BBK LT1902S, LT2202S Schematic
Service Manual
(1906 2206)
HDMI
MST719
2009/10/13 - 1 -
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
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1. Precautions and Safety Notices
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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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.
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2.Specification
Model No.
Display Pixel
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
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
Sound Output 3W ×2 8Ω 3W ×2 8Ω
±85°degree(H), ±80°degree (V)
＜42W Max with speaker
Standby: ＜1.5W
19”
1440 (H) x 900(V) 1680 (H) x 1050(V)
±85°degree(H), ±80°degree (V)
Typical
＜50W Max with speaker
Standby: ＜1.5W
22”
Typical
AV/TV Source
Inputs &
Signals Video Format
Outputs
ANT Main-TV
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/SECAM
PAL,NTSC,SECA
M
connector
Connector types
Video Sound
PH Type None
SCART
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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 A V 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
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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:
1: Ground
2: Ground
3: Y
4: C
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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.
Press VOLUME - or + as right or left select key to select the OSD main menu
item.
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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
HDMI
SCART
VGA
MST719
LVDS
TO PANEL
AV
S-VIDEO
ATV
TV
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.
2009/10/13 - 11 -
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