DAEWOO DTQ-14Q1FS, DTQ-14Q2TS, DTQ-14Q3FS, DTQ-14T1AS, DTQ-14T2FS Service Manual

...

Service Manual

Color Television

CN-201A/B

CHASSIS

MODEL:DTQ-14Q1FS, DTQ-14Q2TS

DTQ-14Q3FS, DTQ-14T1AS DTQ-14T2FS, DTQ-20Q1FS DTQ-20Q2FS, DTQ-20Q3FS DTQ-20T1AS, DTQ-20T2AS DTQ-20T1FS, DTQ-20T2FS DTQ-20T3FS, DTQ-21T1FS DTQ-21T2FS, DTQ-21T5FS DTQ-21T9FS, DTQ-20T1FC

NTSC-M SYSTEM

✔

Caution

: In this Manual, some parts can be changed for improving, their performance without notice in the parts list. So, if you need the

latest parts information,please refer to PPL(Parts Price List) in Service Information Center (http://svc.dwe.co.kr).

DAEWOO ELECTRONICS CO., LT D .

FEATURES

FS (Frequency Synthesizer) Tuning System CATV Ready High Focus Minineck CRT

ELECTRICAL SPECIFICATIONS

POWER INPUT

AC90V - AC250V 50/60Hz DTQ-20T1FC : 120V 60HZ ONLY

POWER RATING

14” Model 60W 20” MONO Model 70W 20” ST Model 80W 21” ST Model 80W

INTERMEDIATE FREQUENCIES

PICTURE IF CARRIER FREQUENCY 45.75MHz SOUND IF CARRIER FREQUENCY 41.25MHz

COLOR SUB CARRIER FREQUENCY 42.17MHz AUDIO OUTPUT RATING MONO(2W) ST(3W+3W) SPEAKER 3W 16ohm 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 6 Important Service Notes 8 Block Diagram 9 General Adjustments 10 Operation Charaeteristic of Power Block 14 Trouble Shooting Charts 22 Description of Semiconductors 28 Printed Circuit Board Diagram 32 Exploded Views 33 Schematic Diagram with Waveforms 50 Parts List 51 Option List 65

PRODUCT SAFETY SERVICING GUIDELINES FOR AUDIO VIDEO PRODUCTS

DO NOT ATTEMPT TO MODIFY THIS PRODUCT IN ANY WAY. NEVER

CAUTION

PERFORM CUSTOMIZED INSTALLATIONS WITHOUT MANUFACTURER S APPROVAL. UNAUTHORIZED MODIFICATIONS WILL NOT ONLY VOID THE WARRANTY, BUT MAY LEAD TO YOUR BEING LIABLE FOR ANT 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. WHILE SERVICING, USE AN ISOLATION TRANSFORMER FOR PROTECTION FROM A.C. LINE SHOCK.

AFTER THE ORIGINAL SERVICE PROBLEM HAS BEEN CORRECTED, A CHECK SHOULD BE MADE OF THE FOLLOWING:

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 MODULES 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, POWER SUPPLY CORDS, AND OTHER HARDWARE HAVE BEEN REINSTALLED PER ORIGINAL DESIGN. BE SURE, THAT THE SAFETY PURPOSE OF THE POLARIZED LINE PLUG HAS NOT BEEN DEFEATED.

3. SOLDERING MUST BE INSPECTED TO DISCOVER POSSIBLE COLD SOLDER JOINTS,

SOLDER SPLASHES OF SHARP SOLDER POINTS. BE CERTAIN TO REMOVE ALL LOOSE FOREIGN PARTICLES.

4. CHECK FOR PHYSICAL EVIDENCE OF DAMAGE OR DETERIORATION TO PARTS AND

COMPONENTS, FOR FRAYED LEADS, DAMAGED INSULATION (INCLUDING A.C. CORD), AND REPLACE IF NECESSARY. FOLLOW ORIGINAL LAYOUT, LEAD LENGTH AND DRESS.

5. NO LEAD OR COMPONENT 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 RESISTOR,

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 STE 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.

