Xoceco T2768, IS-TV040928 Schematic

COLOR TELEVISION

T2768/IS-TV040928

CONTENTS

1. INSTRUCTION………………………………………………………………………………1

2. ALIGNMENT PROCEDURE………………………………………………………………..2

3. FOR FACTORY MENU ADJUSTMENT SEE CHART5~CHART11…………………….5

4. GENERAL DESCRIPTION OF THE SDA 9380-B21……………………………………10

5. INTRODUCTION OF THE VPC 3230D………………………………………………..12

6. INTRODUCTION OF THE MSP 3425G…………………………………………………14

7. GENERAL DESCRIPTION OF THE PW1235…………………………………………15

8. GENERAL DESCRIPTION OF THE TDA6111Q………………………………………18

WIRING DIAGRAM……………………………………………………………………….20

BLOCK DIAGRAM………………………………………………………………………...21

SCHEMATIC DIAGRAM………………………………………………………………….22

ELECTRICAL PARTS LIST………………………………………………………………27

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

REFERENCE. BEFORE SERVICING THIS CHASSIS, PLEASE READ THE

FOLLOWING NOTICE ITEMS.

1. 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 see below chart:

Chart 1 High voltage requirement

Model

T2768 30 kV ±1 kV 35 kV 1.6 mA

T3251 30 kV ±1 kV 35 kV 1.6 mA

High voltage normal

value

Utmost value Beam current

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.

* When checking, main power (B+) should be kept at 135 V (for Toshiba pure flat CRT).

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.

1.4 Testing equipment

HDTV signal generator: VG853 or other same type, 1 set. Signal generator: PM5515 or the same type, 1 set. Voltameter: FULK805A or the same type, 1 set. White balance alignment equipment: 1 set Standard testing jigs: 1 set. Geometry alignment equipment: 1 set. Alignment stick: 1 set. Degaussor: 1 set.

2 Alignment procedure

2.1 Instruction

a) In this chassis since there are a great amount of data needed to be set, these setting all are stored

PROM. To reduce the alignment working, use the aligned E2PROM as a female parent to

in E

copy and then use them. Or refer to appendix chart and preset E

b) To conduct the alignment, the power supply should be AC120 V,60 Hz. The whole unit should be

preheated for 30 minutes.

c) To conduct with color purity, convergence, white balance alignment or other alignment relative to

color, the CRT should be degaussed thoroughly.

d) Since this chassis adopts modulization structure, before mounting, every module should be

conducted with alignment.

e) The factory menu’s alignment should use XOCECO RC-T03-0A remote control. Press power

switch to turn on the set, in turn press button “SLP-MUTE-AV-MENU” to enter into factory menu.

PROM value and then use.

Press SLP or 0 button to exit. Press MUTE button to preset before Out-factory.

f) For the supporting mode in this set see below chart 2.

Chart 2 The supporting mode in this set

Working mode Mode instruction H-frequency

TV TV mode 33.75k 60 Adjust firstly, every item should

1920*1080i/33.75K American HDTV mode 33.75k 60 Horizontal and vertical parameter,

720P*576/45.125K American HDTV mode 33.75k 60 Horizontal and vertical parameter,

640*480i(YCrCb) YcbCr(15.7K,59.97HZ) 33.75k 60 Horizontal and vertical parameter,

640*480p(YPrPb) Progressive

DVD(31.5K,60HZ)

33.75k 60 Horizontal and vertical parameter,

V-frequencyHz Alignment instruction

adjust

white balance

2.2 Alignment procedure

2.2.1 Module alignment

In all the module alignment, use a normal working TV set as an alignment frock, pull the set’s

corresponding module and keep it as an example. Insert the module wanted to be check,

then apply power to alignment.

a) AV board module

AV interface function check: check all the AV input/outputs function, it should meet the Product

Standard requirements.

b) Digital processing board module

No alignment point, apply the power and check whether S-VIDEO, YCbCr, YpbPr input is normal.

c) Main board

No alignment point. Apply the power and measure “B+” voltage, the reading should be 105V,

check there are no assemble error, the OSD,SVM is normal, and it is OK.

