Samsung sct57b service manual

COLOR TELEVISION RECEIVER

Chassis : SCT57B Model: CK569BGT1X/BWT

CK569BGT1X/VWT

COLOR TELEVISION RECEIVER CONTENTS

Precautions

Specifications and IC Data

Disassembly and Reassembly

Alignment and Adjustment

Troubleshooting

Exploded View and Parts List

Electric Parts List

Block Diagram

PCB Layout Diagram

Wiring Diagram

Schematic Diagrams

10.

11.

ELECTRONICS

Samsung Electronics Co., Ltd. MAY.1998

Printed in Korea

3SCT57B-6908

1-1

Precautions

Samsung Electronics

1. Precautions

1. Be sure that all of the built-in protective devices are replaced. Restore any missing protective shields.

2. When reinstalling the chassis and its assemblies, be sure to restore all protective devices, including: nonmetallic control knobs and compartment covers.

3. Make sure that there are no cabinet openings through which people-particularly children--might insert fingers and contact dangerous voltages. Such openings include the spacing between the picture tube and the cabinet mask, excessively wide cabinet ventilation slots, and improperly fitted back covers.

If the measured resistance is less than 1.0 megohm or greater than 5.2 megohms, an abnormality exists that must be corrected before the unit is returned to the customer.

4. Leakage Current Hot Check (Figure 1-1): Warning: Do not use an isolation transformer during this test. Use a leakagecurrent tester or a metering system that complies with American National Standards Institute (ANSI C101.1, Leakage Current for

Appliances), and Underwriters Laboratories (UL Publication UL1410, 59.7).

5. With the unit completely reassembled, plug the AC line cord directly into the power outlet. With the unit's AC switch first in the ON position and then OFF, measure the current between a known earth ground (metal water pipe, conduit, etc.) and all exposed metal parts, including: antennas, handle brackets, metal cabinets, screwheads and control shafts. The current measured should not exceed 0.5 milliamp. Reverse the power-plug prongs in the AC outlet and repeat the test.

6. Antenna Cold Check: With the unit's AC plug disconnected from the AC source, connect an electrical jumper across the two AC prongs. Connect one lead of the ohmmeter to an AC prong. Connect the other lead to the coaxial connector.

7. X-ray Limits: The picture tube is especially designed to prohibit X-ray emissions. To ensure continued X-ray protection, replace the picture tube only with one that is the same type as the original. Carefully reinstall the picture tube shields and mounting hardware; these also provide X-ray protection.

8. High Voltage Limits: High voltage must be measured each time servicing is done on the B+, horizontal deflection or high voltage circuits. Correct operation of the X-ray protection circuits must be reconfirmed whenever they are serviced. (X-ray protection circuits also may be called "horizontal disable" or "holddown".)

Heed the high voltage limits. These include the XÐray Protection Specifications Label, and the Product Safety and X-ray Warning Note on the service data schematic.

LEAKAGE CURRENT

TESTER

DEVICE UNDER

TEST

TEST ALL

EXPOSED METAL

SURFACES

2-WIRE CORD

ALSO TEST WITH

PLUG REVERSED (USING AC ADAPTER PLUG AS REQUIRED)

EARTH

GROUND

(READING SHOULD

NOT BE ABOVE

0.5mA)

1-1 Safety Precautions

Fig. 1-1 AC Leakage Test

Follow these safety, servicing and ESD precautions to prevent damage and protect against potential hazards such as electrical shock and X-rays.

Precautions

1-2

Samsung Electronics

1-1 Safety Precautions (Continued)

15. Observe the original lead dress, especially near the following areas: Antenna wiring, sharp edges, and especially the AC and high voltage power supplies. Always inspect for pinched, out-of-place, or frayed wiring. Do not change the spacing between components and the printed circuit board. Check the AC power cord for damage. Make sure that leads and components do not touch thermally hot parts.

16. Picture Tube Implosion Warning: The picture tube in this receiver employs "integral implosion" protection. To ensure continued implosion protection, make sure that the replacement picture tube is the same as the original.

17. Do not remove, install or handle the picture tube without first putting on shatterproof goggles equipped with side shields. Never handle the picture tube by its neck. Some "in-line" picture tubes are equipped with a permanently attached deflection yoke; do not try to remove such "permanently attached" yokes from the picture tube.