ISOLATION TRANSFORMER DURING THIS TEST

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 (WATER POPE, CONDUIT, ETC.) AND THE EXPOSED METALLIC PARTS, ONE AT A TIME. MEASURE THE A.C. VOLTAGE ACROSS THE COMBINATION OF 1500 OHM RESISTOR AND .15 MFD CAPACITOR. REVERSE THE A.C. PLUG AND REPEAT A.C. VOLTAGE MEASUREMENTS FOR EACH EXPOSED METALLIC PART. VOLTAGE MEASURED MUST NOT EXCEED .75 VOLTS R.M.S THIS CORRESPONDS TO 0.5 MILLIAMP A.C. NAY VALUE EXCEEDING THIS LIMIT CONSTITUTES A POTENTIAL SHOCK HAZARD AND MUST BE CORRECTED IMMEDIATELY.

SUBJECT : GRAPHIC SYMBOLS

SAFETY CHECKS

SUBJECT:FIRE & SHOCK HAZARD

A.C. VOLTMETER

GOOD EARTH GROUND SUCH AS THE WATER PIPE, CONDUIT, ETC.

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 SUFFICIENT

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 ON SERVICE LITERATURE.

0.15µF

1500 OHM

10WATT

DO NOT USE A LINE

USE AN A.C. VOLTMETER,

PLACE THIS PROBE ON EACH EXPOSED METAL PART

SUBJECT : X-RADIATION

1. BE SURE PROCEDURES AND INSTRUCTIONS TO ALL SERVICE PERSONNEL COVER

2. ONLY FACTORY SPECIFIED C.R.T ANODE CONNECTORS MUST BE USED.

3. IT IS ESSENTIAL THAT SERVICE PERSONNEL HAVE AVAILABLE AN ACCURATE AND

4. WHEN THE HIGH VOLTAGE CIRCUITRY IS OPERATING PROPERLY THERE IS NO

5. WHEN TROUBLESHOOTING AND MAKING TEST MEASUREMENTS IN A PRODUCT WITH

6. REFER TO HV, B + AND SHUTDOWN ADJUSTMENT PROCEDURES DESCRIBED IN THE

SUBJECT : IMPLOSION

1. ALL DIRECT VIEWED PICTURE TUBES ARE EQUIPPED WITH AN INTEGRAL IMPLOSION

2. USE ONLY RECOMMENDED FACTORY REPLACEMENT TUBES.

SUBJECT : TIPS ON PROPER INSTALLATION

1. NEVER INSTALL ANY PRODUCT IN A CLOSED-IN RECESS, CUBBYHOLE OR CLOSELY

2. AVOID CONDITIONS OF HIGH HUMIDITY SUCH AS: OUTDOOR PATIO INSTALLATIONS

3. AVOID PLACEMENT WHERE DRAPERIES MAY OBSTRUCT REAR VENTING. THE

4. WALL AND SHELF MOUNTED INSTALLATIONS USING A COMMERCIAL MOUNTING KIT,

5. CAUTION CUSTOMERS AGAINST THE MOUNTING OF A PRODUCT ON SLOPING SHELF

6. A PRODUCT ON A ROLL-ABOUT CART SHOULD BE STABLE ON ITS MOUNTING TO THE

7. CAUTION CUSTOMERS AGAINST THE USE OF A CART OR STAND WHICH HAS NOT

8. CAUTION CUSTOMERS AGAINST THE USE OF EXTENSION CORDS, EXPLAIN THAT A

950ART94

1009

THE SUBJECT OF X-RADIATION. THE ONLY POTENTIAL SOURCE 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, AMY PRODUCE RADIATION IN EXCESS OF DESIRABLE LEVELS.

DEGAUSSING SHIELDS ALSO SERVE AS X-RAY SHIELD IN COLOR SETS. ALWAYS REINSTALL THEM.

RELIABLE HIGH VOLTAGE METER. THE CALIBRATION OF THE METER SHOULD BE CHECKED PERIODICALLY AGAINST A REFERENCE STANDARD. SUCH AS THE ONE AVAILABLE AT YOUR DISTRIBUTOR.

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 EXCEED THE SPECIFIED VALUE AND THAT IT IS REGULATING CORRECTLY. WE SUGGEST THAT YOU AND YOUR SERVICE ORGANIZATION 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

A PROBLEM OF EXCESSIVE HIGH VOLTAGE, AVOID BEING UNNECESSARILY CLOSE TO THE PICTURE TUBE AND THE HIGH VOLTAGE SUPPLY. DO NOT OPERATE THE PRODUCT LONGER THAN IS NECESSARY TO LOCATE THE CAUSE OF EXCESSIVE VOLTAGE.

