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Page 2
CHASSIS: TB1238
2
MODEL:
14RBS3WN
Page 3
3
CONTENT
TB 1238 SERIES I2C BUS CONTROL INSTRUCTION ....................................................................... 4
TYPICAL FAILURE ANALYSE............................................................................................................6
VARIOUS PARAMETERS OF INTEGRATED CIRCUIT.................................................................. 20
CIRCUIT DIAGRAM............................................................................................................................ 22
EXPLODED VIEW................................................................................................................................ 23
Model No: 14RBS3Wn
Version 1.0
Page 4
4
TB 1238 SERIES I2C BUS CONTROL INSTRUSTION
3. The way go into the factory mode
Step 1. Press the numeric keys, switch to the position 12
Step 2. Press the numeric keys again, switch to the position 38
Step 3. Press the MENU key to call up the POS.LOCK menu
Step4. Press the MUTE key
Step5. Press the numeric key to input the password 1, 2, 3, 8. Then the TV will enter into the
factory mode while the "M" displayed on the top of the screen.
4. Under adjusting mode, you can select the item you want by pressing the “ ” keys and you
can adjust the value of the items when you press the “ ” keys.
5. If the adjusting is default, please restore the data as previous or adjust according the table as
follows.
No Item Value Meaning No Item Value Meaning
1 RCUT 20* Red cut-off 35 VP 60 01 60Hz vertical center
2 GCUT 38* Green cut-off 36 HITS FD 50Hz/60Hz vertical size
3 BCUT 44* Blue cut-off 37 VLIN 0A Vertical linearity
4 GDRV 40* Green drive 38 VSC 06 Vertical S correction
5 BDRV 40* Blue drive 39 VLIS FF 50Hz/60Hz vertical linearity
6 CNTX 3F Contrast maximum 40 DPC 00 50Hz pillow distortion correction
7 BRTC 30 Brighter center 41 DPCS 00 50/60Hz pillow distortion
correction
8 COLC 50 Color center 42 KEY 00 50Hz keystone distortion
9 TNTC 40 Tint center 43 KEYS 00 50/60Hz keystone distortion
10 COLP 10 Color center of PAL 44 WID 00 50Hz horizontal size
11 COLS 40 Color center of
SECAM
12 SCNT 0F Sub-contrast 46 VCP 00 Vertical compensation
13 CNTC 20 Sub-contrast center 47 CNR 00 Coner correction
14 CNTN 08 Sub-contrast minimum 48 HCP 00 Horizontal compensation
15 BRTX 20 Sub-bright maximum 49 SBY 08 SECAM B-Y
16 BRTN 20 Sub-bright minimum 50 SRY 08 SECAM R-Y
17 COLX 7F Sub-color maximum 51 RAGC 16 R.F. AGC
18 COLN 00 Sub-color minimum 52 AFT 40* Auto frequency tune
19 TNTX 35 Sub-tint maximum 53 HAFC 00 AFC Gain
20 TNTN 28 Sub-tint minimum 54 V25 55 25 percent Volume
21 ST 3 3F TV-3.58 sharpness 55 V50 6F 50 percent Volume
22 SV 3 3F AV-3.58 sharpness 56 BRTS 00 Sub-bright
23 ST 4 20 TV-4.43 sharpness 57 VM 2 30 (CTS-763A)
24 SV 4 3F AV-4.43 sharpness 58 MOD0 21 Mode 0
26 SHPN 1A Sharpness minimum 60 MOD2 0C Mode 2
27 TXCX 36 OSD contrast
maximum
45 WIDS 00 50/60Hz horizontal size
06 For 14 and 21 inches Mode 1 25 SHPX 30 Sharpness maximum 59 MOD1
17 For 25 and 29 inches Mode 2
61 SELF
VCO
7G* Self-diagnosis VCO
Model No: 14RBS3Wn
Version 1.0
Page 5
No Item Value Meaning No Item Value Meaning
28 RGCN 16 OSD contrast
minimum
29 VMO 7C VCD data 0 63 SELF
30 VM 1 00 VCD data 1 64 SELF
31 HPOS 0B Horizontal position 65 SELF
32 VP 50 04 50 Hz vertical center 66 SELF
33 HIT 19 50 Hz vertical size 67 OSD 00 OSD width adjustment
34 HPS 02 50/60Hz horizontal
center
69 MOD3 07 Language 70 ZOOM
71 ZOOM
OUT
HIT
Note:
1. The items with * in value are very special, do not adjust them at random. The items(1-5) are
2. The general secret code is 2175.
3. If you find the threadlike disturbance on the top of picture, please adjust the VM 2 in the items
4. When E PROM does not work, please exchange the same model chip with data that the
0b Zoom out height
used to debug white-black-balance of set.
