KLH KT2006 User manual

SERVICE MANUAL
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FILE NO. SM-CTV-O-034
COLOR TELEVISION
SERVICE MANUAL
MODEL NO. KT2006
CHASSIS NO. CN-12C1
Please read this manual carefully before service.

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TABLE OF CONTENTS
SPECIFICATIONS..............................................................................................................................1
SAFETY INSTRUCTIONS AND MAINTENANCE...................................................…..2
X-Ray Radiation Precaution..................................................................................................................2
Safety Precaution................................................................................................................……………..2
Product Safety Notice................................................................................................................………..3
Maintenance................................................................................................................……………………3
ADJUSTMENTS...............................................................................................................…………….4
Circuit Adjustments..............................................................................................................…………….4
Set-up Adjustments..............................................................................................................…………….5
Service Mode and Bus Data..............................................................................................…………….8
CONTROL BUTTONS..............................................................................................………………11
Control Buttons..............................................................................................………………………….…11
Remote Control..............................................................................................………………………….…12
STRUCTURE AND CHASSIS FUNCTION DESCRIPTION…………………….…13
Structure Block Diagram..............................................................................……………………………13
Block Diagram for Supply Voltage System.............................................………………………….….14
Block Diagram for Remote Control System...........................................…………………………..….15
Chassis Description.......................................................................................……………………………16
SERVICE DATA .......................................................................................………………………….…17
Technical Data of Key ICs..........................................................................…………………………..…17
Service Data of Key ICs..........................................................................……………………………..…23
Waveforms of Key Points .......................................................................……………………………..…28
Replacement of Parts ..................................................................................………………………….…30
APPENDIX
1. Circuit Diagram
2. Final Wiring Diagram
3. Final Assembly Diagram
4. Printed Circuit Board Diagrams
SPECIFICATIONS

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MODEL KT2006
Television system NTSC-M
Channel coverage VHF 2~13, UHF 14~69
Cable TV coverage
Mid Band (A-8~A-1, A~I);
Super Band (J~W)
Hyper Band (AA~ZZ, AAA, BBB)
Ultra Band (65~94, 100~125)
Channels preset 181
Antenna input 75 ohm (unbalanced)
Screen dimensions 406×305 mm (15.98×12.01 in)
Audio output (THD≤7%) 2W×2
Power source ~120Vac, 60Hz
Weight (Approx.) 25 kg (55 lbs.)
Unit dimensions 566×450×477 mm (22.28×17.72×18.78 in)
Packaged dimensions
(W×H×D) (Approx.) 640×531×540 mm (25.20×20.91×21.26 in)
Power consumption 90W
Designs and specifications are subject to change without notice.
SAFETY INSTRUCTIONS AND MAINTENANCE

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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 nominal EHT for this TV is 25.5±1.5KV at zero beam current (minimum
brightness) operating at AC 120V. The maximum EHT voltage permissible in any operating circumstances
must not exceed 28KV. 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. 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.
SAFETY PRECAUTION
1. The TV has a nominal working EHT voltage. Extreme caution should be exercised when working on the TV with
the back removed.
1) Do not attempt to service this TV if you are not conversant with the precautions and procedures for working on
high voltage equipment.
2) 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.
3) The CRT, if broken, will violently expel glass fragments. Use shatterproof goggles and take extreme care while
handling.
4) 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. Replace blown fuses within the TV with the fuse specified in the parts list.
5. 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 in the circuit diagram and
parts list, it must be the company-approved type and must be mounted as the original.
6. Keep wires away from high temperature components.
PRODUCT SAFETY NOTICE
CAUTION ： FOR YOUR PROTECTION ， THE FOLLOWING PRODUCT SAFETY NOTICE SHOULD BE READ
WARNING: BEFORE SERVICING THIS CHASSIS, READ THE “X-RAY RADIATION PRECAUTION”,
“SAFETY PRECAUTION” AND “PRODUCT SAFETY NOTICE” INSTRUCTIONS BELOW.

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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.
Safety Symbol Description
The lightning symbol in the triangle tells you that the voltage inside this product may be strong
enough to cause an electric shock. Extreme caution should be exercised when working on the TV
with the back removed.
This is an international hazard symbol，telling you that the components identified by the symbol have
special safety-related characteristics.
FDA This symbol tells you that the critical components identified by the FDA marking have special
safety-related characteristics.
UL This symbol tells you that the critical components identified by the UL marking have special
safety-related characteristics.
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.
ADJUSTMENTS

