SANYO C14LT77M Service Manual

SERVICE MANUAL Colour Television

Product Code: 1 113 377 14 (C14LT77M)

1 113 378 14 (C20LB87M)

Original Ver sion

Chassis Series: LC1-B

F5SS/F5TS

FILE NO.

Model No. C14LT77M

C20LB87M

Service Ref. No.C14LT77M-00

C20LB87M-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.

VIDEO MODE

AUDIO MODE

POWER

1 4

3 6 9

▲CH▼

+VOL

RECALL

IMAGE

SLEEP

DISPLAY

MUTE

FXMR

VOL-

REFERENCE NO.SM5110213

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: Mini jack ✕ 1 Sound Output (Music) . . .2.0W

Dimensions . . . . . . . . .Model C14LT77M: 380(W) ✕ 356(H) ✕ 383.5(D)mm

Model C20LB87M: 496(W) ✕ 464(H) ✕ 472(D)mm

Weight . . . . . . . . . . . . .Model C14LT77M: approx. 9.4Kg

Model C20LB87M: approx. 16.7 Kg

Specifications subject to change without notice.

VIDEO

AUDIO

VOL +

VIDEO

AUDIO

VOL +

Contents

-2-

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

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

IC Block Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6

Protection Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Service Adjustments with replacing Memory IC (IC802) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-12

Service Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Purity and Convergence Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Cabinet Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-16

Chassis Electrical Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-28

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

X' TAL-SW1 (PAL-M)

TUNER

(WITH PLL)

ANT

POWER

CIRCUIT

T611

CONVERTER

TRANS.

B1:130V (MAIN HIGH)

B2: 15-18V (AUDIO)

B4: 25V (VERT.)

B5: 12V (MAIN LOW)

FROM IC801(CPU) PIN-33

PAL-M

PAL-N

NTSC

SAW

Filter

IIC BUS CONTROL

OSD

AUDIO

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

Q901

CRT

T401 F.B.T

DEFLECTION

YOKE

Q432

HORIZ.-OUT

HEADPHONE

JACK

SP901

AUDIO

FRONT AV IN

VIDEO

SDA

SCL

IC801

CPU

QXXAVB602

X' TAL-SW2 (PAL-N)

BLK

192021

SDA

SCL

A101

X131

SDA

SCL

6/7

IF IN

IC201 QXXAVB488M

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

BLK

272328

3436

VERT. OUT

HORIZ. OUT

IC501

LA7840

FROM IC801(CPU) PIN-34

IC651

IC001

LA4285

AUDIO AMP.

K1101

VIDEO

AUDIO

K1001

K1111

EXT. AUDIO-IN

CPU X'TAL SW

MAIN SIGNAL PROCESSING CIRCUIT

Chassis Block Diagrams

-4-

SYSTEM CONTROL

KEY SWITCH IN

KEY

SWITCH

BUS SCL

BUS SDA

POWER ON/OFF

PHOTO COUPLE

(ON=HIGH, OFF=LOW)

IC201

IF/VIDEO / CHROMA

IC801

CPU

QXXAVB602

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.

VOLUME OUT

IC001

AUDIO AMP.

A101

TUNER

RESET IN (RESET=LOW)

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

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

VIDEO SIGNAL IN

OPTION IN

AFT S-CURVE IN

IC Block Diagrams

-5-

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

VIF IN

IF AGC OUT

AFT

TV IN

EXT IN

AUDIO

OUT

2725242122412819201830239101445

QXXAVB488

SYNC IN

KILLER FILTER

IDENT FILTER

COLOUR APC

AF AMP

4.5/6.0

SIF IO ADJ

BUS

I/F

DET

LIMITTER

B EXIT

INPUT

R EXIT

INPUT

G EXIT

INPUT

V SYNC

TRIG

SYNC

SEP.

SYSTEM

ELIMINATE

BGP

GENE.

PHASE

CONT

KILLER

DET

LOCK

DET

CHROMA

APC

DET

PAL

SECAM

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

H-OSC

SELF ADJ.

