NOBLEX 27TC643 Service Manual

SERVICE MANUAL Colour Television

Product Code: 1 113 261 05

Original Ver sion

Chassis Series: LA4-A

F3DF

FILE NO.

Model No. 27TC643

Service Ref. No.27TC643-00

(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 . . . . . . . . .AC110V-240V, 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 (R/L) ✕ 2 (436mVr ms, more than 40KΩ) Headphone Jack: Mini stereo jack ✕ 1

Sound Output (RMS) . . . .3W + 3W

Speakers . . . . . . . . . . .5cm ✕ 9cm ✕ 2

Dimensions . . . . . . . . .628 (W) ✕ 568(H) ✕ 523.5(D)mm

Weight . . . . . . . . . . . . .approx. 27.7Kg

Specifications subject to change without notice.

NOBLEX

Contents

-2-

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

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

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

Service Adjustments with replacing Memory IC (IC802) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-17

Service Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Purity and Convergence Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Cabinet Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Chassis Electrical Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-26

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 primary 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 volt power 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-

IC802

MEMORY

24LC04B/P

X' TAL-SW1 (PAL-M)

TUNER

(WITH PLL)

ANT

AC

POWER

CIRCUIT

T611

CONVERTER

TRANS.

B1:130V (MAIN HIGH)

B2: 15-18V (AUDIO)

B4: 25V (VERT.)

B5: 12V (MAIN LOW)

FROM IC801(CPU) PIN-37

PAL-M

PAL-N

NTSC

SAW

Filter

IIC BUS CONTROL

OSD

A-L A-R

REAR AV IN

SIF

FILTER

4.5MHz

B6:9V

B7:5V

B8:5V

REG.IC

VERT. -OUT

AUDIO-OUT

SIF IN

VIF/SIF OUT

INT. VIDEO-IN

EXT. VIDEO-IN

SOUND

CARRIER

TRAP

4.5MHz

R

G

B

Q901

CRT

HV

T401 F.B.T

DEFLECTION

YOKE

Q432

HORIZ.-OUT

HEADPHONE

JACK

SP901

SP902

AUDIO RIGHT

AUDIO LEFT

FRONT AV IN

VIDEO

SDA

SCL

27

28

IC801

CPU

QXXAVB338

X' TAL-SW2 (PAL-N)

37

38

R

G

B

BLK

222324

25

29

30

SDA

SCL

A101

X131

SDA

SCL

10

14

6/7

IF IN

IC201 QXXAVB488M

IF/VIDEO/CHROMA/DEFLECTION ( 1-CHIP IC )

R

G

B

BLK

272328

30

3436

52

3

45

12

21

VERT. OUT

HORIZ. OUT

18

19

20

IC501

LA7841

40

32

FROM IC801(CPU) PIN-38

IC651

IC3401

UPC1851BCU

MTS DECODER/AUDIO CONTROL & SW

7

22

23

39 38

25

26

IC001

LA4600

AUDIO AMP.

3

1

10

8

K1101

VIDEO

A-RA-L

K1001

K1111

MAIN SIGNAL PROCESSING CIRCUIT

Chassis Block Diagrams

-4-

SYSTEM CONTROL

13

KEY SWITCH IN

KEY

SWITCH

SCL

30

29

8

15

SDA

POWER ON/OFF

PHOTO COUPLE

(ON=HIGH, OFF=LOW)

IC201

VIDEO / CHROMA

SLAVE ADDRESS

IC801

CPU

QXXAVB338

25

22

23

24

21

20

33

2728

11

10

7

34

ADJUSTMENT DATA IN

OSD BLK OUT

OSD RED OUT

OSD GREEN OUT

OSD BLUE OUT

DEFLECTION

CIRCUIT

HORIZ. SYNC IN (ACTIVE=LOW)

VERT. SYNC IN (ACTIVE=LOW)

POWER PROTECT IN

(POWER ERROR=LOW)

POWER CIRCUIT

etc.