2.2.2 Chassis adjustment

Correctly insert all modules and parts, connect CRT board parts to CRT, apply power and

check B+ voltage, the reading should be 105V. (on J332/J305)

2.2.3 The whole unit adjustment

Be sure the whole unit has been preheated for 30 minutes.

a) Focus adjustment

1) In TV mode receive crosshatch signal, at the same time set SVM to OFF.

2) Adjust FOCUS inductance L306 on Dynamic Power Board to make R323 dynamic focus

voltage be 1KV+/-50V.

3) Adjust FOCUS potentiometer on FBT and CRT to make horizontal and vertical grid both

thinnest, and consider horizontal grid mainly.

4) Set SVM to ON, check the whole effect.

b) Dark current (SCREEN voltage) adjustment

In TV mode receive gray scale signal, after entering into factory menu status, press “1” button to

enter into “FACTORY MENU 1” factory menu, first preset WHITE-R, WHITE-G, WHITE-B’s value

all to 0, adjust SCREEN potentiometer to make SCREEN LOCK on the screen lower part display

OK and it is OK, at this time, if changing channel, it should not appear flyback line. This state

should also be OK after finish adjusting the white balance. .

c) White balance adjustment

Adjust on the basis of the above step, at standard status use gray scale signal to adjust.

1) Press “1”button to firstly adjust TV input white balance: fix the testing point at about 40 nits gray

scale, then by adjusting WHITE-R,WHITE-G and WHITE-B to make the value meet chart 3’s

requirement.

2) Press “5” button to adjust YpbPr input white balance: use oscilloscope to measure Y signal

output on Digital Processing Board. Adjust G-0 gray scale to make blanking level be even with

black level, adjust G-G to make signal amplitude to be 0.7V and eight level gray scale be even,

then adjust R-G, B-G, R-0, B-0’s value to make white balance meet chart 3’s requirement.

Chart 3: chroma coordinates requirements

Colour temperature 12000K

X coordinate 0.270±0.008 MPDC

Y coordinate 0.283±0.008 MPDC

d) Picture size position and high voltage adjustment

In component mode input 1080I signal

(1) Use crosshatch and electrical circle signal, after entering into factory menu status, press “2”

button to enter into “FACTORY MENU 2” factory menu to adjust picture’s linearity. Adjust

R339 joint point to make the V-center deflection range be within ±5MM(T3251), or

±3MM(T2768).

(2) Change the signal to white background, or greatly change contrast and brightness, or press

PIC button to switch among several kinds of analogue amount to make corresponding

beam current changes, adjust V-EHT-COM, H-EHT-COM to make raster’s size basicly not

change when at different beam current status.

3) According to chart 2 in turn apply every testing signal (firstly apply YpbPr signal, then TV or AV

signal), then press “5” button to enter into “FACTORY MENU 5”, adjust H-S, V-S, H-SIZE, V-SIZE to

make picture normal.

e) Sub-brightness adjustment

Receive split field signal, set colour/contrast/brightness to 0, check whether screen second gray is

slightly bright, otherwise press “6” button, in factory menu select CONTRAST MAX and BRIGHT

MAX to adjust.

f) Filament/beam current/high voltage check and adjustment

1) Filament voltage: receive a TV program signal, set picture mode to “STANDARD”,the filament

voltage effective value should be 6.3±0.2 Vrms.

2) Beam current check: receive all white field signal, set picture mode to “SPORTS”, measure

R360 two terminals’ voltage and the reading should be less than or be equal to 1.6V. If not,

after entering into factory menu status, press “4” button to enter into “RGB MENU” factory

menu, adjust AV BEAM LIMIT item to make beam current meet requirements.

3) High voltage check: receive D8 signal, set picture mode to “STANDARD”, measure CRT high

voltage and the reading should be A value in chart 3. When brightness, contrast is set to

minimum (zero beam current), measure the high voltage, the reading should not exceed B

value in chart 4.

