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Models:
15CTF66BC
21CTF66BC
21CTS65BS
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CONTENTS
1. safety precautions...................................................................................................2
2. block diagram..........................................................................................................3
3 Replacement of memory IC.......................................................................................4
4 Service adjustment...................................................................................................5
5 IC's functional description........................................................................................7
6 Test point waveform................................................................................................10
7 IC's voltages..........................................................................................................11
8 Circuit diagram ..................................................................................................... 12
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.
1. SAFETY RECAUTIONS
2. The design of this product contains special hardware, many 10. manufacturer's replacement components.
circuits and components specially for safety purposes. For 11. Isolation Check
continued protection, no changes should be made to the (Safety for Electrical Shock Hazard)
original design unless authorized in writing by the After re-assembling the product, always perform an isolation
manufacturer. Replacement parts must be identical to those check on the exposed metal parts of the cabinet (antenna
used in the original circuits. Service should be performed by terminals, video/audio input and output terminals, Control
qualified personnel only. knobs, metal cabinet, screwheads, earphone jack, control
shafts, etc.) to be sure the product is safe to operate without
3. Alterations of the design or circuitry of the products should danger of electrical shock.
not be made. Any design alterations or additions will void 11. The surface of the TV screen is coated with a thin film which
the manufacturer's warranty and will further relieve the can easily be damaged. Be very careful with it when handle
manufacturer of responsibility for personal injury or property the TV. Should the TV screen become soiled, wipe it with a
damage resulting therefrom. soft dry cloth. Never rub it forcefully. Never use any cleaner
or detergent on it.
4. Many electrical and mechanical parts in the products have
special safety-related characteristics. These characteristics (1) Dielectric Strength Test
are often not evident from visual inspection nor can the The isolation between the AC primary circuit and all metal
protection afforded by them necessarily be obtained by parts exposed to the user, particularly any exposed metal
using replacement components rated for higher voltage, part having a return path to the chassis should withstand a
wattage, etc. Replacement parts which have these special voltage of 3000V AC (r.m.s.) for a period of one second.
safety characteristics are identified in the parts list of (...Withstand a voltage of 1100V AC (r.m.s.) to an appliance
Service manual. Electrical components having such rated up to 120V, and 3000V AC (r.m.s.) to an appliance
features are identified by shading on the schematics rated 200V or more, for a periode of one second.)
and by ( ) on the parts list in Service manual. The use This method of test requires a test equipment not generally
found in the service trade.
of a substitute replacement which does not have the same
(2) Leakage Current Check
safety characteristics as the recommended replacement
Plug the AC line cord directly into the AC outlet (do not use
part shown in the parts list of Service manual may cause
a line isolation transformer during this check.). Using a
shock, fire, or other hazards
"Leakage Current Tester", measure the leakage current
from each exposed metal part of the cabinet, particularly
5. Don't short between the LIVE side ground and
any exposed metal part having a return path to the chassis,
ISOLATED (NEUTRAL) side ground or EARTH side
to a known good earth ground (water pipe, etc.). Any
ground when repairing. Some model's power circuit is
leakage current must not exceed 0.5mA AC (r.m.s.).
partly different in the GND. The difference of the GND is
However, in tropical area, this must not exceed 0.2mA AC
shown by the LIVE: ( ) side GND, ISOLATED (NEUTRAL) :
(r.m.s.).
( ) side GND and EARTH : ( ) side GND. Don't short
between the LIVE side GND and ISOLATED (NEUTRAL) Alternate Check Method
side GND or EARTH side GND and never measure with a Plug the AC line cord directly into the AC outlet ( do not use
measuring apparatus (oscilloscope etc.) the LIVE side GND a line isolation transformer during this check.). Use an AC
and ISOLATED (NEUTRAL) side GND or EARTH side GND voltmeter having 1000 ohms per volt or more sensitivity in
at the same time. If above note will not be kept, a fuse or the following manner. Connect a 1500 10W resistor
any parts will be broken.
paralleled by a 0.15 F AC-type capacitor between an
6. If any repair has been made to the chassis, it is exposed metal part and a known good earth ground (water
recommended that the B1 setting should be checked or pipe, etc.). Measure the AC voltage across the resistor with
adjusted (See ADJUSTMENT OF B1 POWER SUPPLY). the AC voltmeter. Move the resistor connection to each
exposed metal part, particularly any exposed metal part
7. The high voltage applied to the picture tube must conform having a return path to the chassis, and measure the AC
with that specified in Service manual. Excessive high voltage across the resistor. Now, reverse the plug in the AC
voltage can cause an increase in X-Ray emission, arcing outlet and repeat each measurement. Any voltage
and possible component damage, therefore operation under measured must not exceed 0.75V AC (r.m.s.). This
excessive high voltage conditions should be kept to a corresponds to 0.5mA AC (r.m.s.).
minimum, or should be prevented. If severe arcing occurs, However, in tropical area, this must not exceed 0.3V AC
remove the AC power immediately and determine the cause (r.m.s.).
by visual inspection (incorrect installation, cracked or melted This corresponds to 0.2mA AC (r.m.s.)
high voltage harness, poor soldering, etc.). To maintain the
proper minimum level of soft X-Ray emission, components
in the high voltage circuitry including the picture tube must
be the exact replacements or alternatives approved by the
manufacturer of the complete product.
8. Do not check high voltage by drawing an arc. Use a high
voltage meter or a high voltage probe with a VTVM.
Discharge the picture tube before attempting meter
connection, by connecting a clip lead to the ground frame
and connecting the other end of the lead through a 10k
2W resitor to the anode button.
