DAEWOO DTQ-26S1FC, DTQ-26S1FS, DTQ-26S1FSP, DTQ-29S1FCN, DTQ-29S1FSN Service Manual

Service Manual

Color Television

CHASSIS : CN-200I/A

NTSC-M SYSTEM

MODEL: DTQ-26S1FC/FS/FSP(CN-200I)

DTQ-29S1FCN/FSN/FSP(CN-200I)

DTQ-26S1HC/HS/HSP(CN-200A)

DTQ-29S1HC/HS/HSP(CN-200A)

DAEWOO ELECTRONICS CO., LTD. OVERSEAS SERVICE DEPT.

FEATURES

FS (Frequency Synthesizer) Tuning System

CATV Ready

Monitor Look Design

A/V IN. (Stereo)

Stereo/Mono Function

ELECTRICAL SPECIFICATIONS

POWER INPUT
FC	SERIES	AC 120V 60Hz
FS	SERIES	AC 85V ~ AC 150V 60Hz
FSP SERIES		AC 220V 50Hz/60Hz
POWER RATING
26” MODELS		100W
29” MODELS		105W
INTERMEDIATE FREQUENCIES
PICTURE IF CARRIER FREQUENCY		45.75MHz
SOUND IF CARRIER FREQUENCY		41.25MHz
COLOR SUB CARRIER FREQUENCY		42.17MHz
AUDIO OUTPUT RATING		1.2W 2
SPEAKER		2W 8 ohm 2
ANTENNA INPUT IMPEDANCE		VHF/UHF 75 ohm UNBALANCED
TUNING RANGES
VHF		2 THRU 13
UHF		14 THRU 69
CATV		1 THRU 125

CONTENTS

Safety Precautions	3
Control View	5
Important Service Notes	7
Block Diagram	8
General Adjustments	10
Trouble Shooting Charts	12
Description of Semiconductors	20
Printed Boards	21
Exploded View	23
Schematic Diagram	25
Parts List	27
Option List	36

2

CONTROL VIEW

F-CONNECTOR

300 OHM-75 OHM

COUPLING

TRANSFORMER

VHF

75Ω

FROM 75 OHM

VHF ANTENNA WITH

CABLE OR CABLE

TV SYSTEM

5

1. Overview of Your Equipment

Your TV comes with a remote control. The section below summarizes the buttons,controls, and terminals that you will use with your TV.

2.Your TV's Front Panel

1.POWER

Use this buttom to turn your TV on or off.

2.CH

Use these buttom to change channels on your TV, or to select items in the menu system.

3. VOL

Use these buttom to change your TV s volume, to activate selections in the menu system, or to change audio and video settings.

4.MENU

Use this buttom to turn the TV s menu system on and off.

5.Remote control receiver

This receiver receives a signal from your remote control. Do not block it.

3. Your TV's Back Panel

				1.	Antenna terminal
					Use this terminal to attach an antenna or cable
					system to your TV.
				2.	VIDEO IN
					This terminal allows the TV to receive a video
					signal from another components, such as a VCR.
1	2	4	3	3.	AUDIO R/MONO IN
					This terminal allows the TV to receive an audio
					R/MONO signal from another components, such as
				a	VCR.
				4.	AUDIO L IN
					This terminal allows the TV to receive an audio L
					signal from another components, such as a VCR.

6

BLOCK DIAGRAM (CN-200I)

8

BLOCK DIAGRAM (CN-200A)

9

GENERAL ADJUSTMENTS

1. GENERAL

In the majority of cases, all color televisions will need only slight touch-up adjustment upon installation. Check the basic characteristics such as height, focus and subbasic characteristics such as height, focus and subbright. Observe the picture for good black and white details without objectionable color shading.

2. VERTICAL HEIGHT ADJUSTMENT

1)Tune in an active channel.

2)Adjust brightness and contrast controls for a good picture.

3)Adjust vertical height control (R305) for approximately one half inch over scan at top and bottom of picture screen.

4)Vertical centering adjustment R310 Horizontal centering adjustment R516.

3. FOCUS ADJUSTMENT

1)Tune in an active channel.

2)Adjust brightness, sharpness and contrast controls for a good picture.

3)Adjust focus control (part of T402) for sharp scanning lines and/or sharp picture.

4. RF AGC ADJUSTMENT

1)Tune in an active channel.

2)Using the attenuator, apply the signal of 60dBm to the antenna input terminal.

3)Turn RF AGC control (R113) full clockwise until snow or/and noise appears in the picture, then slowly turn control counter clockwise until snow or/and noise disappears.

5. HIGH VOLTAGE CHECK

High voltage is not adjustable but must be checked to verify that the receiver is operating within safe and efficient design limitations as specified:

1)Operate Receiver for at least 15 minutes at 120V AC line.

2)Set brightness sharpness, contrast and color control to minumum position (Zero beam).

