BBK LT1902S User manual

2009/10/13 - 1 -
Service Manual
(1906 2206)
HDMI
MST719

2009/10/13 - 2 -
Contents
1. Precautions and Safety Notices…………………………………………………………3
2. Specification…………………………………………………………………………………5
3. Function Control Description…………………………………………………………….10
4. Circuit Description…………………………………………………………………………11
5. Adjusting Procedure………………………………………………………………………17
6. Trouble Shooting Flow Chart……………………………............................................23
7. Block Diagrams…………………………………………………………………………….26

Prior to using this service manual, please ensure that you have carefully followed all the
procedures outlined in the user’s manual for this product.
(1) Read all of these instructions.
(2) Save these instructions.
(3) Follow all warnings and instructions a marked on the product.
(4) Unplug this product from the wall outlet before cleaning. Do not use liquid cleaners or
aerosol cleaners, use a damp cloth for cleaning.
(5) Do not use this product near water.
(6) Do not place this product on an unstable cart, stand or table. The product may fall, causing
serious damage to the product.
(7) Slots and openings in the cabinet and the back or bottom are provided for ventilation, to
ensure reliable operation of the product and to protect it from overheating, those openings
must not be blocked or covered. The openings should never be blocked by placing the
product on a bed, sofa, rug, or other similar surface. This product should not be placed in a
built-in installation less proper ventilation is provided.
(8) These products should be operated from the type of power source indicated on the
marketing label. If you are not sure of the type of power available, consult your dealer or
local power company.
(9) This product is equipped with a 3-wire grounding type plug, a plug having a third (grounding)
pin. This plug will only fit into a grounding-type power outlet. This is a safety feature, if you
are unable to insert the plug into the outlet, contact your electrician to replace your obsolete
outlet. Do not defeat the purpose of the grounding-type plug.
(10) Do not allow anything to rest on the power cord. Do not locate this product where persons
will walk on the cord.
(11) If an extension cord is used with this product, make sure that the total of the ampere
ratings on the product plugged into the extension cord to the waplugged into outlet does not
exceed 15 ampere.
(12) Never push objects of any kind into this product through cabinet slots as they may touch
dangerous voltage points or short out parts that could result in a risk of fire or electric shock.
Never spill liquid of any kind on the product.
(13) Do not attempt to service this product yourself, as opening or removing covers may
expose you to dangerous voltage points or other risks. Refer all servicing to service
personnel.
(14) Unplug this product from the wall outlet and refer servicing to qualified service personnel
under the following conditions:
a. When the power cord or plug is damaged or frayed.
b. If liquid has been spilled into the product.
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1. Precautions and Safety Notices

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c. If the product has been exposed to rain or water.
d. If the product does not operate normally, when the operating instructions are followed.
Adjust only those controls that are covered by the operating instructions since improper
adjustment of other controls may result in damage and will often require extension
work by a qualified technician to restore the product to normal operation.
e. If the product has been dropped or the cabinet has been damaged.
f. If the product exhibits a distinct change in performance, indicating a need for service.

2.Specification
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Model No. 19” 22”
Display Pixel 1440 (H) x 900(V) 1680 (H) x 1050(V)
Pixel Pitch 0.285mm (H) x0.285mm (V) 0.282mm (H) x0.282mm (V)
Active Display Area 410.4 (H) x 256.5 (V) 473.76 (H) x 296.1(V)
Pixel Type R+G+B vertical stripe R+G+B vertical stripe
Number of Colors 16.2M 16.7M
View Angle ±85°degree(H), ±80°degree (V)
Typical
±85°degree(H), ±80°degree (V)
Typical
Brightness 300cd/m2 typical 300cd/m2 typical
Contrast Ratio 850:1 typical at CR 10≧700:1 typical at CR 10≧
Brightness Uniformity 75% min. 75% min.
Power Source 100-240V~,50/60Hz,50W 100-240V~,50/60Hz,50W
Power Consumption ＜42W Max with speaker
Standby: ＜1.5W
＜50W Max with speaker
Standby: ＜1.5W
Sound Output 3W ×2 8Ω3W ×2 8Ω
AV/TV Source
Connector types
Inputs &
Outputs
Signals Video Format Video Sound
ANT Main-TV PAL/SECAM PH Type None
VIDEO Video + L/R Audio CVBS RCA x 1 RCA x 2
S-VIDEO S-VIDEO+ L/R Audio Y/C Mini Din 4 Pin RCA x 2
VGA VGA+ L/R Earphone Analog RGB VGA15 Pin Earphone
HDMI HDMI Digital RGB 19 Pin
SCART CVBS/RGB ,Video IN/OUT,
Audio IN/OUT
PAL,NTSC,SECA
M
SCART
connector

