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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 FS SERIES FSP SERIES POWER RATING 26" MODELS 29" MODELS INTERMEDIATE FREQUENCIES PICTURE IF CARRIER FREQUENCY SOUND IF CARRIER FREQUENCY COLOR SUB CARRIER FREQUENCY AUDIO OUTPUT RATING SPEAKER ANTENNA INPUT IMPEDANCE TUNING RANGES VHF UHF CATV AC 120V 60Hz AC 85V ~ AC 150V 60Hz AC 220V 50Hz/60Hz 100W 105W 45.75MHz 41.25MHz 42.17MHz 1.2W 2 2W 8 ohm 2 VHF/UHF 75 ohm UNBALANCED 2 THRU 13 14 THRU 69 1 THRU 125
CONTENTS
Safety Precautions Control View Important Service Notes Block Diagram General Adjustments Trouble Shooting Charts Description of Semiconductors Printed Boards Exploded View Schematic Diagram Parts List Option List 3 5 7 8 10 12 20 21 23 25 27 36
2
Product safety servicing guidelines for color television receivers
CAUTION : Do not attempt to modify this product in any way. Unauthorized modifications will not only void the warranty, but may lead to your being liable for any resulting property damage or user injury. Service work should be performed only after you are thoroughly familiar with all of the following safety checks and servicing guidelines. To do otherwise, increases the risk of potential hazards and injury to the user.
SAFETY CHECKS
After the original service problem has been corrected, a check should be made of the following:
A.C. VOLTMETER
Good earth ground, such as the water pipe, conduit, etc.
0.15µF · 1500 OHM 10WATT · Place this probe on each exposed metal part.
GRAPHIC SYMBOLS :
The lightning flash with arrowhead symbol, within an equilateral triangle, is intended to alert the service personnel to the presence of uninsulated dangerous voltage that may be of sufficienty magnitude to constitute a risk of electric shock. The exclamation point within an equilateral triangle is intended to alert the service personnel to the presence of important safety information in service literature. Fuse symbol is printed on pcb adjacent to the fuse, with RISK OF FIRE REPLACE FUSE AS MARKED . The symbol is explained in the service manual with the following wording or equivalent. CAUTION : FOR CONTINUED PROTECTION AGAINST FIRE HAZARD, REPLACE ONLY WITH SAME TYPE 4A, 125V FUSE and ATTENTION: AFIN D ASSU UNE PROTECTION PERMANENTE CONTRE LES RISQUES D INCENDIE, REMPLACER UNIQUEMENT PAR UN FUSIBLE DE MEME TYPE ET DE 4A, 125V .
SUBJECT : FIRE & SHOCK HAZARD
1. Be sure that all components are positioned in such a way as to avoid possibility of adjacent component shorts. This is especially important on those chassis which are transported to and from the repair shop. 2. Never release a repair unless all protective devices such as insulators, barriers, covers, shields, strain reliefs, and other hardware have been reinstalled per original design. 3. Soldering must be inspected to discover possible cold solder joints, frayed leads, damaged insulation (including A.C. cord), solder splashes or sharp solder points. Be certain to remove all loose foreign particals. 4. Check for physical evidence of damage or deterioration to parts and components, and replace if necessary follow original layout, lead length and dress. 5. No leads or components should touch a receiving tube or a resistor rated at 1 watt or more. Lead tension around protruding metal surfaces must be avoided. 6. All critical components such as fuses, flameproof resistors, capacitors, etc. must be replaced with exact factory types. Do not use replacement components other than those specified or make unrecommended circuit modifications. 7. After re-assembly of the set always perform an A.C. leakage test on all exposed metallic parts of the cabinet, (the channel selector knob, antenna terminals, handle and screws) to be sure the set is safe to operate without danger of electrical shock. Do not use a line isolation transformer during this test. Use an A.C. voltmeter, having 5000 ohms per volt or more sensitivity, in the following manner : connect a 1500 ohm 10 watt resistor, paralleled by a 15 mfd. 150V A.C. type capacitor between a known good earth ground 9water pipe, conduit, etc.) and the exposed metalic parts, one at a time. Measure the A.C. voltage across the combination of 1500 ohm resistor and 0.15 MFD capacitor. Reverse the A.C. plug and repeat A.C. voltage measurements for each exposed metallic part. Voltage measured must not exceed 0.75 volts R.M.S. This corresponds to 0.5 milliamp A.C. Any value exceeding this limit constitutes a potential shock hazard and must be corrected immediately.
