SAMSUNG TXJ2060, TXJ2754, TXJ2066, TXJ2067, TXJ2767 Service Manual

COLOR TELEVISION RECEIVER

Chassis :	K51A
Model:	TXJ2060	TXJ2754
	TXJ2066	TXJ2766
	TXJ2067	TXJ2767
	TXJ2554	TXJ2768
	TXJ2566	TXJ2879
	TXJ2567

COLOR TELEVISION RECEIVER

CONTENTS

1. Precautions

2. Specifications and IC Data

3. Alignment and Adjustments

4. Troubleshooting

5. Exploded Views and Parts List

6. Electric Parts List

7. Block Diagrams

8. Schematic Diagrams

ELECTRONICS

©Samsung Electronics Co., Ltd. APR.1999 Printed in Korea

3K51A-2001

Precautions

1. Precautions

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

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 (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 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 powerplug prongs in the AC outlet and repeat the test.

(READING SHOULD

LEAKAGE

NOT BE ABOVE

DEVICE

CURRENT

0.5mA)

UNDER

TESTER

TEST

TEST ALL

EXPOSED METAL

SURFACES

2-WIRE CORD

ALSO TEST WITH

PLUG REVERSED

(USING AC ADAPTER

EARTH

PLUG AS REQUIRED)

GROUND

Fig. 1-1 AC Leakage 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 “hold-down”.)

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

Samsung Electronics

1-1

Precautions

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 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.

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.

1-2	Samsung Electronics

Precautions

1-2 Servicing Precautions

Warning 1 : 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.

Warning 2 : An electrolytic capacitor installed with the wrong polarity might explode.

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.

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.

Samsung Electronics

1-3

Precautions

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 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 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.

1-4	Samsung Electronics

Specifications and IC Data

2. Specifications and IC Data

2-1 Specifications

			CT-565BZ / 566BWZ			CT-765DWZ
MODEL	CT-5072BWZ		CT-567BWZ / 568BPZ	CT-25D4WZ	CT-29D4WZ	CT-766DWZ
	CT-5072BPZ
			CT-225BZ / 228BWZ			CT-30D6PZ
			CT-22B6PZ			CT-30A9PZ
VOLTAGE					±
			AC100-240V (Mexico: AC127V 10%)
POWER CONSUMPTION		85 WATTS		110 WATTS	120 WATTS	120 WATTS
POWER FREQUENCY			50/60Hz (Mexico: 60Hz)
CHANNELS RECEIVED			VHF; 2~13, UHF; 14~69, CATV; 1,14~125

MODEL	TXJ2048/2060	TXJ2554/2566	TXJ2754/2766	TXJ2879
	TXJ2066/2067	TXJ2567	TXJ2767/2768
VOLTAGE		AC120V
POWER CONSUMPTION	85 WATTS	110 WATTS	120 WATTS	130 WATTS
POWER FREQUENCY		60Hz
CHANNELS RECEIVED	VHF; 2~13, UHF; 14~69, CATV; 1,14~125

	CN-565BWZ		CN-25D4WZ		CN-29D4WZ
MODEL					CN-7202WZ
	CN-566BWZ		CN-663AWZ
					CN-765DWZ
VOLTAGE	AC 100-240V (Argentina: AC 220V)
POWER CONSUMPTION	85 WATTS		110 WATTS		120 WATTS
POWER FREQUENCY		50/60 Hz (Argentina: 50 Hz)
CHANNELS RECEIVED	VHF: 2~13, UHF: 14~69, CATV: 1,14~125

Samsung Electronics

2-1

Specifications and IC Data

2-2 IC Line Up

Table 2 - 1 IC Line - Up

Loc No

No

Specification

Description

Remarks

SF101

1

M3951M

SAW FILTER (VIF)

SF102

2

M9260M

SAW FILTER (SIF)

