NOBLEX 20TC662 Schematic

SERVICE MANUAL Colour Television

Product Code: 111354812

Original Ver sion

Chassis Series: LA5-A

C4AP

FILE NO.

Model No. 20TC662

Service Ref. No.20TC662-00

(Argentina)

Give complete “SERVICE REF. NO.” for parts order or servicing. It is shown on the rating plate at the cabinet back of the unit.

This T.V. receiver will not work properly in foreign countries where the television transmission system and power source differ from the design specifications.Refer to the specification table.

Specifications

Power Source . . . . . . . . .AC220V, 50Hz / 60Hz

Receiving System . . . . . .PAL (M/M, N/N), NTSC (M/M)

Channel Coverage

Antenna mode VHF:CH02-CH13, UHF: CH14-CH69

CATV mode VHF band:CH01-CH13, Mid band: CH14-CH22

Super band: CH23-CH36, Hyper band: CH37-CH64 Ultra band: CH65-CH94 and CH100-CH125

Low mid band: CH95-CH99

Video IF . . . . . . . . . . . . . 45.75MHz

Aerial Input Impedance . . 75Ω Ext.Terminals

Video inputs: Phono jack ✕ 2 (1Vp - p, 75Ω) Audio inputs: Phono jack ✕ 2 (436mVr ms, more than 40KΩ)

Headphone Jack (Mono) ✕ 1

Sound Output (RMS) . . . . 2W

Speakers . . . . . . . . . . . 5 cm x 9 cm x 2 pcs.

Dimensions . . . . . . . . . 660 (W) ✕ 479 (H) ✕ 483 (D) mm

Weight . . . . . . . . . . . . . approx.18.0 Kg

Specifications subject to change without notice.

1AV0U10B22200

JXMMA

POWER

A

U

D

IO

M

O

D

E

V

ID

E

O

M

O

D

E

5

9

6

3

0

2

8

7

4

1

SURROUND

MENU

VOL

CH

NOBLEX

IMAGE

DISPLAY

MUTE

SLEEP

REC

ALL

SOUND

NOBLEX

MENU

▼ CH ▲

-

VOLUME

+

VIDEO

AUDIO

NOBLEX

Contents

-2-

Safety Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Chassis Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

IC Block Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7

Service Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-14

Purity and Convergence Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Cabinet Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Chassis Electrical Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-23

Safety Notice

SAFETY PRECAUTIONS

1: An isolation transformer should be connected in the

power line between the receiver and the AC line when a service is performed on the primar y of the converter transformer of the set.

2: Comply with all caution and safety-related notes pro-

vided on the cabinet back, inside the cabinet, on the chassis or the picture tube.

3: When replacing a chassis in the cabinet, always be

certain that all the protective devices are installed properly, such as, control knobs, adjustment covers or shields, barriers, isolation resistor-capacitor networks etc.. Before returning any television to the customer, the service technician must be sure that it is completely safe to operate without danger of electrical shock.

X-RADIATION PRECAUTION

The primary source of X-RADIATION in television receiver is the picture tube.The picture tube is specially constructed to limit X-RADIATION emissions.For continued X-RADIATION protection, the replacement tube must be the same type as the original including suffix letter.Excessive high voltage may produce potentially hazardous X

- RADIATION. To avoid such hazards , the high voltage must be maintained within specified limit.Refer to this service manual, high voltage adjustment for specific high voltage limit. If high voltage exceeds specified limits, take necessary corrective action.Carefully follow the instructions for + B1 v olt po w er supply adjustment, and high voltage check to maintain the high voltage within the specified limits.

PRODUCT SAFETY NOTICE

Product safety should be considered when a component replacement is made in any area of a receiver. Components indicated by mark in the parts list and the schematic diagram designate components in which safety can be of special significance. It is par ticularly recommended that only par ts designated on the parts list in this manual be used for component replacement designated by mark . No deviations from resistance wattage or voltage ratings may be made for replacement items designated by mark .

