Hitachi 22LD3750DC User manual

CAUTION:
Before servicing this chassis, it is important that the service technician read the “Safety
Precautions” and “Product Safety Notices” in this service manual.
ATTENTION:
Avant d’effectuer l’entretien du châssis, le technicien doit lire les «Précautions de sécurité»
et les «Notices de sécurité du produit» présentés dans le présent manuel.
VORSICHT:
Vor Öffnen des Gehäuses hat der Service-Ingenieur die „Sicherheitshinweise“ und „Hinweise
zur Produktsicherheit“ in diesem Wartungshandbuch zu lesen.
SERVICE MANUAL
MANUEL D'ENTRETIEN
WARTUNGSHANDBUCH
Data contained within this Service
manual is subject to alteration for
improvement.
Les données fournies dans le présent
manuel d’entretien peuvent faire l’objet
de modifications en vue de perfectionner
le produit.
Die in diesem Wartungshandbuch
enthaltenen Spezifikationen können sich
zwecks Verbesserungen ändern.
«MODEL NAMES»
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
No. 0249
22LD3750DC
Colour Television
May 2009
22LD3750DU

TABLE OF CONTENTS
1 INTRODUCTION........................................................................................................................................1
2 GENERAL DESCRIPTION ....................................................................................................................... 1
3 POWER STAGE ..........................................................................................................................................4
4MICROCONTROLLERPORT CONFIGURATION .............................................................................4
5 SIDE BOARDS AND CONNECTORS ......................................................................................................5
5.1 Keypad ......................................................................................................................................... 5
5.2 Infrared& LED............................................................................................................................ 6
5.3 DVB-T .......................................................................................................................................... 6
5.4 DVD ............................................................................................................................................... 8
5.5 LVDS ............................................................................................................................................. 9
5.6 IPS POWER CARD..................................................................................................................... 9
6 IC SPECIFICATIONS .............................................................................................................................. 10
6.1Microcontoller/Video&Audio Processor (VCT4953G) ............................................................ 10
6.2 Scaler/De-interlacer (MST-TSUMU38BF) ...............................................................................13
6.3 Audio Stage (LM358D,MP7721) ................................................................................................ 16
6.4 HeadPhone Amplifier (TDA1308T) ...........................................................................................16
6.5Audio Matrix Switch (TEA6422D)............................................................................................. 19
6.6HDMI Receiver (ANX9021)........................................................................................................ 19
6.7 Video Switch (PI5V512) .............................................................................................................. 20
6.8Tuner (DTT71306) ...................................................................................................................... 21
6.9 SAW Filter (X6966M) ................................................................................................................ 22
6.10 I2C Switch (74HCT4053) .........................................................................................................22
6.11 Audio DAC (CS4334) ............................................................................................................... 23
6.12 IC E2PROM 24LC02 2Kbx8.................................................................................................... 24
6.13 SPDIF Switch (NLAST4599) ....................................................................................................24
6.14 17MB29 Block Diagram ...........................................................................................................26

1
1 INTRODUCTION
The purpose of this document is to define the operation of 17MB29 chassis, capable of driving 22”
TFT LCD panel. It is aimed to provide information to engineering staff to understand the operation and specs
of the TV. The other related technical documents are given in Table1:
Title
1 17MB29 schematics
2 IR receiver and LED display board schematics
3 Keypad board schematics
4 DVD module card schematics
5 DVB-T module card schematics
Table1.1: Related documents
2 GENERAL DESCRIPTION
The system is a low to mid end; 22” 1680 x 1050 TFT TV solution basically for EU market with
VCT4913G microcontroller / video audio processor chip on a 2-layer PCB. Since the target market is EU, the
first release of the TV will support PAL/SECAM B/G/D/K/I/L/L’. The target panel is 22” W 1680 x 1050
TFT-LCD panels. A DVD loader is used to read DVD content and a DVB-T module card is used to support
DVB-T.
Inputs
• 1xTuner (both analog and DVB-T)
• 1xDVD
• 1xScart
• 1xPC (VGA)
• 2xHDMI (optional)
• 1xBack AV (optional)
• 1xSIDE YPBPR (optional)
Outputs
• Speaker (stereo, 2x4 Ω, 2x4Watt)
• Headphone (stereo) (optional)
• Audio line out (stereo and mono) (optional)
• DVD/DVB-T coaxial SPDIF out(optional)