CLAMP

50/60 OUT

TINT

DRIVE

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

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

BLK

VERTICAL

COUNTDOWN

HORIZONTAL

COUNTDOWN

EXIT AUDIO IN

GND

VCC

VIF SIF

SIF IN

4 6 7 2 9 31

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 > LA7840

THERMAL PROTECTION

PUMP UP

AMP

GND

Ver. Output

Output

Stage Vcc

Non Inv. Input

Inverting

Input

Vcc

Pump Up

Output

LA7841

3 4

IC001 < Audio AMP. > LA4285

A B

INT

EXT

1µF

PRE GND

INT/EXT

+5V

DC VOL

D. C

POWER GND

0.1µF

10µF

47µF

1.0Ω

POWER OUT

100µF

1000µF

VCC

AMP

DC VOL

Protection Circuit

This TV set has a built-in power supply protection circuit. It is provided to protect the TV set in case of a power supply circuit malfunctions.When something abnor mality occurs during TV reception, the TV set goes to the stand-by mode.

When an abnormality occurs during TV reception, it causes pin 27 of the CPU to go continually Low(less than

0.75V) for about one second.The CPU detects that this has occurred and outputs the signal from pin 31 to switch off the power supply lines.

Releasing the protective circuit and restoring power supply

To release the protective circuit and restore power supply, turn the power to the TV set OFF and then ON again via either the main power switch or the ON-OFF button on the remote control.This will work only if the power supply trouble was temporary. If there is permanent trouble such as a damaged circuit, power cannot be restored and the circuit will have to be repaired.

LA7840

-7-

Service Adjustments with Replacing Memor y IC(IC802)

VOL +

RECALL

SLEEP

Note:The CPU (IC801) and memory IC (IC802) store the service adjustments data and controls data for each circuit.

When the Memory IC(IC802) is replaced, some of the service adjustments should be readjusted to obtain the best performance. The necessary service adjustments are carr ied out by using the RC handset. Please set up the TV set with following steps [1] to [3].

[1] Initializing Procedure

1. Put a new memory IC.

2.Tur n on the TV set

3. Press and hold the MENU button on the TV set, then press 0 button on the remote control transmitter.

The following picture appears on the screen.

This completes the initialization of memory IC.

Following shows the initialized contents of memory data by this procedure.

1.TV/AV mode :TV mode

2. Antenna or cable setting : Antenna

3. Colour system : AUTO

4. Channel Memor y : Clear

5. Receiving Channel : Ch02

6. Sound Volume : 11/63 steps

7. Color : 30/63 steps

8. Contrast : 63/63 steps

9. Brightness : 32/63 steps

10. Shar pness : 31/63 steps

11.Tint : 31/63 steps

12. Language : Spanish

13. Password : Clear

14. Channel Block : Clear

15. Sleep Timer : Clear

16. Picture Mode : MANUAL

17.Video status (Picture mode data)

Item NORMAL STRONG SOFT MANUAL Colour 28 34 22 28 Contrast 63 63 63 63 Brightness 35 15 40 35 Sharpness 31 31 31 31

-8-

Service Adjustments with Replacing Memor y IC(IC802)

[2] Service Adjustments-1

Following table shows the initial values which have been stored in the CPU ROM, and items for the service adjustments.

No. Item Initial value Range Description

01 H-P 08 00~15 Horizontal centre adjustment 02 V-P 04 00~07 Vertical centre adjustment 03 V-S 64 00~127 Vertical size adjustment 04 OSD 20 01~63 OSD position adjustment 05 AGC 64 00~127 RF AGC adjustment 06 VCO 128 00~255 VCO (AFT) adjustment 07 SIF 00 00 SIF VCO adjustment 08 SELF 00 00~15 SELF-adjusting 09 DLT 02 00~03 DL-time adjustment 10 DL F 00 00, 01 DL-fine adjustment 11 B-ST 00 00, 01 Black stretch on/off setting 12 ABCL 01 00, 01 ABCL adjustment 13 AB-G 00 00, 01 ABCL gain adjustment 14 TRAP 03 00~03 Trap frequency adjustment 15 WBK 00 00, 01 White back setting 16 BBK 00 00, 01 Blue back setting 17 AFCG 02 00~02 AFC gain adjustment 18 RBI 00 00~255 Red bias adjustment 19 GBI 00 00~255 Green bias adjustment 20 BBI 00 00~255 Blue bias adjustment 21 RD 64 00~127 Red drive adjustment 22 BD 64 00~127 Blue drive adjustment 23 DRV -- -- White balance adjustment 24 -- -- -- Y-cut setting 25 CCD 20 1~31 Caption H-Position Adjustment

Service mode adjustments table in CPU ROM

Grey scale adjustment

Notes:

The initial value that the CPU writes down the CPU ROM data to the memory when replaced the memory IC.TV set

may not operate correctly with this initial value. It is required to set up the fine adjustment for service adjustments described below.