and make its value come to 34.
manufacture has already input. 2
62 SELF
AGC
BRTC
CNTC
TNTC
COL
68 OPT 27 Option
IN HIT
69* Self-diagnosis AGC
75* Self-diagnosis bright center
00* Self-diagnosis contrast center
32* Self-diagnosis tint center
23* Self-diagnosis color center
3F Zoom in height
5
Model No: 14RBS3Wn
Version 1.0
Page 6
6
TYPICAL FAILURE ANALYSE
1. Three-None (no raster, no picture, no sound)
This failure is mainly caused by big-power circuit such as power supply, horizontal scanning, vertical
scanning.
The detail checking and repairing steps are as follow.
Model No: 14RBS3Wn
Version 1.0
Page 7
Model No: 14RBS3Wn
Version 1.0
No
Check if V513 collect-emitter
was broken down
Check R502,F501, power
switch, AC cord and plug
Check V513,V512,F501,R502,VD503
300V
Test voltage of V513 base
0.6V
Check T501,VD517
C515,C517,VD552
VD553-VD555
V432,C435,C436
T401,C443,VD411
Voltage of C507
0V
Yes
0V
Check if it get right
when cut off V706
Yes
Test the voltage
of N701 Pin42
4.5-5.5V
CPU has sent the
power-off signal
0V
300V
Check the voltage
of V513 collector
Check T501
>1V
Check V513
0V
Check if V706
is broken down
Test the voltage of C461
<50V
Cut off W320
N0 variation
Test other voltage such
as 180V,24V and 12V
Low
V553,VD561,RP551
R569,V706,V512
C513,VD515,V511
0V
Check VD 551, C561
115V
Recover W320,unplug
XS 401 for a while,then
test the voltage of C561
No variation
Check V432,T401
T402,VE 601
Check L407, L408,
VE601,VD411,C443
115V
Normal
>130V
115V
N201 pin 8 voltage
9V
N201 pin32 voltage
2V
V431 pin C voltage
24V
Check R431,V431
Others
Check V432 pin C voltage
115V
Check T401,V432,R435 Check T401
Check R552,V553,VD561
VD515,V511,V512,R555
Others
Check Z203,C209,N201
0V
Check VD553,C563,R434
C434,T402,C432,V431,R550
0V
7
Page 8
2. Two-None (no picture, no sound)
The failure shows that the set does not display the picture but it has noise wave or blue background or
OSD on the screen. This means that the circuits of power supply, horizontal scanning, vertical scanning
and video amplification are normal and they are not considered in the repairing. The failures are mainly
in the small signal processing circuits.
Before checking these circuits, a kind of practical test method is introduced .It is called Signal-input
way .The detail is described as follow:
W e can use the resistance function of an analog multimeter, connect the red pole (negative in ohm
scope) on the circuit board ground, then touch softly the test point with another pole (black pole) in
ohm scope meanwhile observe the reactivity on the output device.
Note: In the TV test, we mainly observe the noise wave on the CRT and listen to the noise voice liking
as Ka....Ka from the loudspeakers.
