Akira TV CT-14CQS5CPT Schematic

Model:

Model no.:CT-21CQS5CPT.doc version 1.0

CONTENTS

SAFETY INSTRUCTIONS AND MAINTENANCE..........................................................................4

SAFETY PRECAUTION.......................................................................................................................................... 5

PRODUCT SAFETY NOTICE................................................................................................................................. 6

SAFETY SYMBOL DESCRIPTION........................................................................................................................ 7

MAINTENANCE ..................................................................................................................................................... 8

SPECIFICATION.................................................................................................................................................... 9

CONTROL & FUNCTION................................................................................................................................... 10

MECHANICA DISASSEMBLING....................................................................................................12

ADJUSTMENTS..................................................................................................................................14

SET-UP ADJUSTMENTS.......................................................................................................................................14

CIRCUIT ADJUSTMENTS.................................................................................................................................... 16

STRUCTURE AND CHASSIS FUNCTION DESCRIPTION.........................................................23

STRUCTION BLOCK DIAGRAM......................................................................................................................... 23

CHASSIS DESCRIPTION...................................................................................................................................... 23

SERVICE DATA..................................................................................................................................25

APPENDIX.......................................................................................................................................... 38

CIRCUIT DIAGRAM PARTS LIST

Please read this manual carefully before service.

Model no.:CT-21CQS5CPT.doc version 1.0

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.

Model no.:CT-21CQS5CPT.doc version 1.0

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.

Model no.:CT-21CQS5CPT.doc version 1.0

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

Model no.:CT-21CQS5CPT.doc version 1.0

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.

MAINTENANCE

Model no.:CT-21CQS5CPT.doc version 1.0

SPECIFICATION

RF System : Colour / Sound system : PAL/SECAM BG/DK/I, NTSC-M (4.43 & 3.58)

Programs Preset : 236 ( 0 ~ 235 )

Antenna Input : 75 (unbalanced)

Power Source : 110 ~ 240V 50/60Hz

Designs and specifications are subject to change without notice.

Model no.:CT-21CQS5CPT.doc version 1.0

CONTROL & FUNCTION

Front Panel

Rear Panel

* The pictures showed are for function illustration. Please refer to the TV as the standard.

Model no.:CT-21CQS5CPT.doc version 1.0

Remote Control

Model no.:CT-21CQS5CPT.doc version 1.0

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 (2

grounding lead).

3. Disconnect Degaussing coil socket (KE). Picture tube socket, Deflection yoke connector

(KDY). Speaker connectors (KL and KR), and 2

4. Remove chassis completely by sliding it straight back.

anode lead) to the dag coating (picture tube

anode lead.

Model no.:CT-21CQS5CPT.doc version 1.0

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

Model no.:CT-21CQS5CPT.doc version 1.0

ADJUSTMENTS

1 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:

Color purity

Convergence

White balance

Notes:

The purity/convergence magnet assembly and rubber wedges need mechanical positioning.

For some picture tubes, purity/ convergence adjustments are not

required.

1.1 Color Purity Adjustment Preparation:

Before starting this adjustment, adjust the vertical sync, horizontal sync, vertical amplitude

and focus.

•Face the TV set north or south.

•Connect the power plug into the wall outlet and turn on the main power switch of the TV

set. •Operate the TV for at least 15 minutes.

•Degauss the TV set using a specific degaussing coil.

•Set the brightness and contrast to maximum.

•Counter clockwise rotate the R /B low brightness potentiometers to the end and rotate the

green low brightness potentiometer to center.

•Receive green raster pattern signals.

•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. •Slowly move the deflection yoke assembly forward or backward until

a uniform green screen is obtained.

•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.

Model no.:CT-21CQS5CPT.doc version 1.0

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Akira TV CT-14CQS5CPT Schematic

Specifications and Main Features

Frequently Asked Questions

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