TDA8377

ONECHIP TV PROCESSOR

CT566BV/CT567BW/CT568BW/CT766DW

IC201

3

TDA8373

ONECHIP TV PROCESSOR

CT633BW/CT683BW

TDA8375

ONECHIP TV PROCESSOR

CN565BW/CN25D4W/CN663A/CN765DW

IC202

4

LA7510

AUDIO IF AMP/4.5M DETECT

IC301

5

LA7845

VERTICAL AMP IC

TDA7056B

1.5W x 2 (MONO)

IC603

6

SOUND AMP IC

3W x 2 (MONO)

TDA7266S

STEREO MODEL

IC701

7

TDA7449

VOLUME CONTROL IC

IC801

8

KA3S1265R

POWER IC

CT633BW/CT683BW/CT766DW

CT566BV/CT566BW/CT567BW/CT568BW

IC802

9

KA7630

MULTI REGULATOR IC

IC901

10

SZM368ET

MICOM

IC902

11

XL24C08P

EEPROM

ICD01

12

CXA2104S

MTS IC

STEREO MODEL ONLY

2-2	Samsung Electronics

Specifications and IC Data

2-3 Semiconductor Base Diagrams

ELECTROLYTIC-

CONDENSER

DIODE

IC

XLS24C08P (PIN 8)

TDA8377 (PIN 56)

TRANSISTOR	TRANSISTOR		SAW-FILTER
	KSC2073		M3951M
	KSA940		M9260M
	2SD1887	KSC815Y
	2SD1880
		KSA539-Y	1
	KSD5072
	KSD5703

B

C

E

E B C

IC	TRANSISTOR	TRANSISTOR

LA7845

C2331-Y

KSR1010

KA7812

KA7809

IN

G	E C B
out

Fig. 2-1 Semiconductor Base Diagrams

Samsung Electronics

2-3

Specifications and IC Data

2-4 One Chip TV-processor

SOUND IF INPUT										1		56	DECOUPLING SOUND DEMODULATOR
EXT AUDIO INPUT
										2		55	AUDIO DEEMPHASSIS/MPX OUT
VCO REF FILTER
									3			54	TUNER AGC OUTPUT
VCO REF FILTER													AGC DECOUPLING CAPACITOR
										4		53
PLL LOOP FILTER													REREFERENCE CURRENT INPUT
										5		52
IF VIDEO OUTPUT
								6				51	VERT, SAWTOOTH CAPACITOR
													EHT/OVERVOLTAGE PROTECTION INP
BUSINPUT : SCL										7		50
													(X-RAY PROTECTION)
BUSINPUT : SDA
			8									49	IF INPUT
BANDGAP DECOUPLING													IF INPUT
										9		48
CHROMA INPUT
										10		47	VERT. DRIVE NEG
Y/CVBS INPUT
										11		46	VERT. DRIVE POS
MAIN POSITIVE SUPPLY													EAST-WEST DRIVE
										12		45
INT CVBS INPUT
										13		44	GROUND
GROUND
										14		43	PHI1 FILTER
AUDIO OUT
										15		42	PHI2 FILTER / FLASH PROT
DECOUPLING FILTER TUNING
					16							41	SAND CASTLE OUTPUT/FLYBACK INP
EXT CVBS INPUT
				17								40	HOR. OUTPUT
BLACK CURRENT INP
										18		39	BLACK PEAK HOLD CAPACITOR
BLUE OUTPUT										19		38	CVBS OUTPUT
GREEN OUTPUT
										20		37	POSITIVE SUPPLY
RED OUTPUT										21		36	LOOP FILTER BURST PHASE DET
V-GUARD INP/BEAM CUR LIMITER
										22		35	X-TAL (PAL-N (4.43)/PAL-M (3.58))
RED INPUT													X-TAL (3.58)
										23		34
GREEN INPUT													SECAM REF OUTPUT
										24		33
BLUE INPUT							25					32	(R-Y) INPUT
													(B-Y) INPUT
PIP/OSD RGB INSERTION SWITCH INP		26										31
LUMINANCE INPUT						27						30	(R-Y) OUTPUT
											SDIL56
LUMINANCE OUTPUT	28											29	(B-Y) OUTPUT

Fig. 2-2 SDIL56

CVBS : Composite Video Blanking Signal

2-4	Samsung Electronics

Alignment and Adjustments

3. Alignment and Adjustments

3-1 Preadjustment

1.Since there are no VRs in the K51A chassis, all adjustments after parts replacement must be done in the Service 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. WHEN EEPROM (IC902) IS REPLACED

(1)When IC902 is replaced, all adjustment data revert to their initial values. It is necessary to re-program this data.