9. When service is required, observe the original lead dress.
Extra precaution should be given to assure correct lead
dress in the high voltage circuit area. Where a short circuit
has occurred, those components that indicate evidence of
overheating should be replaced. Always use the
2
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2 Block Diagram
V1 IN
V1 IN
TUNER SAW IF1 IN
IF2 IN TDA111XX V2 IN
TDA121XX AL1 IN
RF AGC
AR1 IN
Y IN Y IN
U IN U IN
V IN V IN
SELECT V OUT V OUT
AL IN AL OUT
AR IN AR OUT
EEPROM C IN
LSL OUT
SDA
SCL LSR OUT
RGB OUT S-VIDEO
AUDIO OUT
4052
V OUT V2 IN
H OUT
AL2 IN
AR2 IN
+B
+27V SOUND AMP SPEAKER L
POWER
+12V
AN17821
+8V
+5V
V. DRIVE E/W
H. DRIVE
UNIT
+3.3V
LA78040 (OPTION) EHT
+13V
SPEAKER R
-13V
VIDEO AMP CRT
DEFLECT
3
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3. REPLACEMENT OF MEMORY IC
1. MEMORY IC.
This TV uses memory IC. In the memory IC are memorized data for correctly operating the video and
deflection circuits.
When replacing memory IC, be sure to use IC written with the initial value of data.
2. PROCEDURE FOR REPLACING MEMORY IC
(1) Power off
Switch the power off and unplug the power cord from AC outlet.
(2) Replace IC
Be sure to use memory IC written with the initial data values.
(3) Power On
Plug the power cord into the AC outlet and switch the power On.
4
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4. SERVICE ADJUSTMENT
4.1 Enter the factory menu
PUSH MENU KEY DISPLAY PICTURE MANUAL PUSH DIGITAL KEY "6483" DISPLAY
"B/W BANLANCE" PUSH STANDBY KEY WILL BE EXIT FACTORY MODE
PRESS TEST KEY OR POWER WILL BE EXIT FACTORY MODE
IN TEST MODE .PRESS -/-- KEY WILL BE ENTER BUS OPEN .
4.2 Enter the adjustment menu
IN "B/W BALANCE" MODE,PRESS TEST OR CALL KEY WILL BE ENTER M0.THEN PRESS
MUTE KEY WILL ENTER "M1" AND "M2".
IN "M2" SELECT "SETUP SELECT" TO 1,THEN PRESS MENU KEY WILL BE ENTER"M3"
TO "M9
CHILD LOCK PASS WORD [4100]
DESCRIPTION
Picture vertical center
The vertical positions
The vertical amplitude
The Vertical S-correction
The horizontal position
Receive standard Crosshatch pattern signal for PAL system .
5
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DESCRIPTION
R bais adjusted
bais adjusted
bais adjusted
drive adjusted
drive adjusted
B drive adjusted
Sub Brightness
6
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DESCRIPTION
RF AGC
Vertical position of OSD 0~63
Horizital position of OSD 0~15
Receive 60dBu (1mv)VH color bar signal adjust AGC value voltage from high to low to
picture noise reduce gradually to be just disappeared. Select "shipping", push [V+] [V-]key to
be shipped.
5. IC's functional description
Function : Main IC
7
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SDA output
SCL output
8
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AN17821/17823 Function : audio output
Symbol PIN Function Symbol PIN Function
Vcc 1 Power supply GND 7 ground
Out 1 (+) 2 Ch 1 output (+) In 2 8 Ch 2 input
GND(out 1) 3 Ch 1Ground VOL 9 Volume Control
Out 1 (-) 4 Ch 1 output (-) Out 2 (-) 10 Ch 2 output (-)
Standby 5 Mute input GND(out 2) 11 Ch 2 Ground
In 1 6 Ch 1 input Out 2 (+) 12 Ch 2 output (+)
Note: AN17823 is pin 1 to 9, AN17821 is pin 1 to 12.
STV9302A /LA78040 Function : vertical output
Symbol PIN Function Symbol PIN Function
INV IN 1 Input V OUT 5 Vertical output
9
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VCC1 2 Power VCC2 6 Output power supply
PUMP UP 3 Pump up power NON INV IN 7 Negative feedback
GND 4 Ground
6. Test point Waveforms
2.0Vpp 1.3Vpp 1.2Vpp 1.2Vpp 1.2Vpp
H H H H
TDA111XX PIN1 TDA111XX PIN24 TDA111XX PIN44 TDA111XX PIN45 TDA111XX PIN46
95Vpp 95Vpp 95Vpp 0.9Vpp 5Vpp
H
H H H H
CRT KR CRT KG CRT KB TDA111XX PIN56 TDA111XX PIN57
1Vpp 0.8Vpp 22Vpp 2.7Vpp
1000Vpp
V V H H
H
V451 B V451 C
TDA111XX PIN15 TDA111XX PIN14 HEATER
10
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7. IC's voltages
TDA111XX/TDA121XX
PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
V 1.5 5 8 2.0 0 2.2 2.6 2.2 1.3 2.0 2.4 1.9 1.9 0.7 0.7 0.4
PIN 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
V 2.3 2.3 0 2.3 1.8 5 2.6 1.8 1.8 5 0 0 3.3 0 0 -
PIN 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48
V 3.3 3.8 3.6 0 0 3.3 0 3.3 0 0 3.3 2.2 2.2 2.2 0 2.6
PIN 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64
V 0.5 1.4 1.6 1.6 1.9 5 0 0.6 0.35 2.5 2.5 0.6 2.2 1.4 2.2 1.4
STV9302A/LA78040
PIN 1 2 3 4 5 6 7
V 0.7 15 -12 -15 0.3 15.9 -0.07
AN17821/AN17823
PIN 1 2 3 4 5 6 7 8 9 10 11 12
V 12 7 0 7 3.3 1.4 0 1.4 0 7 0 7
11
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