a. No picture
8
Model No: 14RBS3Wn
Version 1.0
Page 9
Check RF signal input and adaptor
Check L103,N203,U101
Check R120,R121,R714
R715,N701,U101
Check R104,R204,C206,U101,N201
Check L206 ,C122, N101,C120, R258 ,R569
C554,VD554,N201,L209,L201,R218,VD205
Observe if there is snow-noise-wave disturbance on the CRT via using Signal-input way by touching pin 6 and pin8 of N201
Yes
Check if the voltage on pin28 of N201 is 4.6V
<2V
Check C244,C245,
N201,L205,R228
The voltage on pin4 of N201
The voltage on pin13 of N701
0V
Check R720,N701,R202
Model No: 14RBS3Wn
Version 1.0
Observe if there is snow-noise-wave disturbance on the CRT via using Signal-input way by touching pin 47 of N201
Observe if there is snow-noise-wave disturbance on the CRT via using Signal-input way by touching pin 35 of N201
Yes
2.38V
0V
Check N201
Observe if there is snow-noise-wave disturbance on the CRT via using Signal-input way by touching pin 39 of N201
0V
<2V
No picture
No
Check if U101 has input signal
Yes
Check the VT voltage when auto searching
In the 0-33V range
0V
Exam the voltage of AGC on U101 without antenna
0V
Test if there is the sync signal on the pin36 of N701
Check the MB voltage on U101
5V
The voltage between band1 and band2 vary
from 0V to 5V or not when auto searching
Yes
Yes
>3.8V
Test the voltage on pin 1,3,17,28,36 of N201
9V
Test the voltage on pin46 of N201
5V
No
No
No
No
No
Check R780,C715,N701,N201
Observe if there is snow-noise-wave disturbance on the CRT via using Signal-input way by touching pin 18-20 of N201
Check R206-R208,VD202-VD204,XS601,N201
Check R576,C573,VD573,UPC574
Out of the 0-33V range
The voltage on the C573
Check the voltage on the C704
Check R707,C103,U101
Check R706,R705,VD701,R704
R703,V701,R701,R702,N701
0V
Check N203,L203,N201
Check C211,R252-255,V804,V204,V202,N201
ZN01,LN01,RN03,RN02,R244,R240,R227
Yes
No
9
33V
=33V
0-33V
Yes
Check N203,L203,C239,N201
Yes
Check R222,R223,V201,C228,R229
No variation
Yes
Page 10
b. No sound
In this kind of failure, first of all we should observe if there is the picture on the CRT . It proves the
small signal circuit to work correctly with the picture on the CRT and we only check the sound signal
processing and sound amplification circuit. The repairing method (B1) may be referred without picture.
The detail checking and repairing steps are as follow.
Note:
Before repairing, assure that the volume is on and the state of set is in TV.
10
Model No: 14RBS3Wn
Version 1.0
Page 11
Check C251,ZN04,R245
Yes
Check R111,V102,R112,C201,N201
Ye s
Check C303,R352
R362,V303,C807
Yes
Hear if there is the voice liking Ka...ka in the loudspeaker via using Signal-input way by touching pin53 of N201
No
Hear if there is the voice liking Ka...ka in the loudspeaker via using Signal-input way by touching pin1 of N201
No
Hear if there is the voice liking Ka...ka in the loudspeaker via using Signal-input way by touching pin2 and pin5 of N801
No
Hear if there is the voice liking Ka...ka in the loudspeaker via using Signal-input way by touching pin4,pin15 of N801
No
Hear if there is the voice liking Ka...ka in the loudspeaker via using Signal-input way by touching pin1 and pin3 of N301
No
<5V
The voltage on pin 10 of N301
9V
Check R562,C565,VD555,N301
Hear if there is the voice liking Ka...ka in the loudspeaker via using Signal-input way by touching pin9 of N301
No
Check BL301,BL302,N301
Yes
Check C253,C250,C251,N201
Check 9V -power supply
Yes
<9V
The voltage on pin16 of N801
9V
The voltage on pin9-11 of N801
9V
Check V806,R750,R737
11
Model No: 14RBS3Wn
Version 1.0
Page 12
3. Only horizontal line in the middle of the screen
12
If vertical deflection circuit does not work, this kind of failure will happen. In deflection yoke, there
only has horizontal sweeping. The electron beam in the CRT only moves in the horizontal orientation
so form this failure.
(While checking horizontal and vertical deflection circuit s failure, we have better to use an
oscilloscope.)
Model No: 14RBS3Wn
Version 1.0
Page 13
Check N201,C216,C217,R260
Check R259,C403,N401
Check R402,L401,R406
R407,C409,XS401
Abnormal
Abnormal
Abnormal
The waveform on the pin24 of N201
Normal
0V
The voltage on pin3 of N401
24V
Measuring the waveform on pin4 of N401
Normal
Measuring the waveform on pin2 of N401
Normal
Measuring the waveform on the deflection yoke
Normal
The deflection yoke on the CRT
Check VD 401, N4 01
Abnormal
Check N401
13
Model No: 14RBS3Wn
Version 1.0
Page 14
4. Only vertical line in the middle of the screen
This is a dangerous failure. It probable causes flashover and smoking inside the set. Don t let your TV
work for a long time as this failure appears.