Chart 4 High voltage check requirements

Parameters

74 cm(2751) 86 cm(3251)

A 30 kV±0.5 kV 30 kV±0.5 kV

B 34+ kV 34 kV

4) High voltage protection: receive a picture signal, adjust until picture and sound are normal,

short R340 and the circuit should immediately enter into power-off protection state and the

state should keep. Turn off the power switch and then turn on, the picture and sound should

restore to before-testing state.

g) Peak value adjustment

On the condition of SCREEN and beam current has been adjusted properly, in order to show

picture’s contrast well and control picture’s colour tail, apply a little beam current picture (for

example, black and white crosshatch) and set picture’s contrast and brightness to maximum, then

after entering into factory menu status, press “4” button to enter into “RGB MENU” factory menu,

by adjusting PEAK DRIVE LIMIT item to make the whole unit’s picture colour just without colour tail

on the condition of maximum contrast and it is OK.

h) Every control buttons’ check

Check according to Instruction manual.

i) Check all the input/output terminals’ function, please check according to “PRODUCTION

STANDARD”

i) Out-factory setting

Set picture to “Standard”.

Set sound to “Music”.

Set Blue back to ON.

Set OSD language to English.

Set DNR to SOFT.

Set SVM to ON.

Set Volume to 30.

Set Loudness to OFF.

Set AVC to ON.

Set CCD to OFF.

Set child lock password, V-chip password to 0000.

Set V-chip all rating to no rating .

Set the channel to Cable 3. .

CRT Size

3 For factory menu adjustment see Chart 5~Chart 11.

Chart 5 Factory menu (1)WRITE

Item name Item instruction Range

WRITE R Bright balance R BF-3F Refer to white balance adjustment part 1

WRITE G Bright balance G BF-3F Refer to white balance adjustment part 1

WRITE B Bright balance B BF-3F Refer to white balance adjustment part 1

SCREEN

LOCK

2003-XX-XX Version date fix

Dark current

adjustment

OK/OFF OK

Default

value

Adjust SCREEN potentiometer until OK

Chart 6 factory menu (2)

Item Item instruction Range

V SIZE V-size 80-7F 39 To make vertical reproduction rate reach

V SHIFT V-center 80-7F 17 To make picture center and CRT center be

V LINEAR V-linearity 80-7F 41 To make V-linearity distortion minimum.

V S CORR Vertical S-correction 80-7F F7 To make vertical S-correction distortion

H SIZE H-size 80-7F 08 To make horizontal reproduction rate reach

H SHIFT H-center 80-7F 43 To make picture horizontal center be in

V ANGLE Parallelogram correction 80-7F 05 To correct parallelogram distortion

V BOW Arch correction 80-7F 0E To correct arch distortion

PIN AMP Pincushion correction 80-7F 60 To make pincushion distortion minimum

PIN PHASE Trapezoid correction 80-7F AE To make trapezoid distortion minimum

CORNER

LOWER

CORNER

EXT

CORNER

V SYNC

CONT

Upper edge corner

correction

Lower edge corner

correction

Edge and corner

correction

80-7F 20

80-7F 11 To correct upper two corners distortion

80-7F C5 To correct lower tow corners distortion

80-7F C5 Corner edge correction

Default

value

90%-92%

in accordance

minimum.

90%-92%

accordance with CRT center.

Chart 7: factory menu (3)

Item Item instruction Range

V SCROLL Vertical scroll 0-FF 00 Not adjust, set default value

V ASPECT V-size 0-FF 00 Not adjust, set default value

Default

value

Adjusting method

Adjustment method

V EHT Vertical high

voltage correction

H EHT Horizontal high

voltage correction

AFC EHT COM High voltage auto

frequency control

H BLANK TIME Horizontal

blanking width

H BLANK PHASE Horizontal

blanking phase

V BLANK START V-sync phase 80-7F FB Not adjust, set default value

V BLANK END V-sync phase 80-7F 11 Not adjust, set default value

MIN NO.OF LINE H-blanking phase 80-1F 00 Not adjust, set default value

MAX NO.OF LINE H-blanking end

position

PWM CONTROL H-blanking width 80-7F 02 Not adjust, set default value

PLL CONTROL 0 H-blanking width 80-7F 0B Not adjust, set default value

PLL CONTROL 1 H-blanking width 80-7F 62 Not adjust, set default value

80-7F BD To make vertical raster size not change

when beam current changes greatly.