18. Product Safety Notice: Some electrical and mechanical parts have special safety-related characteristics which might not be obvious from visual inspection. These safety features and the protection they give might be lost if the replacement component differs from the original--even if the replacement is rated for higher voltage, wattage, etc.

Components that are critical for safety are indicated in the circuit diagram by shading, ( ) or ( ).

Use replacement components that have

the same ratings, especially for flame resistance and dielectric strength specifications. A replacement part that does not have the same safety characteristics as the original might create shock, fire or other hazards.

9. High voltage is maintained within specified limits by close-tolerance, safety-related components and adjustments. If the high voltage exceeds the specified limits, check each of the special components.

10. Design Alteration Warning: Never alter or add to the mechanical or electrical design of this unit. Example: Do not add auxiliary audio or video connectors. Such alterations might create a safety hazard. Also, any design changes or additions will void the manufacturer's warranty.

11. Hot Chassis Warning: Some TV receiver chassis are electrically connected directly to one conductor of the AC power cord. If an isolation transformer is not used, these units may be safely serviced only if the AC power plug is inserted so that the chassis is connected to the ground side of the AC source.

To confirm that the AC power plug is inserted correctly, do the following: Using an AC voltmeter, measure the voltage between the chassis and a known earth ground. If the reading is greater than 1.0V, remove the AC power plug, reverse its polarity and reinsert. Re-measure the voltage between the chassis and ground.

12. Some TV chassis are designed to operate with 85 volts AC between chassis and ground, regardless of the AC plug polarity. These units can be safely serviced only if an isolation transformer inserted between the receiver and the power source.

13. Some TV chassis have a secondary ground system in addition to the main chassis ground. This secondary ground system is not isolated from the AC power line. The two ground systems are electrically separated by insulating material that must not be defeated or altered.

14. Components, parts and wiring that appear to have overheated or that are otherwise damaged should be replaced with parts that meet the original specifications. Always determine the cause of damage or overheating, and correct any potential hazards.

1-3

Precautions

Samsung Electronics

5. Check the insulation between the blades of the AC plug and accessible conductive parts (examples: metal panels, input terminals and earphone jacks).

6. Insulation Checking Procedure: Disconnect the power cord from the AC source and turn the power switch ON. Connect an insulation resistance meter (500V) to the blades of the AC plug.

The insulation resistance between each blade of the AC plug and accessible conductive parts (see above) should be greater than 1 megohm.

7. Never defeat any of the B+ voltage interlocks. Do not apply AC power to the unit (or any of its assemblies) unless all solid-state heat sinks are correctly installed.

8. Always connect a test instrument's ground lead to the instrument chassis ground before connecting the positive lead; always remove the instrument's ground lead last.

1-3 Precautions for Electrostatically Sensitive Devices (ESDs)

1. Some semiconductor ("solid state") devices are easily damaged by static electricity. Such components are called Electrostatically Sensitive Devices (ESDs); examples include integrated circuits and some field-effect transistors. The following techniques will reduce the occurrence of component damage caused by static electricity.

2. Immediately before handling any semiconductor components or assemblies, drain the electrostatic charge from your body by touching a known earth ground. Alternatively, wear a discharging wrist-strap device. (Be sure to remove it prior to applying power--this is an electric shock precaution.)

3. After removing an ESD-equipped assembly, place it on a conductive surface such as aluminum foil to prevent accumulation of electrostatic charge.

4. Do not use freon-propelled chemicals. These can generate electrical charges that damage ESDs.

5. Use only a grounded-tip soldering iron when soldering or unsoldering ESDs.

6. Use only an anti-static solder removal device. Many solder removal devices are not rated as "anti-static"; these can accumulate sufficient electrical charge to damage ESDs.

7. Do not remove a replacement ESD from its protective package until you are ready to install it. Most replacement ESDs are packaged with leads that are electrically shorted together by conductive foam, aluminum foil or other conductive materials.

8. Immediately before removing the protective material from the leads of a replacement ESD, touch the protective material to the chassis or circuit assembly into which the device will be installed.

9. Minimize body motions when handling unpackaged replacement ESDs. Motions such as brushing clothes together, or lifting a foot from a carpeted floor can generate enough static electricity to damage an ESD.

WARNING1: First read the "Safety Precautions" section of this manual. If some unforeseen circumstance creates a conflict

between the servicing and safety precautions, always follow the safety precautions.