SUBJECT : X-RADIATION
1. Be sure procedures and instructions to all service personnel cover the subject of X-rays in current T.V. receivers is the picture tube. However, this tube does not emit X-rays when the high voltage is at the factory specified level. The proper value is given in the applicable schematic. Operation at higher voltages may cause a failure of the picture tube or high voltage supply and, under certain circumstances, may produce radiation in excess of desirable levels. 2. Only factory specified C.R.T. anode connectors must be used. Degaussing shields also serve as X-ray shield in color sets. Always re-install them. 3. It is essential that the serviceman has available an accurate and reliable high voltage meter. The calibration of the meter should be checked perio dically against a reference standard. Such as the one available at your distributor. 4. When the high voltage circuitry is operating properly there is no possibility of an X-radiation problem. Every time a color chassis is serviced, the brightness should be run up and down while monitoring the high voltage with a meter to be certain that the high voltage does not
3
exceed the specified value and that it is regulating correctly. We suggest that you and your service orgainzation review test procedures so that voltage regulation is always checked as a standard servicing procedure. And that the high voltage reading be recorded on each customer s invoice. 5. When troubleshooting and making test measurements in a receiver with a problem of excessive high voltage, avoid being unnecessarily close to the picture tobe and the high voltage compartment. Do not operate the chassis longer than is necessary to locate the cause of excessive voltage. 6. Refer to HV, B+and Shutdown adjustment procedures described in the appropriate schematic and diagrams(where used).
2. Avoid conditions of high humidity such as : Outdoor patio installations where dew is a factor. Near steam radiators where steam leakage is a factor, etc. 3. Avoid placement where draperies may obstruct rear venting. The customer should also avoid the use of decorative scarves or other coverings which might obstruct ventilation. 4. Wall and shelf mounted installations using a commercial mounting kit, must follow the factory approved mounting instructions. A receiver mounted to a shelf or platform must retain its original feet(or the equivalent thickness in spacers) to provide adequate are flow across the bottom, blots or screws used for fasteners must not touch and parts or wiring. Perform leakage test on customized installations. 5. Caution customers against the mounting of a receiver on sloping shelf or a tilted position, unless the receiver is properly secured. 6. A receiver on a roll-about cart should be stable on its mounting to the cart. Caution the customer on the hazards of trying to roll a cart with small casters across thresholds or deep pile carpets. 7. Caution customers against the use of a cart or stand which has not been listed by underwriters laboratories, inc. For use with their specific model of television receiver or generically approved for use with T.V. s of the same or larger screen size.
SUBJECT : IMPLOSION
1. All direct viewed picture tubes are equipped with an integral implosion protection system, but care should be taken to avoid damage during installation. Avoid scratching the tube. If scratched, replace it. 2. Use only recommended factory replacement tubes.
SUBJECT : TIPS ON PROPER INSTALLATION
1. Never install any receiver in closed-in recess, cubbyhole or closely fitting shelf space over, or close to heat duct, or in the path of heated air flow.
4
Product safety servicing guidelines for color television receivers
CAUTION : Do not attempt to modify this product in any way. Unauthorized modifications will not only void the warranty, but may lead to your being liable for any resulting property damage or user injury. Service work should be performed only after you are thoroughly familiar with all of the following safety checks and servicing guidelines. To do otherwise, increases the risk of potential hazards and injury to the user.
SAFETY CHECKS
After the original service problem has been corrected, a check should be made of the following:
A.C. VOLTMETER
Good earth ground, such as the water pipe, conduit, etc.
0.15µF · 1500 OHM 10WATT · Place this probe on each exposed metal part.
GRAPHIC SYMBOLS :
The lightning flash with arrowhead symbol, within an equilateral triangle, is intended to alert the service personnel to the presence of uninsulated dangerous voltage that may be of sufficienty magnitude to constitute a risk of electric shock. The exclamation point within an equilateral triangle is intended to alert the service personnel to the presence of important safety information in service literature. Fuse symbol is printed on pcb adjacent to the fuse, with RISK OF FIRE REPLACE FUSE AS MARKED . The symbol is explained in the service manual with the following wording or equivalent. CAUTION : FOR CONTINUED PROTECTION AGAINST FIRE HAZARD, REPLACE ONLY WITH SAME TYPE 4A, 125V FUSE and ATTENTION: AFIN D ASSU UNE PROTECTION PERMANENTE CONTRE LES RISQUES D INCENDIE, REMPLACER UNIQUEMENT PAR UN FUSIBLE DE MEME TYPE ET DE 4A, 125V .