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Graphic and Video signal
Output Source
Speaker Out The Speaker Out Output Jack Shall Consist of
1. 3.5mm Mini-stereo ×1
Analog HD15 PC Signal (RGB)
Format R, G, B Analog
Level/Impedance 0.7Vp-p / 75
DDC 1/2B Compliant with Revision 1.3
Sync H/V separate
3V TTL level / 1k
Frequency Fh﹦31～80kHz
Fv﹦56～76Hz
Maximum Pixel Clock 135MHz
Connector Mini VGA 15pin (female) ×1
Video (Composite) CVBS Signal
Format PAL,NTSC,SECAM
Level / Impedance 1.0Vp-p / 75
S-Video (Y/C) Signal
Formal Y, C
Level / Impedance Y: 1.0Vp-p / 75
C: ±286mV / 75
RGB PC Timing
STANDARD RESOLUTION V FREQ
Hz
H FREQ
Hz
CLK
MHz
VESA 640×400 85.081 37.861 31.500
VESA 720×400 85.081 37.861 35.500
VGA 640×480 59.941 31.469 25.175
SVGA 800×600 56.250 35.156 36.000
SVGA 800×600 60.317 37.879 40.000
XGA 1024×768 60.004 48.363 65.000
SXGA 1280×1024 60.020 63.981 108.000
Video & S-Video AV Timing
STANDARD RESOLUTION V FREQ
Hz
H FREQ
KHz
CLK
MHz
NTSC 525 60 15.734 12.65
PAL 625 50 15.625 14.50
HDTV/Component AV Timing
STANDARD STANDARD STANDARD STANDARD STANDARD
SDTV 576i SDTV 576i SDTV 576i SDTV 576i SDTV 576i

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SDTV 576p SDTV 576p SDTV 576p SDTV 576p SDTV 576p
SDTV 480i SDTV 480i SDTV 480i SDTV 480i SDTV 480i
SDTV 480p SDTV 480p SDTV 480p SDTV 480p SDTV 480p
HDTV 720p HDTV 720p HDTV 720p HDTV 720p HDTV 720p
HDTV 720p HDTV 720p HDTV 720p HDTV 720p HDTV 720p
HDTV 1080i HDTV 1080i HDTV 1080i HDTV 1080i HDTV 1080i

Signal Connector Pin Assignment
HMDI connector is a type A receptacle for video/audio mode.
1.TMDS Data 2+ 9.TMDS Data 0- 17.CEC/GND
2.TMDS Data 2 shield 10.Clock + 18.+5V Power
3.TMDS Data 2- 11.Clock shield 19.Hot Plug Detect
4.TMDS Data 1+ 12.Clock -
5.TMDS Data 1 shield 13.CEC
6.TMDS Data 1- 14.NC
7.TMDS Data 0+ 15.DDC CLK
8.TMDS Data 0 shield 16.DDC Data
VGA connector
VGA connector pin assignment
1.Red 6.GND 11.ISP SDA
2.Green 7.GND 12.VGA SDA
3.Blue 8.GND 13.H-sync.
4.ISP SCL 9.+5V 14.V-sync.
5.GND 10. GND 15.VGA SCL
Mini DIN CNC 4 Pins (SCN570S3NS00000) for S-video, the pin assignment is described as below:
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1: Ground
2: Ground
3: Y
4: C