APPROPRIATE SCHEMATIC AND DIAGRAMS (WHERE USED).

PROTECTION SYSTEM. BUT CARE SHOULD BE TAKEN TO AVOID DAMAGE DURING INSTALLATION. AVOID SCRATCHING THE TUBE. OF SCRATCHED REPLACE IT.

FITTING SHELF SPACE, OVER OR CLOSE TO HEAT DUCT, OR IN THE PATH OF HEATED AIR FLOW.

WHERE DEW IS A FACTOR, NEAR STEAM RADIATORS WHERE STEAM LEAKAGE IS A FACTOR, ETC.

CUSTOMER SHOULD ALSO AVOID THE USE OF DECORATIVE SCARVES OR OTHER COVERINGS WHICH MIGHT OBSTRUCT VENTILATION.

MUST FOLLOW THE FACTORY APPROVED MOUNTING INSTRUCTIONS. A PRODUCT MOUNTED TO A SHELF OR PLATFORM MUST RETAIN ITS ORIGINAL FEET (OR THE EQUIVALENT THICKNESS IN SPACERS)TO PROVIDE ADEQUATE AIR FLOW ACROSS THE BOTTOM, BOLTS OR SCREWS USED FOR FASTENERS MUST NOT TOUCH ANY PARTS OR WIRING. PERFORM LEAKAGE TEST ON CUSTOMIZED INSTALLATIONS.

OR A TILTED POSITION, UNLESS THE PRODUCT IS PROPERLY SECURED.

CART. CAUTION THE CUSTOMER ON THE HAZARDS OF TRYING TO ROLL A CART WITH SMALL CASTERS ACROSS THRESHOLDS OR DEEP PILE CARPETS.

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.

FOREST OF EXTENSIONS SPROUTING FROM A SINGLE OUTLET CAN LEAD TO DISASTROUS CONSEQUENCES TO HOME AND FAMILY.

S INVOICE.

Product safety servicing guidelines for color television receivers

A.C. VOLTMETER

CAUTION :

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.

Do not attempt to modify this product in any

SAFETY CHECKS

After the original service problem has been corrected, a check should be made of the following:

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 metallic 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.

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 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 FUSE AS MARKED 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 PROTECTION PERMANENTE CONTRE LES RISQUES D

INCENDIE, REMPLACER UNIQUEMENT PAR UN

FUSIBLE DE MEME TYPE ET DE 4A, 125V

and ATTENTION: AFIN D ASSU UNE

dangerous voltage that

RISK OF FIRE REPLACE

. The symbol is

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 exceed the specified value and that it is regulating correctly. We suggest that you and your service organization 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

5. When troubleshooting and making test measurements in a receiver with a problem of excessive high voltage, avoid being unnecessarily close to the picture tube 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).

s invoice.

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.

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, bolts 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. the same or larger screen size.

s of

CONTROL VIEW

MONO MODEL

STEREO MODEL

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.

Your TV's Front Panel

1 POWER

Use this button to turn your TV on or off.

2 VIDEO IN jack

Use this jack to receive a video signal from another A/V component.

3 AUDIO IN jack

MONO MODEL use this jack to receive an audio signal from another A/V component. But, STEREO MODEL use

this jack to receive audio L/R signal from another A/V component.

4 EARPHONE IN jack

Use this jack to receive a audio signal from your TV.

5 STAND-BY (red) indicator

This indicator lights up when the power is off.

6 Remote control receiver

This receiver receives a signal from your remote control. Don’t block it.

7 CH

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

8 VOL

Use these buttons to change your TV’s volume, to activate selections in the menu system, or to change audio and

video settings.

9 MENU

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

MONO MODEL

POWER VIDEO AUDIO

STEREO MODEL

POWER VIDEO

AUDIO

L R

EARPHONE

STAND-BY

VOL

REMOTE CONTROL UNIT

1 POWER

2 CH

3 VOL

Use this button to turn your TV on or off.

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

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

3 4

5 6

4 MENU

5 RECALL

6 ADD/ERA.

7 MUTE

8 0-9

9 SLEEP

10PREV. CH

10 13

11 TV/VIDEO

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

Press this button to display the channel number.

