SAMSUNG CT25D4WZX-GSU, CT29D4WZX-GSU Service Manual
COLOR TELEVISION RECEIVER
Chassis : K51A
Model : CT25D4WZX/GSU
CT29D4WZX/GSU
COLOR TELEVISION RECEIVER CONTENTS
Precautions
Specifications and IC Data
Alignment and Adjustments
Troubleshooting
Exploded Views and Parts List
Electric Parts List
Block Diagrams
Schematic Diagrams
1.
2.
3.
4.
5.
6.
7.
8.
ELECTRONICS
© Samsung Electronics Co., Ltd. APR. 1999
Printed in Korea
3K51A-2902
1. Precautions
1-1 Safety Precautions
1. Be sure that all of the built-in protective
devices are replaced. Restore any missing
protective shields.
2. When reinstalling the chassis and its
assemblies, be sure to restore all protective
devices, including: nonmetallic control knobs
and compartment covers.
3. Make sure that there are no cabinet openings
through which peopleÑparticularly
childrenÑmight insert fingers and contact
dangerous voltages. Such openings include
the spacing between the picture tube and the
cabinet mask, excessively wide cabinet
ventilation slots, and improperly fitted back
covers.
If the measured resistance is less than 1.0
megohm or greater than 5.2 megohms, an
abnormality exists that must be corrected
before the unit is returned to the customer.
4. Leakage Current Hot Check (Figure 1-1):
Warning: Do not use an isolation
transformer during this test. Use a leakagecurrent tester or a metering system that
complies with American National Standards
Institute (ANIS C101.1, Leakage Current for
Appliances), and Underwriters Laboratories
(UL Publication UL1410, 59.7).
5. With the unit completely reassembled, plug
the AC line cord directly into the power
outlet. With the unitÕs AC switch first in the
ON position and then OFF, measure the
current between a known earth ground (metal
water pipe, conduit, etc.) and all exposed
metal parts, including: antennas, handle
brackets, metal cabinets, screwheads and
control shafts. The current measured should
not exceed 0.5 milliamp. Reverse the powerplug prongs in the AC outlet and repeat the
test.
Fig. 1-1 AC Leakage Test
6. Antenna Cold Check:
With the unitÕs AC plug disconnected from the
AC source, connect an electrical jumper across
the two AC prongs. Connect one lead of the
ohmmeter to an AC prong. Connect the other
lead to the coaxial connector.
7. X-ray Limits:
The picture tube is especially designed to
prohibit X-ray emissions. To ensure continued
X-ray protection, replace the picture tube only
with one that is the same type as the original.
Carefully reinstall the picture tube shields and
mounting hardware; these also provide X-ray
protection.
8. High Voltage Limits:
High voltage must be measured each time
servicing is done on the B+, horizontal
deflection or high voltage circuits. Correct
operation of the X-ray protection circuits must
be
reconfirmed whenever they are serviced.
(X-ray protection circuits also may be called
Òhorizontal disableÓ or Òhold-downÓ.)
Heed the high voltage limits. These include
the XÐray Protection Specifications Label, and
the Product Safety and X-ray Warning Note on
the service data schematic.
Precautions
Samsung Electronics 1-1
LEAKAGE
CURRENT
TESTER
DEVICE
UNDER
TEST
TEST ALL
EXPOSED METAL
SURFACES
2-WIRE CORD
ALSO TEST WITH
PLUG REVERSED
(USING AC ADAPTER
PLUG AS REQUIRED)
EARTH
GROUND
(READING SHOULD
NOT BE ABOVE
0.5mA)
Follow these safety, servicing and ESD precautions to prevent damage and protect against potential
hazards such as electrical shock and X-rays.
1-1 Safety Precautions (Continued)
9. High voltage is maintained within specified
limits by close-tolerance, safety-related
components and adjustments. If the high
voltage exceeds the specified limits, check
each of the special components.
10. Design Alteration Warning:
Never alter or add to the mechanical or
electrical design of this unit. Example: Do not
add auxiliary audio or video connectors. Such
alterations might create a safety hazard. Also,
any design changes or additions will void the
manufacturerÕs warranty.
11. Hot Chassis Warning:
Some TV receiver chassis are electrically
connected directly to one conductor of the AC
power cord. If an isolation transformer is not
used, these units may be safely serviced only
if the AC power plug is inserted so that the
chassis is connected to the ground side of the
AC source.
To confirm that the AC power plug is inserted
correctly, do the following: Using an AC
voltmeter, measure the voltage between the
chassis and a known earth ground. If the
reading is greater than 1.0V, remove the AC
power plug, reverse its polarity and reinsert.
Re-measure the voltage between the chassis
and ground.
12. Some TV chassis are designed to operate with
85 volts AC between chassis and ground,
regardless of the AC plug polarity. These units
can be safely serviced only if an isolation
transformer inserted between the receiver and
the power source.
13. Some TV chassis have a secondary ground
system in addition to the main chassis ground.
This secondary ground system is not
isolated from the AC power line. The two
ground systems are electrically separated by
insulating material that must not be defeated
or altered.
14. Components, parts and wiring that appear to
have overheated or that are otherwise
damaged should be replaced with parts that
meet the original specifications. Always
determine the cause of damage or
overheating, and correct any potential
hazards.