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

Make the following adjustments AFTER setting up purity and convergence:

White Balance Sub-Brightness Vertical Center Vertical Size

Horizontal Size (No use in 21” and 25” models)

3-2 Factory (“SERVICE”) Mode

1.The set must be in Factory (“Service”) Mode. Selection sequence:

STAND-BY → MUTE → 1 →8 → 2 → POWER ON

2.The “ FACTORY MODE” message will be displayed. The Factory Mode has four components : Adjustment, MPX, PIP, Option Byte and Factory Reset.

3. Access the Adjustment Mode by pressing the “VOLUME” keys (▼, The adjustment parameters are listed in the accompanying table. Select them by pressing the CHANNEL keys (▲,▼).

▼)

4.After completing the Factory Mode adjustments, turn the power switch OFF.

Samsung Electronics

3-1

Alignment and Adjustments

3-2-1 Adjustment

1.Selection sequence :

STAND-BY → MUTE → 1 → 8 → 2 → POWER ON

2.Example : Sub-bright Adjustment

SZM368ET1 (R4027)

*FACTORY*

Adjustment

Mpx

Pattern

Option

Reset

↓ Press VOL ▼

AGC	15		V S	3 2
VCO	62		V A	2 7
S B T	7		H S	4 6
SCT	11		EWA	52
S C R	8		EWP	31
S T T	8		EWC	32
R G	3 2		EWT	31
G G	3 2		MAT	off
B G	3 2		P L A	6
SCO	20
VSL	26
		↓	Press CH ▼
AGC	15		V S	3 2
VCO	62		V A	2 7
S B T	7		H S	4 6
SCT	11		EWA	52
S C R	8		EWP	31
S T T	8		EWC	32
R G	3 2		EWT	31
G G	3 2		MAT	off
B G	3 2		P L A	6
SCO	20
VSL	26

↓ Press VOL ▼ or ▼

SBT 3

↓

POWER OFF

SZM368ET2 (R4127)

*SERVICE*

Adjustment

MTS

PIP

Option

Reset

↓ Press VOL ▼

AGC	15			VSLN		30	VSLP	30
VCO	62			VSN		32	VSP	32
S B T	7			VAN		32	VAP	32
SCT	11			HSN		45	HSP	39
S C R	8			EWAN		45	EWAP	46
S T T	8			EWPN		33	EWPP	33
R G	3 2			EWCN		32	EWCP	32
G G	3 2			EWTN		38	EWPT	38
B G	3 2
SCO	20
P L A	5
			↓		Press CH ▼
AGC	15			VSLN		30	VSLP	30
VCO	62			VSN		32	VSP	32
S B T	7			VAN		32	VAP	32
SCT	11			HSN		45	HSP	39
S C R	8			EWAN		45	EWAP	46
S T T	8			EWPN		33	EWPP	33
R G	3 2			EWCN		32	EWCP	32
G G	3 2			EWTN		38	EWPT	38
B G	3 2
SCO	20
P L A	5

