JVC AV-21D41/BK, AV-21D71/VT Service Manual

A

A

SERVICE MANUAL

COLOUR TELEVISION

V-21D41
V-21D71

BASIC CHASSIS

[RM-C368]

AV-21D41
AV-21D71

[AV-21D41

/BK

/VT

/BK

]

CG

CONTENTS

SPECIFICATIONS



SAFETY PRECAUTIONS



FEATURES



MAIN DIFFERENCE LIST



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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･･･････････････････････

･･････････････････････････････････････････････

･･･････････････････････

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･･･

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14
31

2-1

2
3
4
4
5
6

No. 51925

Dec. 2001

A

V-21D41

A

V-21D71

SPECIFICATIONS

ITEM

Dimensions(W×H×D)

Mass

TV RF System

Colour System

Picture Tube

High Voltage

Receiving Frequency

Intermediate
Frequency

CONTENT

AV-21D41

598mm×468mm×478mm

21kg

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

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

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

Visible size: 51cm measured diagonally

26.5kV±1.5kV(at zero beam current)

VHF (VL) 46.25MHz～168.25MHz

VHF (VH) 175.25MHz～463.25MHz

UHF 471.25MHz～863.25MHz

Cable TVs of Mid (X-Z, S1-S10)

CATV

VIF Carrier 38.0MHz

SIF Carrier

Super (S11-S20) & Hyper (S21-S41)
bands receivable

32.5MHz(5.5MHz)

31.5MHz (6.5MHz)

32.0MHz (6.0MHz)

/BK

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

31.5MHz (6.5MHz)

32.0MHz (6.0MHz)

AV-21D71

/VT

Colour Sub Carrier Frequency

Power Input

Power Consumption

Speaker

Audio Output

Aerial Input Terminal

Input

Output

Headphone jack

Remote Control Unit

Rated Voltage AC110～240V, 50 / 60Hz

Video 1V(p-p), 75Ω (Front / Rear)

Audio

Video 1V(p-p), 75

Audio 500mV(rms) (-4dBs), Low impedance,

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

105W (Max) 68W(Avg)

5cm×12 cm, Oval type×2

5W (monaural), Bilingual 5W (monaural)

75Ω Unbalanced

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

Ω

3.5mm mini jack

RM-C368
(Battery size : AA / R06 / UM-3×2)

RM-C367
(Battery size : AA / R06 / UM-3×2)

Design and specifications are subject to change without notice.

2

No. 51925

A

A

SAFETY PRECAUTIONS

V-21D41
V-21D71

1. The design of this product cont ains 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 identic al 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
manufacturer's warranty and will further relieve the manufacturer
of responsibility for personal injury or property damage resulting
theref rom.

3. Many electrical and mechanical parts in the products 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.

components having such features are identified by shading
on the schematics and by (

The us e of a substitute replacement which does not

manual.

have the s ame safety characteristics as the recommended
replacement part shown in the parts list of Service manual may
cause shock, fire, or other hazards.

) on the parts list in Service



Electrical

4.

Don't short between the LIVE side ground and ISOLATED
(NEUTRAL) side ground or EARTH side ground when
repairing.

Some model's power circuit is partly different in the GND. The
differenc e of the GND is shown by 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 measuring apparatus (oscilloscope etc.)
the LIVE side GND and ISOLATED(NEUTRAL) side GND or
EARTH side GND at the same time.
If above note will not be kept, a fuse or any parts 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 high voltage applied to the pictur e tube must conform with
that specified in Service manual. Excessive high voltage can
cause an incr ease in X-Ray emission, arcing and possible
component damage, therefore operation under excessive high
voltage conditions should be kept to a minimum, or should be
prevented. If severe arcing occurs, remove the AC power
immediately and det ermine the caus e by visual inspection
(incorrect installation, cr acked or melted high voltage harness,
poor soldering, etc.). To maintain the proper minimum level of
soft X-Ray emission, components in the high volt age circuitry
including the picture tube must be the exact replacements or
alternatives approved by the manuf acturer of the complete
product.

7. Do not check high voltage by dr awing 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 lead to the ground frame and connecting the other end of
the lead through a 10k: 2W resistor to the anode button.

8. W hen service is required, observe the original lead dress. Extra
precaution should be given to assure correct lead dress in the
high voltage circuit area. W here a short circuit has occurred,
those components that indicat e evidenc e of overheating should
be replaced. Always us e the manufacturer's replacement
components.

9.