Use this button to add a channel to the TV's memory or erase the channel from memory.

Use to turn the TV's sound on and off.

Use these buttons to change channels.

Use this button to program the TV to turn off after a certain time.

Press this button to return to the previous channel you were watching. If you have set Favorite Ch, this key operates to Favorite function.

Use this button to select TV or VIDEO mode.

12 AUTO. PICT

Press this button to return the TV's video settings to their original level.

13 AIR/CABLE

Use the button to set up your TV to receive signals from an antenna (AIR) or a cable system (CABLE).

CONTROL VIEW

MONO MODEL

STEREO MODEL

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.

Your TV's Front Panel

1 POWER

Use this button to turn your TV on or off.

2 VIDEO IN jack

Use this jack to receive a video signal from another A/V component.

3 AUDIO IN jack

MONO MODEL use this jack to receive an audio signal from another A/V component. But, STEREO MODEL use

this jack to receive audio L/R signal from another A/V component.

4 EARPHONE IN jack

Use this jack to receive a audio signal from your TV.

5 STAND-BY (red) indicator

This indicator lights up when the power is off.

6 Remote control receiver

This receiver receives a signal from your remote control. Don’t block it.

7 CH

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

8 VOL

Use these buttons to change your TV’s volume, to activate selections in the menu system, or to change audio and

video settings.

9 MENU

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

MONO MODEL

POWER VIDEO AUDIO

STEREO MODEL

POWER VIDEO

AUDIO

L R

EARPHONE

STAND-BY

VOL

REMOTE CONTROL UNIT

1 POWER

2 CH

3 VOL

Use this button to turn your TV on or off.

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

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

3 4

5 6

4 MENU

5 RECALL

6 ADD/ERA.

7 MUTE

8 0-9

9 SLEEP

10PREV. CH

10 13

11 TV/VIDEO

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

Press this button to display the channel number.

Use this button to add a channel to the TV's memory or erase the channel from memory.

Use to turn the TV's sound on and off.

Use these buttons to change channels.

Use this button to program the TV to turn off after a certain time.

Press this button to return to the previous channel you were watching. If you have set Favorite Ch, this key operates to Favorite function.

Use this button to select TV or VIDEO mode.

12 AUTO. PICT

Press this button to return the TV's video settings to their original level.

13 AIR/CABLE

Use the button to set up your TV to receive signals from an antenna (AIR) or a cable system (CABLE).

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

24.4kv at zero beam current (minimum brightness) under a 120V AC power source. The high voltage must not, under any circumstances, exceed 27kv (28.5kv). Each time a receiver requires servicing, the high voltage should be checked following the HIGH VOLTAGE CHECK procedure on page 6 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 6 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.

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 isola-

Minimum brightness

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

Place this probe on each exposed metallic part.

Good earth ground such as d water pipe, conduit, etc.

1500 ohm 10watt

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.

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.

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. If color shading is evident, demagnetize the receiver. If color shading still persists, perform purity and convergence adjustments. This should be all that is necessary to achieve Optimum receiver performance.

2. SCREEN ADJUSTMENT

1) Turn on TV

2) Press the S2 key of Service Remocon to make the One Horizontal Line

3) Adjust the Screen adj. VR of FBT so that the One Horizontal Line may be cut off.

4) Press the S2 key of Servic Remocon to be normal.

3. FOCUS ADJUSTMENT

1) Receive the Retma Pattern.

2) Adjust the FOCUS adj. VR to optain the clearest picture.

4. HORIZONTAL CENTER ADJUSTMENT

1) Receive the Retma Pattern.

2) Press the S6(59H) key of Service Remocon, select H.Phase, then adjust step so that the L/R Width of picture be alike.

3) Press the RECALL key to store.

4) Initial value of D.P : 5

7. 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 R411(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.

8. White balance ADJUSTMENT

1) Press the S8 key of SERVICE REMOCON, select W/B

2) Adjust the R/G/B BIAS of Low BEAM in order that the R/G/B BIAS of Low BEAM may meet with coordinates.

3) Adjust the R/B DRIVE of High BEAM in order that the R/B DRIVE of High BEAM may meet with coordinates.

4) Confirm the LOW BEAM, HIGH BEAM alternately.

