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Model:
CT-14CAS5CP
Chassis:ETA-1
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CONTENTS
SAFETY INSTRUCTIONS AND MAINTENANCE .......................................................................... 4
SAFETY PRECAUTION .......................................................................................................................................... 5
PRODUCT SAFETY NOTICE ................................................................................................................................. 6
SAFETY SYMBOL DESCRIPTION ........................................................................................................................ 7
MAINTENANCE ..................................................................................................................................................... 8
MECHANICA DISASSEMBLING ......................................................................................................... 9
ADJUSTMENTS .................................................................................................................................. 11
SET-UP ADJUSTMENTS....................................................................................................................................... 11
CIRCUIT ADJUSTMENTS .................................................................................................................................... 14
STRUCTURE AND CHASSIS FUNCTION DESCRIPTION ......................................................... 20
STRUCTION BLOCK DIAGRAM......................................................................................................................... 20
SERVICE DATA .................................................................................................................................. 22
TECHNICAL DATA OF KEY ICs ......................................................................................................................... 22
SERVICE DATA OF KEY ICs ............................................................................................................................... 43
APPENDIX .......................................................................................................................................... 47
CIRCUIT DIAGRAM
PARTS LIST
Please read this manual carefully before service.
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SERVICE SAFETY AND MAINTENANCE
WARNING:
BEFORE EXAMINING AND SERVICING
THIS CHASSIS READ CAREFULLY
THE FOLLOWING SAFETY
INSTRUCTIONS.
X-RAY RADIATION PRECAUTION
1. The EHT must be checked every time the TV is serviced to ensure that the CRT does
not emit X-ray radiation as result of excessive EHT voltage. The maximum EHT voltage
permissible in any operating circumstances must not exceed the rated value. When
checking the EHT, use the High Voltage Check procedure in this manual using an
accurate EHT voltmeter.
2. The only source of X-RAY radiation in this TV is the CRT. The TV minimizes X-RAY
radiation, which ensures safety during normal operation. To prevent X-ray radiation,
the replacement CRT must be identical to the original fitted as specified in the parts list.
3. Some components used in this TV have safety related characteristics preventing the
CRT from emitting X-ray radiation. For continued safety, replacement component
should be made after referring the PRODUCT SAFETY NOTICE below.
4. Service and adjustment of the TV may result in changes in the nominal EHT voltage of
the CRT anode. So ensure that the maximum EHT voltage does not exceed the rated
value after service and adjustment.
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SAFETY PRECAUTION
WARNING:
REFER SERVICING TO
QUALIFIED SERVICE
PERSONNEL ONLY.
1. The TV has a nominal working EHT voltage. Extreme caution should be exercised when
working on the TV with the back removed.
a. Do not attempt to service this TV if you are not conversant with the precautions
and procedures for working on high voltage equipment.
b. When handling or working on the CRT, always discharge the anode to the TV
chassis before removing the anode cap in case of electric shock.
c. The CRT, if broken, will violently expel glass fragments. Use shatterproof
goggles and take extreme care while handling.
d. Do not hold the CRT by the neck as this is a very dangerous practice.
2. It is essential that to maintain the safety of the customer all power cord forms be replaced
exactly as supplied from factory.
3. Voltage exists between the hot and cold ground when the TV is in operation. Install a
suitable isolating transformer of beyond rated overall power when servicing or connecting
any test equipment for the sake of safety.
4. When replacing ICs, use specific tools or a static-proof electric iron with small power (below
35W).
5. Do not use a magnetized screwdriver when tightening or loosing the deflection yoke
assembly to avoid electronic gun magnetized and decrement in convergence of the CRT.
6. When remounting the TV chassis, ensure that all guard devices, such as nonmetal control
buttons, switch, insulating sleeve, shielding cover, isolating resistors and capacitors,
are installed on the original place.
7. Replace blown fuses within the TV with the fuse specified in the parts list. 8. When
replacing wires or components to terminals or tags, wind the leads around the terminal
before soldering. When replacing safety components identified by the international
hazard symbols on the circuit diagram and parts list, it must be the company-approved
type and must be mounted as the original.
8. Keep wires away from high temperature components.
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PRODUCT SAFETY NOTICE
CAUTION:
FOR YOUR PROTECTION
THE FOLLOWING PRODUCT SAFETY NOTICE
SHOULD BE READ CAREFULLY BEFORE
OPERATING AND SERVICING THIS TV SET.
1. Many electrical and mechanical components in this chassis have special safety-related
characteristics. These characteristics are often passed unnoticed by a visual inspection
and the X-ray radiation protection afforded by them cannot necessarily be obtained by
using replacements rated at higher voltages or wattage, etc. Components which have
these special safety characteristics in this manual and its supplements are identified by the
international hazard symbols on the circuit diagram and parts list. Before replacing any of
these components read the parts list in this manual carefully. Substitute replacement
components which do not have the same safety characteristics as specified in the parts list
may create X-ray radiation.
2. Do not slap or beat the cabinet or CRT, since this may result in fire or explosion.
3. Never allow the TV sharing a plug or socket with other large-power equipment. Doing so
may result in too large load, causing fire.
4. Do not allow anything to rest on or roll over the power cord. Protect the power cord from
being walked on, modified, cut or pinched, particularly at plugs.
5. Do not place any objects, especially heavy objects and lightings, on top of the TV set. Do
not install the TV near any heat sources such as radiators, heat registers, stove, or other
apparatus that produce heat.
6. Service personnel should observe the SAFETY INSTRUCTIONS in this manual during use
and servicing of this TV set. Otherwise, the resulted damage is not protected by the
manufacturer.
