SAMSUNG TXH1972, CT5038, CT5039, CT331E, CT331H Diagram

...

9. PCB Layout

9-1 PCB-MAIN

PCB Layout

Samsung Electronics 9-1

D101 53 150 D102 56 130 D103 71 141 D201 135 196 D202 96 105 D203 96 107 D204 96 110 D205 123 92 D206 114 95 D207 114 97 D208 115 74 D210 99 105 D299 99 212 D301 32 139 D302 31 146 D401 85 99 D402 70 98 D403 59 74 D404 72 53 D405 81 38 D407 58 105 D601 124 213 D701 130 136 D702 227 203 D703 210 238 D704 85 159 D802 104 11 D803 150 23 D804 92 183 D805 168 42 D806 150 27 D807 186 51 D808 193 54 D809 186 67 D810 196 66 D814 99 60 D855 157 100 D856 147 101 D901 160 119 D902 163 110 D903 171 130 D904 132 96 D905 231 179 D906 157 131 DL01 105 219 DL02 108 219 DU01 211 118 DX01 116 107 DX02 111 101 DZ801 215 20 DZ802 179 30 DZ803 178 24 DZ806 157 17 DZ807 150 20 DZ901 231 83 DZ902 231 156 DZ903 203 124

IC201 100 164 IC301 50 132 IC601 146 225 IC602 168 221 IC801 155 10 IC802 141 97 IC901 215 153 IC902 219 178 ICK01 69 213

Q151 61 183 Q201 107 129 Q202 101 140 Q203 99 144 Q401 24 85 Q402 63 118 Q501 24 197 Q502 32 197 Q503 12 195 Q601 145 203 Q602 132 223 Q801 100 29 Q902 119 226 Q903 87 115 QL01 80 237 QL03 115 226 QLK1 106 229 QU01 197 173 QU10 195 115 QX01 112 113

Loc. No. X Y

DIODE

Loc. No. X Y

TRANSISTOR

11. Schematic Diagrams

11-1 MAIN 1/4

Schematic Diagrams

Samsung Electronics 11-1

: Power Line

: Signal Line

TP13

IC201 30PIN

TP15

TP17

TP21

TP10

TP11

TP19

IC201 37PIN

IC201 43PIN

IC201 47PIN

IC201 53PIN

IC201 25PIN

IC201 27PIN

TP7

TP8

IC201 23PIN

IC201 22PIN

TP14

IC201 32PIN

TP16

TP18

TP12

TP20

IC201 41PIN

IC201 45PIN

IC201 49PIN

IC201 28PIN

TP9

IC201 24PIN

TP4

TP5

IC201 20PIN

IC201 19PIN

TP6

IC201 21PIN

TP1

TP2

IC201 4 PIN

IC201 2 PIN

TP3

IC201 7PIN

Schematic Diagrams

11-2 Samsung Electronics

TP9

TP10

TP13

TP14

TP15

TP16

TP17

TP18

TP21

TP19

TP20

TP1

TP2

TP3

TP4

TP5

TP6

TP7

TP8

TP11

TP12

11-2 MAIN 2/4

: Power Line

: Signal Line

Schematic Diagrams

Samsung Electronics 11-3

TP25

TP27

TP26

TP24

11-3 MAIN 3/4

TP24

TP26

TP25

IC801 1 PIN

TP27

T444 10 PIN

: Power Line

Schematic Diagrams

11-4 Samsung Electronics

11-4 MAIN 4/4

: Power Line

: Signal Line

COLOR TELEVISION RECEIVER

Chassis : K15A Model: CT331HBZX CT501EBZX

CT331EBZX CT501HX CT331HBX CT5066BZX CT331HX CT5038ZX CT3366BZX CT3338ZX

COLOR TELEVISION RECEIVER CONTENTS

Precautions

Specifications

Disassembly and Reassembly

Alignment and Adjustments

Troubleshooting

Exploded Views and Parts List

Electric Parts List

Block Diagram

PCB Layout

Wiring Diagrams

Schematic Diagrams

10.