15. Observe the original lead dress, especially
near the following areas: Antenna wiring,
sharp edges, and especially the AC and high
voltage power supplies. Always inspect for
pinched, out-of-place, or frayed wiring. Do
not change the spacing between components
and the printed circuit board. Check the AC
power cord for damage. Make sure that leads
and components do not touch thermally hot
parts.
16. Picture Tube Implosion Warning:
The picture tube in this receiver employs
Òintegral implosionÓ protection. To ensure
continued implosion protection, make sure
that the replacement picture tube is the same
as the original.
17. Do not remove, install or handle the picture
tube without first putting on shatterproof
goggles equipped with side shields. Never
handle the picture tube by its neck. Some
Òin-lineÓ picture tubes are equipped with a
permanently attached deflection yoke; do not
try to remove such Òpermanently attachedÓ
yokes from the picture tube.
18. Product Safety Notice:
Some electrical and mechanical parts have
special safety-related characteristics which
might not be obvious from visual inspection.
These safety features and the protection they
give might be lost if the replacement
component differs from the originalÑeven if
the replacement is rated for higher voltage,
wattage, etc.
Components that are critical for safety are
indicated in the circuit diagram by shading,
( ) or ( ).
Use replacement components that have the
same ratings, especially for flame resistance
and dielectric strength specifications.
A replacement part that does not have the
same safety characteristics as the original
might create shock, fire or other hazards.
Precautions
1-2 Samsung Electronics
!
1-2 Servicing Precautions
1. Servicing precautions are printed on the
cabinet. Follow them.
2. Always unplug the unitÕs AC power cord from
the AC power source before attempting to: (a)
Remove or reinstall any component or
assembly, (b) Disconnect an electrical plug or
connector, (c) Connect a test component in
parallel with an electrolytic capacitor.
3. Some components are raised above the printed
circuit board for safety. An insulation tube or
tape is sometimes used. The internal wiring is
sometimes clamped to prevent contact with
thermally hot components. Reinstall all such
elements to their original position.
4. After servicing, always check that the screws,
components and wiring have been correctly
reinstalled. Make sure that the portion around
the serviced part has not been damaged.
5. Check the insulation between the blades of the
AC plug and accessible conductive parts
(examples: metal panels, input terminals and
earphone jacks).
6. Insulation Checking Procedure: Disconnect the
power cord from the AC source and turn the
power switch ON. Connect an insulation
resistance meter (500V) to the blades of the AC
plug.
The insulation resistance between each blade
of the AC plug and accessible conductive parts
(see above) should be greater than 1 megohm.
7. Never defeat any of the B+ voltage interlocks.
Do not apply AC power to the unit (or any of
its assemblies) unless all solid-state heat sinks
are correctly installed.
8. Always connect a test instrumentÕs ground
lead to the instrument chassis ground before
connecting the positive lead; always remove
the instrumentÕs ground lead last.
Precautions
Samsung Electronics 1-3
Warning 1 : First read the “Safety Precautions” section of this manual. If some unforeseen circumstance creates
a conflict between the servicing and safety precautions, always follow the safety precautions.
Warning 2 : An electrolytic capacitor installed with the wrong polarity might explode.
1-3 Precautions for Electrostatically Sensitive Devices (ESDs)
1. Some semiconductor (Òsolid stateÓ) devices
are easily damaged by static electricity. Such
components are called Electrostatically
Sensitive Devices (ESDs); examples include
integrated circuits and some field-effect
transistors. The following techniques will
reduce the occurrence of component damage
caused by static electricity.
2. Immediately before handling any semicon
ductor components or assemblies, drain the
electrostatic charge from your body by
touching a known earth ground. Alternatively,
wear a discharging wrist-strap device. (Be
sure to remove it prior to applying powerÑ
this is an electric shock precaution.)
3. After removing an ESD-equipped assembly,
place it on a conductive surface such as
aluminum foil to prevent accumulation of
electrostatic charge.
4. Do not use freon-propelled chemicals. These
can generate electrical charges that damage
ESDs.
5. Use only a grounded-tip soldering iron when
soldering or unsoldering ESDs.
6. Use only an anti-static solder removal device.
Many solder removal devices are not rated as
Òanti-staticÓ; these can accumulate sufficient
electrical charge to damage ESDs.
7. Do not remove a replacement ESD from its
protective package until you are ready to
install it. Most replacement ESDs are
packaged with leads that are electrically
shorted together by conductive foam,
aluminum foil or other conductive materials.
8. Immediately before removing the protective
material from the leads of a replacement ESD,
touch the protective material to the chassis or
circuit assembly into which the device will be
installed.
9. Minimize body motions when handling
unpackaged replacement ESDs. Motions such
as brushing clothes together, or lifting a foot
from a carpeted floor can generate enough
static electricity to damage an ESD.
