Xoceco TS2753, LET2753 Schematic

COLOR TELEVISION

TS2753

(LET2753)

CONTENTS

Safety Precautions………………………………………………………………………..…… Alignment instruction. ………………………………….…………………………….……. Debugging instruction …………………………………………….…………………………. Block diagram ……………………………..…..…..…..…..…..…….………….…………… IC Block diagram……………………..……………………….……………………………… Wiring diagram……………………………………………………………………………..… Exploded view………..…..…..…..…..…..…..…..…..…..…..…..…..…..…..…..…..…..…...

Part list ………………………………………………………..……………............................

Schematic diagram …………………………………………………………………….……..

1 2 3 9 10 14 15 17 36

Note:This service manual is only for professional service personnel’s reference. Before

1. SAFETY I NSTRUCTION AND GENERAL INSTRUCTION

1.1 X-RAY RADIATION PRECAUTION

1） Excessive high voltage can produce potentially hazardous X-RAY RADIATION. To avoid such

2） Each time a receiver requires servicing, the high voltage should be checked following the HIGH

3） The primary source of X-RAY RADIATION in this TV receiver is the picture tube. For continuous

servicing the unit, please read the following items carefully.

Before servicing and aligning this equipment, please read the following “X-RAY RADIATION PRECAUTION” , “SAFETY PRECAUTION” and “PRODUCT SAFETY NOTICE”.

hazards, the high voltage must not be above the specified limit. The normal value of the high voltage

of this receiver is below 31.5kV at 1.6A beam current, the high voltage must not, under any

circumstances, exceed 33kV.

VOLTAGE CHECK procedure in this manual. It is recommended the reading of the high voltage be

recorded as a part of service record. It is important to use an accurate and reliable high voltage

meter.

X-RAY RADIATION protection, the replacement tube must be exactly the same type tube as

specified in the parts list.

4） Some parts in this receiver have special safety-related characteristics for X-RAY RADIATION

protection. For continuous safety, parts replacement should be undertaken only after referring to the

PRODUCT SAFETY NOTICE below.

1.2 SAFETY PRECAUTION WARNING:

Service should not be attempted by anyone unfamiliar with the necessary precaution on this receiver.

The following are the necessary precautions to be observed before servicing this chassis.

1) Since the power supply circuit of this receiver is directly connected to the AC power line, an isolation

transformer should be used during any dynamic service to avoid possible shock hazard.

2) Always discharge the picture tube anode to the CRT conductive coating before handling the picture

tube. The picture tube is highly evacuated and if broken, glass fragments will be violently expelled.

Use shatter proof goggles and keep picture tube away from the unprotected body while handling.

3) When replacing a chassis in the cabinet, always be certain that all the protective devices are put

back in place, such as: non-metallic control knobs, insulating covers, shields, isolation

resistor-capacitor network etc.

4) When replacing parts or circuit boards, disconnect the power cord.

5) When replacing a high wattage resistor (oxiode metal film resistor) on the circuit board, keep the

resistor 10mm (1/2in) away from circuit board.

6) Connection wires must be kept away from components with high voltage or high temperature.

7) If any fuse in this TV receiver is blown, replace it with the FUSE specified in the chassis parts list.

1.3 PRODUCT SAFETY NOTICE

Many electrical and mechanical parts in the chassis have special safety-related characteristics. These

characteristics are often passed unnoticed by a visual inspection and the X-RAY RADIATION protection

afforded by them cannot necessarily be obtained by using replacement components rated for higher

wattage, etc. Replacement parts which have these special safety characteristics are identified in this

manual and its supplement electrical components having such features are shaded on the schematic

diagram and the parts list. Before replacing any of these components, read the parts list in this manual carefully. The use of

substitute replacement parts which do not have the same characteristics as specified in the parts list

may create shock, fire, X-RAY RADIATION or other hazards.

2 Alignment items and procedur e

The alignment flow chart (see below figure).

EEPROM copy

B+ check

Focus adjust and aging

High-handed

Field breadth and field line

White balance and sub-bright

RF AGC adjust

Audio check

VG2 adjust

H-field and center

field and field breadth

Filament voltage

X-ray protect

Picture and audio

Sub-brightness

White balance

OSD center position

Color pure and assemble

Foucs fine adjust

AV (S.DVD)

The button check

Leave factory state setup

Remote control check

check

Assemble check

Safety check

3 TEST EQUIPMENT

3.1 AUDIO VOLTAMETER

3.2 OSCILLOGRAPH

3.3 HIGH-VOLTAMETER

3.4 DIGITAL MULTIMETER

3.5 AC ATTACK PULL TEST EQUIPMENT

3.6 SCAN frequency signal generator BT-3

4 Debugging instruction

4.1 enter into the factory debugging m enu

use to the remote control(RC-A23),follow to the blow model enter into the factory:

DISPLAY → MUTE → MUTE → MUTE → enter into the factory

press “sleep” button for pages upward, press “return” button for pages downward, press “CH+/-” to

select alignment items and “VOL+/-” to adjust volume, press “MUTE” to exit.

