Service Manuals, User Guides, Schematic Diagrams or docs for : TOSHIBA LCD 20VL44 20vl44
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TOSHIBA
SERVICE MANUAL
COLOUR TELEVISION
20VL44
PRINTED IN UK. 2003 C
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CONTENTS PAGES
Safety instructions 1
Technical specifications 2
Panel Specification 3
Chassis block diagram 4
Scaler block diagram 5
Block diagram of power supply 6
Chassis overwiev 7
Service mode items and explanations 12
Data sheet of important IC's 17
Recommended Part List 29
Frequency list of channels 30
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SAFETY PRECAUTIONS
GENERAL GUIDELINES
1. Always use the manufacturer's replacement safety
components. The critical safety components marked 5 High temperature & high humidity
with on the schematics diagrams should not be reduce the life-time.
by other substitutes. Other substitute may create the LCD is not proper to be used at high temperature
electrical shock , fire or other hazards. Take and high humidity. Please keep specified
attention to replace the spacers with the originals. temperature and humidity condition.
Furthermore where a short circuit has occurred ,
replace those components that indicate evidence of 6- Keep out of Corrosive Gas.
overheating.
Corrosive gas effect the polarizer and the circuit
2. After servicing , see that all the protective devices chemically and cause defects accordingly.
such as insulation barriers, insulation papers, shields
and isolation R-C combinations are correctly 7 - Electrostatic discharge can make
installed.
Damage
3. When the receiver is not being used for a long time
of period of time , unplug the power cord of the There are electro-static sensitive components such
Adaptor from the AC outlet. as CMOS in LCD Module. Please earth human
body when handle the LCD.In addition, please do
not touch the interface connector pin with bare.
Color TFT LCD Module is very sensitive
both electrically and physically.Users,
therefore, are requested to follow the 8- Do not operate for a long time under
"Guidance of handling color TFT LCD the same pattern
Module"on the followings.
Operating LCD for a long time under the same
pattern can cause image persistence and can
1- Be careful not to make scratch on the damage it. Please follow following guidance.
polarizer. 1. Turn the power off when do not use.
Surface of polarizer is soft and can be physically 2. Change the pattern periodically.
damaged easily.
Please do not touch, push or rub polarizer surface
with materials over HB hardness.
2- Keep clean the surface.
Please wear rubber glove when touch the surface of
LCD screen. Please use soft and anti-static material
as cleaner.
3- Keep out of water.
Water on/in the LCD may cause electrical short or
corrosion. Please wipe out dry or water carefully.
4- Prevent swift Temperature &
Humidity change.
Instantaneous temperature and/or humidity change
can make dew or ice which cause nonconformance
such as malfunction.
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L5A TECHNICAL SPECIFICATION
Receiving System PAL B/G+I+D/K SECAM L/L'
Comb Filter Adaptive 4H\2H
Scaling Upto SXGA at 75Hz
Gamma Correction 8 to 10-bit LUT
Histogram Equalization YES
Stereo Decoding
German A2, Nicam
(German A2, Nicam, BTSC)
Stereo L, R In 3
Stereo L, R Out 3
Audio Output Power RMS in Max at 10% THD) 2x3W, 2x5W for 22"W
Level (1.5, 2.5, Teleweb) Teletext 1.5
Teletext Type (Fast\Top\Simple) Simple, Fast, Top
Page Memory 250p or 10p
WSS +
VPS\PDC +
4:3 +
16:9 +
Picture Formats
Panorama +
(4:3, 16:9, 14:9, Panorama, LetterBox, Subtitle)
Letterbox +
Subtitle +
WSS (Wide Screen Signalling) +
ATS (Automatic Tuning System) Frequency Search
Manual Search Channel Table Search
Number of Program Storage 100
No Ident Timer +
Picture Freeze +
Equalizer +
Zapping +
AVL (Automatic Volume Level) +
Sound Status Memory +
Picture Status Memory +
Swap +
Child Lock +
Program Lock +
Picture Format Switching Thru Pin 8 +