WARNING2: An electrolytic capacitor installed with the wrong polarity might explode.

1-2 Servicing Precautions

1. Servicing precautions are printed on the cabinet. Follow them.

2. Always unplug the unit's AC power cord from the AC power source before attempting to: (a) Remove or reinstall any component or assembly, (b) Disconnect an electrical plug or connector, (c) Connect a test component in parallel with an electrolytic capacitor.

3. Some components are raised above the printed circuit board for safety. An insulation tube or tape is sometimes used. The internal wiring is sometimes clamped to prevent contact with thermally hot components. Reinstall all such elements to their original position.

4. After servicing, always check that the screws, components and wiring have been correctly reinstalled. Make sure that the portion around the serviced part has not been damaged.

2-1

Specifications and IC Data

Samsung Electronics

2. Specifications and IC Data

Television System:

Channels:

Intermediate Frequencies (MHz) :

Picture Tube:

Power Requirements: Antenna Input Impedance: Speaker Impedance

NTSC - M

2 - 13 14-69

NTSC - M

38.90

34.40

35.32

PAL/SECAM-

B/G,I

2 - 12

21 - 69

PAL/ SECAM- B/G

38.90

33.40

34.47

System

Band

VHF UHF

SYSTEM

IF Carrier Frequency

Picture IF Carrier

Sound IF Carrier

Color Sub Carrier

PAL, SECAM- D/K

1 - 13

21 - 69

PAL/SECAM-D/K, SECAM-K1

38.90

32.40

34.47

SECAM-K1, PAL-D

2 - 9

13 - 57

PAL - I

38.90

32.90

34.47

MODEL

CI CII CX CK

14 Inch 20 Inch 22 Inch

AC 100 ~ 260V, 50/60Hz or AC 160 ~ 260V, 50/60Hz VHF, UHF : Telescopic dipole antenna (75 ohm unbalanced type ) 10W + 10W/8 ohm, 3W/16 ohm, 5W + 5W/16 ohm

SYSTEM PAL-I (UHF) PAL-I (VHF/UHF) PAL-B/G, SECAM-B/G PAL-B/G, D/K, SECAM-B/G, D/K PAL-B/G, D/K, SECAM-B/G, D/K, NT 4.43 PAL-B/G, D/K, SECAM-B/G, D/K, NT4.43, NT3.58

2-1 Specifications

A34KQV42X A48KRD82X

A53QCA891X

Quick start, in-line-gun,

Black stripe, 90 degree deflection

Specifications and IC Data

2-2

Samsung Electronics

2-2 IC Line Up

No.

1 2

3 4 5 6 7

9 10 11

15 16 17 18

Description IF PRE-AMP PAL-B/G, SECAM-B/G,NTSC, SECAM-L PAL-B/G, SECAM-B/G, SECAM-L PAL-B/G, SECAM-B/G, NTSC, SECAM-L, E/W ADJ. PAL-B/G, SECAM-B/G, NTSC, SECAM-L, E/W ADJ.,16:9 VERTICAL DEFLECTION AMP REGULATOR (12V) RGB DRIVE AMP SOUND-AMP (10W+10W) AUDIO PROCESSOR POWER IC 6A, 800V

POWER IC 8A, 800V PHOTO COUPLER REGULATOR IC REGULATOR (5V, 8V)

TTX-DECODER

µ-com

E2-PROM

SOUND PROCESSOR INTER-CARRIER SOUND DEMODULATOR NICAM+A2 SOUND DEMODULATOR Y.U.V TRANSIENT IMPROVEMENT PROCESSOR

Remarks

RUSSIAN

SOUND MODULE SOUND MODULE SOUND MODULE

Specification PAP102T TDA8844 TDA8843 TDA8375A TDA8375 TDA8350Q KA7812 TDA6107Q TDA7297 TDA9859 KA3S0680

KA3S0880 LTV817B KA78R05 KA7630 SAA5281 P/E

SAA5281 P/H SZM-199EA

SZM-199ER AT24C04

AT24C08 TDA9840 TDA9820 TDA9874H TDA9177

Loc No. HIC101 IC202

IC301 IC401 IC501 IC601 IC701

IC801

IC802 IC803 IC804

ICT01

IC901

IC902

ICA01 ICA02 IC6001 ICL101

Table 2-1 IC Line Up

2-3

Specifications and IC Data

Samsung Electronics

Description ENG/ARAB/FRENCH ENG/CHINESE ENG/CRO/BUL/POLISH/RUMANIAN/CZECH/CRO ENG/GER/FRENCH/SPANISH/SWEDISH/DUTCH/ITALIAN ENG/MAL/IND/VIETNAMESE/THAI ENG/RUSSIAN

RemarksSpecification SZM-199EA SZM-199EC SZM-199EW SZM-199EE SZM-199ET SZM-199ER

Loc No.

