DAEWOO DSC-3270E Service Manual

REAL FLAT 100Hz WIDE TV

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DAEWOO

3270E

DAEWOO ELECTRONICS CO., LTD

D I I

D

DIGITAL TV DEVISION

G

2002. 4

I T A L

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3270E

*SPECIFICATION

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D I G I T A L

1.Outstanding Picture Quality

-32” pure Flat Picture Tube

- 4H COMB Filter

- Color Transient Improvement

- 100 HZ Scanning

- Velocity Modulation Scanning

- Dynamic Double Focus System

2. High Quality Sound

- Dolby Pro-Logic

- 8W + 8W + 5W Speaker

3.Various picture control

- Available for 3 kinds of input

- OSD : various language support

- Still picture

- 4:3 , 16:9 , panorama , Zoom , Zoom+

- Tilt control Circuit

4. Reliability

- Safety Standard : CE , CB

- TSD , OCP

DAEWOO ELECTRONICS CO., LTD

DIGITAL TV DEVISION

2

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* POWER BLOCK * DEFLECTION BLOCK

- Stand-by power Part -Horizontal part

- Main power Part -Vertical part

- Audio power part -Dynamic double Focus part

*Video Block * Audio Block

-Tuner part - Audio signal processing part

-AV switching part - Amplify part

3270E

S Y N O P S I S

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D I G I T A L

-video processing part

-video amplify part

INPUT VOLTAGE : AC 230V, 50Hz

POWER CONSUMPTION : 180W (VOLUME MAX, STANDARD PICTURE)

DIGITAL TV DEVISION

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3270E

Block Diagram

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D I G I T A L

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DIGITAL TV DEVISION

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COMPOSITION

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3270E

OF POWER SUPPLY

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POWER SUPPLY is composed of Fly-back form to supply various power.

Pin No USAGE VOLTAGE CURRENT

8 STAND-BY 5V 5 ± 0.5 V 100mAT801

T802

T804

18

17

15

14

13

11 General Purpose 5 ± 0.5 V 500mA

8

FBT B+ 140V line

SVM AMP Transistor B+

H-DRIVE Trans B+

General Purpose

Audio Amp B+

140± 2 V

130 ± 0.5 V

24 ± 0.5 V

12 ± 0.5 V

9 ± 0.5 V

26 ± 2 V

850mA

200mA

500mA

400mA

1200mA

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DIGITAL TV DEVISION

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3270E

Stand By CIRCUIT

THE AC INPUT POWER IS RECTIFIED AND FLATED BY THE NOISE FILTER, BRIDGE DIODE AND CONDENSER (C806)

THE RECTIFIED AND FLATED VOLTAGE IS

SUPPIED TO TRANS AND SMPS IC (I801)

SECONDARY CIRCUIT OF THE TRANS (T801) SUPPLIES THE STAND-BY POWER FOR MICROPROCESSOR

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D I G I T A L

S/B 5V

NOISE

FILTER

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DIGITAL TV DEVISION

6

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3270E

Degaussing CIRCUIT

PIN3 AT MICOM SUPPIES D/G SW SIGNAL (L->H) TO BASE OF Q802

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D I G I T A L

D/G SW

Q802 ON -> CURRENT FLOWS THROUGH RELAY COIL -> SW ON

AC INPUT CURRENT FLOWS AT D/G COIL THROUGH RV801

R838’S RESISTANCE INCREASES BY THE CURRENT THEN THE RELAY IS OFF

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MAIN POWER CIRCUIT

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D I G I T A L

D/G Relay

PWR Relay

28V

D/G SW

PWR SW

PIN53 AT MICOM SUPPIES POWER SIGNAL (L->H) TO BASE OF Q803

AFTER Q803 ON, CURRENT FLOWS THROUGH RELAY COIL. THEN, THE SWITCH ON

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WHEN VOLTAGE AT THE PIN 9 OF STR-S6709 IS APPROXIMATELY 8V I803 (STR-S6709) IS STARTED.

