Daewoo DTQ-14N3FC, DTQ-20J2FSP, DTQ-20N2FSP, DTQ-20N3FS, DTQ-20N3FSP User Manual
...
Service Manual
Color Television
CN-115I
CHASSIS
NTSC-M SYSTEM
:
MODEL
DTQ-14N2FC/FS/FSP
:
DTQ-20N2FC/FS/FSP
DTQ-14J2FC/FS/FSP
DTQ-20J2FC/FS/FSP
DTQ-14N3FC/FS/FSP
DTQ-20N3FC/FS/FSP
DAEWOO ELECTRONICS CO., LTD.
FEATURES
FS (Frequency Synthesizer) Tuning System
CATV Ready
Monitor Look Design
High Focus Minineck CRT
ELECTRICAL SPECIFICATIONS
POWER INPUT
FC SERIES AC 120V 60Hz
FS SERIES AC 85V - AC 150V 60Hz
FSP SERIES AC 220V 50Hz/60Hz
POWER RATING
14” MODELS 60W
20” MODELS 70W
INTERMEDIATE FREQUENCIES
PICTURE IF CARRIER FREQUENCY 45.75MHz
SOUND IF CARRIER FREQUENCY 41.25MHz
COLOR SUB CARRIER FREQUENCY 42.17MHz
AUDIO OUTPUT RATING 1.3W
SPEAKER 2W 8 ohm
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
Trouble Shooting Charts 14
Description of Semiconductors 20
Printed Circuit Board Diagram 22
Exploded Views 23
Schematic Diagram with Waveforms 29
Parts List 30
Option List 40
2
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
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.
3
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 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.
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
4
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
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
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).
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, 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.
the same or larger screen size.
s of
5
CONTROL VIEW
POWER
CH
F-CONNECTOR
300 OHM-75 OHM
COUPLING
TRANSFORMER
VHF
75Ω
Remote Control receiver
MENU
VOL
FROM 75 OHM
VHF ANTENNA WITH
CABLE OR CABLE
TV SYSTEM
6
1. Overview of Your Equipment
POWER
1
CH VOL MENU
2 3 4 5
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.
7
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 (28.5kw). 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.
8
BLOCK DIAGRAM
96. 5. 30
1702
EEPROM
IL701
SENSOR
REMOCON
CONTROL KEY
POWER
CH UP/DOWN
VOL UP/ DOWN
MENU
L900
D/COIL
ASB1
ANT S/BOX
S-90
JA01
VIDEO IN
AUDEO IN
TA01
TRANS A/V
RL801
RELAY
F801
4A 125V
L801
LINE
FILTER
U101
TUNER
PLL IC
ED
I701
C
MICOM
LC864612A
5V
CONT.BRI COLOR. TINT. SHARP
Q802
REG
RELAY ON/OFF
D801
R818
FUSIBLE
Z101
SAW FILTER
RF-AGC
Q705
R.G.B OSD
YS
VOL. CONTROL
USER CONTROL
SPEAKER
D804
Q804
AFT
H.SYNC
V.SYNC
L802
T801
2519A1
I501 (LA 7674)
IF/V/C/DEF
PIF SIF AGC AFT
SOUND DEC
VIDEO AMP
VIDEO AUDIO IN.
CHROMA AMP
OSD INPUT
DEF,AFC,H.V OUT
AFC
I601
AUDIO AMP
12V
C808
180V
26.5V
B 103V
R-Y R.K
G-Y
B-Y
12V
–Y
I301
V.OUT
Q402
M.OUT
R412
D404
D407
D406
D403
Q901
COLOR
AMP
Q501
VIDEO
DRIVE
Q903
G.K
B.K
OUT
P401
DEF
YOKE
HEATER
T402
FBT
1401SPND
2001SPND
C419
BOOSTER
V901
14”
20”
CRT
H.V
9
H.V
FOCUS
SCREEN
ABL
Q801
PWM CTL
GENERAL ADJUSTMENTS
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. 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 VR316
Horizontal centering adjustment VR556.
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 24kv~26kv
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 counterclockwise.)
4) Rotate the RED, GREEN and BLUE BIAS controls
(R906, R913, R920) 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 (R911,
R918) 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 TP7 (DC 103V Line) using D.V.M
3) Adjust voltage control (R820) for main B+(DC 103V)
10
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 R554 to center and leave
the receiver on five minutes in this state.
5) Watching the picture carefully, adjust the SUB-BRIGHT
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. 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 (R971 and R973)
4) Loosen the clamp screw holding the yoke, and slide
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
8) Check the purity of the red and blue raster by adjusting
9) Obtain a white raster, referring to
10) Proceed with covergence adjustment.
: 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 (R972) if necessary.
the yoke backward th 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.
the BIAS controls.
CRT GRAY SCALE
ADJUSTMENT
RUBBER
WEDGES
PICTURE TUBE
DEFLECTION
YOKE
GLASS CLOTH
TAPE
CONVERGENCE
MAGNET ASS'Y
TEMPORARY
MOUNTING
30 30
30
Fig. 2 Rubber Wedges Location
RUBBER
WEDGES
ADHESIVE
DEF.
YOKE
11
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
NOTE
: This adjustment requires Rubber Wedge Kit.
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 figur32.
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
R G B
(HORIZONTAL LINES)
ADJUSTMENT OF MAGNET
B
G
R
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
12
11. 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
Direct/Low-capacity probe
Tektronix Model 2215A or equivalent.
Tektronix Model P6120 or equivalent
(Accessory of oscilloscope)
Color-Bar/Dot/Crosshatch generator
PIF sweep marker generator
Power supply
Isolation transformer
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
BLOCK DIAGRAM
B+
BIAS
POWER
SUPPLY
A
(16.5V)
AGC
BIAS
POWER
SUPPLY
B
(4-5V)
1) Disconnect the
MAIN BOARD
TP3
TP5
PIF SWEEP/MARKER GEN.
VH
Fig. 5 Picture IF Sweep Alignment
TP6
TP1
TP4
DETIN
OUT
TUNER IF output from TP1 and connect equipment as shown above.
OSCILLOSCOPE
Y
X
45.75MHz
Fig. 6 PIF Response
P
45.75MHz
Fig. 7 AFT Response Curve
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 TP6.
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.
13
Loading...