Precautions
1-4 Samsung Electronics
Specifications and IC Data
Samsung Electronics 2-1
2. Specifications and IC Data
2-1 Specifications
MODEL
VOLTAGE
POWER CONSUMPTION
POWER FREQUENCY
CHANNELS RECEIVED
CN-565BWZ
CN-566BWZ
CN-25D4WZ
CN-663AWZ
CN-29D4WZ
CN-7202WZ
CN-765DWZ
AC 100-240V (Argentina: AC 220V)
85 WATTS 110 WATTS 120 WATTS
50/60 Hz (Argentina: 50 Hz)
VHF: 2~13, UHF: 14~69, CATV: 1,14~125
MODEL
VOLTAGE
POWER CONSUMPTION
POWER FREQUENCY
CHANNELS RECEIVED
AC100-240V (Mexico: AC127V±10%)
CT-5072BWZ
CT-5072BPZ
85 WATTS
50/60Hz (Mexico: 60Hz)
VHF; 2~13, UHF; 14~69, CATV; 1,14~125
CT-565BZ / 566BWZ
CT-567BWZ / 568BPZ
CT-225BZ / 228BWZ
CT-22B6PZ
CT-25D4WZ
110 WATTS
CT-29D4WZ
120 WATTS
CT-765DWZ
CT-766DWZ
CT-30D6PZ
CT-30A9PZ
120 WATTS
AC120V
TXJ2048/2060
TXJ2066/2067
TXJ2754/2766
TXJ2767/2768
TXJ2879
85 WATTS
60Hz
VHF; 2~13, UHF; 14~69, CATV; 1,14~125
120 WATTS 130 WATTS
TXJ2554/2566
TXJ2567
110 WATTS
MODEL
VOLTAGE
POWER CONSUMPTION
POWER FREQUENCY
CHANNELS RECEIVED
Specifications and IC Data
2-2 Samsung Electronics
2-2 IC Line Up
Table 2 - 1 IC Line - Up
Loc No
SF101
SF102
IC201
IC202
IC301
IC603
IC701
IC801
IC802
IC901
IC902
ICD01
Specification
M3951M
M9260M
TDA8377
TDA8373
TDA8375
LA7510
LA7845
TDA7056B
TDA7266S
TDA7449
KA3S1265R
KA7630
SZM368ET
XL24C08P
CXA2104S
Remarks
CT566BV/CT567BW/CT568BW/CT766DW
CT633BW/CT683BW
CN565BW/CN25D4W/CN663A/CN765DW
1.5W x 2 (MONO)
3W x 2 (MONO)
STEREO MODEL
CT633BW/CT683BW/CT766DW
CT566BV/CT566BW/CT567BW/CT568BW
STEREO MODEL ONLY
Description
SAW FILTER (VIF)
SAW FILTER (SIF)
ONECHIP TV PROCESSOR
ONECHIP TV PROCESSOR
ONECHIP TV PROCESSOR
AUDIO IF AMP/4.5M DETECT
VERTICAL AMP IC
SOUND AMP IC
VOLUME CONTROL IC
POWER IC
MULTI REGULATOR IC
MICOM
EEPROM
MTS IC
No
1
2
3
4
5
6
7
8
9
10
11
12
Specifications and IC Data
Samsung Electronics 2-3
2-3 Semiconductor Base Diagrams
ELECTROLYTICCONDENSER
IC
DIODE
XLS24C08P (PIN 8)
TDA8377 (PIN 56)
IC
TRANSISTOR TRANSISTOR
LA7845
KA7812
KA7809
IN
G
out
C2331-Y
KSR1010
TRANSISTOR
TRANSISTOR
KSC2073
KSA940
2SD1887
2SD1880
KSD5072
KSD5703
B
C
E
E B C
KSC815Y
KSA539-Y
M3951M
M9260M
SAW-FILTER
1
E C B
Fig. 2-1 Semiconductor Base Diagrams
Specifications and IC Data
2-4 Samsung Electronics
2-4 One Chip TV-processor
Fig. 2-2 SDIL56
CVBS : Composite Video Blanking Signal
26
27
28
17
18
19
20
21
22
23
24
25
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
SOUND IF INPUT
EXT AUDIO INPUT
VCO REF FILTER
VCO REF FILTER
PLL LOOP FILTER
IF VIDEO OUTPUT
BUSINPUT : SCL
BUSINPUT : SDA
BANDGAP DECOUPLING
CHROMA INPUT
Y/CVBS INPUT
MAIN POSITIVE SUPPLY
INT CVBS INPUT
GROUND
AUDIO OUT
DECOUPLING FILTER TUNING
EXT CVBS INPUT
BLACK CURRENT INP
BLUE OUTPUT
GREEN OUTPUT
RED OUTPUT
V-GUARD INP/BEAM CUR LIMITER
RED INPUT
GREEN INPUT
BLUE INPUT
PIP/OSD RGB INSERTION SWITCH INP
LUMINANCE INPUT
LUMINANCE OUTPUT
DECOUPLING SOUND DEMODULATOR
AUDIO DEEMPHASSIS/MPX OUT
TUNER AGC OUTPUT
AGC DECOUPLING CAPACITOR
REREFERENCE CURRENT INPUT
VERT, SAWTOOTH CAPACITOR
EHT/OVERVOLTAGE PROTECTION INP
(X-RAY PROTECTION)
IF INPUT
IF INPUT
VERT. DRIVE NEG
VERT. DRIVE POS
EAST-WEST DRIVE
GROUND
PHI1 FILTER
PHI2 FILTER / FLASH PROT
SAND CASTLE OUTPUT/FLYBACK INP
HOR. OUTPUT
POSITIVE SUPPLY
LOOP FILTER BURST PHASE DET
X-TAL (PAL-N (4.43)/PAL-M (3.58))
X-TAL (3.58)
SECAM REF OUTPUT
(R-Y) INPUT
(B-Y) INPUT
(R-Y) OUTPUT
(B-Y) OUTPUT
CVBS OUTPUT
BLACK PEAK HOLD CAPACITOR
SDIL56
Alignment and Adjustments
Samsung Electronics 3-1
3. Alignment and Adjustments
3-1 Preadjustment
1. Since there are no VRs in the K51A chassis, all
adjustments after parts replacement must be
done in the Service Mode.