5) Press the RECALL key to store.

9. SUB-BRIGHTNESS ADJUSTMENT

1) Receive the Retma Pattern.

2) Press the S9(5CH) key of Service Remocon, adjust Bright in order that the gradation pattern may set 18%.

3) Press the RECALL key to store.

4) Initial value of D.P :25

5. VERTICAL CENTER ADJUSTMENT

1) Receive the Retma Pattern.

2) Press the S6(59H) key of Service Remocon, select V.DC, then adjust V.DC so that the horizontal line of RETMA PATTERN’S center may meet with the mechanical CENTER of CRT.

3) Press the RECAL key to store.

4) Initial value of D.P:35

6. VERTICAL HIGHT ADJUSTMENT

1) Receive the Retma Pattern.

2) Press the S6(59H) key of Service Remocon, select V.Size, then adjust V.Size so that the center of circumference of big circle may meet with the upper and lower sides of the screen.

3) Press the RECALL key to store.

4) Initial of value of D.P :35

10. CONVERGENCE MAGNET ASSEMBLY

POSITIONING

If Convergence magnet assembly and rubber wedges need mechanical positioning follow figure 2.

10-1. COLOR PURITY ADJUSTMENT

NOTE

1) Demagnetize the picture tube with a degaussing coil.

2) Adjust the CONTRAST and BRIGHTNESS controls to

3) Adjust RED and BLUE Bias controls Service Remocon

4) Loosen the clamp screw holding the yoke, and slide the

5) Remove the Rubber Wedges.

6) Rotate and spread the tabs of the purity magnet (See

7) Move the yoke slowly forward until a uniform green

: Before attempting any purity adjustments, the

receiver should be operated for at least 15 minutes.

maximum

to provide only a green raster. Adjust the GREEN BIAS control Service Remocon if necessary.

yoke backward to provide vertical green belt(zone)in the picture screen.

figure 2) around the neck of the picture tube until the green belt is in the center of the screen. At the same time, center the raster vertically.

screen is obtained. Tighten the clamp screw of the yoke temporarily.

8) Check the purity of the red and blue raster by adjusting the BIAS controls.

9) Obtain a white raster, referring to ADJUSTMENT

10) Proceed with convergence adjustment.

White Bodance

RUBBER WEDGES

PICTURE TUBE

DEFLECTION YOKE

GLASS CLOTH TAPE

CONVERGENCE MAGNET ASS'Y

TEMPORARY MOUNTING

30 30

Fig. 2 Rubber Wedges Location

RUBBER WEDGES

ADHESIVE

DEF. YOKE

10-2. CONVERGENCE ADJUSTMENTS

NOTE

: Before attempting any purity adjustments, the

receiver should be operated for at least 15 minutes.

A. CENTER CONVERGENCE ADJUSTMENT

1) Receive crosshatch pattern with a crosshatch signal generator.

2) Adjust the BRIGHTNESS and CONTRAST Controls for a good picture.

3) Adjust two tabs of the 4-Pole Magnets to change the angle between them (See Fig. 3) and superimpose red and blue vertical lines in the center area of the picture screen. (See Fig. 4)

4) Turn both tabs at the same time keeping their angles constant to superimpose red and blue horizontal lines at the center of the screen. (See Fig. 4)

5) Adjust two tabs of 6-Pole Magnets to superimpose red/blue line with green on top of each other. Adjusting the angle affects the vertical lines and rotating both magnets affects the horizontal lines.

6) Repeat adjustments 3), 4), 5) keeping in mind red, green and blue movement, because 4-Pole Magnets and 6-Pole Magnets interact and make dot movement complex.

B. CIRCUMFERENCE CONVERGENCE ADJUSTMENT

: This adjustment requires Rubber Wedge Kit.

NOTE

1) Loosen the clamping screw on deflection yoke to allow the yoke to tilt.

2) Place a wedge as shown in figure 2 temporarily. (Do not remove cover paper on adhesive part of the wedge.)

3) Tilt front of the deflection yoke up or down to obtain better convergence in circumference. (See Fig. 4) Push the mounting wedge into the space between picture and the yoke to hold the yoke temporarily.

4) Place other wedge into bottom space and remove the cover paper to stick.