SUBJECT : FIRE & SHOCK HAZARD
1. Be sure that all components are positioned in such a way as to avoid possibility of adjacent component shorts. This is especially important on those chassis which are transported to and from the repair shop. 2. Never release a repair unless all protective devices such as insulators, barriers, covers, shields, strain reliefs, and other hardware have been reinstalled per original design. 3. Soldering must be inspected to discover possible cold solder joints, frayed leads, damaged insulation (including A.C. cord), solder splashes or sharp solder points. Be certain to remove all loose foreign particals. 4. Check for physical evidence of damage or deterioration to parts and components, and replace if necessary follow original layout, lead length and dress. 5. No leads or components should touch a receiving tube or a resistor rated at 1 watt or more. Lead tension around protruding metal surfaces must be avoided. 6. All critical components such as fuses, flameproof resistors, capacitors, etc. must be replaced with exact factory types. Do not use replacement components other than those specified or make unrecommended circuit modifications. 7. After re-assembly of the set always perform an A.C. leakage test on all exposed metallic parts of the cabinet, (the channel selector knob, antenna terminals, handle and screws) to be sure the set is safe to operate without danger of electrical shock. Do not use a line isolation transformer during this test. Use an A.C. voltmeter, having 5000 ohms per volt or more sensitivity, in the following manner : connect a 1500 ohm 10 watt resistor, paralleled by a 15 mfd. 150V A.C. type capacitor between a known good earth ground 9water pipe, conduit, etc.) and the exposed metalic parts, one at a time. Measure the A.C. voltage across the combination of 1500 ohm resistor and 0.15 MFD capacitor. Reverse the A.C. plug and repeat A.C. voltage measurements for each exposed metallic part. Voltage measured must not exceed 0.75 volts R.M.S. This corresponds to 0.5 milliamp A.C. Any value exceeding this limit constitutes a potential shock hazard and must be corrected immediately.
SUBJECT : X-RADIATION
1. Be sure procedures and instructions to all service personnel cover the subject of X-rays in current T.V. receivers is the picture tube. However, this tube does not emit X-rays when the high voltage is at the factory specified level. The proper value is given in the applicable schematic. Operation at higher voltages may cause a failure of the picture tube or high voltage supply and, under certain circumstances, may produce radiation in excess of desirable levels. 2. Only factory specified C.R.T. anode connectors must be used. Degaussing shields also serve as X-ray shield in color sets. Always re-install them. 3. It is essential that the serviceman has available an accurate and reliable high voltage meter. The calibration of the meter should be checked perio dically against a reference standard. Such as the one available at your distributor. 4. When the high voltage circuitry is operating properly there is no possibility of an X-radiation problem. Every time a color chassis is serviced, the brightness should be run up and down while monitoring the high voltage with a meter to be certain that the high voltage does not
3
exceed the specified value and that it is regulating correctly. We suggest that you and your service orgainzation review test procedures so that voltage regulation is always checked as a standard servicing procedure. And that the high voltage reading be recorded on each customer s invoice. 5. When troubleshooting and making test measurements in a receiver with a problem of excessive high voltage, avoid being unnecessarily close to the picture tobe and the high voltage compartment. Do not operate the chassis longer than is necessary to locate the cause of excessive voltage. 6. Refer to HV, B+and Shutdown adjustment procedures described in the appropriate schematic and diagrams(where used).
2. Avoid conditions of high humidity such as : Outdoor patio installations where dew is a factor. Near steam radiators where steam leakage is a factor, etc. 3. Avoid placement where draperies may obstruct rear venting. The customer should also avoid the use of decorative scarves or other coverings which might obstruct ventilation. 4. Wall and shelf mounted installations using a commercial mounting kit, must follow the factory approved mounting instructions. A receiver mounted to a shelf or platform must retain its original feet(or the equivalent thickness in spacers) to provide adequate are flow across the bottom, blots or screws used for fasteners must not touch and parts or wiring. Perform leakage test on customized installations. 5. Caution customers against the mounting of a receiver on sloping shelf or a tilted position, unless the receiver is properly secured. 6. A receiver on a roll-about cart should be stable on its mounting to the cart. Caution the customer on the hazards of trying to roll a cart with small casters across thresholds or deep pile carpets. 7. Caution customers against the use of a cart or stand which has not been listed by underwriters laboratories, inc. For use with their specific model of television receiver or generically approved for use with T.V. s of the same or larger screen size.
SUBJECT : IMPLOSION
1. All direct viewed picture tubes are equipped with an integral implosion protection system, but care should be taken to avoid damage during installation. Avoid scratching the tube. If scratched, replace it. 2. Use only recommended factory replacement tubes.