2. The Factory Mode adjustments are necessary
when either the EEPROM (IC902) or the CRT
is replaced.
3. Do not tamper with the Ò AdjustmentÓ screen
of the Factory Mode menu. This screen is
intended only for factory use.
4. WHEN EEPROM (IC902) IS REPLACED
(1) When IC902 is replaced, all adjustment data
revert to their initial values. It is necessary to
re-program this data.
(2) After IC902 is replaced, warm up the TV for
10 seconds.
Make the following adjustments AFTER
setting up purity and convergence:
White Balance
Sub-Brightness
Vertical Center
Vertical Size
Horizontal Size (No use in 21Ó and 25Ó
models)
3-2 Factory (“SERVICE”) Mode
1. The set must be in Factory (ÒServiceÓ) Mode.
Selection sequence:
STAND-BY ® MUTE ® 1 ®8 ® 2 ® POWER ON
2. The Ò FACTORY MODEÓ message will be displayed. The Factory Mode
has four components : Adjustment, MPX, PIP, Option Byte and Factory
Reset.
3. Access the Adjustment Mode by pressing the ÒVOLUMEÓ keys ( , )
The adjustment parameters are listed in the accompanying table.
Select them by pressing the CHANNEL keys (▲,▼).
4. After completing the Factory Mode adjustments, turn the power switch
OFF.
▼
▼
AGC 15
VCO 62
SBT 7
SCT 11
SCR 8
STT 8
RG 32
GG 32
BG 32
SCO 20
VSL 26
VS 32
VA 27
HS 46
EWA 52
EWP 31
EWC 32
EWT 31
MAT off
PLA 6
*FACTORY*
¯
Press VOL
Press CH
Press VOL or
SBT 3
POWER OFF
Adjustment
Mpx
Pattern
Option
Reset
▼
AGC 15
VCO 62
SBT 7
SCT 11
SCR 8
STT 8
RG 32
GG 32
BG 32
SCO 20
VSL 26
¯
▼
¯
¯
▼
▼
VS 32
VA 27
HS 46
EWA 52
EWP 31
EWC 32
EWT 31
MAT off
PLA 6
VSLN 30
VSN 32
VAN 32
HSN 45
EWAN 45
EWPN 33
EWCN 32
EWTN 38
*SERVICE*
¯
Press VOL
Press CH
Press VOL or
SBT 3
POWER OFF
Adjustment
MTS
PIP
Option
Reset
▼
AGC 15
VCO 62
SBT 7
SCT 11
SCR 8
STT 8
RG 32
GG 32
BG 32
SCO 20
PLA 5
¯
▼
¯
¯
▼
▼
VSLP 30
VSP 32
VAP 32
HSP 39
EWAP 46
EWPP 33
EWCP 32
EWPT 38
VSLN 30
VSN 32
VAN 32
HSN 45
EWAN 45
EWPN 33
EWCN 32
EWTN 38
AGC 15
VCO 62
SBT 7
SCT 11
SCR 8
STT 8
RG 32
GG 32
BG 32
SCO 20
PLA 5
VSLP 30
VSP 32
VAP 32
HSP 39
EWAP 46
EWPP 33
EWCP 32
EWPT 38
3-2-1 Adjustment
1. Selection sequence :
STAND-BY ® MUTE ® 1 ® 8 ® 2 ® POWER ON
2. Example : Sub-bright Adjustment
Alignment and Adjustments
3-2 Samsung Electronics
SZM368ET1 (R4027)
SZM368ET2 (R4127)
Alignment and Adjustments
Samsung Electronics 3-3
MEMORY SPECIFICATION
765DWZ
8
63
2
7
0
7
32
32
32
14
25
26
34
46
51
24
32
32
5
OFF
87
00
13
46
32
275
295
35
275
295
1.4
2.4V
Table 3 - 1 Memory Specification
FUNCTION
A
D
J
U
S
T
M
E
N
T
OP
M
P
X
MODE
(OSD)
AGC
VCO
SBT
SCT
SCR
STT
RG
GG
BG
SCO
VSL
VS
VA
HS
EWA
EWP
EWC
EWT
PLA
SEP
29D4WZ
8
63
2
7
0
4
32
32
32
14
26
32
29
48
33
34
32
32
0
OFF
95
00
13
46
32
275
295
40
275
295
1.4
2.4V
225BZ
8
63
2
7
0
4
20
20
20
14
24
32
36
46
47
4
32
32
6
OFF
82
00
OFF
OFF
OFF
275
295
45
275
295
1.4
2.4V
25D4WZ
8
63
2
7
0
4
32
32
32
14
23
32
27
41
32
36
32
32
0
OFF
85
00
13
46
32
268
275
40
277
283
1.4
2.4V
565BZ
8
63
2
7
0
4
20
20
20
14
24
32
36
46
47
4
32
32
6
OFF
82
00
OFF
OFF
OFF
275
295
45
275
295
1.4
2.4V
566BWZ
8
63
2
7
0
4
20
20
20
14
24
32
36
46
47
4
32
32
6
OFF
87
00
13
46
32
275
295
45
275
295
1.4
2.4V
228BWX
8
63
2
7
0
4
20
20
20
14
24
32
36
46
47
4
32
32
6
OFF
87
00
13
46
32
268
275
45
277
283