Because the electron beam can not move in the horizontal orientation, the failure should be in the
horizontal deflection circuit. We mainly check the open-circuit fault in horizontal deflection circuit.
The detail checking and repairing steps are as follow:
14
Model No: 14RBS3Wn
Version 1.0
Page 15
Check if there is bad solder between
XS401,and the main board
Check L407,L408,VD411,C443, especial in inductive components and connector
Yes
The horizontal yoke is opened or not
Whether XS401 is opened
Vertical line
Yes
Repair CRT
No
No
15
Model No: 14RBS3Wn
Version 1.0
Page 16
5. CPU does not work
In television, remote-control system is similar with the computer system. In theory, it can work if it
holds two conditions as follow:
1) The power supply: In general, it is 5V, the error is not above 10% and the disturbance
pulse is as small as possible.
2) The clock pulse: In TB 1238 circuit, the clock pulse is generated by pin31/ pin32 of
N701 and a 8M crystal oscillator.
Television s remote-control system also needs reset circuit that can preset the values in internal register.
The circuit around pin33 of N701 is called auto-reset circuit. If CPU detects errors in resetting, it will
come to the state of programme protected.
The detail checking and repairing steps are as follow:
16
Model No: 14RBS3Wn
Version 1.0
Page 17
Check Z701,N701
Check R753,VD704
No
4.98V
Check N701
4.98V
Check R741
<3.6V
N701 does not work
5V
The voltage on the pin42 of N701
Observe if there is sine wave on t he pin31
or pin32 of N701 with an oscilloscope
Yes
Check the voltage on the pin33 of N701
<4.98V
Check the voltage on the emitter of V705
<4.98V
Check the voltage on the positive pole of VD 704
=3.6V
Check R754, V705, R752
<5V
Check the voltage on the positive pole of C566
<7V
>5V
Check alternant voltage
on secondary coil of T502
<5V
Check T501
Check T501,VD556,C556
Check N705
17
Model No: 14RBS3Wn
Version 1.0
Page 18
6. No OSD (On Screen Display)
This failure is usually cause by the circuit of character generated and located. Most of reasons are that
the horizontal and vertical flyback pulse signals do not come to CPU.
We can judge this failure by measuring the wave of the character in an oscilloscope.
The detail checking and repairing steps are as follow:
18
Model No: 14RBS3Wn
Version 1.0
Page 19
Check N201
Check L701,N701
Yes
No
Check the horizontal and vertical flyback pulse on the pin26 and pin 27 of N701
Check FBT,N401
Observe if there is character wave on the pin14-17 of N201
Observe if there is character wave on the pin22-24 of N701
Observe if there is oscillating wave on the pin28-29 of N701
Check the wave on the base of V703,V704
No
Check the wave on the pin5 o f FBT
Check the wave on the pin7 of N401
Check C720,R766,R736,C711,R738,R739,C461,R410
No OSD
No
Yes
No
Check R727-R732,C707C709,C210-C212
Ye s
Yes
No
Check N701
Ye s
No
Check V703,V704, R747
R748,R740,R735
Yes
19
Model No: 14RBS3Wn
Version 1.0
Page 20