2
General default features
• Multi System Reception: PAL-SECAM BG-DK-I/I’-L/L’
• Menu system (multi language)
• 100 program storage locations
• OSD (on-screen display)
• Teletext
• IR Control (RC5 and other customer specific protocols)
• “No Ident” Timer
• Child Lock
• Sleep Timer
• WSS (16:9/4:3 Aspect Ratio Auto Switch)
Sound Features
• Equalizer
• FM Radio
• Linear Stereo
• German-NICAM Stereo
• 5-Band Equalizer Control
• SRS TRU Surround (OPT)
• SRS TRU Bass (OPT)
• BBE, WOW (OPT)
Picture Features
• WIDE PANEL---4:3,16:9, Auto(opt), Subtitle(opt), Zoom(opt), Panoramic(opt)
• Picture Modes ( Bright, Standard, Soft)
• Media Window Enhancement (MWE)
• Backlight brightness setting (movie/normal/bright)
• Multi System Reception : PAL-SECAM BG-DK-I/I’-L/L’
• NTSC Video Playback
• WSS (16:9 / 4:3 Aspect Ratio Auto Switch)
• Channel Type Sorting (Favorite/Sport/Music/News/Movie)
Tuning Options
• FST
• Frequency Search (Optional)
• APS (Auto Search/Name/Sort)
• Auto Search
• CATV/HYPERBAND
Keyboard
• Volume -/ +Button
• Program -/+ Button
• Menu Button
• TV / AV Button

3
Teletext/OSD
• Simple Text 10 Pages
• Fastext & Top Text (OPT)
• Teletext Languages (ALL)
• Character Based OSD
Electrical features
•IPS generates 12V and 5V DC supply.
•<1W standby power consumption
System Building Blocks
17MB29 chassis main blocks are as follows:
•Analog Front End : VCTI (Microcontroller+Video Proccessor+Audio Proccessor+IF
Demodulator+ Teletext Decoder+ OSD Generator)
•Back End : MST-TSUMU38BF(Scaler, Deinterlacer, OSD Generator)
Analog Front End
17MB29 main board consists of two major blocks. The first block is analog front-end and this
block is handled by VCTI chip that is highly multifunctional. VCTI performs Tuner IF demodulation,
CVBS, RGB, SVHS and audio input selection and processing. The audio processor (MSP) supports
equalizer, tone control, volume control, AVL, surround effect etc. The video processor (VSP) handles
video processing such as color standard detection and demodulation, picture alignment (brightness,
contrast, color etc.). The IC also has a teletext decoder with fastext memory. The processed video output
is sent to MST-TSUMU38BF, scaler/deinterlacer in RGB format together with a composite sync.
The TV tuner is PLL controlled symmetrical IF output type. The IF signal is filtered by a single
SAW filter. Inter-carrier sound demodulation is performed by the system. After the SAW filter block, IF
signal is processed by VCTI IF demodulator. Audio signal is digitally filtered in the IF demodulator
block. The same IF signal is buffered and sent to DVB-T module card, tdm1300.Since VCTI can handle
all the audio processing, there is no need for additional audio processor solution on the board.
MSP has two audio inputs which are assigned to the Scart in L/R and Audio Switch L/R output.
MSP has three audio outputs which are assigned to the headphone amplifier L/R input, audio amplifier
L/R input and Audio switch L/R input. The board employs MP7721 and TDA1308 to drive speaker and
headphone outputs, respectively. Switching control for other audio inputs and outputs (HDMI, Back AV,
PC, DVD, and DVB-T) is achieved by an I2C controlled audio switch (TEA6422).