SUBJECT : TIPS ON PROPER INSTALLATION
1. Never install any receiver in closed-in recess, cubbyhole or closely fitting shelf space over, or close to heat duct, or in the path of heated air flow.
4
CONTROL VIEW
F-CONNECTOR
300 OHM-75 OHM COUPLING TRANSFORMER VHF
75 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. 3.
CH
Use these buttom to change channels on your TV, or to select items in the menu system.
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
IMPORTANT SERVICE NOTES
1. X-RAY RADIATION PRECAUTION
1) Excessive high voltage can produce potentially hazardous X-RAY RADIATION. To avoid such hazards, the high voltage must not be above the specified limit. The nominal value of the high voltage of this receiver is 27kv at zero beam current (minimum brightness) under a 120V AC power source. The high voltage must not, under any circumstances, exceed 32kv. Each time a receiver requires servicing, the high voltage should be checked following the HIGH VOLTAGE CHECK procedure on page 3 of this manual. It is recommended as a parts of the service record. It is important to use an accurate and reliable high voltage meter. 2) This receiver is equipped with X-RADIATION PROTECTION circuit which prevents the receiver from producing an excessively high voltage even if the B+voltage increases abnormally. Each time the receiver is serviced, X-RADIATION PROTECTION circuit must be checked to determine that the circuit is properly functioning, following the X-RADIATION PROTECTION CIRCUIT CHECK procedure on page 3 of this manual. 3) The only source of X-RAY RADIATION in this TV receiver is the picture tube. For continued X-RAY RADIATION protection, the replacement tube must be exactly the same type tube as specified in the parts list. 4) Some parts in this receiver have special safety-related characteristics for X-RAY RADIATION protection. For continued safety, parts replacement should be undertaken only after referring to the PRODUCT SAFETY NOTICE below. tion transformer during this check). Use an AC voltmeter having 5000 ohms per volt or more sensitivity in the following manner. Connect at 1500 ohm 10 watt resistor, paralleled by a 0.15 mfd. AC type capacitor, between a known good earth ground (water pipe, conduit etc.) and the exposed metallic parts, one at a time. Measure the AC voltage across the combination of 1500 ohm resistor and 0.15 mfd capacitor. Voltage measured must not exceed 0.3 volts RMS. This corresponds to 0.2 millliamp. AC. Any value exceeding the limit constitutes a potential shock hazard and must be corrected immediately.
AC VOLT METER
0.15MFD 1500 ohm 10watt Place this probe on each exposed metallic part.
Good earth ground such as d water pipe, conduit, etc.
3. PRODUCT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These characteristics are often passed unnoticed by a visual inspection and the protection afforded by them cannot necessarily be obtained by using replacement components rated for higher voltage, wattage, etc. Replacement parts which have these special safety characteristics are identified in this manual and its supplements; electrical components having such features are identified by shading on the schematic diagram and the parts list. Before replacing any of these components, read the parts list in this manual carefully. The use of substitute replacement parts which do not have the same safety characteristics as specified in the parts list may create Xray radiation or other hazards.
2. SAFETY PRECAUTION
WARNING : Service should not be attempted by anyone
unfamiliar with the necessary precaution on this receiver. The following are the necessary precaution to be observed before servicing. 1) Since the chassis of this receiver has hazardous potential to ground whenever the receiver is plugged in (floating chassis), an isolation transformer must be used during servicing to avoid shock hazard. 2) Always discharge the picture tube anode to the CRT conductive coating the picture tube. The picture tube is highly evacuated and if broken, glass fragments will be violently expelled. Use shatterproof goggles and keep picture tube away from the body while handling. 3) When placing chassis in the cabinet, always be certain that all the protective devices are put back in place, such as; nonmetallic control knobs, insulating covers, shields, isolation resistor-capacitor network, etc. 4) Before returning the set to the customer, always perform an AC leakage current check on the exposed metallic parts of the cabinet, such as antennas, terminals, screw-heads, metal overlays, control shafts etc. to be sure the set is safe to operate without danger of electrical shock. Plug the AC line cord directly into a 120V AC outlet (do not use a line isolaMinimum brightness
4. SERVICE NOTES
1) When replacing parts or circuit boards, clamp or bend the lead wires to terminals before soldering. 2) When replacing a high wattage resistor (metal oxide film resistor) in the circuit board, keep the resistor min 1/2 inch away form circuit board. 3) Keep wires away from high voltage or high temperature components.
7
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 sub- basic characteristics such as height, focus and sub- bright. Observe the picture for good black and white details without objectionable color shading. 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.
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.
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.