SCL

SDA

IC802

MEMORY

OSC

32.768KHZ

CPU OSC OUT

CPU OSC IN

LED

ON-TIMER LED OUT (ON=LOW)

RC SIGNAL IN

(ACTIVE=LOW)

RC PRE-AMP.

5

SOUND MUTE OUT

(ACTIVE=HIGH)

IC001

AUDIO AMP.

A101

TUNER

RESET IN (RESET=LOW)

17

X'TAL-SW1(PAL-M) ON=HIGH

37

X'TAL-SW2(PAL-N) ON=HIGH

38

19

VIDEO SIGNAL IN

RELAY OUT FOR DEGAUSSING

(ON=HIGH)

6

1

2

STEREO/MONO OPTION

HIGH(OPEN)=MONO, LOW=STEREO

PIP OPTION HIGH(OPEN)=NON, LOW=PIP

IC Block Diagrams

-5-

IC201 < IF/Video/Chroma/Def. > QXXAVB488

VIF IN

IF AGC OUT

AFT

TV IN

EXT IN

AUDIO

OUT

33

29

35

26

37

40

32

13

44

43

11

15

16

12

2725242122412819201830239101445

QXXAVB488

SYNC IN

KILLER FILTER

IDENT FILTER

COLOUR APC

AF AMP

4.5/6.0

SIF IO ADJ

BUS

I/F

FM

DET

LIMITTER

B EXIT

INPUT

R EXIT

INPUT

G EXIT

INPUT

V SYNC

TRIG

SYNC

SEP.

SYSTEM

ID

EQ

ELIMINATE

BGP

GENE.

PHASE

CONT

KILLER

DET

LOCK

DET

ID

DET

CHROMA

APC

DET

PAL

SW

SECAM

FF

SELF

ADJ

V.RAMP

AFC

1H DL

VCXO

ACC

DET

F/F

2ND AMP

CHROMA

BPF

1ST AMP

(ACC)

HPF

AFT

AFT OUT

VIDEO

MUTE

H STOP

H.PHASE

AUDIO MUTE SW

SDA

SCL

FAST BLK

B IN

R IN

B-OUT

R- OUT

G-OUT

G-IN

H-VCC

SECAM REF

V.SIZESERVICE

SW

H-OSC

SELF ADJ.