If the remote sensor designed for alignment is unavailable, press the following buttons to enter by

using user remote sensor

4.2 B+ voltage adj ustment

Check B+ voltage ( negative pole of VD509) by using DC voltmeter DC 200V of 135V±2.

4.3 AGC adjustment

Measure the voltage of RF AGC by connecting digital DC voltmeter with TP3, receive weak signal

(40dBu) and the static AGC voltage of TP1 AGC should be V1=4V±0.2V; the receive antenna signal

(60dBu), adjust the value of P6 RF. AGC of factory menu and the start-control voltage of TP1 AGC

should be V2=3.5V±0.2.if V2>3.5V, then the voltage is -1 or -2,if V2<3.5V, then the voltage is+1 or+2. the

antenna input 100dBu signal, after the picture should not be appeared no-sync , distortion and moire;

input 35-40dBu weak signal ,it should not be appeared distortion and no-sync and sound abnormity

electrophoresis of it.

4.4 White balance and screen-grid voltage adjustment

After enter P5 of factory menu, use remote sensor directly to adjust white balance by pressing the

following digital buttons:

“1”=R.BIAS(+) “2”=G.BIAS(+) “3”=B.BIAS(+)

“4”=R.BIAS(-) “5”=G.BIAS(-) “6”=B.BIAS(-)

press “p-p” button to select picture mode custom→T1→T2→bright→soft→nature→user→custom will

be display on the screen.

The T1 mode has the maximum value of brightness and contrast with all the other items minum. Value of

all the analog are minimum while in T2 mode.

Before adjustment you should set the following items: SUB-BRIGHT=50, R.B=100, G.B=100, B.B=100,

R.D=100, G.D=15, B.D=100

press “P-P” button to select T2 picture mode, press CH+/- to select LINE, press vol+ to let the field

scanning fail to oscillate, adjust the screen-grid potentiometer on FBT clockwise to let horizontal bright

line just appear on the screen; let the value of G.B unchanged, adjust R-B and B-B to let the horizontal

bright line appear white. If the green horizontal line don’t appear firstly, fine-turn the screen-grid voltage,

green and blue just appear. After adjustment press VOL- to obtain normal field scanning mode.

4.5 Receive signal (A7), enter P6 of factory menu, adjustment SUB-BRIGHT to let picture on the screen

micro-bright.

4.6 receive white balance adjustment signal

enter P5 of factory menu, press PP to select T1 picture mode, let the value of G.D unchange, adjust R.D

and B.D to let the white part of the picture appear “white”.

4.7 Use white balancer to rectify the white balance under following conditions

color temperature:12000K+8MPCD x =0.270± 0.008 Y=0.283±0.008; dark space: 4.5nit, bright space:

60nit

Note:1. While the colour saturation changed from maximum to minimum, if the dark balance appears

changeable,adjust RY.TV and BY.TV (P12) to let it coincide with white balance.

2. If the dark balance appears changeable while connected with DVD, adjust BY.YUV and RY.YUV

(P12) to let it conincide with white balance.

4.8 line-filed scanning amplitude and linearity and center adjustment and raster correct adjstment.

4.9 receive signal (A28), press the PP button the picture model, set standard adjustment the P1 of

V.SIZE and V.SHIFT and H..PAHSE and V.LINE and VSC, let the P2 coincide with request.

4.10 receive signal (G43), press the PP button the picture model, set standard adjustment the P3 of

V.SIZE and V.SHIFT and H..PAHSE and V.LINE and VSC, let the P4 coincide with request.

4.1 1 Hi gh voltage and filament voltage check

Connect a high-voltage meter between anode cap of picture tube and the ground, measure the filament

voltage using rms voltmeter, set the picture mode to “standard”, the high-voltage: 29KV±1.5KV,filament

voltage: 6.3±0.1Vrms.

4.12 x -ray protection check

Receive local TV signal, set the picture mode to “standard”, shorten the circuit and measure the

value of TP1-TP2, restart the TV 30 seconds after turn off the power source and it should return to

normal.