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OPERATION OF STR--

OPERATION OF STR

R807 START RESISTOR

Q801

DARLINGTON TR

D804

S6709

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CHARGED VOLTAGE AT C818 THROUGH START RESISTOR IS APPROXIMATELY 8V THEN, STR-S6709 START

AFTER START, THE STABLE VOLTAGE IS SUPPLIED TO #9 THROUGH THE D WINDING OF T802

T802

DURING d1 VOLTAGE IS RISING TO 8V. RECTIFIED d2 VOLTAGE IS USED

Vin

DAEWOO

D I G I T A L

STARTING POINT

RECTIFIED

d2 VOLTAGE

I803

STR-S6709

DAEWOO ELECTRONICS CO., LTD

C818

D806

D805

7.5V ZENER DIODE

DIGITAL TV DEVISION

d1 VOLTAGE

9

PROTECTIVE FUNCTION

DAEWOO

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3270E

OF STR--

OF STR

S6709

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OCP (Over Current Protection)

OCP IS OPERATED DIRECTLY BY DETECTION OF THE COLLECTOR CURRENT

THROUGH Rocp (R808)

TSD (Thermal ShutDown)

TSD IS OPERATED IN THE CASE THAT FRAME TEMPERATURE OF THE IC IS OVER 150℃

OVP (Over Voltage Protection)

OVP IS OPERATED WHEN THE TERMINAL VOLTAGE OF #9 IS OVER 11V

& BY FEED-BACK WHEN THE SECONDARY OUTPUT IS OVERVOLTAGE

LET THE OPERATION OF POWER CITCUIT SHUT DOWN

BY MAKING THE OUTPUT OF OSCILLATOR TO LOW STATE

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LATCH FUNCTION

WHEN OVP/TSD IS OPERATED,

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PROTECTION CIRCUIT

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FBT PROTECT

PROTECT to u-COM PIN43

IN NORMAL STATE, Q804 IS OFF

IN ABNORMAL STATE,

R838 DETECTS THE FAULTS.

THEN Q804 ON

PROTECT SIGNAL IS TRNASFERED TO MI-COM

MI-COM MAKE THE TV-SET TO STAND-BY STATE

142V

DAEWOO ELECTRONICS CO., LTD

142V

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Troubleshooting

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D I G I T A L

NO power

Stand-by LED doesn’t light up

C806’s VDC is approximately 280v

The following waveform is to drain of I801

Vp-p

320

100KHz

no

Check F801 & D801

Check the impedance value of

between Source and Drain to I801 .

If the value is near 0 ohm ,

I801 is dead

Check if voltage to PW803 #7 is

supplied to I701

DAEWOO ELECTRONICS CO., LTD

Check the parts caused a short-

circuit to secondary circuit

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Troubleshooting

no

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NO power

no

Check

D802,R803

and D825

Relay (Y802) operation is OK If the base of Q803 is on 5V?

yes

Is R803 is on 280Vdc ?

yes

Check the I803 #1.

50~80KHz

380

Vp-p

no

yes

Change

Q803 or

Y802

Check the primary circuits of

SMPS IC , and replace defective

parts

no

Check

stand-by

power

Check the parts caused a short-

circuit to secondary circuit

DAEWOO ELECTRONICS CO., LTD

yes

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Horizontal deflection

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D I G I T A L

1) H-drive part

2)H-DY Scanning part

3)High voltage part

4)E-W compesation part

* Making H-drive pulse

* Generating H-DY scanning pulse

* Generating High voltage 29.5KV

* Overlapping E-W signal to H-DY pulse

12 Vp-p

31.25KHz

1.2 KVp-p

31.25KHz

6.5 uS

25 Vp-p

100Hz

5)innerpincushion part

DAEWOO ELECTRONICS CO., LTD

* Switching s-correction condenser

DIGITAL TV DEVISION

C410

Q453(FET)