20
VARIOUS PARAMETERS OF INTEGRATED CIRCUIT
A. Pin voltage of N201
PIN 1 2 3 4 5 6 7 8 9
VOL. 4.9V 3.5V 4.1V 2.4V 0V 2V 2V 1.2V 4.2V
FUNC. DE
EMP A-OUT
PIN 10 11 12 13 14 15 16 17 18
VOL. 2.4V 3.8V 0V 0V 3V 3V 3V 9.1V 2.5V
FUNC. APC XCO Y/C
PIN 19 20 21 22 23 24 25 26 27
VOL. 2.4V 2.5V 6.1V 4.6V 5.3V 1V 1.8V 3.9V 4.1V
FUNC. G
OUT B OUT
PIN 28 29 30 31 32 33 34 35 36
VOL. 9.3V 3.8V 0.4V 4V 2V 0V 1.3V 5.3V 3V
FUNC. H
VCC
PIN 37 38 39 40 41 42 43 44 45
VOL. 2.5V 2.5V 3.1V 7.3V 1.6V 0V 3.2V 2.3V 2.8V
FUNC. B-Y
IN
PIN 46 47 48 49 50 51 52 53 54
VOL. 5.4V 3.8V 4.6V 0V 8.2V 8.2V 9.1V 4.7V 5.6V
FUNC. Y/C
VCC
PIN 55 56
VOL. 4.3V 3.5V
FUNC. EXT
A IN
Model No: 14RBS3Wn
Version 1.0
ID
CW
R-Y
IN
IF
DET
FM
DET
IF
VCC
GND
ABL V
FBP
IN
Y IN H AFC EXT
LOOP
FIL
AFT
GND
FB R IN G IN B IN RGB
RAMP
SYNC
OUT
VCD
GND
IF
GND
V FB V
H
OUT
Y IN
VC 01 Vc02 VCO
IF IN 1 IF IN 2 RF-
V AGC SCL SDA
OUT
DEF
GND
DIG
GND
SCP CVBS
TV Y
IN
VCC
AGC
VCC
OUT
BLA
CK
DET
SIF
IN
IF AGC
R OUT
DIG VCC
C IN
REG
Page 21
B. Pin voltage of N701
PIN 1 2 3 4 5 6 7 8 9
VOL. 0V 4.8V 5V 0V 3.8V 3.8V 0V 5V 5V
FUNC. GND VT RMT
OUT
PIN 10 11 12 13 14 15 16 17 18
VOL. 0V 5V 5V 2.4V 0V 4.8V 4.9V 0V 0V
FUNC. BAND2 SCL0 SDA0 AFC IN KARA
PIN 19 20 21 22 23 24 25 26 27
VOL. 0V 0V 0V 0V 0V 0V 0V 4.4V 4.8V
FUNC. SGV KARA
ENA
PIN 28 29 30 31 32 33 34 35 36
VOL. 5V 5V 0V 1.4V 2.2V 5V 0.6V 4.5V 4.8V
FUNC. OSC1 OSC2 TEST X IN X OUT RESET TV/AV REMOTE H SYNC
PIN 37 38 39 40 41 42
VOL. 3.8V 4V 0.2V 0.2V 0V 5V
FUNC. SCL1 SDA1 S
C. Pin voltage of N401 (TA8427)
PIN 1 2 3 4 5 6 7
VOL. 0V 14.1V 27.2V 0.93V 0.83V 26.8V 1.33V
FUNC. GND V OUT PUMP
Model No: 14RBS3Wn
Version 1.0
GND OSD R OSD G OSD B OSD Y HD VD
VIDEO
MUTE VOL1 VOL2 POWER LED BAND1
KEY IN 1 KEY IN 2 KARA
SW
IF 1 IF 1 VCC
POWER
INPUT PHASE
COMPEN.
POWER
SUPPLY
CLK
PULSE OUT
21
KARA
DATA
Page 22
Notice:
1. All resistance values are in ohms. k represents k . M represents M
. k =103 . M=10
6
2.The rated power of all resistance is 1/6W unless otherwise noted.
3. All capacitance values without unit are in pF . m represents mF, n represents nF ,m=106 ,n=103 .
4. The rated voltage of all capacitances is 50V unless otherwise noted.
5. Product safety should be considered when a component replacement is made in any area of a receiver.
The values of the components indicated by a mark in this circuit diagram have special
Significance to product safety . It is particularly recommended that only the parts specified in service
Manual be used for components replacement pointed out by the mark.
6. This circuit diagram covers a basic or representative chassis by only. The re may be some components
or partial circuit differences between the actual chassis and the circuit diagram.
CIRCUIT DIAGRAM
n
Model No: 14RBS3Wn
Version 1.0
22
Pin Voltage of N701(Unit:V)
Pin Voltage of N201(Unit:V)
Pin Voltage of N401(Unit:V)
Page 23
EXPLODED VIEW
Model No: 14RBS3Wn
Version 1.0
23
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