3)Connect accurate high voltage meter to CRT anode. The reading should be 26kv~28kv

If a correct reading cannot be obtained, check circuity for malfunctioning components.

6. X-RADIATION PROTECTION CIRCUIT TEST

When service has been performed on the horizontal deflection system, high voltage system or B+system, the X- RADIATION protection circuit must be tested for proper operation as follows:

1)Operate receiver for at least 15 minutes at 120V AC line.

2)Adjust all customer controls for normal picture and sound.

3)Short R414(X-RAY Short test), and remove short clip.

4)If the operation of horizontal osc. does not stop in step The circuit must be repaired, before the set is returned to the customer.

7. CRT GRAY SCALE ADJUSTMENT

1)Tune in an active channel.

2)Set the COLOR control to minimum.

3)Turn the SCREEN control (on T402 fully counter-

clockwise.)

4)Rotate the RED, GREEN and BLUE BIAS controls (R917, R918, R919) counterclock wise from the maximum, set them to the position where notches in the knobs become parallel to the surface of P.C. Board.

5)Set the GREEN and BLUE DRIVE controls (R920, R921) to the mid position.

6)Turn the service switch SW901 (Service Position) on the CRT board.

7)Rotate the SCREEN control (on T402) gradually clockwise until the second horizontl line following the first line appears slightly on the screen. Then turn fully counterclockwise the two BIAS controls corresponding to the colors of the first and the second horizontal lines to eliminated the lines.

8)Set the SCREEN control to the position where the third horizontal line lights slightly on the screen.

9)Adjust the two BIAS control set to the minimum in item 7) above to obtain the slightly lighted horizontal line in the same levels of three (red, green, blue) colors. (The line should be white if the BIAS controls are adjusted properly.)

10)Turn the service switch SW901 again (Normal position on the CRT board.)

11)Press PICTURE-SEL, P-UP and set the brightness and contrast controls to the maximum.

12)Adjust the BLUE and GREEN DRIVE control to obtain proper white-blanced picture in high light areas.

13)Using P-SEL, P-DN key, set the brightness and contrast controls to obtain dark gray raster. Then check the white balance in low brightness. Of the white balance is not proper, retouch the BIAS controls and DRIVE controls to obtain a good white balance in both low and high light areas.

8. MAIN B+(103V) ADJUSTMENT

1)Tune in an active channel

2)Check TP10 (DC 103V Line) using D.V.M

3)Adjust voltage control (R809) for main B+(DC 103V)

9. SUB-BRIGHTNESS ADJUSTMENT

1)Tune in a color program.

2)Set the CONTRAST control to maximum and the BRIGHTNESS control to maximum and the SHARPNESS control to the center position.

3)Set the COLOR and TINT controls to center.

4)Set the SUB-BRIGHT control R522 to center and leave the receiver on five minutes in this state.

5)Watching the picture carefully, adjust the SUBBRIGHT control in the position where the picture does not show evidence of blooming in high brightness area and not appear too dark in low bright area.

6)Check for BRIGHTNESS controls at both extremes.

7)If the picture does not appear dark with the CONTRAST and BRIGHTNESS control turned to minimum, or not appear bright with the controls turned to maximum, adjust the SUB-BRIGHT control again for an acceptable picture.

10

10. PICTURE IF/AFT ADJUSTMENTS

NOTE : THIS RECEIVER IS TRANSISTORIZED AND SPECIAL CARE MUST BE TAKEN WHEN SERVICING. READ THE FOLLOWING (NOTES BEFORE ATTEMPTING ALIGNMENT)

Alignment requires an exacting procedure and should be undertaken only when necessary.

Isolation transformer must be used to prevent shock hazard.

The test equipment specified or its equivalent is required to perform the alignment properly. Use of equipment which does not meet these requirements may result in improper alignment.

Accurate equipment is essential to obtain proper alignment of this receiver.

Use of excessive signal from a sweep generator can cause overloading of receiver circuit Overloading should be avoided to obtain a true response curve. Insertion of markers from the marker generator should not cause distortion of the response curve.

The AC Power line voltage should be kept 120 volts while alignment is being performed. Do not attempt to disconnect any components while the receiver is in operation.

Make sure the power cord is disconnected before replacing any parts in the receiver.

TEST EQUIPMENT

Digital voltmeter National Model VP-2600A or equivalent

Oscilloscope Tektronix Model 2215A or equivalent.

Direct/Low-capacity probe Tektronix Model P6120 or equivalent (Accessory of oscilloscope)

Color-Bar/Dot/Crosshatch generator Tektronix Model 146 or equivalent.