1.4
2.4V
RANGE
63
127
15
13
13
13
63
63
63
63
63
63
63
63
63
63
63
63
10
31
FF
FF
15
63
63
x
y
Y ± 5
x
y
Y ± 0.2
28B2
8
63
2
7
0
4
32
32
32
20
28
20
38
44
42
45
32
32
5
OFF
8F
03
13
46
32
275
295
33
275
295
1.4
2.4V
No
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
BYTE 0
BYTE 1
ATT
SPECTRAL
WIDEBAND
HIGH - LIGHT
LOW - LIGHT
WHITE
BALANCE
ADJUSTMENT
MEASURING PULS ADJUSTMENT VOLTAGE
VIDEO MUTE
AUDIO MUTE
NO ATS
NO V - CHIP
NO VIDEO MUTE
NO AUDIO MUTE
ATS
V-CHIP
USA
PAL M/N
Alignment and Adjustments
3-4 Samsung Electronics
3-2-2 Option Table
NOTE : The Option Adjustment must be done in the Service Mode.
3-2-2 (A) OPTION BYTE 00
Table 3-2 Option Byte 00
NAME
V-SYNC
AUTO ON
PIP
CATV
S-VIDEO
TONE
CRT
MPX
NOT USED
NOT USED
NO PIP FUNCTION
AIR/STD/HRC/IRC
NOT USED
NO TONE CONTROL
4 : 3 CRT
NOT USED
USED ( NO V-SYNC, POWER OFF)
USED
PIP FUNCTION
AIR/STD/HRC/AFN
USED
TONE CONTROL
12.8 : 9 CRT
USED
REMARK
ARMY : 1
3-2-2 (B) OPTION BYTE 01
BYTE : 00
D7
D6
D5
D4
D3
D2
D1
D0
FUNCTION
01
Table 3-3 Option Byte 01
NAME
AREA
LANGUAGE
NO VIDEO MUTE
NO AUDIO MUTE
ATS
V-CHIP
REMARK
SYSTEM/LANGUAGE
PAL
PAL
NT
NT
BYTE : 01
D7
D6
D5
D4
D3
D2
D1
D0
FUNCTION
01
00 : ENGLISH
01 : SPANISH (SEDA)
02 : PORTUGUESE
11 : NOT USED
Alignment and Adjustments
Samsung Electronics 3-5
3-2-4 Factory Reset
When Ò Factory ResetÓ is selected, the User-Control data reverts to the initial values.
The User-Control data is available at MENU (picture, sound and the other functions).
Note : When Ò Factory ResetÓ is selected, the Factory Mode Data does not change.
Selection sequence :
Stand-By ® MUTE ® 1 ® 8 ® 2 ® POWER ON
* FACTORY *
Press VOL
Execute
Press CH
¯
▼
¯
▼
¯
Adjustment
Mpx
Pattern
Option
Reset
Adjustment
Mpx
Pattern
Option
Reset
* SERVICE *
Press VOL
Execute
Press CH
¯
▼
¯
▼
¯
Adjustment
MTS
PIP
Option
Reset
Adjustment
MTS
PIP
Option
Reset
3-3 Other Adjustments
3-3-1 General
1. Usually, a color TV needs only slight touch-up
adjustment upon installation. Check the basic
characteristics such as height, horizontal and
vertical sync and focus.
2. Observe the picture for good black and white
details. There should be no objectionable
color shading. If color shading is present,
perform the purity and convergence
adjustments described below.
3. Use the specified test equipment or its
equivalent.
4. Correct impedance matching is essential.
5. Avoid overload. Excessive signal from a
sweep generator might overload the front-end
of the TV. When inserting signal markers, do
not allow the marker generator to distort test
results.
6. Connect the TV only to an AC power source
with voltage and frequency as specified on the
backcover nameplate.
7. Do not attempt to connect or disconnect any
wires while the TV is turned on. Make sure
that the power cord is disconnected before
replacing any parts.
8. To protect against shock hazard, use an
isolation transformer.
SZM368ET1 (R4027)
SZM368ET2 (R4127)
Alignment and Adjustments
3-6 Samsung Electronics
3-3-2 Automatic Degaussing
A degaussing coil is mounted around the
picture tube, so external degaussing after
moving the TV should be unnecessary.
However, the receiver must be properly
degaussed upon installation.