Chassis Block Diagrams

-3-

T611B

Q432

IC501

LA78040

VERT-OUT

T471

HV

IC802

IC801

CPU

QXXAVC479P

5

6

3

4

TUNER

SAW

IC201

LA76818AM

AUDIO

IC001

SDA

SCL

ON-TIME

STANDBY

RGB

BLK

OSD

32

31

19

20

21

22

SDA

SCL

1

2

X161

A101

ANT

IF IN

5/6

SCL

SDA

R

G

B

BLK

12

11

14 15

16 17 42

EXT VIDEO IN

K1001

K1002

REAR AVIN

FRONT AVIN

VIDEO

A-L

19

20

21

R

G

B

7

AC

POWER

CIRCUIT

CONVERTER

TRANS

130V(MAIN HIGH)

20V(AUDIO)

12V(MAIN LOW)

24V(VERT)

9V

IC202

REG.IC

5V-2

REG.IC

IC681

5VRC

2723

HORIZ-OUT

FBT

VERT.OUT

HORIZ.OUT

EXT AUDIO IN

AMP

LA4266_2W

1

AUDIO OUTPUT

51

5

Q900

CRT

IF/VIDEO/CHROMA/DEFLECTION

(WITH PLL)

FILTER

MEMORY

IIC BUS CONTROL

15

C-CAPTION IN

40

SELECTED VIDEO OUT

MAIN SIGNAL PROCESSING CIRCUIT

Chassis Block Diagrams

-4-

SYSTEM CONTROL

QXXAVC479P

15

C-CAPTION IN

IC001

*Stereo Model

only

IC Block Diagrams

-5-

IC201 < IF/Video/Chroma/Def. > LA76818A

1

DC

VOL

SW

FM

DET

2

3

4

56

IF

AGC

RF

AGC

VIF

7

8

9

10

IF

VCC 5V

11

12

13

BUS

PEAKING

CORING

BLACK

STRETCH

SYNC

SEP

14

15

ABL

DC

REST

CLAMP

OSD

CONTRAST

BRIGHT

16

17

18

19 20

CONTRAST

BRIGHT

RGB

MATRIX

OSD

SW

DRIVE/OUT-OFF

VCC

21

22

23

FSC/

SYNC SW

24

25

26 27

VER

RAMP

HOR

VCC

H

VCC

VER

C/D

HOR

OUT

PHASE

SHIFTER

AFC2

AFC1

VER

SEP

HOR

C/D

1/256

COLOR

CLAMP

LPF

ALC

+

SW

CLAMP

DEMO

PAL

SW

ACC

BPF

ON/OFF

DELAY

LINE

SW

TRAP

AFT

VIDEO

DET

TRAP

LIM

AMP

BPF

SPLL

BPF

VIDEO

AMP

IF

IDENT

VIDEO

SW

APC1

TINT

VXO

DDS

APC2

DC ADS.

CLAMP

VCO

1H DELAY

HOR

VCO

FBP

2829

30

31

32

1H

VCC

33

34

353637

38

39

40

41

42

CLMP

43

4445

CLMP

V/C VCC

5V

46

47

48

4950

A2C

PLL

51

525354

Audio Output

FM Output/Selected Audio Output

PIF AGC

RF AGC Output

PIF Input1

PIF Input 2

IF Ground

IF Vcc

FM Filter

AFT Output

Bus Data

Bus Clock

ABL

Red Input

Green Input

Blue Input

Fast Blanking Input

RGB Vcc

Red Output

Green Output

Blue Output

fsc output or C Sync output

Vertical Output

Ramp ALC Filter

Horizontal/BUS Vcc

Horizontal Output

Horizontal AFC Filter

Flyback Pulse Input

VCO IREF

Clock (4MHz) Outupt

CCD Vcc

CCD Filter

CCD/Horizontal Ground

SECAM B-Y Input (Cb Input)

SECAM R-Y Input (Cr Input)

Chroma APC2 Filter

Clamp Filter

4.43 MHz Crystal

Chroma APC1 Filter

Selected Video Output

Video/Vertical/BUS Ground

External Video Input(Y-IN)

Video/Vertical Vcc

Internal Video Input (S-C IN)