IC901

Table 2-2

Option: OSD Language

Specifications and IC Data

2-4

Samsung Electronics

Fig.2-1 Semiconductor Base Diagrams

2-3 Semiconductor Base Diagrams

ELECTROLYTICCONDENSER

DIODE

TDA4665(Pin 16) TDA837X(Pin 56) Z8933112PSC(Pin 42) X24CO4P(Pin 8) TDA8395(Pin 16) TDA4665(Pin 16)

TRANSISTOR TRANSISTOR

TDA8133

KA7812

OUT

TRANSISTOR

2SD1651 2SD1650 KSD5072 KSD5071 KSD1711

E B C

KSA815-Y KSA539-Y

UPC574J

KA33V

G1962 K2950M K9253M

SAW-FILTER

E C B

KSR1012 KSR1010 KSR2010

3-1

Disassembly and reassembly

Samsung Electronics

3. Disassembly and Reassembly

3-1 Back Cover Removal

1. After removing the 9 screws, pull the cabinet backwards.

Disassembly and reassembly

3-2 Samsung Electronics

3-2 Speaker Removal

1. Loosen the 4 screws and remove the holder speakers.

3-3

Disassembly and reassembly

Samsung Electronics

3-3 CRT Removal

1. Spread a soft mat on the floor. Place the TV set face down.

2. Remove the 4 screws mounting the CRT to the front cabinet.

3. Lift the CRT.

3-4 Samsung Electronics

MEMO

4-1

Alignment and Adjustments

Samsung Electronics

4. Alignment and Adjustments

4-1 Preadjustment

4-1-1 Factory Mode

1. Do not attempt these adjustments in the Video Mode.

2. The Factory Mode adjustments are necessary when either the EEPROM (IC902) or the CRT is replaced.

3. Do not tamper with the "Adjustment" screen of the Factory Mode menu. This screen is intended only for factory use.

4-1-2 When EEPROM (IC902) Is Replaced

1. When IC902 is replaced all adjustment data revert to initial values. It is necessary to reprogram this data.

2. After IC902 is replaced, warm up the TV for 10 seconds

4-1-3 When CRT Is Replaced

1. Make the following adjustments AFTER setting up after setting up purity and convergence:

White Balance Sub-Brightness Vertical Center Vertical Size Horizontal Size Fail Safe (This adjustment must be the last step.)

2. If the EEPROM or CRT is replaced, set PSL and PVA to 15 and 63 (Factory Mode).

4-2 Factory/Service Mode

4-2-1 Procedure for the "Adjustment" Mode

1. This mode uses the standard remote control. The Service Mode is activated (1) by pressing

the (Display → (FACTORY) service key or (2)

by entering the following remote-control sequence:

STAND-BY→DISPLAY→ P-STD → MUTE →

POWER ON

2. The "SERVICE (FACTORY)" message will be displayed. The Service Mode has four components: Adjustment, Test Pattern, Option Bytes and Reset.

3. Access the Adjustment Mode by pressing the

"VOLUME" keys ( Up or Down). The adjustment parameters are listed in the accompanying table. Select them by pressing

the CHANNEL keys (▲,▼).

4. Selection sequences for the PAL system:

DOWN or UP key:

VCO>SBT>SCT>SCR>SC>RG>CDL>STT>LCO >LA>PSL>PVS>PVA>PHS>PEW>PEP>PEC>P ET>LSC>TSC>SA>NSL>NVS>NVA>NHS>NE W>NEP>NEC>NET

5. Selection sequences for the NTSC system:

DOWN or UP key:

NVS>NVA>NSL>NHS>NEW>NEP>NEC>NET

6. The VOLUME keys increase or decrease the adjustment values, (stored in the non-volatile memory when Adjustment Mode is cancelled).