80-7F 9D To make horizontal raster size not change

when beam current changes greatly.

20-1F 08 Not adjust, set default value

80-7F E4 Not adjust, set default value

80-7F F9 Not adjust, set default value

80-7F FF Not adjust, set default value

Chart 8 Factory menu (4)RGB MENU

Item Item instruction Range

INT H-SYNC

PHASE

AV BEAM LIMIT Beam current limit 80-7F 1A Refer to beam current adjustment part

AV BEAM LIMIT

CHA

PEA DRIVE LIMIT Peak value limit 80-7F 00 Refer to peak value adjustment part

PEAK DRIVE TOP Top peak value

PEA DRIVE

BOTTOM

PEA DRIVE L-R Left/right edge

DEFLECT 0 80-7F 03 Can not adjust, set default value

DEFLECT 1 80-7F 05 Not adjust, set default value

RGB CONTROL 0 80-7F 84 Not adjust, set default value

RGB CONTROL 1 80-7F 18 Not adjust, set default value

RGB CONTROL 2 80-7F 20 Not adjust, set default value

RGB CONTROL 3 80-7F 03 Not adjust, set default value

V INPUT MODE 80-7F 85 Not adjust, set default value

H-sync phase 80-7F 12 Not adjust, set default value

Beam current limit 80-7F 81 Refer to beam current adjustment part

80-7F 10 Not adjust, set default value

limit

Bottom peak

value limit

peak value limit

80-7F 47 Not adjust, set default value

80-7F 88 Not adjust, set default value

Default

value

Adjustment method

Chart 8 factory menu FACTORY 5(HDTV mode)

Item Item insturction Range

R-G Red gun gain 00-FF 80 Refer to white balance adjustment part2

G-G Green gun gain 00-FF 80 Refer to white balance adjustment part2

B-G Blue gun gain 00-FF 80 Refer to white balance adjustment part2

R-O Red gun bias value 00-FF 80 Refer to white balance adjustment part2

G-O Green gun bias value 00-FF 80 Refer to white balance adjustment part2

B-O Blue gun bias value 00-FF 80 Refer to white balance adjustment part2

H-S H-phase 00-FF Geometrical adjustment

V-S V-phase 00-FF Geometrical adjustment

H-SIZE H-size 00-FF Geometrical adjustment

V-SIZE V-size 00-FF Geometrical adjustment

Default

value

Adjustment method

Chart 9: factory menu 6

Item Item instruction Range

CONTRAST

MAX

CONTRAST

CEN

CONTRAST

MIN

BRIGHT

MAX

BRIGHT

CEN

BRIGHT

MIN

COLOR

MAX

COLOR

CEN

COLOR MIN Colour minimum value 00-7F 00 Not adjust, set to default value

SHARP

MAX

TINT CEN Tint center value 00-7F 00 Not adjust, set to default value

Contrast maximum 00-7F 7F Not adjust, set to default value

Contrast center value 00-7F 3F Not adjust, set to default value

Contrast minimum value 00-7F 00 Not adjust, set to default value

Brightness maximum value 00-7F 7F Not adjust, set to default value

Brightness center value 00-7F 3F Not adjust, set to default value

Brightness minimum value 00-7F 00 Not adjust, set to default value

Colour maximum value 00-7F 3F Not adjust, set to default value

Colour center value 00-7F 20 Not adjust, set to default value

Sharpness maximum

value

00-7F 7F Not adjust, set to default value

Default

value

Adjustment method

Chart 10 Factory menu 7

Item Item instruction Range

VOLUME-1 Sound curve 00-7F 0F Not adjust, set to default value

VOLUME-25 Sound curve 00-7F 1F Not adjust, set to default value

Default

value

Adjustment value

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