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CIRCUIT ADJUSTMENTS
1. General Description
All adjustments are thoroughly checked and corrected before the TV outgoing. Therefore the TV should
operate normally and deliver proper colour pictures upon installation. However, several minor adjustments
may be required depending on the particular location where the TV is operated.
This TV is shipped completely in carton. Carefully take out the TV from the carton and remove all packing
materials. Connect the power cord into a 120V AC, 60Hz two-pin power outlet. Turn on the TV. Check and
adjust all the customer controls such as brightness, contrast and colour to obtain natural colour pictures.
2. Automatic Degaussing
A degaussing coil is mounted around the CRT so that external degaussing after moving the TV is generally
unnecessary, providing it is properly degaussed upon installation. The degaussing coil operates in about 1
second after power on. If the set is moved or faced to a different direction, the power switch must be switched
off for at least 30 minutes in order that the automatic degaussing circuit operates properly. Should the chassis
or parts of the cabinet become magnetized to cause poor colour purity, use an external-degaussing coil. Slowly
move the degaussing coil around the screen, the sides and front of the TV and slowly withdraw the coil to a
distance of about 2m before unplug it. If colour shading still exists, perform the Colour Purity Adjustment and
Convergence Adjustment procedures.
3. Supply Voltage Adjustment
Caution: +B voltage has close relation to high voltage. To avoid X-ray radiation, +B voltage should be +130V.
1) Set RP551 to the mechanical center and AC power supply to 120±2V.
2) Connect a digital voltmeter to two pins of C561, and then turn on the TV.
3) Receive Philips test pattern signals.
4) Adjust RV801 to make the voltmeter read 130±1V.
4. High Voltage Inspection
Caution: No high voltage adjustment should be done in the chassis.
1) Connect a precise high voltmeter to the second anode of the CRT.
2) Turn on the TV and set the brightness and contrast to minimum (i.e. set beam current of the CRT to zero).
3) The high voltage tested should be 25.5±1.5KV.
4) Set the brightness to minimum or maximum, and ensure high voltage not beyond limitation of 28KV in any
case.
5. Focus Adjustment
1) Use the remote control to set the contrast to maximum and the brightness, chroma to medium.
2) Set H. V. lines near Philips pattern center to thinnest with the FCB on the FBT. After finishing adjustment,
ensure that no poor focusing exists near the center or around of the frame.

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BeforeAdjusting AfterAdjusting
SET-UP ADJUSTMENTS
●The following adjustments should be made when a complete realignment is required or a new CRT is installed.
Perform the adjustments in order as follows.
1. Colour purity
2. Convergence
3. White Balance
Note:
The purity/convergence magnet assembly and rubber wedges need mechanical positioning. Refer to Fig. 11.
1. Colour Purity Adjustment
Note:
Before attempting any purity adjustment, the TV should be operated for at least 15 minutes.
1) Demagnetize the CRT and cabinet using a degaussing coil.
2) Set the brightness and contrast to maximum.
3) Receive the green raster test signals.
4) Loosen the clamp screw holding the deflection yoke and slide it backward or forward to display vertical green
belt (zone) on the screen.
5) Remove the rubber wedge.
6) Rotate and spread the tabs of the purity magnet around the neck of the CRT until the green belt is on the centre
of the screen.
7) Slowly move the deflection yoke forward or backward until a uniform green screen is obtained.
Tighten the clamp screw of the yoke temporarily.
8) Check purity of the red and blue raster.
Deflection Coil
Dummy Wedge
Rubber Wedge
Adhesive
Deflection Yoke
Purity/Convergence
Ma
g
net Module
Glass Cloth Tapes Fig. 1
6-pole Magnet

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2. Convergence Adjustment
Note:
Before attempting any convergence adjustment, the TV should be operated for at least 15 minutes.
●Center convergence adjustment
1) Receive crosshatch test pattern.
2) Set the brightness and contrast properly.
3) Adjust two tabs of the 4-pole magnet to change the angle between them and red and blue vertical
lines are superimposed on the center area of the screen.
4) Turn both tabs at the same time keeping the angle constant to superimpose red and blue horizontal
lines on the center of the screen.
5) Adjust two tabs of 6-pole magnet to superimpose red/blue line and green line. Adjusting the angle
affects the vertical lines and rotating both magnets affects the horizontal lines.
6) Repeat steps 3)～5) keeping in mind red, green and blue movement. 4-pole magnet and 6-pole
magnet interact each other, resulting in complicating and dot movement.
●Circumference convergence adjustment
1) Loosen the clamping screw of the defection yoke slightly to allow it to tilt.
2) Temporarily put a wedge as shown in Fig. 1. (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.
Push the mounted wedge into the space between the CRT and yoke to fix the yoke temporarily.
4) Put other wedge into bottom space and remove the cover paper to stick.
5) Tilt front of the deflection yoke right or left to obtain better convergence in circumference.
6) Keep the deflection yoke position and put another wedge in either upper space. Remove cover paper and stick
the wedge on the CRT to fix the yoke.
7) Detach the temporarily mounted wedge and put it in another upper space. Stick it on the CRT to fix the yoke.
8) After fixing three wedges, recheck overall convergence.
Tighten the screw firmly to fix the yoke and check if the yoke is fixed.
9) Stick three adhesive tapes on wedges as shown in Fig. 1.
Ad
j
ust the An
g
le
(
Vertical Lines
)
Fixed
Rotate Two Tabs At the
Same Time
(
Horizontal Lines
)
Adjustment of Magnets
Purity Magnet
Conver
g
ence Ma
g
net Assembl
y
4-pole Magnet
Fig. 2
BLURed Red/BLUGRN