The degaussing coil operates for about 1
second after the power is switched ON. If the
set has been moved or turned in a different
direction, disconnect its AC power for at least
10 Minutes.
If the chassis or parts of the cabinet become
magnetized, poor color purity will result. If
this happens, use an external degaussing coil.
Slowly move the degaussing coil around the
faceplate of the picture tube and the sides and
front of the receiver. Slowly withdraw the coil
to a distance of about 6 feet before removing
power.
3-3-3 High Voltage Check
CAUTION : There is no high voltage
adjustment on this chassis. The B+ power
supply must be set to either +135V or +125V
(for 20Ó screen). Conditions : Full color bar
input and normal picture level.
1. Connect a digital voltmeter to the second
anode of the picture tube.
2. Turn on the TV. Set the Brightness and
Contrast controls to minimum (zero beam
current).
3. The high voltage must not exceed 29.5KV.
4. Adjust the Brightness and Contrast controls to
both extremes. Ensure that the high voltage
does not exceed 29.5KV under any conditions.
3-3-4 FOCUS Adjustment
1. Input a black and white signal.
2. Adjust the tuning control for the clearest
picture.
3. Adjust the FOCUS control for well defined
scanning lines in the center area of the screen.
3-3-5 B+Line Check
There are 3 power modes :
1. ÒAÓ : When AC power supply is connected ;
Ò Stand-ByÓ mode.
2. ÒBÓ : When Ò Set Power-ONÓ button is
pressed.
3. ÒCÓ : Driven by FBT.
Each voltage is marked on its lead-in wire.
( )
3-3-6 F/S (Fail Safe) Circuit Check
1. The failsafe circuit check is the final step after
servicing.
2. Turn the power switch on and adjust the
screen for ÒNormalÓ.
3. Temporarily short Pin R and Pin X on the
chassis (RX05, RX04). Sound and picture will
disappear.
4. The TV should remain in this state. This
shows that the failsafe circuit is working
properly.
5. To restore picture and sound, temporarily turn
off the AC power supply. After about 30
seconds, switch power ON.
21”±1
27.5KV
25”
29.5KV
29”
29.5KV
29”± 1
29.5KV
SIZE
MAX
H-VOLTAGE
Alignment and Adjustments
Samsung Electronics 3-7
3-3-7 Color Purity Adjustment
1. Warm up the receiver. Operate it for 20
minutes, with the Brightness control set to
maximum.
2. Fully degauss the receiver. Use an external
degaussing coil.
3. Roughly adjust convergence by rotating the
Convergence Magnet.
4. Input a black and white signal.
5. Loosen the Deflection Yoke clamp screw, and
move the Deflection Yoke as close to the
purity magnet as possible.
6. Loosen the Purity Magnet clamp. Adjust the
purity magnet so that the vertical green raster
is precisely at the center of the screen. Then
tighten the clamp.
7. Slowly move the Deflection Yoke forward, and
adjust it for the best overall green screen.
8. Tighten the Deflection Yoke clamp screw.
Fig. 3-1 Tube Assembly
RUBBER WEDGES
30
30
LOCATION
DEFLECTION
YOKE
30
RUBBER WEDGE
ADHESIVE
RUBBER
WEDGES
KIT
RUBBER
WEDGES
PURITY AND
CONVERGENCE
MAGNET ASS'Y
CRT
DEFLECTION
YOKE
TAPE
CLOTH
GRASS
(1-3/16")
31 mm
Fig. 3-2 Purity and Convergence Magnets
2 POLE
PURITY
YOKE
CLAMP
SCREW
6 POLE
CONVERGENCE
4 POLE
CONVERGENCE
ADJUST THE ANGLE
(VERTICAL LINES)
FIXED
ROTATE TWO TABS
AT THE SAME TIME
(HORIZONTAL LINES)
Alignment and Adjustments
3-8 Samsung Electronics
3-3-8 Center Convergence Adjustment
Note: Before attempting any convergence
adjustment, make sure that the receiver has
been powered ON for at least twenty minutes.
1. Input a crosshatch pattern from a color bar
generator.
2. Adjust the Brightness and Contrast controls
for a well defined pattern.
3. Adjust the two tabs of the 5-pole magnets.
Change the angle between the tabs, and
superimpose red and blue vertical lines in the
center area of the picture screen.
4. Next, turn both tabs at the same time. Keep
the angle between the tabs constant, and
superimpose the red and blue horizontal lines
at the center of the screen.
5. Adjust the two tabs of the 6-pole magnets.
Superimpose the red/blue lines on the green.
Adjusting the angle affects the horizontal
lines.
6. Repeat adjustments 3, 4 and 5. The dot
movement is complex because the 4-pole and
6-pole magnets interact.
Fig. 3-3 Center Convergence Adjustment
RED
BLUE
BLUE
RED
4-Pole Magnet Movement
GREEN
RED/BLUE
RED/BLUE
GREEN
6-Pole Magnet Movement
3-3-9 AGC Adjustment
1. Input a COLOR-BAR pattern. (CH2)
2. Set the RF input signal to 70 dBmV.
3. Use Generator for PM5518 & PM5418.
4. Set AGC (in the Factory Mode) so that the DC level of IC TDA8377
Pin 53 is 3.0±0.05V.