6. X-RADIATION PROTECTION CIRCUIT TEST
When service has been performed on the horizontal deflection system, high voltage system or B+system, the XRADIATION 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-
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 Oscilloscope Direct/Low-capacity probe Color-Bar/Dot/Crosshatch generator PIF sweep marker generator Power supply Isolation transformer BLOCK DIAGRAM National Model VP-2600A or equivalent Tektronix Model 2215A or equivalent. Tektronix Model P6120 or equivalent (Accessory of oscilloscope) Tektronix Model 146 or equivalent. Nihon Tsushinki Model 4723 or equivalent Academy Model 150A or equivalent Voltage adjustable type having capacity of at least 150 watts
B+ BIAS POWER SUPPLY A (12V)
MAIN BOARD TP3 TP5 TP7 TP6
OSCILLOSCOPE
X
Y 45.75MHz
AGC BIAS POWER SUPPLY B (4-5V) Fig. 6 PIF Response PIF SWEEP/MARKER GEN.
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) OPERATE? YES NO GO TO GO TO
A B
A
CHECK #30 (7.5V DC) R816 15K 2WATT 30 I501 CHECK TP10 (MAIN B+ LINE) 103VDC IF #26 NORMAL & NO OUTPUT AT #23 THEN CHANGE I501 24 26 DOES SHUT DOWN CIRCUIT OPERATE?
Q402 H. OUTPUT
CHECK Q402 COLLECTOR T402 F.B.T
D406 12V CHECK 12V LINE D403 12V
103V(B+) CHECK ALL THE POINTS THEN CHANGE I701
B
QC706 RESET SHOULD BE 4.3V-5.2V 5V Q802 REGULATOR R808 CHECK F801 125V 5A CHECK LEAD SOLDERING L801 LINE FILTER OPEN LOAD THEN CHECK #42 ON STATE 4 ~5V QC701 POWER CONTROL 16 I701 36 12 LC864616A 42 NORMAL: 5V RESET: 0V PWR CONTROL KEY
KEY OPERATE? CHECK DIODE D701 & SWITCH KEY BOARD
T801
12
NO PICTURE
CHECK THE WAVE FORM OF I501 #44 (2Vp-p) OK GO TO
C D
NG GO TO
C
FC COMPOSITE VIDEO INPUT
H
21
FS I501 LA 7674
H
QC201
Y-OUT
42 C506
QC501 VIDEO DRIVE
CONTRAST CHECK CONTROL (NORMAL) VOLTAGES #39: 5.0V #31: 3.9V BRIGHT
39 31 11 14
R522 SUB-BRIGHT CHECK 9V LINES #11,14 CHECK ABL Ib = 1.2mA H. BLANKING T402 FBT ABL H.T
CHECK 210V KINE
D505 ABL
D404 R413
R412
D
AGC ENA DATA CLK U101 TUNER 9V VT (33V) CHECK HEATER 6.3Vrms
IF I701 LC864616A
5V
10
11
ADJUST RF-AGC R113
DETECTOR OUTPUT
Z101 SAW FILTER
8 9
10
I501 LA7674
44 11 14
TO QC201
CHECK CSB503E
CHECK IF AGC VTG. 5VDC TP2
2
H
CHECK 9V LINE #11, 14
13
NO SOUND(CN-200I)
CHECK FOR SIGNAL AT I501 #1 GO TO
E F
GO TO
E
CHECK MONO 100% MOD -> 0.424 Vp-p
#1 #2 9V(B+) I601
#19 CHECK EXT SOUND SIGNAL OFF:L #12 #13 #18 (MUTE)#17 CHECK 1Vp-p MUTE ON: 5V OFF: 0V
#1 9V(B+)
#4 CHECK 1Vp-p
#2(0~5V) #6 I602 #8(0~5V)
I604/I603 CHECK SOUND INPUT #3
#7 #6 #5
CHECK 12VDC
CHECK SOUND OUTPUT
F
#11 CHECK 9V #14 #44 I501 LA7674 #4 Z201 #48 CHECK FM DET CIRCUIT #1 COMPOSITE SIGNAL I601 #1
CHECK SOUNDIF INPUT
14