4.13 AV function check

according to the owner’s manual require, connect to the AV equipment and the AV interface:

VIDEO IN: 1 Vp-p 75OHM AUDIO IN: (-8±3)dBm>47 kOHM

S interface Y IN: 1 Vp-p 75OHM C IN: 0.3 Vp-p 75OHM

DVD Y IN: 1 Vp-p 75OHM Cr IN: 0.7 Vp-p 75OHM

Cb IN: 0.7 Vp-p 75OHM

4.14 AV parts check

incept to standard the TV signal:

a） AV and crossfire and allophone and shake ; b） The user control function ana picture model c） The remote control function check; d） Color pure and converge check.

4.15 leave factory state setup

Picture model (PP) STENDARD

language All the country language

Color system AUTO

C.CAPTION C1

CCD ON MUTE OFF

RECEPTION AIR

AFT ON

MTS AUTO

PASSWORD CLEAR

volume 30

4.16 the factory menu adjustment model pre-set

OSD item Pre-set model

P1-60

V SIZE 60HZ field amplitude 63 4.9

V SHIFT 60HZ field center 0 4.9

H-PHASE 60HZ H-center 15 4.9

V LINE 60HZ V-line 15 4.9

V SC 60HZ field S-correct 23 4.9

V COMP field amplitude compensate 7 fixed

L.BLK Left blanking 7 fixed

R.BLK Right blanking 0 fixed

P2-EW-60

COR.SW margin correct 1 Fixed

H.SIZE.COMP High voltage compensate 7 fixed

TILT 60HZ echelon correct 44

DC 60HZ H-amplitude 32

AMP 60HZ pincushion correct 25 COR.TOP 60HZ Top margin correct 4 COR.BOT 60HZ bottom margin correct 3

V SIZE 50HZ field amplitude 75 4.10

V SHIFT 50HZ field center 0 4.10

H-PHASE 50HZ H-center 10 4.10

V LINE 50HZ V-line 16 4.10

V SC 50HZ field S-correct 20 4.10

P4 EW-50

TITL 50HZ echelon correct 49

DC 50HZ H-amplitude 35

AMP 50HZ pincushion correct 41 COR.TOP 50HZ Top margin correct 6 COR.BOT 50HZ bottom margin correct 10

LINE Level bright line 0 0=normal 1= Level bright line

RB Red cut off 100 4.4

GB Green cut off 100 4.4

BB Blue cut off 100 4.4 RD Red driver 100 4.4 GD Green driver 15 4.4

BD Blue driver 100 4.4

RF AGC RF AGC 30 4.3

SUB-BRI Sub-brightness 60 4.4

SUB-CNT Sub-contrast 31 fixed

Receive signal A12, adjust the linearity scanning and

geometric distortion and over-scanning coincide with it

P3-50

Receive signal G35, adjust the linearity scanning and

geometric distortion and over-scanning coincide with it

SUB-COL Sub-colour 3 fixed

SUB-SHP Sub-definition 0 fixed

SUB-TINT Sub-tint 28 fixed

VOL.FIL Volume control ADC filter 0 fixed

OSD.COT OSD contrast 5 fixed

OSD.HPOS OSD center 10 fixed

AFT

VIF SW IF3=45.75MHZ 3 fixed

SIF SW Sound IF0=4.5MHZ 0 fixed

VIDEO LEVEL VIDEO LEVEL 2 fixed

A2 .SW 0 fixed

GY ANGLE G-Y demodulation angle 0 fixed

V.R TM Filed scan strting time 0 fixed

R/B ANG R-Y/B-Y demodulation angle 8 Fixed

R/B BAL

C TRAP Color trap filter 6 fixed

H FREQ H-frequency 16 fixed

C.BPF TEST

OVER.MOD.SW

OVER.MOD.LVL

BLK.STR

BLK.GAIN Dark level expand gain 2 Fixed,0=MIN 2=MAX

Y.APF Selection color trap filter 1 0=trap filter,1= direct pass(YcbCr&Y/C)

PRE.ADJ Pre-shoot 3 fixed, 0=narrow 3=width

OVER ADJ overshoot 3 Fixed,a 0=narrow 3=width

C.VCO.ADJ

BRT.ABL.DEF Brightness ABL 0 fixed,0=ABL ON 1=ABL OFF

MID.STP.DEF ABL start control point 0 fixed

BRT.ABL.THR ABL threshold 7 fixed

WPL.OPE White peak limit 2 fixed

V BLK.SW Field blanking switch 0 fixed ,0=nomarl;1=width model

Line AFC loop gain and sync

gate switch

R-Y/B-Ydemodulation

balance

Color band filter center

frequency

Selection over-modulation

function

Adjustment over-modulation

working point

Dark level expand starting

control point

Color VCO frequency

adjustment

8 fixed

0 fixed

0 Fixed,0=nothing 1=have

0 fixed

2 Fixed,0=40IRE 2=60IRE 3-OFF

4 fixed,0－4－7=-120KHZ-0-90KHZ

P10

fixed

FBP BLK SW Horizontal blanking switch 1 fixed,0=inside produce;1=FBP and inside logic “and”

DC REST DC recover rate 1 fixed,0=100% 1=107%

CD.MODE

CORE GAIN Noise reduction 2 fixed,0=OFF 1=MIN 3=MAX

γ.GAMA r-correct 0 fixed,0=OFF

RGB TEMP.SW

A.MONI SW Selection pin5 output 1 fixed，1=SAO

SVO OR FSC Selection pin5 output 0 fixed,0=VIDEO 1=FSC(color sub-carrier wave)

CROSS B/W Selection test signal 0 fixed,0=TV

CRAY.MODE Test signal 0 fixed,0=white(75%)1=grey(15%)

BY TV Blue chromatism DC level 8 4.4 adjustment dark white balance(TV/AV model)

RY TV Red chromatism DC level 8 4.4 adjustment dark white balance(TV/AV model)

BY YUV

RY YUV

S.TRAP.TEST Sound trap filter adjustment 6 fixed

LOW.BRI Min-brightness 28 fixed

LOW.CONT Min-contrast 30 fixed

COL.KILL Achromatic level 7 fixed,0=-30dB 3=-40dB

VCO.FREQ VCO frequency 32 fixed

VM.GAIM VM gain adjustment 0 fixed

VM.DELAY ADJ VM relay time adjustment 0 fixed

VCO TEST VCO adjustment 0 fixed

VPOS-50

VPOS-60

Y GAIN 0 fixed

Y TH 0 fixed

B OFFSET 0 fixed

B WIDTH 0 fixed

C OFFSET 0 fixed

C WIDTH 0 fixed

CAN.V CHIP V-CHIP 0/1 1=CAN.V-CHIP

Field frequency division

model

RGB DC output

temperature speciality

DVD input Blue chromatism

DC level

DVD input Red chromatism

DC level

50HZ field center voltage

adjustment

60HZ field center voltage

adjustment

0 fixed,0=auto

P11

1 fixed

P12

8 4.4 adjustment dark white balance (DVD input)

8 4.4 adjustment dark white balance(DVD input)

P13

P14

OPTION

fixed

AV AV selec t i o n 3 AV input select(3=AV1/AV2/S/DVD)

MTS MTS IC selection 1/0 0=nothing,1=72700 2=AN5832

V.OFF.MOTE Turn off model 1 0=discharge,1=close

PWR.MEM Turn on model 0/2 0=standby,1=auto turn on,2=memory

1115 select LV1115 0 fixed,0=nothing;1=have

BLCK GROND

N/PN

VOL.OFFSET 0

GAIN 3

PWM LOGIC 0

AVL MODE 2

AVL DET LEVEL 0

AVL SLOPE 0

PWM.VOL Volume control of PWM set 1 fixed

1-CHIP.VOL Volume control of mono 0 fixed

VOL 1 1% volume control speciality 20 fixed

VOL 25 25%volume control speciality 60 fixed

VOL 50 50%volume control speciality 90 fixed

VOL 75 75%volume control speciality 100 fixed

ALC ALC 1 fixed ,1=ALC ON

VOL

SAP LEVEL SAP level 1 fixed

SIF.M/BB.M SIF and baseband model 0 fixed,0=SIF MODE 1=BB MODE

AGC 1 fixed

No signal background

selection

South America and North

America selection

Baseband model ,input level

adjustment

1 0=nothing 1/3=blue background;2=black background

1/0 0=south america;1=north america

1115(the unit no use)

PWM SET

72700

0 The unit no use

5832

Note:above “/” are the adjustment data for north america, below it are for south america.

BLOCK DIAGRAM

IR TX

M3428M1-D48GP

T101

TUNER

IR RX

MEMORY

N202

M24C08

Y Cr C b

REM

S IN

VIDEO

V SWITCH

4053

A SWI TCH

AUDIO

OUT

4053

VIN

Y Cr Cb

TV OUT

SIF

A OU T

MTS

V OUT

I2C BUS LINE

CPU

CHROMA

H VCC

2SC2539

V302

SAWF

PIF

DEFLECTION

VIDEO

HOUT

L 78041

N301

LA76932

5V-1

VOUT

N503

VIDEO

OUT

POWER

N501

CQ12656RT

UDIOAMPAN7522

14V

C 120V

110 V

110V

DRIVE

CRT

T301

FBT

EHV

28V

MAIN IC

LA76930 BLOCK DIAGRAM

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