7. Cancel the Adjustment Mode by re-pressing the "Factory" or "Power on" keys.

Alignment and Adjustments

4-2 Samsung Electronics

ADJUSTMENT DATA

60 ~ 75

6 ~ 10

7 15 FIXED 11 FIXED

25 ~ 45 25 ~ 45

0 ~ 10

63 FIXED

20 ~ 25 25 ~ 35

35 35 ~ 45 35 ~ 45

0 ~ 10

15 ~ 30

15 ~30

31 FIXED

10 ~ 30

25 FIXED

RANGE

0 ~ 63 STEP

0 ~ 127 STEP

0 ~ 23 STEP 0 ~ 23 STEP 0 ~ 23 STEP 0 ~ 63 STEP

0 ~ 7 STEP

0 ~ 127 STEP

0 ~ 9 STEP 0 ~ 63 STEP 0 ~ 63 STEP 0 ~ 63 STEP 0 ~ 63 STEP 0 ~ 63 STEP 0 ~ 63 STEP 0 ~ 63 STEP 0 ~ 63 STEP 0 ~ 63 STEP 0 ~ 63 STEP 0 ~ 63 STEP 0 ~ 63 STEP 0 ~ 63 STEP 0 ~ 49 STEP 0 ~ 63 STEP

INITIAL

15 63

7 15 11 31 31

5 63

5 25 31 31 40 38 22 22 30 25 15 25 25

OSD ABBREVIATION

AGC VCO

SBT SCT

SCR

SC RG

BG CDL STT LCO

LA PSL PVS

PVA PHS PEW

PEP PEC PET

VSC

TSC

NSL

FUNCTION AUTO GAIN CONTROL VOLTAGE CONTROLLED OSCILLATOR SUB BRIGHT SUB CONTRAST SUB COLOR S-CORRECTION RED DRIVE (GAIN) BLUE DRIVE (GAIN) CATHODE DRIVE LEVEL SUB TINT SECAM-L CONTROLLED OSCILLATOR SOUND LEVEL ADJUSTMENT PAL VERTICAL SLOPE PAL VERTICAL SHIFT PAL VERTICAL AMPLITUDE PAL HORIZONTAL SHIFT PAL EW-WIDTH PAL EW-PARABOLA PAL EW CORNER PARABOLA PAL EW-TRAPEZIUM VERTICAL SCROLL TTX SUB CONTRAST SEPARATION ADJUSTMENT NTSC VERTICAL SLOPE

Table 4-1 Main Adjustment Parameter (Zilog µ-com)

4-2-2 Main Adjustment Parameter

4-3

Alignment and Adjustments

Samsung Electronics

NOTE : PVS,PVA, PHS, NVS, NVA,NHS parameters must be aligned using both the

50Hz and 60Hz vertical-field rates.

4-2-3 Test Pattern

1. This mode can be used during servicing, or for confirming that the convergence and purity adjustments are correct.

2. Access the Test Pattern parameters by pressing a CHANNEL

keys (▲,▼) while the Service Mode is on. The cursor will move

to the test pattern. Press the VOLUME keys. On-screen display:

■ RED

■ GREEN

■ BLUE

3. AGING Mode (Reference Only)

This pattern is used for pre-heating the CRT during manufacturing--it is accessed in the factory by twice pressing the "HIDDEN" key .

Even if the TV power is cut off, the Aging Mode is not cancelled, The patterns are displayed at 5 sec intervals. The AGING mode is cancelled by repressing the "HIDDEN" key.

ADJUSTMENT DATARANGE INITIALOSD ABBREVIATIONFUNCTION

35 ~ 45 25 ~ 35 35 ~ 50 35 ~ 45 15 ~ 30

0 ~ 63 STEP 0 ~ 63 STEP 0 ~ 63 STEP

0 ~ 127 STEP

0 ~ 63 STEP

44 28 45 37 21 20 30

NVS NVA NHS

NEW

NEP

NEC

NET

NTSC VERTICAL SHIFT NTSC VERTICAL AMPLITUDE NTSC HORIZONTAL SHIFT NTSC EW-WIDTH NTSC EW PARABOLA NTSC EW-CORNER PARABOLA NTSC EW-TRAPEZIUM

Table 4-1 Main Adjustment Parameter (Zilog µ-com)(Continued)

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