PIF sweep marker generator Nihon Tsushinki Model 4723 or equivalent

Power supply Academy Model 150A or equivalent

Isolation transformer Voltage adjustable type having capacity of at least 150 watts

BLOCK DIAGRAM

	B+		MAIN BOARD		OSCILLOSCOPE
	BIAS		TP3	TP7
	POWER
	SUPPLY			TP6
	A		TP5			Y
					X
	(12V)
	AGC						45.75MHz
						Fig. 6	PIF Response
	BIAS	PIF SWEEP/MARKER GEN.
	POWER
	SUPPLY
	B
	(4-5V)	V	H	DETIN	OUT
							P 45.75MHz
		Fig. 5 Picture IF Sweep Alignment				Fig. 7	AFT Response Curve

1)Disconnect the TUNER IF output from TP6 and connect equipment as shown above.

2)Set the sweep/marker generator for 30 Vrms.

3)Observe 1 Vp-p on scope by adjusting power supply B (4~5V).

4)Adjust PIF coil L505 for according beat signal with 45.75 MHz marker on scope (See Fig. 6).

5)Connect the DET IN to TP7.

6)Adjust AFT coil L504 for center display at 45.75 MHz on scope (See Fig. 7).

7)After completing the above steps, disconnect equipment and adjust the AGC delay circuit as explained in the General Adjustments section of this manual.

11

TROUBLE SHOOTING CHARTS

NO POWER
DOES QC701(POWER ON/OFF TR)			YES		GO TO	A
OPERATE?
			NO		GO TO	B
A
			CHECK
			#30
			(7.5V DC)
		R816 15K
		2WATT	30		DOES
					SHUT DOWN
					CIRCUIT
				I501	OPERATE?
CHECK TP10	103VDC				24
			26
(MAIN B+
LINE)		IF #26 NORMAL
		& NO OUTPUT AT
		#23 THEN		Q402
		CHANGE I501		H. OUTPUT		CHECK
						Q402
						COLLECTOR
		12V	D406	12V	T402
					F.B.T
		CHECK
		12V LINE
			D403		103V(B+)
						CHECK
B						ALL THE POINTS
						THEN CHANGE
		NORMAL: 5V				I701
	QC706	RESET: 0V
	RESET
SHOULD		16 I701		36	PWR
BE			42		CONTROL
4.3V-5.2V		12 LC864616A			KEY
5V
Q802				OPEN LOAD		KEY OPERATE?
REGULATOR				THEN CHECK
						CHECK DIODE
R808				#42 ON STATE
						D701 & SWITCH
				4 ~5V
						KEY BOARD
CHECK
F801	T801	QC701
125V 5A
		POWER
CHECK
		CONTROL
LEAD
SOLDERING
L801
LINE FILTER
		12

NO PICTURE

OK

CHECK THE WAVE FORM OF

I501 #44 (2Vp-p)

NG

C

	FC	COMPOSITE			21
		VIDEO INPUT	FS	I501
		H		LA 7674
	QC201		C506	42
	CONTRAST			39
CHECK	BRIGHT
CONTROL				31
(NORMAL)				11	14
VOLTAGES
#39: 5.0V	D505	R522
#31: 3.9V			CHECK
	ABL	SUB-BRIGHT
			9V LINES
			#11,14
				CHECK
				ABL
				Ib = 1.2mA

GO TO	C
GO TO	D
H

	Y-OUT	QC501
		VIDEO
		DRIVE
			CHECK
			210V
	H. BLANKING		KINE

T402

FBT D404

R413

ABL H.T

R412

D

		AGC				CHECK
						HEATER
ENA			9V			6.3Vrms
	DATA	U101 TUNER	VT (33V)
	CLK
		IF	5V
I701
LC864616A				ADJUST
10	11			RF-AGC
				R113	DETECTOR
					OUTPUT
		Z101	8		10
		SAW FILTER	9	I501	44	TO QC201
				LA7674
CHECK		CHECK		2	11 14
CSB503E		IF AGC				H
		VTG.
		5VDC

TP2	CHECK
	9V LINE
	#11, 14

13

NO SOUND(CN-200I)
CHECK FOR SIGNAL					GO TO	E
AT I501 #1
					GO TO	F
E
CHECK		#1
MONO 100% MOD
		#2 9V(B+)
-> 0.424 Vp-p
		I601
				#19	CHECK 1Vp-p
CHECK		#12		#18
EXT SOUND		#13	(MUTE)#17		MUTE ON: 5V
SIGNAL OFF:L
					OFF: 0V
		#1 9V(B+)	#4	CHECK 1Vp-p
		#2(0~5V)	#6
		I602
		#8(0~5V)
			#7	CHECK 12VDC
		I604/I603
CHECK SOUND INPUT		#3	#6
			#5	CHECK SOUND OUTPUT
F
	#11		#1	COMPOSITE SIGNAL
CHECK 9V
	#14				I601 #1
	#44	I501
		LA7674
			#4		CHECK FM DET
					CIRCUIT
Z201	#48
CHECK SOUNDIF INPUT
		14