Isolation Check
(Safety for Electrical Shock Hazard)

After re-assembling the product, always perf orm an isolation
check on the exposed metal parts of the cabinet (antenna
terminals, video/audio input and output terminals, Control knobs,
metal c abinet, screwheads, earphone jack, c ontrol shafts, etc.)
to be sure the product is safe to operate without danger of
electr ic al shoc k.

(1)

Dielectric Strength Test

The isolation between the AC primary circuit and all metal parts
exposed to the user, particularly any expos ed metal part having a
return path to the chass is should withstand a voltage of 3000V
AC (r.m.s.) for a period of one second.

(. . . . Withstand a voltage of 1100V AC (r.m.s.) to an applianc e

rated up to 120V, and 3000V AC (r.m.s.) to an appliance rated
200V or more, for a period of one second.)
This method of test requires a test equipment not gener ally found
in the s ervice trade.

(2)

Leakage Current Check

Plug the AC line cord directly into the AC outlet (do not use a line
isolation transformer dur ing this check.). Using a " Leakage
Current T ester", 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 leakage c urrent must not exceed

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

Alternate Check M ethod

zzzz

Plug the AC line cord directly into the AC outlet (do not use a line
isolation transformer during this check. ). Use an AC voltmeter
having 1000 ohms per volt or more sensitivity in the f ollowing
manner. Connect a 1500: 10W resistor paralleled by a 0.15PF
AC-type capacitor between an expos ed 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 resist or. Now, reverse the plug in the AC
outlet and repeat each measurement. Any voltage meas ured
must not exceed 0.75V AC (r.m.s.). This corresponds to 0.5mA
AC (r.m.s.).
However, in tr opical area, this must not exc eed 0.3V AC (r.m.s.).
This corresponds to 0.2mA AC (r.m.s.).

AC VOLTMETER

0.15μF AC-T YPE

1500

GOOD EARTH GROUND

:

(HAVING 1000
OR MORE SENSITIVITY)

10W

/V,

:

PLACE THIS PROBE
ON EACH EXPOSED
METAL PART

No.51925

3

A

V-21D41

A

V-21D71

FEATURES

New chassis design enables use of an interactive on-screen control.

z

Wide range voltage (110V～240V) AC power input.

z

With AUDIO / VIDEO INPUT & OUTPUT terminal.

z

MUTING button can reduce the audio level to zero instantly.

z

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

z

By means of AUTO PROGRAM, the TV stations can be s elected automatically and the TV channels can als o be rearranged automatically.

z

Built-in AI ECO (ECONOMY, ECO LOGY) sensor.

z

In accordance with the brightness in a room, the brightness and / of contrast of the picture can be adjusted automatically to make the
optimum picture which is easy on the eye.

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

z

Built–in PICTURE BOOSTER circ uit newly, to amplif y the broadcasting wave in the area where wave is weak.

z

2

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

I

z

SYSTEM BLOCK DIAGRAM

IC702

MEMORY

SCL2/SDA2

IC701

MICRO

COMPUTER

IC301

VIDEO/CHROMA

DECORDER

SCL1/SDA1

MAIN DIFFERENCE LIST







PARTS NAME AV-21D41/BK AV-21D71/VT

MAIN PW BOARD SCG-1303A-BK SCG-1304A-CK

POWER CORD QMPR010-200-E2 QMP40D0-200J5

FRONT CABINET LC11129- 006A-H LC11129- 009A-HK

TU001

TUNER

PICTURE TUBE A51LMV20X A51JSW51X07



DEG COIL QQW0006-001 CELD029-004J6(inc.DY)



DEF YOKE CE20336-00A



REAR COVER GG10130-005A-H GG10130-005A-HK



INST BOOK LCT1031- 001A-H LCT1032-001A



4

No. 51925

×

A

A

FUNCTIONS

■■■■

FRONT CONTROL

①

②

[AV-21D71/VT]

①③

②

④⑤

⑥⑦

⑧⑨ ⑩

HEADPHONE jack

①

VIDEO/AUDIO INPUT terminal

②

MENU buttons

③

CHANNEL －/＋ buttons

④

VOLUME －/＋ buttons

⑤

ECO sensor

⑥

REMOTE CONTROL sensor

⑦

ON TIMER lamp

⑧

POWER lamp

⑨

MAIN POWER button

⑩

V-21D41
V-21D71

■■■■

REAR TERMINAL

①

■■■■

REMOTE CONTROL UNIT

①
②

③

④
⑤

⑥

⑦

⑧

⑨
⑯

⑩

⑱

⑪
⑫

⑬

⑭

⑮

⑰

[RM-C368GY]