CLAMP

50/60 OUT

R

TINT

B

R

DRIVE

B

G

ABCL

ID CUT

BLUEBACK

WHITE

BACK

COLOR

CONTRAST

SERVICE

BRIGHT

STATION DET

STATION

SYSTEM SET

SYSTEM

IF AGC

DELAY ADJ

DEFEAT

DL TIME

DL FINE

VIDEO VCC

VIDEO GND

DEFLECTION GND

TRAP

SW

D.TRAP

F.TRAP

BLACK STRECH OFF

F AGC

VIDEO

DET

VIF

AMP

APC

DET

ADJ

DET

BLACK

STRECH

VIDEO

TONE

CHROMA

TRAP

VIDEO

MUTE

CLAMP

SHARPNESS

CONTRAST

DELAY

FEF

FILTER

AGC

R-Y IN

B-Y IN

H OUTPUT

SYSTEM

DECODE

BRIGHT

CHROMA

DEMODULATOR

DR/VE

AMP

AFC GAIN

RGB MATRIX

CONTRAST

32 FH

VCO

MUTE

DET

HV

BLK

VERTICAL

COUNTDOWN

HORIZONTAL

COUNTDOWN

EXIT AUDIO IN

GND

VCC

VIF SIF

SIF IN

47

48

46

1

8

3

42

52

51

50

49

5

4 6 7 2 9 31

38

36

34

39

V-OUT

V-FB

V RAMP

BLK

AUDIO DIRECT OUT

AF DC FB

HI VCC

IF OUT

IF APC

IF VCO

BLACK PEAK

ACL/CLK

Y-SW OUT

X TAL 4.43

X TAL 3.58

BLACK PEAK

IC Block Diagrams

-6-

IC501 < Ver tical Output > LA7841

THERMAL PROTECTION

PUMP UP

AMP

-

+

GND

Ver. Output

Output

Stage Vcc

Non Inv. Input

Inverting

Input

Vcc

Pump Up

Output

LA7841

1

2

3 4

5

6

7

IC001 < Audio AMP. > LA4600

10

7

Standby SW

Ch1 Input amplifier

R

f1

Ch1 input

9

Small signal GND

8

Ch2 Input

6

P.P

REF amplifier

R

f2

R

Nf1

R

Nf2

Ch2 Input amplifier

Pop noise prevention block

Predrive amplifier

4

1

Output amplifier

TSD protector

2

Ch1 output

Large signal GND

3

Output amplifier

Ripple filter

5

Filter

Standby

Vcc

Ch2 output

IC611 < Switching Regulators > QXXAVB325

START

O.V.P

LATCH REG.

T.S.D

Iconst

Rconst+

Rconst-

R2

O.S.C

-

+

Comp.2

Vth(2)

C1

R1

DRIVE

-

+

Comp.1

Vth(1)

R4

R3

5

1

2

3

Drain Terminal

Source Terminal

Over current/ Feed Back Terminal

GND

4

Power Supply

O.V.P: Overvoltage protection circuit T.S.D: Thermal shutdown circuit

IC Block Diagrams

-7-

7

12

8

9

10

11

15

18 14

13 17 16 20

Noise BPF

Noise

Detector

I

2

C Bus

Interface

SAP Demodulation Block

Composite

Signal Input

2.2µF

0.1µF

0.047µF

SAP Signal

Detector

SAP Offset

Absorption

0.47µF

0.1 µF

68KΩ

5.1

KΩ

16.6

KΩ

Noise

Detector

+

23

22

24 46 3

5

4.7µF

1µF

0.1µF

+

1KΩ

2

22µF

+

1/2Vcc

42

1µF

+

34

35

38

36

39

37

41

40

Filter

Control

Stereo

Demodulation

Block

fH

LPF

fH

Trap

Switch

75

µS

De-emphasis

Offset

Absorption

dbx Noise

Reduction

Block

Matrix

Selector

Block

Surround

Block

Tone Control Block

Volume Control Block

33

32

31

26

25

21

28 29

302719

1

2.2µF

+

0.1µF 2200pF

+

Vcc

+

10 µF

D/A

2.2µF

+

0.1µF

+

2200pF

0.022µF

4.7µF

+

1 µF

+

10 µF

+

3.3 µF

+

1 µF

+

1 µF

+

3

KΩ

1 µF

+

D/A

Input

Attenuator

I

2

C Bus

Interface

D/A

Filter

Power Supply

Reference Voltage

Pilot Detector 1

Pilot Detector 2

Phase Detector 1

Phase Detector 2

SAP Signal Output

SAP Signal Input

Spectral Timing Setting

VCA Offset Absorption

Wide-band Timing Setting

Wide-band RMS Setting

Spectral RMS Setting

Variable Emphasis Input Offset Absorption

Variable Emphasis Offset Absorption

Analog Ground

Timing Current Setting

SDA

SCL

GND(

I

2

C bus)

R-channel

Output

L-channel

Output

Surround Timing Setting

R-channel Offset Absorption

R-channel Capacity of High Frequency Band Width

R-channel Capacity of Low Frequency Band Width

L-channel Offset Absorption

L-channel Capacity of High Frequency Band Width

L-channel Capacity of Low Frequency Band Width

External R-channel Input 3

External L-channel Input 3

External R-channel Input 1

External R-channel Input 2

External L-channel Input 1

External L-channel Input 2

L-channel Fixed Output

Monaural Offset Absorption

R-channel Fixed Output

IC3401 < MTS Decoder, Audio Control & Switch> UPC1851BCU