↓ Press VOL ▼ or ▼

SBT 3

↓

POWER OFF

3-2	Samsung Electronics

Alignment and Adjustments

MEMORY SPECIFICATION

Table 3 - 1 Memory Specification

	FUNCTION			No				MODE				RANGE			28B2									228BWX						565BZ			566BWZ			765DWZ
																		29D4WZ			225BZ						25D4WZ
								(OSD)
				1				AGC				63			8			8			8			8			8			8			8			8
				2				VCO				127			63			63			63			63			63			63			63			63
				3				SBT				15			2			2			2			2			2			2			2			2
				4				SCT				13			7			7			7			7			7			7			7			7
	A			5				SCR				13			0			0			0			0			0			0			0			0
	D			6				STT				13			4			4			4			4			4			4			4			7
	J			7				RG				63			32			32			20			20			32			20			20			32
	U			8				GG				63			32			32			20			20			32			20			20			32
	S			9				BG				63			32			32			20			20			32			20			20			32
	T			10				SCO				63			20			14			14			14			14			14			14			14
	M			11				VSL				63			28			26			24			24			23			24			24			25
	E			12				VS				63			20			32			32			32			32			32			32			26
	N			13				VA				63			38			29			36			36			27			36			36			34
	T			14				HS				63			44			48			46			46			41			46			46			46
				15				EWA				63			42			33			47			47			32			47			47			51
				16				EWP				63			45			34			4			4			36			4			4			24
				17				EWC				63			32			32			32			32			32			32			32			32
				18				EWT				63			32			32			32			32			32			32			32			32
				19				PLA				10			5			0			6			6			0			6			6			5
				20				SEP				31			OFF			OFF			OFF			OFF			OFF			OFF			OFF			OFF
	OP						BYTE 0					FF			8F			95			82			87			85			82			87			87
							BYTE 1					FF			03			00			00			00			00			00			00			00
	M							ATT				15			13			13			OFF			13			13			OFF			13			13
	P					SPECTRAL						63			46			46			OFF			46			46			OFF			46			46
	X
					WIDEBAND							63			32			32			OFF			32			32			OFF			32			32
												x			275			275			275			268			268			275			275			275
					HIGH - LIGHT							y			295			295			295			275			275			295			295			295
	WHITE											Y ± 5			33			40			45			45			40			45			45			35
	BALANCE
					LOW - LIGHT							x			275			275			275			277			277			275			275			275
ADJUSTMENT
												y			295			295			295			283			283			295			295			295
												Y ± 0.2			1.4			1.4			1.4			1.4			1.4			1.4			1.4			1.4
	MEASURING PULS ADJUSTMENT VOLTAGE														2.4V			2.4V			2.4V			2.4V			2.4V			2.4V			2.4V			2.4V

Samsung Electronics

3-3

Alignment and Adjustments

3-2-2 Option Table

NOTE : The Option Adjustment must be done in the Service Mode.

3-2-2 (A) OPTION BYTE 00

Table 3-2 Option Byte 00

FUNCTION

BYTE : 00

NAME

REMARK

0

1

D7

V-SYNC

NOT USED

USED ( NO V-SYNC, POWER OFF)

D6

AUTO ON

NOT USED

USED

D5

PIP

NO PIP FUNCTION

PIP FUNCTION

D4

CATV

AIR/STD/HRC/IRC

AIR/STD/HRC/AFN

ARMY : 1

D3

S-VIDEO

NOT USED

USED

D2

TONE

NO TONE CONTROL

TONE CONTROL

D1

CRT

4 : 3 CRT

12.8 : 9 CRT

D0

MPX

NOT USED

USED

3-2-2 (B) OPTION BYTE 01

Table 3-3 Option Byte 01

FUNCTION

BYTE : 01

NAME

REMARK

0

1

D7

D6

AREA

USA

PAL M/N

SYSTEM/LANGUAGE

D5

00 : ENGLISH

01 : SPANISH (SEDA)

LANGUAGE

PAL

02 : PORTUGUESE

D4

11 : NOT USED

D3

NO VIDEO MUTE

PAL

VIDEO MUTE

NO VIDEO MUTE

D2

NO AUDIO MUTE

AUDIO MUTE

NO AUDIO MUTE

D1

ATS

NO ATS

ATS

NT

D0

V-CHIP

NO V - CHIP

V-CHIP

NT

3-4	Samsung Electronics

Alignment and Adjustments

3-2-4 Factory Reset

When “ Factory Reset” is selected, the User-Control data reverts to the initial values. The User-Control data is available at MENU (picture, sound and the other functions).