Auto RGB Detect Thru Pin 16 +
PC Plug & Play (DDC\CI) +
Off Timer (Sleep Timer) +
Timer
On Timer +
Picture Smart (User, Soft, Natural, Rich) +
Sound Smart (User, Music, Sports,
+
Cinema, Speech)
Scart 2
S-video (DIN) 1
AV In (3 RCA) 1
AV Out (3 RCA) 1 (ONLY L, R)
D-Sub 15 1
Headphone 1
CVBS In 3
Y\C In 1
RGB+FB -Video 1
RGB+HS, VS In -Graphics 1
CVBS Out 2
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PANEL SPECIFICATION
14" 15" 17" 17W" 20" 22W" 23W"
Samsung
Hannstar CMO
Manufacturer AUO Samsung Samsung Samsung
CMO AUO
AUO Sanyo
Double TTL\Single Single TTL\Single
Interface Single LVDS Dual LVDS Single LVDS Single LVDS Single LVDS
LVDS LVDS
SVGA (800x600)
Resolution VGA (640x480) XGA (1024x768) SXGA (1280x1024) WXGA (1280x768) WXGA (1280x720) WXGA (1280x768)
VGA (640x480)
Brightness (cd/m2)> 450 250 300 400 500 450 450
Contrast> 500 300 400 400 500 500 400
Response Time
25 35 25 25 16 25 25
(Tr+Tf) msec <
Viewing Angle R\L\H\L > 85/85/85/85 60/60/40/50 70\70\60\60 70/70 50/60 80\80\60\60 85/85 85/85 85/85 85/85
Adaptor Input
12V 12V 12V 12V 15V 15V 24V
Power consumptions
48W 48W 60W 60W 75W 100W
St-By Power Consumption <3W <3W <3W <3W <3W <3W <3W
Input Range 100-240V/50, 60Hz 100-240V/50, 60Hz 100-240V/50, 60Hz 100-240V/50, 60Hz 100-240V/50, 60Hz 100-240V/50, 60Hz 100-240V/50, 60Hz
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BLOCK DIAGRAM OF MAIN CHASSIS (L5A)
SVHS-Y/C SC1-RGB
YUV
CVBS-IF YUV
Video Decoder Scaler PANEL
Tuner IF
VPC 3230D Stage
HS/VS
HS/VS
RGB HS/VS
HS/VS RGB FB CVBS
VGA-IN EEPROM
24LC02
EEPROM Teletext Decoder
24LC16 SDA 5550
K6T1008V2E M29W040
SRAM Flash
(Optional) Memory
TDA1571
L
Stereo
R R Amplifier
MSP3410G
AUDIO DECODER
L L TDA1308
R R Headphone
Amplifier
SIF/AM-mono
Scart 1 Scart 2 SVHS/FAV
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BLOCK DIAGRAM OF SCALER
BAC LIGHT UNIT Panel_En Standby Mute Reset
S508 (LVDS) S500(TTL)
BR1_ADJ BLK_EN
HS/VS
RGB LVDS
GM 5221 U500 CONNECTOR
LCD (20 OR 30 PINS)
VGA_RGB
(S503,S502)
P
VGA HS/VS
CONTROLLER A
N
S506
CONN. DAUGHTER E
BOARD L
FOR TTL
INTERFACES
U501
PARALEL U503 KEYBOARD
FLASH SERIAL FLASH CON. S509
MEMORY MEMORY
M29W040B M25P40
(OPTIONAL)
U502
S505
EEPROM
PROGRAMING
24C16
CON
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L5A POWER SUPPLY BLOCK DIAGRAM
3.3V-STBY
S600 LM1117
V-INV 3.3V
DC Jack +15V-STBY
F600 LM2576 15V,12V LM2576 +5V-STBY
U600 U607 LM1117 1.8V-STBY
Fuse 1.8V
S602 5A U605
F601
V-INV
V-INV
78L08 +8V
U606 2.5V
LM117-3.3V
+5V U604 3.3V
INPUT: 12V FOR 14,15,17 INCH 5V-STBY U602
15V FOR 20, 22 INCH + 12V SDI9933ADY
78L12
24V FOR 23 INCH Panel
U608
+12V Power
ONLY FOR 23 "
ONLY FOR 20, 22, 23 " PNL-EN Power STBY
+8V
78L08
U606
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L5-A Low-to-Mid End LCD-TV BOARD OVERVIEW
L5-A Low-to-Mid End LCD TV board incorporates the LCD Controller gm2221, to create a
high quality, stand-alone LCD-based TV system for consumer applications. Figure 1
illustrates the Block diagram of the board.
This board supposed to have two versions:
1. Low-End (to drive 14''-15'' 4:3 panels)
2. Mid-End (to drive 17''-20'' 4:3 and 17''-22''-23'' 16:9 panels)
LOW TO MID END LCD TV WITH GM2221
Graphics RGB, HS, VS
Upto SXGA at 75Hz FLASH
UXGA at 60Hz GM2221
QSS NVRAM 15",
SDA,SCL 17",
EDID
Multimedia VGA ADC+PLL 20''
Tuner CVBS 1p, 2p\clk 4:3
ITU 656 LVDS
Chroma De-interlace
Decoder Scaling 17''
EXT. CVBS, S-video ITU 656 24-bit TTL
VPC 3230D MCU X86 22''
HS, VS, DE
8-bit OSD(4bit\pixel) 16:9
Scart RGB, FB Upto SXGA at 75Hz
2 LVDS Tx TFT
LCD
3.3V 2.5V 1.8V
5V
Selected
RGB, FB
Teletext
Video
QSS
8V
Ext L/R Audio
Decoder
Step Down MSP 3410G
& Lineer
Regulators Teletext FLASH HP Main
Decoder +MCU L/R L/R
SDA5550 SDRAM HP AudioAmp
TDA1308T TDA1517P
12V L R
Figure 1 System Block Diagram
L5-A board supports 5 types of video and graphics inputs. These inputs are: Analog
terrestrial tuner input for multisystem PAL/SECAM transmission, SCART input (x2), S-VHS
input, RCA input and analog PC video input.