5) Tilt front of the yoke right or left to obtain better convergence in cicumference. (See Fig. 4)

6) Hold the yoke position and put another wedge in either upper space. Remove cover paper and stick the wedge on picture tube to hold the yoke.

7) Detach the temporarily mounted wedge and put it in another upper space. Stick it on picture tube to fix the yoke.

8) After placing three wedges, re-check overall convergence. Tighten the screw firmly to hold the yoke tightly in place.

9) Stick 3 adhesive tapes on wedges as shown in figure32.

4-POLE

PURITY MAGNETS

MAGNETS

4DJUST THE ANGLE (VERTICAL

CONSTANT

LINES)

ROTATE TWO TABS AT THE SAME TIME

CONVERGENCE MAGNET ASSEMBLY

BLUE

BLUE RED

RED

RED/BLUE

GRN

RED/BLUE

Fig. 3

GRN

B G R

R G B

(HORIZONTAL LINES)

ADJUSTMENT OF MAGNET

B G R

BGR

4-Pole Magnets Movement 6-Pole Magnets Movement Incline the Yoke up(or down) Incline the Yoke right(or left)

Center Convergence by Convergence Magnets Circumference Convergence by DEF. Yoke

BGR

R G B

Fig. 4 Dot Movement Pattern

11. APC DET & PLL Tunning ADJUSTMENT

1) Receive the signal of RF 100% Full Color bar 85dBuV.

2) Press the S5(58H) key of Service Remocon, then execute Auto adj Start.

3) Confirm the OSD of Auto adj. OK.

4) If it was Auto adj. NG, Receive the signal of adjacent channel, then perform Auto adj. Start again.

5) Press the RECALL key to store. (Initial value of D.P APC:30, PLL:40)

12. RF AGC ADJUSTMENT

1) Receive the attenuate signal of RF 100% Full Color Bar 60dBuV.

2) Connect Scope to TP101(OR P101).

3) Press the S5 key of Service Remocon, select RF AGC.D, then adjust the maximum voltage of Scope to attenuate 1V. (Initial value of the maximum voltage : About 7V) For example if initial maximum voltage is 7V, adjust it to 6V

4) Press the RECALL key to store. (Initial value of D.P :25)

13). Stereo/Sap ADJUSTMENT

1) Receive the ZENITH MTS signal of 1KHz(OR 3KHz)CH.

2) Press the S10(5D) key of Service Remocon, select Auto Off, then execute Auto on.

3) Press the RECALL key to store.

4) Slect L ONLY OR R ONLY Channel, then confirm stereo Seperation.

If you have only User Remocon, A way of using is as follows;

1) Press the 1 key

2) Press the MUTE key

3) Press the RECALL Key

4) Press the MUTE key then the Service mode will appear.

5) Use the CH buttons to select the mode you wish to adjust.

1 MUTE RECALL MUTE

OPERATION CHARACTERISTICS OF POWER BLOCK(I801)

This chassis designed for free voltage(AC 100V ~ AC 220V) power. power block contains power IC, SMPS transformer and several passive components.

The power IS STR-S5707 has power transistor. oscillator circuit, voltage comparator circuit, thermal protection circuit, OCP(over current protection)circuit inside.

1. STR-S5707 BLOCK DIAGRAM

2. PIN DESCRIPTION

PIN NO SYMBOL NAME FUNCTION

1 C COLLECTOR POWER TRANSISTOR COLLECTOR 2 GND GROUND GROUND(POWER TRANSISTOR EMITTER) 3 B BASE POWER TRANSISTOR BASE 4 SINK SINK BASE URRENT(Is) INPUT 5 OCP OVER CURRENT PROTECTION OVERCURRENT SENSING SIGNAL INPUT 6 INH INHIBIT/LATCH SYNC, OFF TIME/LATCH CIRCUIT CONTROL INPUT 7 F/B(SENS) FEED BACK(SENSING)INPUT CONSTANT VOLTAGE CONTROL SIGNAL INPUT 8 DRIVE DRIVE BASE DRIVE CURRENT(Id)OUTPUT 9 Vin Vin SUPPLY VOLTAGE FOR CONTROL CIRCUIT

3. OTHER FUNCTION

Symbol Function

OVP Built-in Overvoltage Protection Circuit TSD Built-in Thermal Shutdown Circuit

4. EXPLANA TION OF CIRCUIT OPERATION

1) VINterminal, start-up circuit

A Start-up circuit is to start and stop a operation of a control IC by detecting a voltage appearing at a VINterminal(pin-

9).At start up of a power supply, when a voltage at the VINterminal reaches to 8V by charging up C809 by the function of a start-up resistor, Rs, a control circuit starts operating by the function of the start-up circuit. As shown in Fig. 2, since a circuit current is suppressed 200 maximum (at VIN= 7.5V) until the control circuit starts its operation.