C453

14

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4)E-W compesation part

3270E

5)innerpincushion part

deflection

HH--deflection

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3)High voltage part

DAEWOO

D I G I T A L

E-W

2)H-DY Scanning part

1) H-drive part

H-drive

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DIGITAL TV DEVISION

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Vertical Deflection & focus

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D I G I T A L

1) Vertical Deflection

* Generating vertical D-Y scanning Sawtooth signal

2)Dynamic Double Focus

* Overlapping parabora signal to Focus voltage

35V

100HZ

-9V

1100V

600V

gnd

DAEWOO ELECTRONICS CO., LTD

100HZ

DIGITAL TV DEVISION

-500V

16

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Vertical & Focus

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D I G I T A L

1Vp-p

100hz

VERT(+)

12Vdc

2Vp-p

100hz

VERT(-)

-12Vdc

200mVp-p

100hz

For vertical sync

5Vp-p

100hz

240Vdc

100Vp-p

31.25Khz

DAEWOO ELECTRONICS CO., LTD

For horizontal sync

45Vp-p

31.25Khz

DIGITAL TV DEVISION

Parabola

output

To FBT#11

17

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PWM signal

input.

WHEN you

adjust tilt MENU

then PWM’s

duty is changed

3270E

Tilt circuit

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D I G I T A L

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DC vlotage

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Trouble shooting

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NO RASTER

LED light on Check stand-by 5V

yes

LED light on Yellow Check u-COM

yes

Secondary voltage is OK

yes

Check the ID04 #8

12Vp-p

31.25Khz

yes

Check the base of Q404

no

Check the parts caused a

short-circuit to secondary

circuit

Check ID04

Check H-drive block

Check thecollector of Q403

DAEWOO ELECTRONICS CO., LTD

yes

1.2KVp-p

31.25Khz

no

DIGITAL TV DEVISION

Check D402

19

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The screen get widen all of sudden

EW-PARA is Able to be controlled by SVC remocon

Trouble shooting

no

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yes

Check the

Innerpincushion

block

Check the D404

DAEWOO ELECTRONICS CO., LTD

Check ID04 #21

1.5Vp-p

100hz

yes

Check between R420

yes

DIGITAL TV DEVISION

& L403

25Vp-p

100hz

no

Check the ID04

Check the Q408

20

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Tuner block

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D I G I T A L

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video Signal block

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D I G I T A L

SCART 1 -> CVBS in, RGB/FB in , tuner cvbs out

SCART 2 -> CVBS in, RGB/FB in , monitor cvbs out

SCART 3 -> CVBS in, Y/C in , tuner cvbs out

AV4 -> CVBS in, S-VHS in

DIGITAL TV DEVISION

DAEWOO ELECTRONICS CO., LTD

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VPC3215 block

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CIP3250 block

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D I G I T A L

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DDP3310 block

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D I G I T A L

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NO PICTURE

(cvbs or s-vhs)

Trouble shooting

Another

problem

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NO PICTURE

(R/G/b)

DAEWOO

D I G I T A L

no

Check

external

video

equipment

yes

OSD is on the screen Check ID04

AV RF

Check

input

signal

yes

Check I903’s

output signal

no

Check

I101#12

yes

no

#9,#11

Check

tuner

block

Check

I903

CVBS is on the

screen

Check input signal

Check PW901

Check ID02 #61#63 #65 #67

Another

problem

Check

external

video

equipment

Check I902

&I901

DAEWOO ELECTRONICS CO., LTD

DIGITAL TV DEVISION

26

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Switched main

3270E

Audio block

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D I G I T A L

SCART 1 -> R , L in tuner R , L out

SCART 2 -> R , L in monitor R , L out

SCART 3 -> R , L in tuner R , L out

AV4 -> R , L in

DAEWOO ELECTRONICS CO., LTD

DIGITAL TV DEVISION

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MSP3410 block

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D I G I T A L

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DIGITAL TV DEVISION

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DPL3519 block

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D I G I T A L

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DIGITAL TV DEVISION

29

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Trouble shooting

NO sound

RFAV

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D I G I T A L

Check I903

Check input sound signal

yes

no

Check sound

switching output

Check I601,I602’s output pin

yes

Check amp output

Check I101#24 SIF

signal

yes

no

Check tuner

no

Check I601,I602

block

DAEWOO ELECTRONICS CO., LTD

DIGITAL TV DEVISION

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