Black Level Detector

Video Output

VCO Filter

VCO Coil 2

VCO Coil 1

APC Filter

Ext. Audio Input

SIF Output

SIF APC Filter

SIF Input

IC Block Diagrams

-6-

IC201 <IF System Block Diagram> LA76818A

11

12

BUS

Interface

SAW

5

6

4

8

7

PIF

In1

PIF

In2

IF In

9V

30K

RF AGC

Out

120K

IF VCC

IF

GND

VIF AMP

VIF 1

VIF 2

VIF 3

IF AGC

Drive

RF

AGC

2ndIF

AGC

RF AGC

Delay

6bit

IF AGC

Def

1bit

+

-

(6 Vcc)/7

To

BUS

3

0.022u

PIF

AGC

IF

AGC

Data

Clock

APC

Det

+π/4

-π/4

Snd

Det

Amp

52

SIF.Out

Sound

Trap

Video

Det

Buzz

Canceller

50

APC

Filter

330

0.47u

+

PLL Pull-in SW

To

BUS

Lock

Det

Video.Level

3bit

Amp

54

10p

SIF.In

Sound

BPF

VCO.Coil

VCO

COIL1

VCO

COIL2

48

49

VIF

VCO

Chroma

Counter

B/N

INV

IF

Ident

OSC

C/D

Amp

SIF. Sys

2bit

pre-

scaller

SIF

VCO

500K

BPF

SIF

APC

Filter

1K

0.01u

1000p

53

LIM

AMP

FM

Det

FM.Level

5bit

Chroma

C/D

APC

Det

500K

Det

To

BUS

Chroma

VCO

VIF

Counter

Reset

Pulse

VCO

Ident

VIF.Sys

2bit

Phase

Detector

A.MUTE

1bit

VOLUME

D/A

VOLUME

Filter

A.SW

1bit

Input

Select

VOLUME

(ATT)

-

+

-

+

2.5V

Amp

FM Gain

1bit

Deem-TC

1bit

De-

emph

FM Mute

1 bit

2

9

46

51

1

A.Fil.Def

1bit

VOLUME

7bit

47

VCO

Alignment

AFT

10

AFT

Vcc

100K

0.1u

VCO

Filter

+

0.47u

Audio.out

+

Audio in

10u

Video

Out

FM

Filter

+

1u

FM

Out

0.01u

+

to BUS Line

+

IC Block Diagrams

-7-

IC001 < Audio AMP. > LA42052-E

1

2

3

PRE GND

4

6

7

8

9

NC

10

AMP

5

POWER GND

NC

FILTER

NC

VCC

INPUT

OUT PUT

NFL

30KΩ

300Ω

Thermal

Protection

-

+

AMP

Pump

Up

1

INVERTING

INPUT

2

Vcc

3

PUMP UP

OUT

4

GND

5

Ver. OUTPUT

6

OUTPUT

STAGE Vcc

7

NON INV.

INPUT

IC501 < Ver tical Output > LA78040N, TDA9302H

-8-

Service Adjustments

S1.00110000 S2.11111000

ADDRESS DATA

02 H-PHA 08

Item No.

Item

Data value

General

This set has an On-screen Service Menu system included in the CPU thar allows remote operation for most of the service adjustments.

Service Adjustment-1

1. Enter the Service Menu

While pressing the MENU button on the television, press the Number Key 2 on the remote control unit.The Service Menu now appear.

2. Service Adjustments:

Press the CHANNEL UP or CHANNEL DOWN button on the remote control handset to select the desired service menu item you want to adjust.

Use the VOLUME + or-to adjust the data.The + or

-

button will increase or decrease the data

sequentially.

3. Exit from the Service Menu

Press the MENU button to turn off the Service Menu display. The data which is set in the service mode is stored into the memory IC automatically.

[ Service Mode Display ]

VIDEO MODE

MENU

VOL

CH

IMAGE

VIDEO MODE

MENU

VOL

CH

IMAGE

[ Entering the Service Menu ]

VOLUME +

VOLUME

-

CHANNEL UP

CHANNEL DOWN

[ Service Adjustment ]

[ Exit from the Service Menu ]

3

21

MENU

▼ CH ▲

AUDIO

NOBLEX