3-3-10 AFT (VCO Adjustment)
1. Input an AGC adjustment signal.
2. Select Factory Mode VCO and press the MUTE key one time.
3. GEOMATRIX adjustments
VS EWA
VA EWP
VSL EWC
HS EWT
Alignment and Adjustments
Samsung Electronics 3-9
3-3-11 White Balance Adjustment
3-3-11 (A) SCREEN ADJUSTMENTS
1. Input a TOSHIBA pattern.
2. Check R506 ÒGÓ pin on the CRT PCB with an
oscilloscope.
3. Enter the Horizontal Line Mode.
4. Adjust the Screen Control on the FBT so that
the waveform of the 21st line is DC 2.0
(±0.5)V.
3-3-11 (B) HIGH-LIGHT ADJUSTMENT
1. NOTE : If a color analyzer is not available,
then approximate the following color
adjustments Òby eyeÓ.
2. Input a TOSHIBA pattern.
3. Set high-light to 290/300 (X,Y) with a color
analyzer.
4. Set low-light to 1.4F/L.
5. Adjust RG, BG and set GG to step 32.
3-3-11 (C) SUB-CONTRAST ADJUSTMENT
1. Set SCT so that the brightness level in highlight is 40 F/L (for a 29Ó SCREEN).
3-3-11 (D) SUB-BRIGHTNESS ADJUSTMENT
1. Input a TOSHIBA pattern.
2. Set SBT so that the brightness level in lowlight is 1.4 F/L.
3-3-11 (E) SUB-COLOR ADJUSTMENT
Set ÒSCRÓ in the Service Mode to step 0.
3-3-11 (F) SUB-TINT ADJUSTMENT
Set ÒSTTÓ in the Service Mode to step 4.
3-3-11 (G) VERTICAL SIZE ADJUSTMENT
1. Input a lion head pattern.
2. Set VS to 32 in the Factory Mode.
3. Set VA so that the top margin is 4.0. Adjust SL
so that the bottom margin is 4.0. If the top
and bottom margins are different, adjust VA so
that their sum is 8.0.
3-3-11 (H) HORIZONTAL SHIFT ADJUSTMENT
1. Input a lion head pattern.
2. Adjust ÒHSÓ in the Service Mode so that the
left and right margins of the lion head pattern
are 5.0 ± 0.5 : CT633BW/CT683BW, 6.3 ± 0.5 :
CT566BV/CT566BW/CT568BW/CT765DW/
CT766DW/CT762B/CT25D4/CT29D4.
SIZE
DC
29”
2.4
26”
2.4
22”
2.4
HEIGHT
LIGHT
30”
33 ± 5
29”
37 ± 5
26”
45 ± 5
22”
45 ± 5
<TOSHIBA PATTERN>
High-Light
Low-Light
For the power system of K51A chassis, all
output voltages remain the same during
stand-by. So, to reduce power consumption, it
is necessary to cut the leakage current flowing
through FBT B+(130V) and tuner port VT(33V)
during stand-by (Picture OFF).
The power consumption reduction circuit cuts
leakage current. A P-channel MOSFET is used
as a switching element.
The operating principles are as follows:
1. In stand-by, the voltage of the power control
port (micom IC) becomes low (0V). During
power ON, however, it becomes high (over
4V).
2. The voltage between S-G (Q801 P-channel
MOSFET) should be over 3.5V, so that the S-D
current (Q801) can keep flowing.
3. When the voltage of the power control port
becomes low, the current flowing through
Q903 (R812) is cut.
4. When the voltages across R803 become less
than 3.5V, the S-D current (Q801) is cut.
5. DZ809 is required for protecting the G-port
(Q801).
3-3-13 Precautions when servicing
1. Q801 can sustain a continuous flow of 11ADC.
If Q801 is destroyed, the S-D is shorted.
But, the TV functions normally and only the
power consumption during stand-by increases
(2.5W® 6W).
2. No Picture ON : Q903 is open or DZ809 is
shorted. At this time, check both Q903 and
DZ809. If the power-consumption reduction
circuit does not work normally after checking
both Q903 and DZ809, then short the S-D
ports of Q801.
Alignment and Adjustments
3-10 Samsung Electronics
3-3-12 Power Consumption Reduction
Circuit during Stand-by (Option)
OmA
R801
FBT B
+
OmA
TUNER 33V
OmA
Q903
130 RECTIFIED
DZ809
Q801
SFP9640
R812
R910
10K
POWER
CONTROL
4. Troubleshooting
4-1 No Raster and No Sound
Troubleshooting
Samsung Electronics 4-1
Measure the B
+
Voltage at the Cathode
of D812 (D811)
No Raster and No Sound
Normal
Less than 50V
More than 130V
Check/Replace
IC801 Q801
Check the horiz
output signal at TR
collector.
Measure the B+
voltage at the cathode
of D812*
No Voltage
More than 130V
Normal
Normal
Check/Replace F801
Abnormal
Check/Replace AVR
Circuit, Horiz Output
Circuit and B+
Voltage Line.