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SERVICE MODE AND BUS DATA
BLU
Red
4-pole Magnet Movement 6-pole Magnet Movement
Center Convergence by Convergence Magnets
Red/BLU
GRN
Incline the Yoke up (or down) Incline the Yoke Right(or left)
Circumference Convergence by DEF Yoke
Fig. 3

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1. How to Enter the Service Mode with the Remote Control
1) Decrease volume to 0.
2) Press the MUTE button on the remote control and VIDEO button on the TV at the same time.
3) Adjust the TV with the MENU SELECT buttons on the remote control.
4) Press the button on the remote control to quit the Service mode.
2. Bus Data
MENU. 00 MENU. 01
V.POS /50H 34 SUB-BRIGHT 59
H.PHSE /50H 8 SUB-CONT 63
V.SIZE /50H 84 V.KILL 0
V.POS /60H 37 RF.AGC 15
H.PH /60H 13 R.BIAS 32
V.SIZE /60H 55 G.BIAS 60
V.SC 4 B.BIAS 16
V.LINE 18 R.DRIVE 72
V.SIZE CMP 7 G.DRIVE 15
B.DRIVE 93
MENU. 02 MENU. 03
H.AFC 0 FM.MUTE 0
H.BLK.L 4 AUDIO.MUTE 0
H.BLK.R 4 VIDEO.MUTE 0
CROS.BW 0 SND.TRAP 0
VIDEO.LVL 4
FM.LEVEL 1
MENU. 04 MENU. 05
SUB.COLOR 31 BLINK.DEF 0
SUB.TINT 24 BLK.ST.DEF 1
SUB.SHARP 31 FBP.BLK.SW 0
CORING 1 FILT.SYS 0
C.EXT 0 VOL.FIL 0
C.BYPASS 0 VIF.SYS.SW 0
C.KILL.ON 0 VIDEO.SW 0
MENU. 06 MENU. 07
R/B ANGLE 9 BRT.ABL.TH 7
GRAY MODE 0 EM.ABL.DEF 0
V.SEPUP 1 BRT.ABL.DF 0
B.GAM.SEL 3 MID.STP.DF 0
RG.GAM.DEF 1
MENU. 08 MENU. 09
DIGTAL OSD 0 H.FREQ 27
OSD.CONT 1 C.KILL.OFF 0
OSD.H.POS 22 AUDIO.SW 0
T. DI SBL E 1
OPT.LOGO 0

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OPT.VID SW 0
MENU. 10
OPT.TV.AV 1
OPT.AV1/2 0
OPT.AV3 0
OPT.COLOR 0
OPT.V-CHIP 1
OPT.CCD 1
OPT.CLOCK 1 SRCH.SPEED 0
OPT.P-ON 0 ROM CORREC 0
Notes:
①The data sheet may differ dependent on different models.
②The data sheet may differ dependent on different CRTs for the same model.
3. Service Mode Adjustment
1) Sub-brightness
a) Receive colour signals.
b) Set the contrast to maximum and brightness to medium.
c) Set the chroma to medium.
Enter the TV to the Service mode. Select “SUB-BRIGHT” by pressing the ←/→buttons on the remote control，
and set the data to 31 by pressing the data adjustment buttons. Operate the TV for 5 minutes in the mode.
d) Adjust the sub-bright data until blurry picture does not appear on the high bright area of the screen and too dim
picture not on the low-bright area.
e) Set the contrast and brightness to maximum or minimum, and then test normal picture alternation.
f) If the picture does not become dark when the contrast and brightness are set to minimum, or not become bright
when set to maximum, then adjust the sub-bright data to get normal picture.
2) White balance adjustment
a) Turn on the TV and preheat it for over 7 minutes.
b) Use the remote control to set the contrast to maximum and the brightness to medium. Set the chroma to
minimum.
c) Enter the TV to the Service mode, and set the following data without changing other items.
R-DRIVE············70
G-DRIVE············15
B-DRIVE············70
d) Pull out the external antenna and press the MUTE button once on the remote control until a right horizontal line
appears on the screen. Adjust the R-DRV data to get 160V±0.5 green gun voltage across the CRT RGB PCB.
e) Adjust the G-DRV and B-DRV data according to Step 4 so that the bright horizontal line turns to yellow, then to
white.
3) Horizontal centering adjustment