After the control circuit starts its operation, power source is obtained by smoothing voltage appearing at L1 winding. Once the control circuit starts operating, as its voltage doesn’t reach the fixed voltage at once, VINterminal voltage starts dropping. However, as a shut-down voltage is set low(at 4.9V), while VINterminal voltage reaches a shutdown voltage, L1 winding voltage reaches the fixed voltage earlier so that the control circuit can continue on operating.

2) Oscillator, F/B terminal voltage (Pin #7)

A oscillator generates pulse signals which turns a power transistor on and off by making use of charge and discharge of C1 and C2 incorporated in the Hybrid IC.

Constant voltage control of a switch-mode power supply is performed by changing both ON-time and OFF-time except when the load is light (ex. remote control stand-by mode of TVs).

Fig. 4 shows how the oscillator works when the Hybrid IC independently operates (with no F/B nor INH signals). When the power thransistor is on, C2 Is charged to the set voltage (approx 2.3V at Ta = 25 ). On the other hand, C1 starts charging up through R1 from almost OV and the voltage across C1 reaches approx. 0.75V (Tc = 25 ). the output from the oscillator is reversed and the power transistor turns off. At the same time C1 is quickly discharged by the function of a internal circuit of the oscillator and the voltage across it decreases to almost OV. When the power transistor turns off, C2 starts discharging through R2 and the voltage across C2 decreases with the inclination determined by the product of C2 decreases to about 1V. the output from the oscillator is reversed again and the transistor consequently turns on. The power transistor continues turning on and off by repeating the above-mentioned operations.

As the circuit in Fig. 3 shows, the ON-time is controlled by changing a current charged by C1, which is as the result of that the detection winding (L1), which detects a change of voltage in a secondary side, connected to the sensing terminal (Pin No. 7) has the current in accordance with an output signal from an output voltage detection circuit (an error amplifier) built in. As an AC input voltage to the power supply gets the higher and a load current the smaller, the current flowing to the SENS terminal gets the larger, and the ON-time gets the shorter.

3) Function of INH terminal (Pin #6), control OFF-time

Signal to the INH terminal is used as inputs to COMP.1 and COMP.2 inside of the control IC.A threshold voltage of COMP.1 V

is in OFF mode) when a voltage at the INH terminal reaches the V lower than V set at 1.5V (Ta = 25 ). When the INH terminal voltage reaches V

is set at 0.75V (Ta = 25 ) and an input signal to a drive circuit becomes almost OV (the power transistor

. As long as the INH terminal voltage does not get

. the power transistor sustains OFF mode. On the other hand, a threshold voltage of COMP.2 V

, an output from COMP.2 reverses and, as a

, is

result, C2, the OFF-tim of the oscillator which has been determined by the product of C2 and R2 ( 55 sec) can be quicker up to approx. 2 sec. As long as the INH terminal voltage does not get lower than V

, A Voltage across C2

stays at almost 0V and a output from the oscillator keeps the power transistor being on. The relation between the INH terminal voltage and the function of the oscillator described above is shown in Fig. 6 and FIg. 7

4) Quasi-resonant operation

By inputting a voltage signal which is synchronized with the energy discharge time of a secondary winding of a transformer to the. INH terminal, quasi-resonant operation can be achieved. As shown in Fig. 8, the voltage of L1 winding which is synchronized. with the energy discharge time of a secondary winding. S1. shall be input to the INH terminal through D804 and R809. Since V

is set at 1.5V typical, a voltage at the INH terminal. V

INH

, shall be set at

Fig. 9 shows waveforms of VCE, Ic and V

INH

of the transistor, voltage across C807 in the oscillator as well as an output

from the oscillator when operating in quasi-resonant mode.

when the power transistor turns off and a voltage than V and then starts charging again. Even after the discharge of energy of a secondary winding is completed, V

immediately increases. When it gets lower than V impedance of the IC and C

INH

, has past, the transistor turns on.

is applied to the INH terminal, C807 immediately discharges

INH

does not

after the time,tr, which is determined by the production of internal

5) Drive circuit

The STR-S5707 applies the proportional drive system in order to minimize turn-on and saturation loss, and storage time. In the conventional RCC system, turn-on loss and switching noise due to the surge current appearing when the power transistor turns on are high as because the transistor is driven by the drive current shown in FIg. 10-1. In addition, since is decreases linearly when the transistor turn off and a peak value of l

long and the V

voltage is high, which results in large turn-off loss. The circuit and the waveforms of the proportional

(

SAT

)

is not large, the storage time is

drive system which is applied to the STR-S5707 in order to reduce these switching loss and shorten the storage time are shown in Fig. 10-2 respectively.

6) OCP (overcurrent protection)function

Overcurrent protection is performed pulse by directly detecting collector current of the power transistor. Configuration of the OCP circuit is shown in. Detecting voltage is set to-1V below a reference point of GND (ground). In

addition, since the detecting voltage is set by a comparator, very stable characteristics against temperature is achieved and drift of the deteting voltage against temperature change is almost OV.

7) Latch circuit

It is a circuit which sustains an output from the oscillator low and stops operation of the power supply when overvoltage protection (OVP) circuit and thermal shutdown (TSD) circuit are in operation. As the sustaining current of the latch circuit is 500 maximum when VINterminal voltage is 4V. the power supply circuit sustains the off state as long as current of 500 maximum flows to VINterminal from a start-up resistor. In order to prevent a malfunction to be caused by a noise and so on, delay time is provided by C1 incorporated in the IC and, therefore, the latch circuit operates when the OVP of TSD circuit is in operation, of an external signal input is provided. for about 10 sec or longer. In addition, even after the latch circuit start operating, the constant voltage regulator (Reg) circuit is in operation and the circuit current is at high level. As a result. VINterminal voltage rapidly decreases. When V than the shutdown voltage, V reaches the ON-state voltage. VIN(ON), (8V typical), V

(OFF), (4.9V typical), it starts in-creasing as the circuit current is below 500 . When it

terminal voltage starts decreasing because the circuit current

terminal voltage becomes lower

increases again.

when the latch circuit is on. VINterminal voltage increases and decreases with-in the range from 4.9V typical to 8V typical and is prevented from abnormally rising. Fig. 12 shows an example of VINterminal voltage waveform. Cancellation of the latch-is done by decreasing VINterminal voltage below 3.3V. The power supply can be restarted disconnecting an AC input to the power supply once.

8) Thermal shutdown, circuit

It is a circuit to trigger the latch circuit when the frame temperature of the IC exceeds 150 (typical). Although the temperature is actually sensed at the control chip. lt works against overheating of the power transistor as the power transistor and the control IC are mounted on the same lead frame.

9) Overvoltage protection circuit

lt is a circuit to trigger the latch circuit when Vin terminal voltage exceeds 11V (typical). Although it basically functions as protection of Vin terminal against overvoltage, since Vin terminal is usually supplied from the drive winding of the transformer and the voltage is proportional to the output voltage, it also functions against the overvoltage of secondary output which causes when the control circuit opens or in some other events.

5. OCP (OVER CURRENT PROTECTION) CIRCUIT

This circuit is designed to protect the circuit from over current due to overload occurred at the rear of 123[V] line

1) CONFIGURATION OF OCP CIRCUIT

2) EXPLANATION OF THE OPERATION

There is very little voltage drop at R423 of 123[V] line. In case that the overload occurs at the rear of 123[V] line, the increase of the voltage drop at R423 bring down the base voltage of the Q407 os as to drive the Q407 Because of the overload at the rear of the R423, the voltage of the point decreases. And this makes Q407 turn on so that a voltage is applied to the #31 of l701. In case that OCP operates by the #31 of the l1701, the set is protected by power off (#42 of l1701 LOW).

+ 51 hidden pages

DAEWOO DTQ-14Q1FS, DTQ-14Q2TS, DTQ-14Q3FS, DTQ-14T1AS, DTQ-14T2FS Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual