SAMSUNG CK765DSX3X-NWT Service Manual

COLOR TELEVISION RECEIVER

Chassis : S51A Model: CK765DSX3X/NWT

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. JAN.1999

Printed in Korea

3S51A-6504

1. Precautions

1-1 Safety 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 peopleÑparticularly childrenÑmight 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 (ANIS 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 unitÕs 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 powerplug prongs in the AC outlet and repeat the test.

Fig. 1-1 AC Leakage Test

6. Antenna Cold Check: With the unitÕs 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

Òhorizontal disableÓ or Òhold-downÓ.)

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.

Precautions

Samsung Electronics 1-1

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)

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

1-1 Safety Precautions (Continued)

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 manufacturerÕs 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.

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 Òintegral implosionÓ 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 Òin-lineÓ picture tubes are equipped with a permanently attached deflection yoke; do not try to remove such Òpermanently attachedÓ 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 originalÑeven 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.

Precautions

1-2 Samsung Electronics

1-2 Servicing Precautions

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

2. Always unplug the unitÕs 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.

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 instrumentÕs ground lead to the instrument chassis ground before connecting the positive lead; always remove the instrumentÕs ground lead last.

Precautions

Samsung Electronics 1-3

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. Some semiconductor (Òsolid stateÓ) 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 semicon ductor 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 powerÑ 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 Òanti-staticÓ; 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.

Precautions

1-4 Samsung Electronics

1-3 Precautions for Electrostatically Sensitive Devices (ESDs)

Specifications and IC Data

Samsung Electronics 2-1

2. Specifications and IC Data

2-1 Specifications

Televisio n System:

C hann els:

Interm ediate-F requ en cies(MHz ):

P icture T ub e:

Power Requirements: AC 230 V, 50Hz or AC 220 ~ 240 V, 50Hz

Antenna Input Impedan ce :

VHF ,UHF: Telesc opic dipo le antenna (75Wunb alanced type)

Speak er Im ped ance :

10W + 10W or 16

W , 5W + 5W (533C only)

MODEL SYSTEM

CI PAL-I (UHF)

CII PAL-I (VHF/UHF) CX P AL -B/G,SEC AM-B/G CK PAL-B/G,D/K,SE CAM-B/G ,D/K CB PAL-B/G CF SECAM-L/L' , PAL/SECAM-B/G

SYSTEM

BAND

PAL/SECAM

-B/G,I

PAL/SECAM

-D/K

SECAM-K1,

PAL-D VHF 2-12 1-13 2-9 UHF 21-69 21-69 13-57

SYSTEM

BAND

PAL/SECAM

-B/ G

PAL/SECAM

-D/K,K1

PAL-I SECAM-L

Picture IF Carrier 38.90 38.90 38.90 38.90

Sound IF C arrier 33.40 32.40 32.90 34.40

Color Sub Carrier 34.47 34.47 34.47 34.47

25 Inch

A51EER131X31

Quick start,in-line-gun, Black stripe,90¡degree d eflection

28 Inch 30 Inch

A66EAK071X01 (Normal)

A70QBZ791X

SECAM-L'

34.50

41.00

38.93

A66EAK552X21 (Invar)

A59EAK071X01 (Normal) A59EAK552X21 (Invar)

21 Inch

2-2 IC Line Up

Specifications and IC Data

2-2 Samsung Electronics

LOC NO NO Specification Description Remarks

HIC101 1 PAP103T IF PRE-AMP

IC201 2

TDA8844 PAL/SEC AM/NTSC/SEC AM-L

TDA8843 PAL/NTSC IC301 3 LA7845 VER TICAL DEF LE C TION AMP IC501 4 TDA6108 RGB DRIVE AMP

IC601 5

TDA7297 SOUND AMP(10W/CH)

TDA7266S SOUND AMP(5W/C H) IC701 6 TDA9859 AUDIO PROCESSOR IC801 7 KA3S1265R SMPS IC( 12A) IC802 8 PC123Y PHOTO C OUP LE R IC803 9 78R05 SWITCHING RE GULATOR IC804 10 K A7630 SWITCHING RE GULATOR(5,8V) IC901 11 SPM171EE MICOM IC902 12 24W16 EEPROM ICE01 13 455 8 EW DR IVE AMP ICN01 14 TDA9814T SIF DETECTOR (SECAM-L)

NICAM

MODULE

ICN02 15 TDA9874H NIC AMDE MODULATOR ICA01 16 LA7567N SIF DE TEC TOR

A2 STEREO

MODULE

ICA02 17 TDA9873H A2 DEMODULATOR

ICM01 18 LA7566 SIF & FM DETECTOR MONO ICS01 19 TEA5114 VIDE O SWITC H

16K

RGB -S/W

2-3 Semiconductor Base Diagrams

Specifications and IC Data

Samsung Electronics 2-3

ELECTROLYTICCONDENSER

DIODE

TDA884X(Pin 56) SPM171EX(Pin 52) 24W16(Pin 8) TDA9859(Pin 32)

TRANSISTOR TRANSISTOR

KA7630

KA7812

OUT

TRANSISTOR

2SD1651 2SD1650 KSD5072 KSD5071 KSD1711

E B C

KSA815-Y KSA539-Y

UPC574J

KA33V

G1962 K2950M K9253M G3956M

SAW-FILTER

E C B

KSR1012 KSR1010 KSR2010

Fig. 2-1 Semiconductor Base Diagrams

2-4 Samsung Electronics

MEMO

Disassembly and reassembly

Samsung Electronics 3-1

3. Disassembly and Reassembly

3-1 Back Cover Removal

1. After removing the 7 screws, pull the cabinet backwards.

3-2 Main Board Removal

Disassembly and reassembly

3-2 Samsung Electronics

1. Separate the TBC-wire 2P connector from GT501,GT502.

2. Separate the CRT Assembly from the CRT socket.

3. Remove the Anode Cap from the CRT.

4. Separate the D-Coil Connector from CN802.

5. Separate the AC cord from CN801.

6. Separate the DC connector from CN401.

7. Separate the CN501B 8P CRT connector from CN501.

8. Separate the CNA05 5P A/V side connector from CN602.

9. Separate the CNA01 8P CRT connector from CN701.

10. Separate the Focus Screen Wire from the FBT clamper.

11. Separate the TBC wire 2P, speaker wires from the wire clamper.

12. Separate the CN701, CN602 connector from the wire clamper.

13. Separate the AC cord from the wire clamper.

14. Remove the main board by pulling it with both hands.

3-3 Speaker Removal

Disassembly and reassembly

Samsung Electronics 3-3

1. Remove the speaker by pressing the tension rib.

1. Separate the speaker wires from D-coil

(located on the bottom to the right side).

2. Remove the screws.

Disassembly and reassembly

3-4 Samsung Electronics

3-4 CRT Removal

1. Remove the 4 nuts that mount the CRT to the front cabinet. Pull the CRT backwards.

2. Caution: Because of the high vacuum and large surface area of the picture tube, be careful while handling it: (1) Always lift the picture tube by grasping it firmly around the faceplate, (2) Never lift the tube by its neck. (3) Do not scratch the picture tube or apply excessive pressure. Fractures of the glass may cause an implosion.

Alignment and Adjustments

Samsung Electronics 4-1

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 ÒAdjustmentÓ 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 re-program 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, Sub-Contrast Vertical Center Vertical Size Horizontal Size Fail Safe (This adjustment must be the last step).

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 by entering the following remote-control sequence :

(1) STAND-BY® DISPLAY® MENU® MUTE

®POWER ON.

2. The ÒSERVICE (FACTORY)Ó message will be displayed. The Service Mode has three components: Adjustment, Option and Reset.

3. Access the Adjustment Mode by pressing the ÒVOLUMEÓ keys ( Up or Down). The adjustment parameters are listed in the accompanying table, and selected by pressing the

CHANNEL keys (▲ ,▼).

4. Selection sequences for the PAL system:

DOWN or UP key:

AGC↔VCO↔SBT↔SCT↔SCR↔SC↔RG↔

BG↔CDL↔STT↔LCO↔VOL↔PSL↔PVS↔ PVA↔PHS↔PEW↔PEP↔PEC↔PET↔VSC↔ TSC↔SA↔QEW↔PCT↔PTT↔PHM↔PVP↔

PHP↔NSR↔PDL↔AGC.

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

6. Cancel the Adjustment Mode by re-pressing the ÒHIDDENÓ or ÒPower OFF/ONÓ keys.

7. After adjustments are completed, re-start

the TV set.

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