4
Back End
MST-TSUMU38BF has two ADC inputs. First ADC input is assigned to the VCTI RGB output.
Other RGB/YPbPr inputs are multiplexed for the second ADC input. HDMI receiver ANX9021 analog
output, VGA RGB input and the synchronization signals are multiplexed by a primary RGB switch
(PI5V512). MST-TSUMU38BF has an embedded LVDS transmitter. There are three PWM output ports.
PWM0 is assigned to analog/digital dimming control for the backlight, PWM1 is used for backlight
on/off and panel logic power supply on/off control and PWM2 is used to control PC/HDMI switch IC
(PI5V512).
3 POWER STAGE
The DC voltages required at various parts of the chassis and inverters are provided by a main power
supply unit and power interface board. IPS generates 12V and 5V DC supply. Power stage which is
on-chasis generates +12V for audio amplifier and 5V stand by voltage and 33V, 12V, 5V, 3.3V and 1.8V
supplies for other different parts of the chassis.
4 MICROCONTROLLER PORT CONFIGURATION
PIN
NO
PORT
NAME
SIGNAL NAME TYPE FUNCTION
47 P10 MST_RESET O Scaler reset
PROTECT I Short circuit detection
48 P11 TV_RXD I IDTV UART receive signal
49 P12 TV_TXD O IDTV UART transmit signal
50 P13 IRQ O IDTV interrupt request signal
51 P14 KEY I Keyboard function select
52 P15 SC_PIN8 I Scart function select
53 P16 DVD_IR_ON/OFF O DVD infrared signal on/off control
54 P17 POWCON O Standby on/off control

5
PIN
NO
PORT
NAME
SIGNAL NAME TYPE FUNCTION
55 P20 HDMI_HP_INV O HDMI hot plug signal
56 P21 CS O Switching control for Mstar bus and system I2C
62 Safety VCTI_HS O VCTI composite sync output
78 FBIN DVD_SENSE I DVD module detection
85 Vert+ TV/DVB_SW O IDTV/TV I2C and AGC switch control for tuner
27 P22 WP O Write protection control for NVM
28 P23 IR I Infrared input
Table 4.1 VCTI port configuration
5 SIDE BOARDS & CONNECTORS
5.1 Keyboard
A four-pin connector is used between 17mb29 and the keyboard:
KEY signal is sent directly to microcontroller ADC port and depending on the voltage level of
KEY signal, microcontroller performs one of these actions: menu, program+, program-, volume+,
volume- and source.
SOFT_SW signal is used to switch between “power-off” and “standby” modes.

6
5.2 Infra-red & LED
A five-pin connector is used between 17MB29 and the LED board: Pin2 and pin3 carry the control
signals for the LED. Pin4 carries the infra-red signal to the microcontroller. Pin5 is used to power up the
LED board.
5.3 DVB-T module board
DVB-T module board (TDM1300) is used to receive digital terrestrial broadcast signals. Three
cables are used to connect 17MB29 and TDM1300: power, data and IF.
12V (500mA) is sent to TDM1300 by power cable:
Analog RGB(YPbPr), CVBS, stereo audio, tuner control (SCL, SDA, AGC), and three GPIO port
outputs of TDM1300, together with UART ports (TV_RXD, TV_TXD, IRQ) are carried by data cable.

7
TDM1300 board has no tuner on it. Instead, the tuner of 17MB29 is used for both analogue and
digital reception. Tuner is controlled by either the 17MB29 microcontroller (VCTI), or TDM1300 board
microcontroller. The IF (intermediate frequency) output of the tuner is sent to TDM1300 board for digital
reception.

8
5.4 DVD module board
DVD module board has two parts: a loader and an electronic card. Electronic card controls the
loader and has connections with 17MB29 and DVD keypad.
Three cables are used to connect 17MB29 and DVD electronic card: power, data and sense.
12V (500mA) is sent to DVD electronic card by power cable:
Y/C and/or CVBS video, stereo audio outputs and infra-red input of DVD module board is carried on
data cable:
When a DVD is inserted into the loader, the DVD electronic card sends an interrupt signal
(DVD_SENSE) to the 17MB29 microcontroller: