Xoceco TS2053, LET2053 Schematic

COLOR TELEVISION

LET2053

(TS2053)

CONTENTS

Safety Precautions………………………………………………………………………..……

Alignment instruction. ………………………………….…………………………….…….

Debugging instruction …………………………………………….………………………….

IC Block diagram ……………………………..…..…..…..…..…..…….………….………….

Function introduction to pin……………………..……………………….…………………..

Wiring diagram……………………………………………………………………………..…

Exploded view………..…..…..…..…..…..…..…..…..…..…..…..…..…..…..…..…..…..…...

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

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

AUTION: THIS SERVICE MANUAL IS ONLY FOR PROFESSIONAL SERVICE PERSONNEL’S

REFERENCE. BEFORE SERVICING THIS CHASSIS, PLEASE READ THE

FOLLOWING NOTICE ITEMS.

1. SAFETY I NSTRUCTION AND GENERAL INSTRUCTION Before servicing and aligning this equipment, please read the following “X-RAY RADIATION PRECAUTION” ,”SAFETY PRECAUTION” and “PRODUCT SAFETY NOTICE”.

1.1 X-RAY RADIATION PRECAUTION

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

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

of this receiver is under 24.5kV(21”) and 22.5KV(14”) at zero beam current (minimum brightness),

the high voltage must not, under any circumstances, exceed 30kV.

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

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.

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

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-radial 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

14”110 V±1 V CRT 21”PF 100 V CRT A15QDX992X002(H)

21”110 V±1 V CRT 54SX503Y22-CD01 A51LVV898X12

4.3 AGC adjustment

Measure the voltage of RF AGC by connecting digital DC voltmeter with TP1, receive weak signal

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

(60dBu), adjust the value of PAGE8 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.

after adjustment the picture should not appear no-sync , distortion and moire.

White balance and screen-grid voltage VG2 adjustment

After enter PAGE3 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 “pp” button to select picture mode→T1→T2→bright→soft→nature→user→ the current picture

mode will be display on the screen.

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

Adjustment method: 1. press PP button to select T2 picture mode, press CH+/- to select V.K, 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-BIAS and

B-BIAS to let the horizontal bright line appear white. If the green horizontal line don’t appear firstly,

fine-turn the screen-grid voltage, the adjust R.B and B.B until red , green and blue just appear. After

adjustment press VOL- to obtain normal field scanning mode.

4.4 Receive grey-scale signal (D8), enter PAGE4 of factory menu, press PP to select T2 picture mode,

adjustment SUB-BRIGHT to let picture on the screen microbright.

4.5 receive white balance adjustment signal

enter PAGE3 of factory menu, press PP to select T1 picture mode, let the value of GD unchange, adjust

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

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

colour temperature:12000K+8MPCD

x =0.270± 0.008 Y=0.283±0.008 dark space : 4.5nit, bright space: 60nit

Note:1. Check the white balance of bright field and dark field by receiving monochrome signal or

adjusting the degree of saturation to minimum under maintenance condition, adjust RGB BIAS in dark

field and RGB DRIVE in bright area, adjust bright/dark balance repeatedly until the bright and dark

field have no colour drift.

2. While the colour saturation changed from maximum to minimum, if the dark balance appears

changeable, adjust RY.DC.LVL and BY.DC.LVL (page3) to let it coincide with white balance.

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

YUV.RY.DC (PAGE4) to let it conincide with white balance.

4.7 High 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: 24.5KV±1KV of 21”,

22.5KV±1KV of 14”,filament voltage: 6.3±0.1Vrms.

4.8 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.

4.9 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

4.10 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.

4.11 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

4.12 the factory menu adjustment model pre-set

OSD item Pre-set model

P1-60

V SIZE 60HZ field amplitude 50 4.5.1

V SHIFT 60HZ field center 0 4.5.1

H-PHASE 60HZ H-center 9 4.5.1

V LINE 60HZ V-line 15 4.5.1

V SC 60HZ field S-correct 10 4.5.1

V COMP field amplitude compensate 7 fixed

L.BLK Left blanking 3 fixed

R.BLK Right blanking 3 fixed

P3-50

V SIZE 50HZ field amplitude 50 4.5.2

V SHIFT 50HZ field center 0 4.5.2

H-PHASE 50HZ H-center 6 4.5.2

V LINE 50HZ V-line 13 4.5.2

V SC 50HZ field S-correct 10 4.5.2

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 127 4.4

SUB-CNT Sub-contrast 31 fixed

SUB-COL Sub-colour 15 fixed

SUB-SHP Sub-definition 15 fixed

SUB-TINT Sub-tint 28 fixed

VOL.FIL Volume control ADC filter 0 fixed

OSD.COT OSD contrast 2 fixed

OSD.HPOS OSD center 6 fixed

AFT

VIF SW IF3=45.75MHZ 3 fixed

Line AFC loop gain and sync

gate switch

fixed

SIF SW Sound IF0=4.5MHZ 0 fixed

VIDEO LEVEL VIDEO LEVEL 3 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 R-Y/B-Ydemodulation balance 8 fixed

C TRAP Color trap filter 6 fixed

H FREQ H-frequency 16 fixed

C.BPF TEST

Color band filter center

frequency

0 fixed

OVER.MOD.SW

OVER.MOD.LVL

BLK.STR

Selection over-modulation

function

Adjustment over-modulation

working point

Dark level expand starting

control point

0 Fixed,0=nothing 1=have

0 fixed

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

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

Y.APF Selection color trap filter 0 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

Color VCO frequency

adjustment

fixed,0－4－7=-120KHZ-0-90KHZ

P10

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

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 Field frequency division model 0 fixed,0=auto

P11

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

γ.GAMA

RGB TEMP.SW

RGB DC output

temperature speciality

A.MONI SW Selection pin5 output 1

SVO OR FSC Selection pin5 output 0

r-correct 0 fixed,0=OFF

1 fixed

fixed，1=SAO

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%)

P12

BY TV Blue chromatism DC level 8

RY TV Red chromatism DC level 8

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

P13

COL.KILL Achromatic level 5 fixed,0=-30dB 3=-40dB

VCO.FREQ VCO frequency 32 fixed

P14

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

OPTION

AV AV selec t i on 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

1115(the unit no use)

VOL.OFFSET

GAIN

PWM LOGIC

AVL M OD E

AVL DET LEVEL

AVL SLOPE

PWM SET

DVD input Blue chromatism

DC level

DVD input Red chromatism

DC level

No signal background

selection

South America and North

America selection

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

4.4 adjustment dark white balance (DVD

4.4 adjustment dark white balance(DVD

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

4.4 adjustment dark white

balance(TV/AV model)

4.4 adjustment dark white

balance(TV/AV model)

input)

background

VOL 1 1% volume control speciality 30 fixed

VOL 25 25%volume control speciality 32 fixed

VOL 50 50%volume control speciality 68 fixed

VOL 75 75%volume control speciality 82 fixed

72700

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

5832

AGC 1 fixed

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

Baseband model ,input level

adjustment

0 The unit no use

IC BLOCK DIA GRAM

LA76931

+ 25 hidden pages