②
④

⑤

③

ANT Terminal

①

VIDEO INPUT Terminal

②

VIDEO OUTPUT Terminal

③

AUDIO INPUT Terminal

④

AUDIO OUTPUT Terminal

⑤

ECO SENSOR key

①

COLOUR SYSTEM key

②

SOUND SYSTEM key

③

TV/VIDEO key

④

Key

⑤ Ⅰ/Ⅱ

[Only for AV-21D41/BK(RM-C368)]

OFF TIMER key

⑥

CHANNEL SCAN key

⑦

RETURN＋key

⑧

DISPLAY key

⑨

CHANNEL key

⑩

POWER key

⑪

PICTURE MODE key

⑫

Number (CH.) key

⑬

⑭ －/－－

MUTING key

⑮

MENU key

⑯

MENU ▲/▼ key

MENU －/＋ key

VOLUME－/＋ key

⑰

PICTURE BOOSTER

⑱

[AV-21D41/VT(RM-C368) ONLY]

key

No. 51925

5

A

V-21D41

A

V-21D71

SPECIFIC SERVICE INSTRUCTIONS

DISASSEMBLY PROCEDURE

REMOVING THE REAR COVER

1. Unplug the power plug.

2. As shown in figure, remove the

marked

3. Withdraw the rear cover t oward you.

.

B

REMOVING THE MAIN PW BOARD

After removing the rear cover.

z

1. Slightly raise the both sides of the MAIN PW BOARD by hand.

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

REMOVING THE SPEAKER

After removing the rear cover.

z

1. As shown in figure, remove the

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

screws marked A and a screw

7

screws marked C.

4

CHECKING THE MAIN PW BOARD

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

1) Pull out the MAIN PW Board. (Ref er to REMOVING THE MAIN
PW Board)

2) Erect the PW Board vertic ally so that you can easily check the
back side of the PW Board.

[CAUTION]

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

z

contac ting with oth er PW Boar d.

Before turning on pow er, make sur e that the CRT earth wire and

z

other connector are properly connected.

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. 51925

A

A

FRONT CABINET

V-21D41
V-21D71

This exploded view described about AV­21D41/BK. Although AV-21D71/VT is slightly
different from this illustration, when if you
disassemble the AV-21D71/VT, you can do it

as same as this illustration.

C

SPEAKER

CRT SOCKET PWB

MAIN PWB

SPEAKER

C

REAR COVER

POWER CORD

B

A

No. 51925

7

A

V-21D41

A

y

V-21D71

REPLACEMENT OF MEMORY ICs

1. MEMORY ICs

This model uses memory ICs. This memory IC data are for proper operation of the video and deflection circ uits.
When replacing memory ICs, be sure to use ICs written with the initial values of data.

2. PROCEDURE FOR REPLACING MEMORY ICs

(1) Power off

Switch the power off and disconnect the power plug from the outlet.

(2) Replace ICs

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

(3) Power on

Connect the power plug to the outlet and switch the 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 SERVICE MENU screen of Fig. 1 will be displayed.

3) W hile the SERVICE MENU is displayed, again press the

PICTURE MODE

screen of Fig. 2 will be displayed.

4) Check the setting values of the SYSTEM CONSTANT SET of Table 1. If the
value is different, s elect the setting item with the

the correct value with the

5) Press the

DISPLAY

(5) Receive channel of setting

Refer to the

(channels preset) as described

(6) User Setting

Check the user setting value of Table 2, and if setting value is different, set

the correct value.

For setting, refer to the

(7) Setting of SERVICE MENU

Verify the setting items of the SERVICE MENU of T able 3, and reset where

necessary.

For setting, refer to the

key and the

PICTURE MODE

key of the REMOTE

DISPLAY

key simultaneously, then the SYSTE M CONST ANT SET

▼/▲key, and set

MENU

- / + key.

MENU

key twice, and return to the normal screen.

OPERATING INSTRUCTIONS

OPERATING INSTRUCTIONS

SERVICE ADJUSTM ENTS

and set the receive channels

.