SCART connector
Pin No. Signal Inter Connection Pin No.
1 Audio right channel output (0.5 Vrms, < 1K ohms) 2
2 Audio right channel input (0.5 Vrms, > 10K ohms) 1
3 Audio left channel output (0.5 Vrms, < 1K ohms) 6
4 Audio ground 4
5 Blue signal ground 5
6 Audio left channel input (0.5 Vrms, > 10K ohms) 3
7 Blue signal I/O (0.7 Vp-p, 75 ohms) 7
8 Function switching I/O (L: < 2V, H: > 10V, 10K ohms) 8
9 Green signal ground 9
10 Intercommunication data line No. 1 10
11 Green signal I/O (0.7 Vp-p, 75 ohms) 11
12 Intercommunication data line No. 2 12
13 Red signal ground 13
14 Blanking signal ground 14
15 Red signal I/O (0.7 Vp-p, 75 ohms) 15
16 Blanking signal I/O (L: < 0.4V, H: >1.0V, 75 ohms) 16
17 Composite video signal ground 18
18 Blanking signal ground 17
19 Composite video signal output (1 Vp-p, 75 ohms, sync: negative) 20
20 Composite video signal input (1 Vp-p, 75 ohms, sync: negative) 19
21 Plug shield (common ground) 21
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3. Function Control Description
Operation, Adjust and Programming
1.POWER Button
Push this button to turn the unit on, and press it one more time to turn it off.
2.MENU Button
Press this key to pop up the OSD menu under the current selected input mode.
3.TV/AV Button
Press this key to select input sources.
4.CHANNEL (+, - ) Buttons
Press CHANNEL -or + to browse through the TV channels which are not
skipped.
Press CHANNEL -or + as up or down select keys to select the OSD menu item.
5.VOLUME (+ ,-) Buttons
Press VOLUME -or + to adjust the audio volume increase and decrease.
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Press VOLUME -or + as right or left select key to select the OSD main menu
item.

4. Circuit Description
(1) SMPS and Voltage Regulator circuit
The LCD TV power board should be designed so that AC power supply AC 100V to 240V and the
input frequency within 50/60Hz can be applied.
(2) Video Circuit
Video Decoder / De-interlace / Scaler MST719
The MST719 is a high performance and fully integrated IC for multi-function LCD monitor/TV
with resolutions up to SXGA(1280x1024)/WXGA+(1440x900). It is configured with an integrated
triple-ADC/PLL, a multi-standard TV video and audio decoder, a video de-interlacer, a scaling engine,
an on-screen display controller, an 8-bit MCU, and a built-in output panel interface. To further reduce
system costs, the MST719 also integrates intelligent power management control capability for
green-mode requirements and spread-spectrum support for EMI management.
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VGA
S-VIDEO
AV
TV
SCART
MST719 LVDS TO PANEL
ATV
HDMI

(3) Audio Circuit
Multiplexer 4052
DESCRIPTION
The UTC 4052 analog multiplexers is digitally controlled analog switch. The device feature low ON
impedance and very low OFF leakage current. Control of analog signals up to the complete supply
voltage range can be achieved.
FEATURES
*Triple Diode Protection on Control Inputs
*Switch Function is Break Before Make
*Supply Voltage Range=3.0 Vdc to 18 Vdc
*Analog Voltage Range(VDD-VEE)=3.0 to 18V
*Note:VEE must be≤Vss
*Linearized Transfer Characterisstics
*Low-noise-12nV/√Cycle ,f≥1.0kHz Typical
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2-channel multiplexer PI5V330
DESCRIPTION
Pericom Semiconductor's PI5V330 is a true bidirectional Quad 2-channel multiplexer/
demultiplexer recommended for both RGB and composite video switching applications. The
switch can bi driven from a current output RAMDAC or voltage output composite video source.
FEATURES
*High-performance solution to switch between video sources
*Wide bandwidth:200MHz
*Low On-Resistance:3Ω
*Ultra-low quiescent power(0.1µA typical)
*Single supply operation:+5.0V
*Fast switching:10ns
*High-current output:100mA
*Packaging(Pb-free & Green Available):
―16-pin 300-mil wide plastic SOIC(S)
―16-pin 150-mil wide plastic SOIC(W)
―16-pin 150-mil wide plastic QSOP(Q)
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Stereo D/A Converter CS4334
DESCRIPTION
The CS4334 family members are complete, stereo digital to analog out put systems including
interpolation, 1-bit D/A conversion and out put analog filtering in an 8-pin package. The CS4334
support all major audio data interface formats, and the individual devices differ only in the supported
interface format.
The CS4334 family is based on delta-sigma modulation, where the modulator output controls the
reference voltage input to an ultra-linear analog low-pass filter. This architecture allows for infinite
adjustment of sample rate between 2kHz and 100kHz simply by changing the master clock frequency.
FEATURES
*Complete stereo DAC system: Interpolation D/A, Output analog filtering.
*24bit Conversion.
*96dB dynamic range.
*-88dB THD+N
*Low clock jitter sensitivity.
*Filtered line level outputs
*On-Chip digital de-emphasis
*Popgaurd technology.
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Audio Processor MSP3415G
DESCRIPTION
The MSP 34×5G family of single-chip Multistandard Sound Processors covers the sound
Processing of all analog TV standards worldwide, as well as the NICAM digital sound standards. The
full TV sound processing, starting with analog sound IF signal-in, down to processed analog AF-out, is
performed in a single chip. Figure 1-1 shows a simplified functional block diagram of the MSP 34×5G.
FEATURES
*A2-Systems *JapanStereo
*NICAM-Systems *FM-SatelliteSound
* Very high deviation FM-Mono *FM-Stereo-Radio
*BTSC-Stereo *StandardSelection
*BTSC-Mono+SAP *AutomaticCarrierMute
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Block Diagram

