. 51918

A

FUNCTION

FRONT PANEL

■

MENU buttons

1

CHANNEL －/＋ buttons

2

VOLUME －/＋ buttons

3

ECO sensor

4

REMOTE CONTROL sensor

5

ON TIMER lamp

6

POWER lamp

7

MAIN POWER button

8

A/V INPUT terminal

8

HEADPHONE jack

A

V-14F71

⑩⑨ ①②③④⑤⑥⑦

REAR PANEL

■■■■

1

REMOTE CONTROL UNIT

■■■■

⑧

2

4
5

3

ANT Terminal

1

VIDEO INPUT Terminal

2

VIDEO OUTPUT Terminal

3

AUDIO INPUT Terminal

4

AUDIO OUT PUT Term i n al

5

PICTURE BOOSTER key

1

ECO SENSOR key

2

COLOUR SYSTEM key

3

COLOUR SYSTEM key

4

TV/VIDEO key

5

OFF TIMER key

6

CHANNEL SCAN key

7

RETURN＋key

8

DISPLAY key

9

CHANNEL－/＋ key

A

POWER key

B

PICTURE MODE key

C

Number (CH.) key

D

－/－－key

E

MUTING key

F

MENU key

G

MENU ▲/▼ key
MENU －/＋ key

VOLUME－/＋ key

H

No. 51918

5

A

V-14F71

SPECIFIC SERVICE INSTRUCTIONS

DISASSEMBLY PROCEDURE

REMOVING THE REAR COVER

1. Unplug the power plug.

2. As shown in figure, remove the 5 screws marked
a screw marked

3. Withdraw the rear cover toward you.

""""

.

REMOVING THE MAIN PW BOARD

After rem ovi ng the rear cover.

"

1. Slight ly raise t he both s ides of th e MAIN PW BOAR D by hand
and remove the PWB stopper marked

2. Withdraw the MAIN PW BOARD backward.
(If necessary, take off the wire clamp , connectors etc.)

from the fro n t ca bi n e t.

####

REMOVING THE SPEAKER

After rem ovi ng the rear cover.

"

1. As shown in figure, remove the

2. Follow the same steps when removing the other hand speaker.

screws marke d

4

!!!!

$$$$

and

.

CHECKING THE MAIN PW BOARD

1. To check the back side of the PW Board.

4. Pul l out the MAIN PW Board . (Refer to REMO VING THE MAI N
PW Board)

1) Erect the PW Board ver t ically s o that you c an easily c h eck the
back side of the PW Board.

[CAUTION]

When erecting the PW Board, be careful so that there will be no

"

co n tactin g with other PW Board .

Before turning on power, make sure that the CRT earth wire and

"

other conn ec tor are proper l y c onn ec ted.

WIRE CLAMPING AND CABLE TYING

1. Be sure to clamp the wire.

2. Never remove the cable tie used for tying the wires together.
Should it be inadvertently removed, be sure to tie the wires with a
new cable tie.

6

No. 51918

A

FRONT CABI.

CRT SOCKET

PWB

MAIN PWB

SPEAKER

D

V-14F71

(

4)

××××

POWER

CORD

C

REAR

COVER

B

(

1)

××××

A

(

5)

××××

No. 51918

7

A

V-14F71

REPLACEMENT OF MEMORY ICs

1. MEMORY ICs

This mod el uses memory ICs . This m em ory IC data are f or pr op er oper ation of the vid eo an d d efl ec t i on circuits.
When replaci n g m emor y ICs , be sure to use ICs written with the ini ti al v alu es of d ata.

2. PROCEDURE FOR REPLACING MEMORY ICs

(1) Power off

Switch th e p ow er off and disconn ec t t h e power pl ug from the wall outlet.

(2) Replace ICs

Be sure to u se memory ICs written with the initial data values.

(3) Power on

Connect the power plug int o t h e wall outlet and s witc h t h e power on.

(4) Check and set SYSTEM CONSTANT SET

It must not adjust without adjustment signals.

・・・・

1) Press the

DISPLAY

CONTROL UNIT simultaneously.

2) The SERVIC E ME NU screen of Fig. 1 will be displ ay ed.

3) While the SER VICE MENU is dis play ed, ag ain pr ess th e

PICTURE MODE

screen of Fi g. 2 will be displayed .

4) Check t h e s ett i ng values of the SYST EM C O N S T A NT SET of Table 1 If the
value is dif ferent, s elect the s etting it em with the

the correct value with the

5) Press the

DISPLAY

(5) Receive channel of sett i ng

Refer to the
(channels preset) as described

(6) User Setting

Check th e user set ting val ue of T able 2, and if setti ng valu e is diff erent, s et
the correct value.
For setting, refer to the

(7) Setting of SERVICE MENU

Verif y the s etting items of th e SE RV IC E ME NU , an d r es et w h ere necessary.
For setting, refer to the

KEY ASSIGNMENT OF REMOTE CONTROL UNIT

key and the

PICTURE MODE

key of the REMOTE

DISPLAY

key s imultaneous ly, and th e SYSTEM CONSTAN T SET

▼/▲key, and set

MENU

- / + key.

MENU

key twice, and return to the normal screen.