NO SOUND(CN-200A)
CHECK FOR SIGNAL AT I501 #1 GO TO
E F
GO TO
E
#38 CHECK MONO 100% MOD -> 0.693 Vp-p #30 9V(B+) #2(9VDC) IM601 #15 #39 CHECK 4.5V #40 #13 (MUTE)#8 L OUT R OUT MUTE ON: 5V OFF: 0V CHECK R/L OUTPUT #22 #21 #20 CHECK 4.5V
#1 9V(B+)
#4 CHECK 1Vp-p
#2 (0~5V) #6 I602 #8 (0~5V)
I604/I603 CHECK SOUND INPUT #3
#7 #6 #5
CHECK 12VDC
CHECK SOUND OUTPUT
F
#11 CHECK 9V #14 #44 I501 LA7674 #4 Z201 #48 CHECK FM DET CIRCUIT #1 COMPOSITE SIGNAL I601 #1
CHECK SOUND IF INPUT
15
CH DON'T STOP
CHECK INPUT SIGNAL CONDITIONS GOOD BAD GO TO LOSS OF SIGNAL OR WEAK SIGNAL
G
G
IF OUTPUT U101 TUNER CHECK AFT WINDOW VTG. 1.6V ~ 3.4V 2 3 4 9 8 I701 LC864616A 13 47 ADJUST PIF & AFT REFER TO GENERAL ADJUSTMENTS PIF ADJUST RF AGC R113 8, 9 I501 LA7674 45 AFT 10 46
33 L: NO SIGNAL H: SIGNAL
44
S.D SIGNAL DETECTION
16
NO COLOR
CHECK 9VDC CENTER 3.5V
11
TINT
41 12
X502 APC FILTER
COLOR
36
13
CENTER 4V I501 LA7674 CHECK 9VDC CHECK CRYSTAL 3.579545MHZ
COMPOSITE VIDEO
C506
42
FS
14 18 19
R-Y G-Y B-Y Q901 Q902 Q903 R G B
QC201 Emitter
20
FC
21
LUMINANCE (-Y)
VIDEO B (210V)
+
CHECK CONNECTOR P901
NO VERTICAL DEFLECTION
CHECK 9VDC CHECK 9VCC
14
I501 LA7674
CHECK VERT.OUT
1
I301 LA7837
28
R301 R304 R305
2 4 12 8
CHECK 25VDC
D402
R417
VR305 V,HEIGHT
C413 C307 C417 CHECK THE WAVEFORM I301 #12 NO OUTPUT: CHANGE IC301
R311
+
V.D.Y.
17
ON SCREEN DISPLAY DOES NOT OPERATE
CHECK FOR,60Hz / VS
19 20 10
CHECK FOR, 15, 734Hz I701
21 22 23 24 11
R G B BL IF OSD DOES NOT OPERATE, CHANGE I701 R, G, B, BL CHANGE
/ HS
OSC CHECK
REMOTE CONTROL DOES NOT OPERATE
IL01 REMOCON SENSOR GND 5V OUT
CHECK WAVEFORM
I701 LC864616A
34
18
PIN ASSIGN OF IC LC864616A(I701)
VIDEO MUTE(O) DATA(O) CLOCK(O) ENABLE(O) SOUND MUTE(O) TV/VIDEO(O) MPX1(O) MPX2(O)
1 P10 2 P11 3 P12 4 P13 5 P14 6 P15 7 P16 8 P17 9 DVss 10 CF1 11 CF2 12 DVdd
P07 42 POWER(O) KEY OUT P06 P05 P04 P03 P02 P01 P00 P73/INT3/TOIN P72/INT2/TOIN P71/INT1 P70/INT0 PWM5 PWM4 PWM3 PWM2 PWM1 PWM0 BL B G 41 KEY OUT 40 KEY OUT 39 KEY IN 38 KEY IN 37 KEY IN 36 KEY IN 35 CH DN VOL MENU : Switch : Option Diode CH UP VOL + POWER MN/ST EEPROM 3-LAN SAP TV/VID
34 REMOCON(IN) 33 SD(IN) 32 X-Ray IN 31 AC 60Hz IN 30 CONTRAST 29 BRIGHTNESS 28 COLOR 27 TINT 26 SHARPNESS 25 VOLUME 24 23 22
AFC IN N. C N. C
13 P90/AN0 14 P91/AN1 15 P92/AN2 16 /RESET 17 FILT
1Vpp IN 18 CVIN 19 /VS 20 /HS 21 R
NOTE) CF is used 503KHz RESONATOR
19
TROUBLE SHOOTING CHARTS
NO POWER
DOES QC701(POWER ON/OFF TR) OPERATE? YES NO GO TO GO TO
A B
A
CHECK #30 (7.5V DC) R816 15K 2WATT 30 I501 CHECK TP10 (MAIN B+ LINE) 103VDC IF #26 NORMAL & NO OUTPUT AT #23 THEN CHANGE I501 24 26 DOES SHUT DOWN CIRCUIT OPERATE?