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Audio Amp. TDA1517
Description
The TDA1517P is an integrated class-B dual output amplifier in a 18-lead dual in-line (DIP18)
plastic medium power package. The device is primarily developed for multi-media applications.
FEATURES
*Requires very few external components
*High output power
*Fixed gain
*Good ripple rejection
*Mute/stand-by switch
*Load dump protection
*AC and DC short-circuit-safe to ground and Vcc
*Thermally protected
*Reverse polarity safe
*Capability to handle high energy on outputs (Vcc=0V)
*No switch-on/switch-off plop
*Protected against electrostatic discharge

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5. Adjusting Procedure
ITEM
Program
Menu
Equipments
Requirement
s
Procedure & SPEC
1. M/B Voltage
confirmation
Digital
Multimeter
Connect with
AC Adapter
‧ Connect Power to check if Power LED displays the
RED light
‧ Use voltmeter to measure output position, and
check voltage CON1/Pin1-2(12V);
CON25/Pin1-2(5V)
‧ Please refer to appendix A if there is abnormal
phenomenon.
2. Manual
adjustment VGA
Auto adjustment
VG828
Pattern
Generator
‧ To select the SOURCE then choose VGA.
‧ Press MENU button and use the up/down button to
select the AUTO SYNC of SCREEN menu.(do
twice and confirm the complete action.)
3. Color Temp.
Adjustment
White-balance
calibrate
VG828
Chroma/7110
‧ Select SOURCE then choose VGA
‧ Enter the factory area
‧ Select Calibration
‧ Enter Color Temp. to User
‧ Enter User Color temp and adjust the R G B
offset/gain value
a. Natural
adjustment
Select Natural
Enter R.G.B
adjustment
screen
‧ Auto adjustment R.G.B value, make the color
temperature of the white screen to
b. Warm
adjustment
Select Warm
Enter R.G.B
adjustment
screen
‧
A
uto adjustment R.G.B value, make the color
temperature of the white screen to
c. Cool adjustment Select Cool
Enter R.G.B
adjustment
screen
‧
A
uto adjustment R.G.B number, make the color
temperature of the white screen to
4. VIDEO
adjustment
DVD
Video Cable
Play DVD
Set DVD to
interlaced
output
 Screen is clear and fluent
5.S-VIDEO
adjustment
DVD
S-Video
Play DVD
Set DVD to
 Screen is clear and fluent