The analog RGB signals coming from the PC input (via D-Sub15 connector P401) are
directly connected to the gm2221 analog input port.
One EDID IC (U400) is provided on board to support VESA standard plug-and play
compatibility.
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On the board, one high quality video decoder (U100) is provided (VPC3230D of Micronas)
to process video inputs coming from the video sources. The video processor can process 3
composite video inputs and 1 S-Cideo input from the NTSC/PAL video sources. The CVBS
output recovered from the tuner module is made available to one of the video inputs of the
video decoder.
The digitized video output (in ITU-656 format) from U100 is fed to the dedicated video Port
of gm2221 for decoding and processing.
Gm2221 makes it possible to perform scaling and de-interlacing for the video input.
A 4Mbit serial flash ROM (U503) is used for storing system firmware. Also the footprint for
a parallel flash ROM, which can be upto 2Mbits, is available on the board. This option can
be used either for development or for production purposes.
The gm2221 provides direct connect via the integrated LVDS transmitters to LCD panels
with integrated LVDS receivers. Both single LVDS (via S503) and double LVDS(via S502)
panels can be supported directly from the L5-A main-board. For single LVDS panels, only
S503 connector is soldered on the main-board, which is a 20 pin connector. For Double
LVDS panels, only S502 connector is soldered on the main-board, which is a 30 pin
connector. For supporting different LVDS panels, different LVDS cables (either single or
double LVDS) can be made used.
For supporting different single or double TTL panels, a daughter board interface is used via
40 pin S506 connector. On this connector, the signals are 3x8bit RGB with TTL control
signals (i.e. HSync, VSync, CLK, O/E etc.) to support a wide variety of LCD panels.
Depending on the panel used, different daughter boards will be used to support that
particular panel. For single TTL panels, the daughter board will just be a routing the RGB
and control signals to the particular connector interface for that particular panel. For double
TTL panels, there will be two LVDS receiver IC's on the daughter board (double TTL is not
directly from GM2221 but double LVDS is supporter due to IC packaging problems) to
demodulate double LVDS signal into double TTL signal.
The LCD panel resolution supported can be up to SXGA at 75 Hz or UXGA at 60 Hz.
It is important to note that at any point in time gm2221 could drive only one type of Panel.
When LVDS Panel is connected (to connector S503 or S502) ensure that the panel
backlight is connected to S508. The integrated PWM output from gm2221 is used to
control the LCD panel backlight intensity for dimming functions.
The on screen display is implemented using OSD capability of gm2221. Infra Remote (IR)
controller connector (S507) is provided as a primary control interface for connecting IR
detector to the GPIO of gm2221. An IR remote controller unit and detector provide remote
OSD menu access at user convenience.
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A keypad connector (S507) is provided which utilizes the integrated low bandwidth ADC in
gm2221 for scanning 5-6 keys (menu,V+,V-,P+,P- keys standard- source key optional) on
the keypad. The keypad allows access to the OSD without using the remote IR controller.
The L5-A board also has In System Programming (ISP) capability for the external flash
ROM using DDC2Bi. This can be done using the D-Sub 15 (PC) connector on the board.
ISP can also be performed using G-probe through the RS232 interface.
One channel of the dual channel FET power switch (U602) is used to control the power
sequencing to the LCD panel. Depending on the type of the panel, the input voltage to this
FET device can be chosen as shown below:
For +3.3V panels J601 is soldered on the main-board
For +5V panels J600 is soldered on the main-board
For +12V panels J603 is soldered on the main-board
An LM2576, a step-down regulator IC (U600), is used to generate the main +5V_STBY
voltage on the board. This IC can deliver up-to 3 Ampers of 5Volts. There is no stand-by
control for this regulator, which means this IC is always on, as soon as power is supplied
to the board.
U603(+3.3V_STBY) and U605 (+1.8V_STBY) linear regulators are used to supply the
voltage necessary for the GM2221 IC and some peripherals. These voltages are also
available in stand-by mode to power the microprocessor inside gm2221, LED, IR receiver
IC and EEPROM. These devices are necessary to wake up the board from stand-by state.
Second channel of the dual channel FET power switch (U602) is used to control cut some
voltages in stand-by mode. These voltages are +5V, +3.3V and +2.5V. These voltages are
used by the video processor (VPC 3230D), audio processor (MSP 34x0G), teletext
processor (SDA5550), tuner and some peripheral IC's and circuitry. In order to limit the
stand-by power consumption, these voltages are not available in stand-by mode. Also the
audio amplifier (TDA1517) is also in its stand-by mode using its dedicated stand-by pin.
The board employs MSP3410G, a multi-system audio processor solution from Micronas.
The system supports 4 audio input ports, one of which is not used on the L5-A board.
Audio output is provided with speaker and headphone jacks (S409, S401) provided on the
board. The sound IF signal from the tuner is connected to the audio processor directly.
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4. GM2221 LCD TV CONTROLLER
The gm2221 IC is a highly integrated single channel scaler that can be used for both LCD
monitors up to SXGA/UXGA resolutions and rear projection systems with DLP and HTPS
LCD engines up to 1280x720 (720P). Some of the key features include:
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