Q402 H. OUTPUT
CHECK Q402 COLLECTOR T402 F.B.T
D406 12V CHECK 12V LINE D403 12V
103V(B+) CHECK ALL THE POINTS THEN CHANGE I701
B
QC706 RESET SHOULD BE 4.3V-5.2V 5V Q802 REGULATOR R808 CHECK F801 125V 5A CHECK LEAD SOLDERING L801 LINE FILTER OPEN LOAD THEN CHECK #42 ON STATE 4 ~5V QC701 POWER CONTROL 16 I701 36 12 LC864616A 42 NORMAL: 5V RESET: 0V PWR CONTROL KEY
KEY OPERATE? CHECK DIODE D701 & SWITCH KEY BOARD
T801
12
NO PICTURE
CHECK THE WAVE FORM OF I501 #44 (2Vp-p) OK GO TO
C D
NG GO TO
C
FC COMPOSITE VIDEO INPUT
H
21
FS I501 LA 7674
H
QC201
Y-OUT
42 C506
QC501 VIDEO DRIVE
CONTRAST CHECK CONTROL (NORMAL) VOLTAGES #39: 5.0V #31: 3.9V BRIGHT
39 31 11 14
R522 SUB-BRIGHT CHECK 9V LINES #11,14 CHECK ABL Ib = 1.2mA H. BLANKING T402 FBT ABL H.T
CHECK 210V KINE
D505 ABL
D404 R413
R412
D
AGC ENA DATA CLK U101 TUNER 9V VT (33V) CHECK HEATER 6.3Vrms
IF I701 LC864616A
5V
10
11
ADJUST RF-AGC R113
DETECTOR OUTPUT
Z101 SAW FILTER
8 9
10
I501 LA7674
44 11 14
TO QC201
CHECK CSB503E
CHECK IF AGC VTG. 5VDC TP2
2
H
CHECK 9V LINE #11, 14
13
NO SOUND(CN-200I)
CHECK FOR SIGNAL AT I501 #1 GO TO
E F
GO TO
E
CHECK MONO 100% MOD -> 0.424 Vp-p
#1 #2 9V(B+) I601
#19 CHECK EXT SOUND SIGNAL OFF:L #12 #13 #18 (MUTE)#17 CHECK 1Vp-p MUTE ON: 5V OFF: 0V
#1 9V(B+)
#4 CHECK 1Vp-p
#2(0~5V) #6 I602 #8(0~5V)
I604/I603 CHECK SOUND INPUT #3
#7 #6 #5
CHECK 12VDC
CHECK SOUND OUTPUT
F
#11 CHECK 9V #14 #44 I501 LA7674 #4 Z201 #48 CHECK FM DET CIRCUIT #1 COMPOSITE SIGNAL I601 #1
CHECK SOUNDIF INPUT
14
NO SOUND(CN-200A)
CHECK FOR SIGNAL AT I501 #1 GO TO
E F
GO TO
E
#38 CHECK MONO 100% MOD -> 0.693 Vp-p #30 9V(B+) #2(9VDC) IM601 #15 #39 CHECK 4.5V #40 #13 (MUTE)#8 L OUT R OUT MUTE ON: 5V OFF: 0V CHECK R/L OUTPUT #22 #21 #20 CHECK 4.5V
#1 9V(B+)
#4 CHECK 1Vp-p
#2 (0~5V) #6 I602 #8 (0~5V)
I604/I603 CHECK SOUND INPUT #3
#7 #6 #5
CHECK 12VDC
CHECK SOUND OUTPUT
F
#11 CHECK 9V #14 #44 I501 LA7674 #4 Z201 #48 CHECK FM DET CIRCUIT #1 COMPOSITE SIGNAL I601 #1
CHECK SOUND IF INPUT
15
CH DON'T STOP
CHECK INPUT SIGNAL CONDITIONS GOOD BAD GO TO LOSS OF SIGNAL OR WEAK SIGNAL
G
G
IF OUTPUT U101 TUNER CHECK AFT WINDOW VTG. 1.6V ~ 3.4V 2 3 4 9 8 I701 LC864616A 13 47 ADJUST PIF & AFT REFER TO GENERAL ADJUSTMENTS PIF ADJUST RF AGC R113 8, 9 I501 LA7674 45 AFT 10 46
33 L: NO SIGNAL H: SIGNAL
44
S.D SIGNAL DETECTION
16
NO COLOR
CHECK 9VDC CENTER 3.5V
11
TINT
41 12
X502 APC FILTER
COLOR
36
13
CENTER 4V I501 LA7674 CHECK 9VDC CHECK CRYSTAL 3.579545MHZ
COMPOSITE VIDEO
C506
42
FS
14 18 19
R-Y G-Y B-Y Q901 Q902 Q903 R G B
QC201 Emitter
20
FC
21
LUMINANCE (-Y)
VIDEO B (210V)
+
CHECK CONNECTOR P901
NO VERTICAL DEFLECTION
CHECK 9VDC CHECK 9VCC
14
I501 LA7674
CHECK VERT.OUT
1
I301 LA7837
28
R301 R304 R305
2 4 12 8
CHECK 25VDC
D402
R417
VR305 V,HEIGHT
C413 C307 C417 CHECK THE WAVEFORM I301 #12 NO OUTPUT: CHANGE IC301
R311
+
V.D.Y.
17
ON SCREEN DISPLAY DOES NOT OPERATE
CHECK FOR,60Hz / VS
19 20 10
CHECK FOR, 15, 734Hz I701
21 22 23 24 11
R G B BL IF OSD DOES NOT OPERATE, CHANGE I701 R, G, B, BL CHANGE
/ HS
OSC CHECK
REMOTE CONTROL DOES NOT OPERATE
IL01 REMOCON SENSOR GND 5V OUT
CHECK WAVEFORM
I701 LC864616A
34
18
PIN ASSIGN OF IC LC864616A(I701)
VIDEO MUTE(O) DATA(O) CLOCK(O) ENABLE(O) SOUND MUTE(O) TV/VIDEO(O) MPX1(O) MPX2(O)
1 P10 2 P11 3 P12 4 P13 5 P14 6 P15 7 P16 8 P17 9 DVss 10 CF1 11 CF2 12 DVdd
P07 42 POWER(O) KEY OUT P06 P05 P04 P03 P02 P01 P00 P73/INT3/TOIN P72/INT2/TOIN P71/INT1 P70/INT0 PWM5 PWM4 PWM3 PWM2 PWM1 PWM0 BL B G 41 KEY OUT 40 KEY OUT 39 KEY IN 38 KEY IN 37 KEY IN 36 KEY IN 35 CH DN VOL MENU : Switch : Option Diode CH UP VOL + POWER MN/ST EEPROM 3-LAN SAP TV/VID
34 REMOCON(IN) 33 SD(IN) 32 X-Ray IN 31 AC 60Hz IN 30 CONTRAST 29 BRIGHTNESS 28 COLOR 27 TINT 26 SHARPNESS 25 VOLUME 24 23 22
AFC IN N. C N. C
13 P90/AN0 14 P91/AN1 15 P92/AN2 16 /RESET 17 FILT
1Vpp IN 18 CVIN 19 /VS 20 /HS 21 R
NOTE) CF is used 503KHz RESONATOR
19
DESCRIPTION OF SEMICONDUCTORS
LA7674 (VIF/SIF/VIDEO/CHROMA/DEFLECTION) 1. Case Outline : SDIP 52P 2. Pin Connections/Block Diagram
IC501 LA7674 IF/VIDEO/CHROMA/DEF
FM DET IF AGC EX AIN FM DET NFB AOUT GND IF IN IF IN RF AGC VCC APC VXO VCC RIN GIN BIN R-Y G-Y B-Y -Y FBPIN HOUT HOD HOSC HAFC 1 2
VIDEO DET VCO LOCK DET APC DET
52 51 50 49
IFAPC VCD VCO RF AGC SIF IN AFT OUT AFT AFT VDET AV S.W IN VIN TINT EX. VIN CONT VIDEO GND COLOR BDET YIN SHARP CLAMP BRIGHT VCCH S. SEP V. OUT H.DET
3 4 5 6 7
AFT FMDET ATT FMDET LIM AMP VIDEO AMP
48 47 46
8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
HOR DRIVER
VIF AMP
45 44
RFAGC
43
IFAGC APC
42 41 40
VCO
TINT
ACC KILLER
39 38 37
2NA BPA IST BPA
OSD
36 35
BLACK EXPAND
OSD-SWITCH
FBTDET
-Y OUT FBT-DET
CARRIER-F -Y OUT FBT-DET
COLOR DEMO CONTRAST
34 33
SOFT
SHARP
32 31
23 24 25 26
AFC 2
CLAMP BRIGHT
D.L
30 29
HOR C/D AFC 1
SYNC/ SEP
VER SYNCSEP
HOR OSC
VER C/D HOR COIN
28 27
20
DTQ-26S1FC/FS/FSP/HC/HS/HSP EXPLODED VIEW
23
DTQ-29S1FCN/FSN/FSP/HC/HS/HSP EXPLODED VIEW
24