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Enter the TV to the Service mode and receive Philips test pattern. Select “H.PH/60H” by pressing the ←/→
buttons on the remote control, and adjust horizontal picture position in the centre of screen by pressing the
data adjustment buttons.
4) Vertical centering adjustment
Enter the TV to the Service mode and receive Philips pattern. Select “V.POS/60H” by pressing the ←/→
buttons on the remote control，and adjust vertical picture position in the centre of screen by pressing the data
adjustment buttons.
5) Vertical amplitude adjustment
Enter the TV to the Service mode and receive crosshatch pattern. Select “V.SIZE/60H” by pressing the ←/→
buttons on the remote control, and adjust vertical amplitude by pressing the data adjustment buttons so that
vertical amplitude is not enough. Continue to adjust vertical amplitude by pressing the data adjustment button
until the first bar on crosshatch pattern touches edge of the screen.

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Control Buttons
1.Control Buttons
1.1 Front panel
1.2 Side panel
1.3 Rear panel
STANDBY
POWER INDICATOR
INFRARED SENSOR
TV/VIDEO SELECT
MENU SELECT
VOLUME
DOWN/UP CHANNEL DOWN/UP

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VIDEO
STANDBY
FUNCTION
100+
CH+/-
VOL+/-
DISPLAY
MENU
ARROWS
MUTE
TIMER
PICTURE
SCAN
RECALL
CC
KEYPAD
2. Remote Control
FUNCTION Used for volume control and child lock
KEYPAD Use to select channels by number
100+ Three digit select
TIMER Accesses the Timer menu
ARROWS Used to navigate the TV menus
SCAN Scans all the active channels
PICTURE Selects the various Picture Modes
RECALL Returns to the last channel viewed
STANDBY Turns on/off the TV
CH+/- Used to change the current channel
VOL+/- Used to adjust the volume level
DISPLAY Brings up the TV/Video display
MENU Brings up the main Menu
MUTE Mutes or restores the TV volume
VIDEO Cycles through the Video/TV modes
CC Activates Closed Captioning
K12B-C12

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STRUCTURE AND CHASSIS FUNCTION DESCRIPTION
1. Structure Block Diagram

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2. Block Diagram for Supply Voltage System

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3. Block Diagram for Remote Control System

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4. Chassis Description
This TV uses CN-12C1 chassis which mainly includes a small signal processor LA76814 (N101), microcontroller
LC863248A, vertical output circuit LA7840 and sound power amplifier TDA7056B. LA76814, a small signal
processing chip developed by Japan-based Sanyo, is designed for use in NTSC televisions, featuring
high-integrity, performance & reliability and advanced functions. Microcontroller LC863248A, developed by Sanyo,
is an I2C bus control 8-bit CMOS single-chip microprocessor.
The CN-12C1 chassis mainly uses the following ICs and assemblies.
Table 1 Key ICs and Assemblies
Serial No. Position No. Model No. Function Description
1 N101 LA76814 Small signal processor
2 N301 LA7840 Vertical output circuit
3 N503 L7805 Tri-terminal regulator
4 N191 TDA7056B Sound power amplifier
5 D701 LC86F3248A Microcontroller
6 D702 AT24C08 EEPROM
7 U101 TDQ-3B8/136-F Tuner

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SERVICE DATA
Technical Data of Key ICs
LA76814 Small Signal Processing IC
1. Introduction of LA76814 IC
LA7684 is a NTSC-M only system color TV specific monolithic IC developed by SANYO Co., which is controlled
by Inter IC Bus. LA76814 includes a IF processing circuit，a luminance and chroma signal processing circuit,
horizontal/frame scanning small signal processing circuit, etc. It has following features.
*Number of external component adjustments reduced by the use of an I2C bus and by reducing the number of
on-board rheostats.
An I2C bus is used for controlling this IC, and this allows the number of adjustment that require trimmers on the
printed circuit board to be reduced.
*Number of adjustments reduced by the adoption of adjustment-free technology. The VCO coil adjustment and
the AFT coil adjustment are now handled by adjustment-free technology.
*Number of external components reduced by the adoption of circuit technologies.
-S-TRAP, S-BPF
The sound trap and sound band pass filter circuits, which were previously implemented using external
components, are now provided on chip.
-Horizontal oscillator element
The horizontal oscillator element, which was previously an external component is now provided on chip.
-Single crystal operation provided by DDS technology
The functions of the two or three crystal oscillator elements previously required for color demodulation can now be
handled by a single crystal oscillator element due to the adoption of DDS technology.

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2. Block Diagram
3. Refer to Table 2 about Functions and Service Data of LA76814's Pins.
Fig. 7