Wednesday, 25 July 2018

TCL L32M61S3 – service mode and adjustments – working principle - Troubleshooting


TCL L32M61S3/L32E62S3/L32M71S3 (MS19) – 32 inch LCD TV – How to enter the service mode and service mode adjustments – working principle
This Chassis adopts Taiwan semiconductor plant MSTar’s integrative chip MST9E19A.It 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, an integrated DVI/HDCP/HDMI receive a multi-standard TV video and audio decoder, a video de-interlacer, a scaling engine, the MStarACE-3 color engine an on-screen display controller, an 8-bit MCU, and a built-in output panel interface. To further reduce system costs, the MST9E19A also integrates intelligent power management control capability for green-mode requirement and spread-spectrum support for EMI management. Therefore, MS19 is a high cost performance Chassis.
Modes L32M61S3/L32E62SE/L32M71S3 just different in frame, their chassis includes hardware and software almost are same. To match the frame, just key board and remote control receive board have a little difference. Beside, the three modes TV support NTSC-M, PAL M and PAL N.
So that, the following alignment procedure adapt to the three modes above said.
 How to enter factory mode (service menu, service mode)
Method one, press MENU, input “1”,”9”,”5”,”0” in 3 seconds.
Method two, press “GO BACK” key directly. (Remark: it is must under conditions of, in factory mode, enter PRODUCTING, FACTORY HOT KEY set as ON.)
Factory menu explain
Enter factory menu, press the remote control’s UP, DOWN, LEFT, RIGHT key set or adjustment, press MENU key return parent menu, press MENU OR CLEAR KEY exit factory menu.
Aging
While TV need aging, pleas enter factory mode, set the WARM UP STATUS in producing as ON, then set power mode as ON in set up menu. If TV need standby aging, please set power mode as STB.
 ADC correct
This chassis can ADC correct when input YPBPR or PC signal resource. Enter factory mode, switch the source as YPBPR or PC, input 100% color bar signal, enter ADC ADJ item, choose AUTOTUNE item, press right key on remote control to start auto correct, when screen display OK 7 seconds later, it shows that ADC correct success. Then exit menu.
Remark: Before white balance adjustment, must do ADC correct OK in YPBPR and PC signal input.
White balance adjustment.
Normal, warm and cool three situations’ white balance color temperature value must obey the enterprise standard. Before adjust the white balance, please confirm if finished ADC correct under YPBPR and PC sources, in addition, the picture mode must be normal.
This chassis white balance adjustment must be adjusted in three signal sources.
(1)AV/TV/S-Video’s white balance adjust under AV signal source input. Signal should be NTSC-M eight-grey bar signal.
(2)YPBPR and HDMI white balance adjust under YPBPR signal source input. Signal must be 16-grey bar signal.
(3)PC white balance adjustment must be under PC signal input. The signal should be 16 grey bar signal.
Factory producing white balance adjustment according to the software interface agreement and working guide, setting relevant offsets to operate.
If it need human adjustment, please enter factory menu adjust WB items.
 leave factory setting.
Leave factory setting items have been listed in factory menu. Please set each character according to customers requirement. Or obey the default value. Before TV leave factory, please do “SHOP INIT DO”. Operate method is press left or right key on remote control to initial it. While OK display on screen, it finished the initial. Then turn TV off just OK..
Chassis MS19 circuitries include: tuner, decoder and scanner, audio amplifier, remote control receive, key input and power supply unit and so on. It adopted ICs as following, MST9E19A-LF 208PI, ISL8105IBZ, TDA7266 , TDA1308T/N2, TL431ACLP, M24C32, KD1084A-18.
I. Video signal input processing circuit.
Radio frequency signal from antenna or cable input tuner, after it processed, Pin17 of tuner output video signal, then input Pin49/50 of U8(MST9E19A).