OPERATING INSTRUCTIONS

OPERATING INSTRUCTIONS

SERVICE ADJUSTMENTS

and set the receive channels

.

.

key an d

SERVICE MENU

1.IF 2.V/C

3.DEF 4.VSM PRESET

5.PRESET

6.TURBO TIMER OFF

1-6 SELECT DISP : EXIT

******

***********

***** **

************

**********

*** ** **

*** ** **** ***

*** ** ***** ** **

**.***

****

** ***

** ***** ***

Fig.1

SYSTEM CONSTANT-

SYSTEM CONSTANT SET 1

COLOUR : MULTI
BILINGUAL : NO
TUNER : MU
ECO SENSOR : YES
LANGUAGE : E / V

: SELECT

/

- / + : OPERATE DISP : EXIT

SYSTEM CONSTANT-

SYSTEM CONSTANT SET 2

B/B SOUND : OFF
LOCK : 180
COLOUR AUTO : NO
QSS : MINT
ALC : NO
TEXT RATE : 20

: SELECT

/

- / + : OPERATE DISP : EXIT

SYSTEM CONSTANT-

***

******

ⅠⅠⅠⅠ

ⅡⅡⅡⅡ

ⅢⅢⅢⅢ

SYSTEM CONSTANT SET 3

PICTURE

MODE key

NUMBERS

AMP TUNER : YES
VNR : YES
TEXT TABLE : CYL

key

: SELECT

/

- / + : OPERATE DISP : EXIT

Fig.2

DISPLAY ke y

MENU

- / + key

8

MENU

key

▼/▲

No. 51918

A

SETTING OF SYSTEM CONSTANT SET

A

Setting item Setting contents Setting value

V-14F71

COLOUR

BILINGUAL

TUNER

ECO SENSOR

LANGUAGE

B/B SOUND

LOCK

COLOUR AUTO

QSS

ALC

TEXT RATE

AMP TUNER

VNR

TEXT TABLE

MULTI.

YES

MU

YES NO

E/V E

ON OFF

YES 10 20

YES

MINT

YES NO

10 20 40 80

YES

YES

RA CYL

NO

MA

NO

MQSS

NO

NO

PALTRIPLE

230 240 250

～

MULTI

NO

MU

YES

E/V

OFF

180

NO

MINT

NO

20

YES

NO

CYL

Table 1

USER SETTING VALUES

Setting item Setting value Setting item Setting value

SUB POWER ON LANGUAGE VIET
CHANNEL POSITION 1 POSITION CHANNEL PRESET Refer to OPERATING INSTRUCTION
VOLUME Ab out 10 ECO SENSOR OFF

TV/VIDEO
ON SCREEN DISPLAY

COLOUR SYSTEM PAL ON TIMER PR1 0:00
SOUND SYSTEM B / G BLUE BACK OFF
OFF TIMER OFF OSD.Shows 00 CHILD LOCK OFF
PICTURE MODE (VSM) BRIGHT PICTURE BOOSTER OFF

TV VNR OFF
POSITION INDICATION AUTO SHUTOFF OFF

Table 2

No. 51918

9

A

V-14F71

INITIAL SETTING VALUE OF SERVICE MENU

1. Adjustment of the SERVICE MENU is made on the basis of the initial setting values ; however, the new setting values which
set the screen in its optimum condition may differ from the initial setting.

2. Do not change the initial Setting Values of the Setting (Adjustment) items not listed In “ADJUSTMENT”.

3. V/C

Setting item

2. DRIVE

3. BRIGHT

4. CONT.

5. COLOUR

6. TINT

7. SECAM BL ADJ.

8. SHARP

9. AMP T.SHARD

3. DEFLECTION

1. VER. POSITI ON

2. HOR. POSITION

Do Not Adj.

Setting item Variable range

Colour system

RED
GREEN1. CUT OFF
BLUE
RED
BLUE

TV
VIDEO

TV
VIDEO

Do Not Adj.

Variable

range

-128～+127

-128～+127

-127～+127

-63～+63

-63～+63

-63～+63

-31～+31

-32～+31

-04 ～ +03 - 2 - 3

-16 ～ +15 +1 + 4

PAL SECAM NTSC 3.58 NTSC 4.43

-50

+ 0

+ 0
+ 0
+ 0

+ 0

- 15(Fixed)
+5(Fixed)

- 14

fv : 50Hz MODE fv : 60Hz MODE

Initial settin g val ue

+ 0 + 0
+ 8 + 0

Initial settin g val ue

3. VER. HEIGHT

4. VER. LINEARITY

5. VER. SCURVE

6. HOR. VCO ADJUST

4.VSM PRESET

VSM mode

Setting item

SETTING VALUE

TINT
COLOUR
BRIGHT
CONT.
SHARP

SETTING VALUE

SETTING VALUE

SETTING VALUE

SETTING VALUE

10

Do Not Adj.

VSM preset

-64 ～ +63 -40 + 0

-32 ～ +31 +13 - 3

-32 ～ +31 -32 + 0

-63 ～ +62 + 0 + 0

BRIGHT STANDARD SOFT

+15
+15
+15
+30 +15 +11
+15 +12

No. 51918