.

key and

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 :
BILINGUAL :
TUNER : MU
ECO SENSOR : YES
LANGUAGE :

: 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

ⅠⅠⅠⅠ

ⅡⅡⅡⅡ

KEY ASSIGNMENT OF REMOTE CONTROL UNIT

AV-21D41/BK

ONLY

PICTURE

MODE ke y

NUMBERS ke

SYSTEM CONSTANT-

SYSTEM CONSTANT SET 3

AMP TUNER : YES
VNR : NO
TEXT TABLE : CYL

: SELECT

/

- / + : OPERATE DISP : EXIT

ⅢⅢⅢⅢ

Fig.2

DISPLAY key

MENU

key

－/＋

MENU

▼/▲

key

[RM-C368]

8

No. 51925

A

A

SETTING OF SYSTEM CONSTANT SET

A

V-21D41
V-21D71

Setting item Setting contents

COLOUR

BILINGUAL

TUNER

ECO SENSOR

LANGUAGE

B/B SOUND

LOCK

COLOUR AUTO

QSS

ALC

TEXT RATE

AMP TUNER

VNR

TEXT TABLE

MULTI.

YES NO

MA

MU

YES NO

AV-21D41/BK AV-21D71/VT

E/T

YES 10

E

ON OFF

240 250

～

YES NO

MINT MQSS

YES NO

10 20 40 80

YES

YES

RA CYL

NO

NO

PALTRIPLE

E/V

AV-21D41/BK AV-21D71/VT

TRIPLE MULTI

YES

MU

YES

E

E/T

OFF

180

NO

MINT

NO

20

YES

NO

CYL

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

MAIN POWER SW OFF PICTURE MODE (VSM) BRIGHT

THAI

SUB POWER ON LANGUAGE

CHANNEL POSITION 1 POSITION CHANNEL PRESET Refer to OPERATING INSTRUCTION

VOLUME

TV/VIDEO

ON SCREEN DISPLAY POSITION INDICATION AUTO SHUTOFF OFF

COLOUR SYSTEM PAL ON TIMER PR1 0:00

SOUND SYSTEM B / G BLUE BACK OFF

BILINGUAL MODE

OFF TIMER OFF ( show : 00 ) PICTURE BOOSTER OFF

About 10 ECO SENSOR OFF

TV VNR OFF

[AV-21D41/BK only]

Ⅰ

CHILD LOCK OFF

Table 2

VIET

[AV-21D71/VT]

[AV-21D41/BK]

No. 51925

9

A

V-21D41

A

V-21D71

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”.

2. V/C

Colour system

Setting item

2. DRIVE

3. BRIGHT

4. CONT.

5. COLOUR

6. TINT

7. SECAM BL ADJ.

8. SHARP

(Do not adjust)

9. AMP T. SHARP

3. DEFLECTION

Setting item Variable range

1. VER. POSITION

2. HOR. POSITION

RED

GREEN1. CUT OFF

BLUE

RED

BLUE

TV

VIDEO(BK/VT)

TV

VIDEO

Variable

range

-128～+127

-128～+127

-127～+127

-63～+63

-63～+63

-63～+63

-31～+31

-32～+31

-32～+31

-04 ～ +03

-16 ～ +15

Initial setting value

PAL SECAM NTSC 3.58 NTSC 4.43

-50

+ 0

+ 0

+ 0

+ 0

+ 0

-7(Fixed)

+15(Fixed)

-12 -12 -12 -12

fv : 50Hz MODE fv : 60Hz MODE

- 1 - 3

+ 3 + 3

-50 -50 -50

+ 0+ 0+ 0

+ 0+ 0+ 0

+ 0+ 0+ 0

+ 0+ 0+ 0

+ 0 + 0

+ 8 + 0/+4

+ 0

-7(Fixed) -7(Fixed) -7(Fixed)

+15(Fixed) +15(Fixed) +15(Fixed)

Initial setting value

+ 0 + 0

3. VER. HEIG HT

4. VER. LINE ARIT Y

5. VER. SCURVE

6. HOR. VCO ADJUST

(Do not adjust)

4. VSM PRESET

VSM preset

VSM mode

Setting item

TINT

COLOUR

BRIGHT

AV-21D41/BK +30 +19 +14

CONT.

AV-21D71/VT +30 +15 +11

AV-21D41/BK +20 +20 +15

SHARP

AV-21D71/VT +15 +15 +12

10

-64 ～ +63

-32 ～ +31

-32 ～ +31

-63 ～ +62

BRIGHT STANDARD SOFT

+15 +15 +15

+15 +15 +15

+15 +15 +15

-35 + 1

+15 - 1

-32 + 0

+ 0 + 0

No. 51925