AV signal input processing circuit.
AV1/AV3 through socket P14 input Pin45/Pin47 of U8, S-video input through socket P15 input Pin42/Pin43/Pin44 of U8. YCbCr Video Signal input through socket P16 input.
HDMI video signal input through socket P12 input Pin1-Pin15 of U8.
VGA input through socket P13 input Pin16-Pin28 of U8.
Audio signal input, the audio signal through antenna process and output from Pin7 of Tuner and input Pin54/Pin55 of U8.The AV1’s audio signal input Pin63/Pin64 of U8,AV2’s audio signal input Pin66/Pin67 of U8; AV3’s audio signal input Pin69 and Pin69 of U8.
All channels audio signal through inside circuitry process, output from Pin74/Pin75 of U8, send to audio amplifier U19( TDA7266SA) processing and driver speaker phonating.
Audio Amplifier and Mute Control
The audio signal after MST IC decoder and get out from Pin74/75 of MST IC, and through integral circuitry (R33,R38,C76 and R45,R50,C82) send to Pin4/12 of audio power amplifier U19 to drive speaker.
AV Output Audio Amplifier Section
The phone audio signal output from Pin71/Pin 71,through the integral circuitry R34/R36/C37 and R47/R51/C83 send to U16 and output from P17.
HDMI EDID Introduction
Extended display identification data (EDID) is a data structure provided by a computer display to describe its capabilities to a graphics card. It is what enables a modern personal computer to know what kind of monitor is connected. EDID is defined by a standard published by the Video Electronics Standards Association (VESA). The EDID includes manufacturer name, product type, phosphor or filter type, timings
supported by the display, display size, luminance data and (for digital displays only) pixel mapping data.
The channel for transmitting the EDID from the display to the graphics card is usually the I2C bus. The combination of EDID and I²C is called the Display Data Channel version 2, or DDC2. The 2 distinguishes it from VESA's original DDC, which used a different serial format.
Before DDC and EDID were defined, there was no standard way for a graphics card to know what kind of display device it was connected to. Some VGA connectors in personal computers provided a basic form of identification by connecting one, two or three pins to ground, but this coding was not standardized.
The EDID is often stored in the monitor in a memory device called a serial PROM (programmable read-only memory) or EEPROM (electrically erasable PROM) that is compatible with the I²C bus.
HDCP Section
High-bandwidth Digital Content Protection (HDCP) is a form of Digital Rights Management (DRM) developed by Intel Corporation to control digital audio and video content as it travels across Digital Visual Interface (DVI) or High-Definition Multimedia Interface (HDMI) connections. The specification is proprietary, and creating an implementation of HDCP requires a license .HDCP is licensed by Digital
Content Protection, a subsidiary of Intel. In addition to paying fees, licensees agree to limit the capabilities of their products. For example, high-definition digital video content must be restricted to DVD quality on non-HDCP compliant video outputs when requested by the source. DVD-Audio content is restricted to DAT quality on non-HDCP digital audio outputs (analog audio outputs have no quality limits).
Licensees cannot allow their devices to make copies of content, and must design their products in ways that "effectively frustrate attempts to defeat the content protection requirements."
Each HDCP capable device has a unique set of keys; there are 40 keys, each 56 bits long. These keys are confidential and failure to keep them secret may be seen as a violation of the license agreement. For each set of keys a special key called a KSV (Key Selection Vector) is rated. Each KSV has exactly 20 bits set to 0 and 20 bits set to 1.
During the authentication process, both parties exchange their KSVs. Then each device adds (without overflow) its own secret keys together according to a KSV received from another device. If a particular bit in the vector is set to 1, then the corresponding secret key is used in the addition, otherwise it is ignored. Keys and KSVs are generated in such a way that during this process both devices get the same 56 bit number as a result.
That number is later used in the encryption process. As result that, this chassis adopts 24C04 to storage KSV and license makes digital signal resource output.
EEPROM for Software
It adopts Winbond company’s W25X40 flash which has 4M-bit/526 bytes and 2048pages.It is used for storage the main system software. The devices operate on a single 2.7V to 3.6V power supply with current consumption as low as 5mA active and 1uA for power-down.
EEPROM for User Information
It adopts I2C compatible electrically erasable programmable memory (EEPROM) devices are organized as 4096x8 bits(32k).This is a two-wire series interface that uses a bi-directional data bus and serial clock. It is used for storage user’s information, such as channel search and timer on and off, and picture standard and other information what user’s easy to change by local key board and remote control.
Panel ON/OFF Control Section
While the TV is turn on, the TV is standby situation. While command turn on is send out, 5v voltage will through regulator and equal get 3.3V voltage or 1.8V voltage supply for U8. After reset and crystal Y1 working, the main system software will be loaded, the panel –ON/OFF command will be sent out, makes the dual-MOSFET U3 turn on and send V/12V/3.3V voltage to the panel.
Panel ON/OFF Control Section
While the TV is turn on, the TV is standby situation. While command turn on is send out, 5v voltage will through regulator and equal get 3.3V voltage or 1.8V voltage supply for U8. After reset and crystal Y1 working, the main system software will be loaded, the panel –ON/OFF command will be sent out, makes the dual-MOSFET U3 turn on and send V/12V/3.3V voltage to the panel.
Power Logic Sequence
While the power cord plug in, the TV is in standby situation, power supply unit provide 5Vstb 200mA for load. There is no 12v amplifier power supply and 24V inverter voltage supply. The 5Vstb through D7 and regulator U5 get 3.3VA supply for IC (MST19E),the another path of circuit is 5Vstb through regulator U6 get 3.3V then regulated by U7(regulator) get 1.8V supply for U8(MST19E),drive the LED lighting, and standby circuitry working, and CPU controlling, reset circuitry,crystal.So that it makes the CPU can receive and send kinds of command. while there is turn on command(low level) send out from Pin150 of U8(MST19E),power supply unit provide 12V and 24V voltage.12V voltage supply for U1/U2,change to 5V voltage, regulate by U6, change to 3.3V supply for U8 others parties. 24V voltage supply for inverter board of Panel.

Troubleshooting

Defective picture
No picture
Not working
Picture OK but No sound
                               

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