Check +12.5 Line
Check/Replace FS
circuit
Check/Replace
AVR circuit
(ADJ Pin of STR)
Check/Replace
the AVR circuit.
Open
Check/Replace
1) D801
2) Short the
Degaussing Coil
3) C801
Check/Replace
the power switch
Normal
4-2 No Raster (Sound OK)
Troubleshooting
4-2 Samsung Electronics
Check
that CRT Heater
is Lighting
No Raster (Sound Ok)
Check H.V of CRT
Yes
Abnormal
No
Check/Replace
FBT
Check/Replace
IC201
Normal
Check I
2
C Data
Normal
Abnormal
Check CRT
Drive Circuit
Check Heater plus
Abnormal
Check/Replace
FBT
Normal
Check/Replace
CRT Drive Circuit
Troubleshooting
Samsung Electronics 4-3
4-3 No Vert Scan (Horizontal Line)
Check D812 (D811)
In the Factory Mode, select
" V-sync Not Used"
(See " Option Byte Table 3-2")
Abnormal
Power OFF
(after 10 ~ 15 seconds)
Normal
Check IC301
Pin ,
2
4
Normal
Check/Replace
IC301
Check/Replace
IC201
Check T444
Pin , ,
R410, R409
6
8
Check/Replace
FBT
Abnormal
Check IC201
Pin ,
46
47
Abnormal
Abnormal
Troubleshooting
4-4 Samsung Electronics
4-4 No Sound
Check IC701
Pin ,
Check IC603
Pin , , ,
No Sound
Normal
Normal
Check/Replace
IC603
Check/Replace
IC701 Pin ,
Normal
1
2
Check
Speaker
Abnormal
Abnormal
Check IC603
Pin
12
6
9
Check ICD01
Pin ,
Check/Replace
IC701
Normal
1
2
Check ICD01
Pin
Abnormal
11
Check ICD01
Pin , ,
Check/Replace
ICD01
Abnormal
4
14
15
19
20
3
16
Troubleshooting
Samsung Electronics 4-5
4-5 No Color
Check ICP01
OSD " PAL-M" or
"PAL-N" or " NTSC"
appear?
Push "Display" Button
on the Remocon
It's not normal
signal
Abnormal
Check IC901
,
No
Check QL01, QL02
XL01, XL02 and X202
Check/Replace
IC201
Normal
8
16
No Color
Check B+ (5V),
Replace ICH01
Normal
Check/Replace
that part
Abnormal
Yes
4-6 Samsung Electronics
MEMO
5-1 CT25D4WZX/GSU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
5-2 CT29D4WZX/GSU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Exploded Views & Parts List
Samsung Electronics 5-1
5. Exploded Views & Parts List
Exploded Views & Parts List
5-2 Samsung Electronics
5-1 CT25D4WZX/GSU
Exploded Views & Parts List
Samsung Electronics 5-3
1 AA64-31269T CABINET-FRONT -,25D4,DG703P EGH,HIPS,HB,BLK,-,- 1
1-1 AA64-70117D BADGE-BRAND AL,SS,GOLD,L65,R2000,-,- 1
1-2 AA64-10782A KNOB-POWER -,254,294,299D,-,ABS,HB,G3676 1
1-3 AA61-60003J SPRING-CS -,SUS304,0.5,OD6,H12,N7,-,-,- 1
1-4 AA65-30105A CLAMP-WIRE NYLON 66,V2,NTR,15MM,ALL MODEL 1
1-5 AA61-40113A STOPPER-PCB 501H,HIPS,NTR,HB,-,- 1
1-6 3001-001071 SPEAKER 5W,8ohm,90dB,180Hz 2
1-7 6003-001026 SCREW-TAPTITE RH,+,B,M4,L15,ZPC(BLK),SWR 4 SPK+CF
1-8 AA64-10783A KNOB-CONTROL -,254,294,294D,G3676,ABS,HB 1
1-9 6003-001026 SCREW-TAPTITE RH,+,B,M4,L15,ZPC(BLK),SWR 1 KC+CF
1-10 AA64-40506A INDICATOR-LED -,294,299D,-,ACRYL,HB,CLR, 1
1-11 AA64-40505B WINDOW-REMOCON -,29D4,-,PC,V0,VIOLET,- 1
1-12 6003-001026 SCREW-TAPTITE RH,+,B,M4,L15,ZPC(BLK),SWRCH18 1 WR+CF
2 AA03-10016M CRT-COLOR -,A59KPR84X01(D),-300mG,25,11 1
2-1 AA60-10050R SCREW-ASSY WC,HH,+,M5,L31.5,SWRCH18A,ZPC 4
2-2 AA65-30105A CLAMP-WIRE NYLON 66,V2,NTR,15MM,ALL MODE 2
3 AA64-31270E CABINET-BACK -,254D,-,HIPS,HB,BLK,-,- 1
3-1 AA60-10050T SCREW-TAPPING RH,+,2S,M4,L20,ZPC(BLK),SWRCH1 4 CB+CF
4 AA39-10006X POWER-CORD -,KKP419C,KLCE-2F,2.286MT,3P, 1
No. Code No. Description Specification Q’ty Remark
Exploded Views & Parts List
5-4 Samsung Electronics
5-5-2 CT29D4WZX/GSU
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