Cable interlaced
output
6. TV
de-interlacing
FLUKE
54200
Or other
seem rate of
equipment
‧ To send out the TV signal by 54200
‧ To set up the Reduce of OSD to be Strong, and to
reduce snowflakes.
‧ To set up the Reduce of OSD to be OFF, and the
image will display serious snowflakes.
7. VGA PC
VGA Cable
PC Mode ‧ Each Mode can display normally. If there is a
specific Mode that is not appropriate after switch,
press Auto Adjust will to automatically adjust for
appropriate screen.
‧ Confirm PC can automated identify the model of
LCD
8. VGA TV BOX
VGA Cable
‧ Utilize external-connect TV BOX, watching the TV
program; the screen is clear and fluent.
9.
PICTURE/VIDEO
Brightness
adjustment
Contrast
adjustment
DVD
S-Video
Cable
Video Cable
or TV Signal
Generator
“FLUKE
54200” or the
same rank
and approved
equipment.
Play DVD test
disc VIDEO
ESSENTIAL(
A-1) Play
DVD
‧ Select the SOURCE to be or AV2
Set DVD to
interlaced
output Visual
examining
conditions as
follow:
1. Observing
distance
is about
35cm
2. Ambient
brightness
is about
150 LUX
3. Observing
angle: 90
degree
(measure
from the
central of
‧ Then press MENU Key to enter the adjustment
mode.
‧ Sending the signal from DVD test disc (second
paragraph).
‧ DVD PLUGE w_Gray Scale
‧ Adjust BRIGHTNESS to increase the value.
‧ Then see this line and adjust the default value to
be 50.
‧ Selects MENU to exit after finishing.
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‧ Screen changes evenly. (contrast: turn from min to
max).

the panel
as 90
degrees)
4. Ambient
temperatu
re: 25±5 C
5. Ambient
humidity:
65±20%
10. Display Mode
Test
PC
DVD
S-Video
Cable
Video Cable
TV Signal
HDMI Cable
HDTV
VGA
HDMI
‧ Select the source to be
TV,SCART,Video,S-Video,VGA,HDMI.
‧ Press MENU to select the Screen and Select the
Display Mode to be 16:9, 4:3, Zoom or
Anamorphic.
‧ Make sure the each of Display Mode is normal
work.
11.
PICTURE/VIDEO
TINT adjustment
COLOR
adjustment
DVD
S-Video
Cable
Video Cable
TV Signal
GENERTOR
FLUKE54200
or the same
rank and
approved
equipment.
Play DVD test
disc VIDEO
ESSENTIALS
(A-1)
Set DVD to
interlaced
output. Hue
(COLOR)
adjusts from
maximum to
minimum and
color present
variation
between
black and
white.
‧ Select source then choose VIDEO or S-VIDEO.
‧ Then press MENU Key to enter the adjustment
mode.
‧ Sending the signal from DVD test disc (fifth
paragraph)
‧ TINT_COLOR
‧
A
djust TINT value to meet the requirement, and
collocate blue attachment slice to see the color
identical from up to down. Default value is 50.
‧
A
djust COLOR value to meet the requirement and
collocate blue attachment slice to see the color
identical from up and down. Default value is 30 or
25. Select MENU to exit after finishing.
12.
PICTURE/VIDEO
3D COMB FILTER
DVD
S-Video
Cable
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Video Cable
Play DVD test
disc VIDEO
ESSENTIALS
(A-1)
Interlaced
‧ Select source then choose VIDEO or S-VIDEO.
‧ Sending the signal from DVD test disc (twelfth
paragraph)

output(NTSC
Mode)
‧
‧ Under S-VIDEO MODE, watch the movable circle
pattern is normal without tint. The pattern is normal
under 300 and 400.
‧ Under VIDEO MODE, watch the movable circle
patter, static state is normal without the tint, and
movement contains the tint (it is normal
phenomenon). Pattern is normal under 300 and
400, if set DVD to PAL, it will contain tint under
VIDEO MODE.
13. WINDOWS.
OVERSCAN(6%)
DVD
S-Video
Cable
Video Cable
Play DVD test
disc VIDEO
ESSENTIALS
(A-1)
Set DVD to
interlaced
output
‧ Select source then choose VIDEO or S-VIDEO.
‧ Sending the signal from DVD test disc (eighth
paragraph)
‧
‧ Watch the screen to check if sees the block screen
within SAFE ACTION.
14. WINDOWS
FREEZE Window
DVD
S-Video
Cable
Video Cable
Play DVD test
disc VIDEO
ESSENTIALS
(A-1)
Set DVD to
interlaced
output
‧ Select source then choose VIDEO or S-VIDEO.
‧ Sending the signal from DVD test disc (twelfth
paragraph)
‧
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‧ Select Freeze Windows function to ON and Check
if the screen is pause, then restoring the function to
Default value OFF.