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SAFETY SYMBOL DESCRIPTION
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MAINTENANCE
1. Place the TV set on a stable stand or base that is of adequate size and strength to
prevent it from being accidentally tipped over, pushed off, or pulled off. Do not
place the set near or over a radiator or heat register, or where it is exposed to direct
sunlight.
2. Do not install the TV set in a place exposed to rain, water, excessive dust,
mechanical vibrations or impacts.
3. Allow enough space (at least 10cm) between the TV and wall or enclosures for
proper ventilation.
4. Slots and openings in the cabinet should never be blocked by clothes or other
objects.
5. Please power off the TV set and disconnect it from the wall immediately if any
abnormal condition are met, such as bad smell, belching smoke, sparkling,
abnormal sound, no picture/sound/raster. Hold the plug firmly when disconnecting
the power cord.
6. Unplug the TV set from the wall outlet before cleaning or polishing it. Use a dry soft
cloth for cleaning the exterior of the TV set or CRT screen. Do not use liquid
cleaners or aerosol cleaners.
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MECHANICA DISASSEMBLIES
CABINET BACK REMOVAL
1. Refer to Figure 1, remove 7screws.
2. Pull off cabinet back and remove.
CHASSIS REMOVAL
1. Remove cabinet back.
2. Discharge the picture tube anode (2nd anode lead) to the dag coating (picture tube
grounding lead).
3. Disconnect Degaussing coil socket (KE). Picture tube socket, Deflection yoke connector
(KDY). Speaker connectors (KL and KR), and 2nd anode lead.
4. Remove chassis completely by sliding it straight back.
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PICTURE TUBE REMOVAL
CAUTION: Do not disturb the deflection yoke or magnet assembly on the picture tube Neck.
Care must be taken to keep these assemblies intact, unless picture tube is being replaced.
Discharge the picture tube to the coating before handing the Tube.
1. Remove chassis, referring to Chassis Removal instructions.
2. Place cabinet front face down on the soft surface.
3. Remove the screw one ach corner of the picture tube and GENTLY lift the picture tube out
of the cabinet.
4. Install a replacement picture tube in reverse order.
5. Properly install the degaussing coil and picture tube grounding lead on the picture tube.
SeeFigure2.
Note: If the Picture Tube is being replaced, mount the Degaussing Coi l on the picture tube. See
following Figure1.Cabinet Back Removal
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ADJUSTMENTS
SET-UP ADJUSTMENTS
The following adjustments should be made when a complete realignment is required or a new
picture tube is installed.
Perform the adjustments in the following order:
1. Color purity
2. Convergence
3. White balance
Notes:
1. The purity/convergence magnet assembly and rubber wedges need mechanical ositioning.
Refer to Fig1, 2.
2. For some picture tubes, purity/ convergence adjustments are not required.
1. Color Purity Adjustment
Preparation:
Before starting this adjustment, adjust the vertical sync, horizontal sync, vertical amplitude and
focus.
1.1 Face the TV set north or south.
1.2 Connect the power plug into the wall outlet and turn on the main power switch of the TV set.
1.3 Operate the TV for at least 15 minutes.
1.4 Degauss the TV set using a specific degaussing coil.
1.5 Set the brightness and contrast to maximum.
1.6 Counter clockwise rotate the R /B low brightness potentiometers to the end and rotate
the green low brightness potentiometer to center.
1.7 Receive green raster pattern signals.
1.8 Loosen the clamp screw holding the deflection yoke assembly and slide it forward
or backward to display a vertical green zone on the screen. Rotate and spread the
tabs of the purity magnet around the neck of the CRT until the green zone is
located vertically at the center of the screen.
1.9 Slowly move the deflection yoke assembly forward or backward until a uniform
green screen is obtained.
1.10 Tighten the clamp screw of the assembly temporarily. Check purity of the red raster
and blue raster until purities of the three rasters meet the requirement.
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2. Convergence Adjustment
Preparation:
Before attempting any convergence adjustment, the TV should be operated for at least 15
minutes.
2.1 Center convergence adjustment
2.1.1 Receive dot pattern.
2.1.2 Adjust the brightness/contrast controls to obtain a sharp picture.
2.1.3 Adjust two tabs of the 4-pole magnet to change the angle between them and red and blue
vertical lines are superimposed each other on the center of the screen.
Fig. 1
2.1.4 Turn both tabs at the same time keeping the angle constant to superimpose red and blue
horizontal on the center of the screen.
2.1.5 Adjust two tabs of the 6-pole magnet to superimpose RED/BLUE line and green line.
2.1.6 Remember RED and BLUE movement. Repeat step 2.1.3 ~ 2.1.5 until optimal
convergence is obtained.
2.2 Circumference convergence adjustment
2.2.1 Loosen the clamp screw holding the deflection yoke assembly and allow it tilting.
2.2.2 Temporarily put the first wedge between the picture tube and deflection yoke assembly.
Move front of the deflection yoke up or down to obtain better convergence
in circumference. Push the mounted wedge in to fix the yoke temporarily.
2.2.3 Put the second wedge into bottom.
2.2.4 Move front of the deflection yoke to the left or right to obtain better convergence in
circumference.
2.2.5 Fix the deflection yoke position and put the third wedge in either upper space. Fasten the
deflection yoke assembly on the picture tube.
2.2.6 Detach the temporarily mounted wedge and put it in either upper space. Fasten the
deflection yoke assembly on the picture tube.
2.2.7 After fastening the three wedges, recheck overall convergence and ensure to get optimal
convergence. Tighten the lamp screw holding the deflection yoke assembly.
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3. White Balance Adjustment
Generally, white balance adjustment is made with professional equipment. It's not practical to
get good white balance only through manual adjustment. For TVs with I