Note : When “ Factory Reset” is selected, the Factory Mode Data does not change.

Selection sequence :

Stand-By → MUTE → 1 → 8 → 2 → POWER ON

SZM368ET1 (R4027)		SZM368ET2 (R4127)

↓

* FACTORY *

Adjustment

Mpx

Pattern

Option

Reset

↓ Press CH ▼

Adjustment

Mpx

Pattern

Option

Reset

↓ Press VOL ▼

Execute

↓

* SERVICE *

Adjustment

MTS

PIP

Option

Reset

↓ Press CH ▼

Adjustment

MTS

PIP

Option

Reset

↓ Press VOL ▼

Execute

3-3 Other Adjustments

3-3-1 General

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

2.Observe the picture for good black and white details. There should be no objectionable color shading. If color shading is present, perform the purity and convergence adjustments described below.

3.Use the specified test equipment or its equivalent.

4.Correct impedance matching is essential.

5.Avoid overload. Excessive signal from a sweep generator might overload the front-end of the TV. When inserting signal markers, do not allow the marker generator to distort test results.

6.Connect the TV only to an AC power source with voltage and frequency as specified on the backcover nameplate.

7.Do not attempt to connect or disconnect any wires while the TV is turned on. Make sure that the power cord is disconnected before replacing any parts.

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

Samsung Electronics

3-5

Alignment and Adjustments

3-3-2 Automatic Degaussing

A degaussing coil is mounted around the picture tube, so external degaussing after moving the TV should be unnecessary.

However, the receiver must be properly degaussed upon installation.

The degaussing coil operates for about 1 second after the power is switched ON. If the set has been moved or turned in a different direction, disconnect its AC power for at least 10 Minutes.

If the chassis or parts of the cabinet become magnetized, poor color purity will result. If this happens, use an external degaussing coil. Slowly move the degaussing coil around the faceplate of the picture tube and the sides and front of the receiver. Slowly withdraw the coil to a distance of about 6 feet before removing power.

3-3-3 High Voltage Check

CAUTION : There is no high voltage adjustment on this chassis. The B+ power supply must be set to either +135V or +125V (for 20” screen). Conditions : Full color bar input and normal picture level.

1.Connect a digital voltmeter to the second anode of the picture tube.

2.Turn on the TV. Set the Brightness and Contrast controls to minimum (zero beam current).

3.The high voltage must not exceed 29.5KV.

4.Adjust the Brightness and Contrast controls to both extremes. Ensure that the high voltage does not exceed 29.5KV under any conditions.

SIZE	21”± 1	25”	29”	29”± 1
MAX	27.5KV	29.5KV	29.5KV	29.5KV

H-VOLTAGE

3-3-4 FOCUS Adjustment

1.Input a black and white signal.

2.Adjust the tuning control for the clearest picture.

3.Adjust the FOCUS control for well defined scanning lines in the center area of the screen.

3-3-5 B+ Line Check

There are 3 power modes :

1.“A” : When AC power supply is connected ; “ Stand-By” mode.

2.“B” : When “ Set Power-ON” button is pressed.

3.“C” : Driven by FBT.

Each voltage is marked on its lead-in wire.

(

)

3-3-6 F/S (Fail Safe) Circuit Check

1.The failsafe circuit check is the final step after servicing.

2.Turn the power switch on and adjust the screen for “Normal”.

3.Temporarily short Pin R and Pin X on the chassis (RX05, RX04). Sound and picture will disappear.

4.The TV should remain in this state. This shows that the failsafe circuit is working properly.

5.To restore picture and sound, temporarily turn off the AC power supply. After about 30 seconds, switch power ON.

3-6	Samsung Electronics

Alignment and Adjustments

3-3-7 Color Purity Adjustment

1.Warm up the receiver. Operate it for 20 minutes, with the Brightness control set to maximum.

2.Fully degauss the receiver. Use an external degaussing coil.

3.Roughly adjust convergence by rotating the Convergence Magnet.

4.Input a black and white signal.

5.Loosen the Deflection Yoke clamp screw, and move the Deflection Yoke as close to the purity magnet as possible.

6.Loosen the Purity Magnet clamp. Adjust the purity magnet so that the vertical green raster is precisely at the center of the screen. Then tighten the clamp.

7.Slowly move the Deflection Yoke forward, and adjust it for the best overall green screen.

8.Tighten the Deflection Yoke clamp screw.

	DEFLECTION
	YOKE
CRT	PURITY AND
	CONVERGENCE
	MAGNET ASS'Y

RUBBER	RUBBER WEDGE
WEDGES
30	30

	31 mm		DEFLECTION	ADHESIVE
	(1-3/16")	30	YOKE
	GRASS			RUBBER
	CLOTH	RUBBER WEDGES
				WEDGES
	TAPE	LOCATION
				KIT

Fig. 3-1 Tube Assembly

2 POLE PURITY

ADJUST THE ANGLE (VERTICAL LINES)

FIXED

YOKE

CLAMP

SCREW

6 POLE CONVERGENCE

4 POLE CONVERGENCE

ROTATE TWO TABS AT THE SAME TIME (HORIZONTAL LINES)

Fig. 3-2 Purity and Convergence Magnets

Samsung Electronics

3-7

Alignment and Adjustments

3-3-8 Center Convergence Adjustment

Note: Before attempting any convergence adjustment, make sure that the receiver has been powered ON for at least twenty minutes.

1.Input a crosshatch pattern from a color bar generator.

2.Adjust the Brightness and Contrast controls for a well defined pattern.

3.Adjust the two tabs of the 5-pole magnets. Change the angle between the tabs, and superimpose red and blue vertical lines in the center area of the picture screen.

4.Next, turn both tabs at the same time. Keep the angle between the tabs constant, and superimpose the red and blue horizontal lines at the center of the screen.

5.Adjust the two tabs of the 6-pole magnets. Superimpose the red/blue lines on the green. Adjusting the angle affects the horizontal lines.

6.Repeat adjustments 3, 4 and 5. The dot movement is complex because the 4-pole and 6-pole magnets interact.

BLUE		RED			RED/BLUE			GREEN
BLUE					RED/BLUE
RED					GREEN
4-Pole Magnet Movement					6-Pole Magnet Movement

Fig. 3-3 Center Convergence Adjustment

3-3-9 AGC Adjustment

1.Input a COLOR-BAR pattern. (CH2)

2.Set the RF input signal to 70 dBμV.

3.Use Generator for PM5518 & PM5418.

4.Set AGC (in the Factory Mode) so that the DC level of IC TDA8377 Pin 53 is 3.0±0.05V.

3-3-10 AFT (VCO Adjustment)

1.Input an AGC adjustment signal.

2.Select Factory Mode VCO and press the MUTE key one time.

3.GEOMATRIX adjustments

VS	EWA
VA	EWP
VSL	EWC
HS	EWT

3-8	Samsung Electronics

3-3-11 White Balance Adjustment

3-3-11 (A) SCREEN ADJUSTMENTS

1.Input a TOSHIBA pattern.

2.Check R506 “G” pin on the CRT PCB with an oscilloscope.

3.Enter the Horizontal Line Mode.

4.Adjust the Screen Control on the FBT so that the waveform of the 21st line is DC 2.0 (±0.5)V.

SIZE	29”	26”	22”
DC	2.4	2.4	2.4

3-3-11 (B) HIGH-LIGHT ADJUSTMENT

1.NOTE : If a color analyzer is not available, then approximate the following color adjustments “by eye”.

2.Input a TOSHIBA pattern.

3.Set high-light to 290/300 (X,Y) with a color analyzer.

4.Set low-light to 1.4F/L.

5.Adjust RG, BG and set GG to step 32.

		30”	29”	26”	22”
	HEIGHT	33 ± 5	37 ± 5	45 ± 5	45 ± 5
	LIGHT

3-3-11 (C) SUB-CONTRAST ADJUSTMENT

1.Set SCT so that the brightness level in highlight is 40 F/L (for a 29” SCREEN).

Alignment and Adjustments

3-3-11 (D) SUB-BRIGHTNESS ADJUSTMENT

1.Input a TOSHIBA pattern.

2.Set SBT so that the brightness level in lowlight is 1.4 F/L.

<TOSHIBA PATTERN>

High-Light

Low-Light

3-3-11 (E) SUB-COLOR ADJUSTMENT

Set “SCR” in the Service Mode to step 0.

3-3-11 (F) SUB-TINT ADJUSTMENT

Set “STT” in the Service Mode to step 4.

3-3-11 (G) VERTICAL SIZE ADJUSTMENT

1.Input a lion head pattern.

2.Set VS to 32 in the Factory Mode.

3.Set VA so that the top margin is 4.0. Adjust SL so that the bottom margin is 4.0. If the top and bottom margins are different, adjust VA so that their sum is 8.0.

3-3-11 (H) HORIZONTAL SHIFT ADJUSTMENT

1.Input a lion head pattern.

2.Adjust “HS” in the Service Mode so that the left and right margins of the lion head pattern are 5.0 ± 0.5 : CT633BW/CT683BW, 6.3 ± 0.5 : CT566BV/CT566BW/CT568BW/CT765DW/ CT766DW/CT762B/CT25D4/CT29D4.

Samsung Electronics

3-9

Alignment and Adjustments

3-3-12 Power Consumption Reduction Circuit during Stand-by (Option)

			Q801	OmA
			SFP9640
130 RECTIFIED				FBT B+
	DZ809	R812		OmA
				TUNER 33V
OmA
			R801
POWER			Q903
CONTROL
	R910
	10K

For the power system of K51A chassis, all output voltages remain the same during stand-by. So, to reduce power consumption, it is necessary to cut the leakage current flowing through FBT B+ (130V) and tuner port VT (33V)

during stand-by (Picture OFF).

The power consumption reduction circuit cuts leakage current. A P-channel MOSFET is used as a switching element.

The operating principles are as follows:

1.In stand-by, the voltage of the power control port (micom IC) becomes low (0V). During power ON, however, it becomes high (over 4V).

2.The voltage between S-G (Q801 P-channel MOSFET) should be over 3.5V, so that the S-D current (Q801) can keep flowing.

3.When the voltage of the power control port becomes low, the current flowing through Q903 (R812) is cut.

4.When the voltages across R803 become less than 3.5V, the S-D current (Q801) is cut.

5.DZ809 is required for protecting the G-port (Q801).

3-3-13 Precautions when servicing

1.Q801 can sustain a continuous flow of 11ADC. If Q801 is destroyed, the S-D is shorted.

But, the TV functions normally and only the power consumption during stand-by increases (2.5W→ 6W).

2.No Picture ON : Q903 is open or DZ809 is shorted. At this time, check both Q903 and DZ809. If the power-consumption reduction circuit does not work normally after checking both Q903 and DZ809, then short the S-D ports of Q801.

3-10	Samsung Electronics

Troubleshooting

4. Troubleshooting

4-1 No Raster and No Sound

No Raster and No Sound

		No Voltage	Measure the B+
			Abnormal
			Voltage at the Cathode
			of D812 (D811)
			Normal
			Check +12.5 Line
	Check/Replace	Normal	More than 130V	Check the horiz
				output signal at TR

IC801 Q801	collector.

Check/Replace AVR

Normal

Measure the B+

Circuit, Horiz Output

voltage at the cathode

Circuit and B+

of D812*

Voltage Line.

Open

Check/Replace F801

More than 130V

Less than 50V

Normal

Check/Replace FS

Check/Replace

Check/Replace

AVR circuit

circuit

the AVR circuit.

(ADJ Pin of STR)

Check/Replace

Check/Replace

1) D801

the power switch

2)Short the Degaussing Coil

3)C801

Samsung Electronics

4-1