11.

ELECTRONICS

Samsung Electronics Co., Ltd. JUN. 1998 Printed in Korea

3K15A-0101

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

Samsung Electronics 2-1

2. Specifications

2-1 Specifications

Television System 14"/20"/21" NTSC COLOR TV SIGNAL

Power Consumption 14" : 57 WATTS NOMINAL,

20" : 70 WATTS NOMINAL 21" : 75 WATTS NOMINAL,

Picture Tube 14" : A34KQV42X

20" : A48KRD82X (H) 21": : A51KQJ63X (H)

Power Requirement AC 120V, 60Hz /AC 100 ~ 240, 50Hz, 60Hz

Operating System REMOCON SYSTEM (SZM354ET)

Tuning Ranges VHF CH : 2-13, UHF CH : 14-69, CABLE CH : 1,14-125

Antenna Input Impedance 75 ohm UNBALANCED TYPE FOR VHF/UHF

Intermediate Frequency PICTURE 45.75MHz, SOUND 41.25MHz,

COLOR SUB CARRIER 42.17MHz

Speaker Impedance Single:

Dual : 8 ohm 3W x 2 Dual : 16 ohm , 3W x 2 (CT-33H1, CT-50H1)

8 ohm 3W

Disassembly and Reassembly

Samsung Electronics 3-1

3. Disassembly and Reassembly

3-1 Back Cover Removeal

Fig. 3-1

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

3-2 Main Board Removal

Disassembly and Reassembly

3-2 Samsung Electronics

Fig. 3-2

Fig. 3-3

1. Separate the socket board from the CRT neck.

2. Remove the Anode Cap from the CRT.

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

Warning: The FBT is charged with high voltage. Before removing the Anode Cap, discharge the voltage through one of the heat sinks on the main board.

Disassembly and Reassembly

Samsung Electronics 3-3

3-3 Speaker Removal

1. Loosen the screws and remove the speakers.

Fig. 3-4

Disassembly and Reassembly

3-4 Samsung Electronics

3-4 CRT Removel

Fig. 3-5

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

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

3. Lift the CRT.

4. 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 Service Mode Adjustments

4-1-1 Service Mode Menus

Since there are no VRs in the K15A chassis, all adjustments after parts replacement must be done in the Service Mode. Service Mode adjustments are necessary when either the EEPROM (IC902) or the CRT is replaced.

4-1-2 Entering the Service Mode

Press the following transmitter keys while in STAND-BY mode:

MUTE—>1—>8—>2—>POWER “Factory Mode Menu” is displayed

<---selected (violet)

RC XXX VCO XX GC XXX SBT XX BC XX SCT XX VA XX SCR XX VS XX STT XXX HS XX GG XXX SS XX BG XXX SVC : MUTE

AGC XX

AGC XX RC XXX

GC XXX SBT XX BC XX SCT XX VA XX SCR XX VS XX STT XXX HS XX GG XXX SS XX BG XXX SVC : MUTE

VCO XX

VCO

AGC XX XXX

XXX XX XX XX VA XX XX VS XX XXX HS XX XXX SS XX XXX

SVC : MUTE

VCO XX

RC GC

SBT

BC SCT SCR STT GG BG

ADJUSTMENT PATTERN OPTION RESET

Enter Service Mode using the Volume

+,- keys. Service Mode Menu:

Return to the Service mode by pressing MENU.

Change the data with “Volume +, - “ keys.

Return to the Factory mode via the MENU key.

Press POWER to enter the Stand-by mode.

Select a mode to be adjusted, using the channel down key. Example: VCO.

POWER

OFF

Item Function

Range

MICOM Data 1 AGC RF AGC Adjustment 0~63 50 2 VCO PIF VCO Adjustment 0~127 63 3 SCT SUB-CONTRAST Adjustment 0~63 48 4 SCR SUB-COLOR Adjustment 0~27 13 5 STT SUB-TINT Adjustment 0~27 7 6 RC RED-CUT OFF Adjustment 0~255 0 7 GC GREEN-CUT OFF Adjustment 0~255 0 8 BC BLUE-CUT OFF Adjustment 0~255 0 9 SVC Input a Horiz line pattern

10 GG GREEN-GAIN Adjustment 0~255 127 11 BG BLUE-GAIN Adjustment 0~255 127 12 SBT SUB-BRIGHTNESS Adjustment 0~63 31 13 VA VERTICAL SIZE Adjustment 0~63 39 14 VS VERTICAL CENTER Adjustment 0 0 15 HS HORIZONTAL Phase Adjustment 0~31 15 16 SS SUB-SHARPNESS Adjustment 0~31 4

BYTE 0 : 0 0

ADJUSTMENT PATTERN OPTION RESET

Initalized

Alignment and Adjustments

4-2 Samsung Electronics

4-1-3 Adjustment in Option Mode

This adjustment is necessary whenever the EEPROM is replaced. Input data (as marked on the back cabinet).

Select “SET OPTION” by pressing the Channel key twice.

Press the Volume +, - keys to enter the set Option mode.

Press MENU to go back to the factory mode.

Select RESET with channel key.

Press volume + key.

▼

4-1-4 Service Mode Adjustments

1. The Pattern Adjustment is done only in the factory. Do not attempt to readjust it.

2. Refer to 4-2 for other adjustments.

3. Set OPTION data.

4-1-5 Service Mode Adjustment Ratings

Note : The initial MICOM data values take effect when IC902 is replaced.

Alignment and Adjustments

Samsung Electronics 4-3

4-2 Alignment and Adjustment

4-2-1 General Alignment Instructions

1. Usually, a color TV needs only slight touch-up adjustment upon installation. Check the basic characteristics such as picture height, focus and a horizontal and vertical sync.

2. Observe the picture and check for good back and white details. There should be no objectionable color shading: If color shading is present, demagnetize the receiver. If color shading persists, perform purity and convergence adjustments described below.

3. To protect against shock hazard, use an isolation transformer.

4-2-2 Power Supply Check

Check the following: A: Power plug is connected; “Stand-by” mode B: Power On when “Power ON” button is pressed C: Power On by FBT Each supply is marked on

its lead-in wire. ( )

4-2-3 Focus Adjustment

Adjust the focus control on the FBT for well defined scanning lines.

4-2-4 Fail Safe Circuit Check (FS) (OPTION)

1. The failsafe check must be the final step in servicing.

2. Turn the power switch ON and adjust customer controls for normal operation.

3. Temporarily short pin X to pin R on the main board (RX06, RX04) with a jumper wire. Raster will disappear.

4. The TV must remain in this state even after removing the jumper wire. This shows that the failsafe circuit is working properly.

5. To recover picture and sound, temporarily turn off the TV and allow the failsafe circuit more than 30 seconds to reset. Then switch power ON to produce normal picture and sound.

4-2-5 IC902 Replacement

1. When IC902 is replaced, all values are reset to “Initialized MICOM Data” and readjustment is necessary.

2. Press the POWER button 10 seconds after plug-in.

3. To enter the Service Mode, refer to Fig. 4-1 (Service Mode Adjustment).

4-2-6 PIF VCO Adjustment

1. Use a Pattern Generator or an off-air signal.

2. Open pin 11 of Micom (IC901) or one side of lead pin for R237.

3. Adjust VCO in the service mode to set IC101 Pin 44 (AFT) to 2.5V ± 0.4V.

4. Connect the opened site.

4-2-7 RF-AGC Adjustment

1. Input a PHILLIPS pattern.

2. Set the input signal to 60 dB.

3. Enter into the AGC in the service mode.

4. Adjust AGC until color bar noise disappears.

+ 44 hidden pages