Adjustments Service Mode No. & Item

Horizontal centre adjustment Item 01, H-P Vertical centre adjustment Item 02, V-P Vertical size adjustment Item 03, V-S OSD position adjustment Item 04, OSD RF AGC adjustment Item 05, AGC AFT adjustment Item 06, VCO Grey scale adjustment Item 18-24

Further adjustment please refer to pages 10 and 11.

-9-

00100100

23 DRV R 64 B 64

Service Adjustments with Replacing Memor y IC(IC802)

[Entering to Service Mode]

1. Press and hold the MENU button on the TV set and press the 2 button on the remote control handset.Following

setting items appears on the screen.

Display for [H-P] Horizontal centre adjustment

00100100

01 H-P 08

Read Status

Item No. Item

Data value

Data value for Red

Display for [DRV] White balance adjustment

Read Status

Item No. Item

Data value for Blue

To retur n to nor mal TV mode, press the MENU button on the TV set or remote control handset.

2. Select item by pressing the CHANNEL DOWN (Item No.UP) or CHANNEL UP (Item No.DOWN) button on the

remote control handset.

3. Adjust data value by pressing the VOLUME + or VOLUME

button on the remote control handset.

Example

▲CH▼

DISPLAY

MUTE

▲CH▼

+VOL

IMAGE

VOL-

01➔02➔03➔04➔05......27

27➔26➔25➔24➔23......01

▲CH▼

+VOL

DISPLAY

MUTE

VOL-

VOL +

-10-

Service Adjustments with Replacing Memor y IC(IC802)

(1)Receive the monochrome circular pattern. (2)Set the brightness and contrast to normal. (3) Select [H-P] in the service mode. (4)Change value to be optimum horizontal centre position. (5)Exit from the service mode.

(1)Receive the monochrome circular pattern. (2)Set the brightness and contrast to maximum. (3) Select [V-P] in the service mode. (4)Change value to be optimum vertical centre position. (5)Exit from the service mode.

(1)Receive the monochrome circular pattern. (2)Set the brightness and contrast to maximum. (3) Select [V-S] in the service mode. (4)Change value to be optimum vertical size. (5)Exit from the service mode.

(1)Receive the monochrome circular pattern. (2)Set the brightness and contrast to normal. (3) Select [OSD] in the service mode. (4)Change value to be proper OSD position. (5)Exit from the service mode.

NOTE: Do not attempt this adjustment with weak signal. (1)Tune the receiver to most clearest (or strongest) VHF

station in your area. Set the brightness and contrast controls to maximum. Set the colour control to mini-

mum. (2) Select [AGC] in the service mode. (3)Change value until the snow noise just disappears. (4)Exit from the service mode.

(1)Connect DC meter to TP-D and the ground. (2) Tune the receiver to the clearest station. (3) Disconnect RF input. (Disconnect antenna plug from

the antenna socket.) (4)Select same channel. (If you have selected channel 03

in step 2, press “0” button next “3”button on the remote

control to select channel 03.) (5)Connect antenna plug to the antenna socket. (6)Select [VCO] in the service mode. (7) Change value until the voltage (on TP-D) to be

4.5±0.2V at OK point.

(8) Exit from the service mode.

(1) Tune receiver to a CAPTION channel. (2) Check that CAPTION position is in the horizontal

center of TV screen.If CAPTION center is too right or

left, perform steps 3-6. (See Figure below.) (3) Select [CCD] in the service mode. (4) Adjust the data with + or - key for proper horizontal

center. (5) Exit from the service mode.

±CAPTION H-POSITION ADJUSTMENT

4.5V ±0.2V

255

VCO DATA

TP-D VOLTAGE

±Item 06 [VCO] AFT

Item 05 [AGC] AGC

Item 04 [OSD] OSD POSITION

Item 03 [V-S] VERTICAL SIZE

Item 02 [V-P] VERTICAL CENTRE

Item 01 [H-P] HORIZONTAL CENTRE

Horizontal centre

Vertical centre

Vertical size

IC001

AUDIO AMP.

IC802

MEMORY

IC201

MAIN BOARD

TP-D (J146)

XXX XXXX XXXX XXX

Caption H-Position Adjustment

A=B

+ 23 hidden pages