Service Manuals, User Guides, Schematic Diagrams or docs for : . Various CHINA TV LCD LC-37R25
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LCD TELEVISION
LC-37R25
CONTENTS
Safety precautions...................................................................................... 1
Alignment instructions ................................................................................. 3
Working principle analysis of the unit...............................................................7
Block diagram.............................................................................................8
IC block diagram.........................................................................................9
Wiring diagram ......................................................................................... 19
Troubleshooting......................................................................................... 20
Schematic diagram .................................................................................... 26
APPENDIX-A: Main assembly list
APPENDIX-B: Exploded view
Attention: This service manual is only for service personnel to take reference with. Before
servicing please read the following points carefully.
Safety precautions
1. Instructions
Be sure to switch off the power supply before replacing or welding any components or
inserting/plugging in connection wire Anti static measures to be taken (throughout the entire
production process!):
a) Do not touch here and there by hand at will;
b) Be sure to use anti static electric iron;
c) It's a must for the welder to wear anti static gloves.
Please refer to the detailed list before replacing components that have special safety requirements.
Do not change the specs and type at will.
2. Points for attention in servicing of LCD
2.1 Screens are different from one model to another and therefore not interchangeable. Be sure to
use the screen of the original model for replacement.
2.2 The operation voltage of LCD screen is 700-825V. Be sure to take proper measures in
protecting yourself and the machine when testing the system in the course of normal operation or
right after the power is switched off. Please do not touch the circuit or the metal part of the module
that is in operation mode. Relevant operation is possible only one minute after the power is
switched off.
2.3 Do not use any adapter that is not identical with the TV set. Otherwise it will cause fire or
damage to the set.
2.4 Never operate the set or do any installation work in bad environment such as wet bathroom,
laundry, kitchen, or nearby fire source, heating equipment and devices or exposure to sunlight etc.
Otherwise bad effect will result.
2.5 If any foreign substance such as water, liquid, metal slices or other matters happens to fall into
the module, be sure to cut the power off immediately and do not move anything on the module lest it
should cause fire or electric shock due to contact with the high voltage or short circuit.
2.6 Should there be smoke, abnormal smell or sound from the module, please shut the power off at
once. Likewise, if the screen is not working after the power is on or in the course of operation, the
power must be cut off immediately and no more operation is allowed under the same condition.
2.7 Do not pull out or plug in the connection wire when the module is in operation or just after the
power is off because in this case relatively high voltage still remains in the capacitor of the driving
circuit. Please wait at least one minute before the pulling out or plugging in the connection wire.
2.8 When operating or installing LCD please don't subject the LCD components to bending, twisting
or extrusion, collision lest mishap should result.
2.9 As most of the circuitry in LCD TV set is composed of CMOS integrated circuits, it's necessary
to pay attention to anti statics. Before servicing LCD TV make sure to take anti static measure and
ensure full grounding for all the parts that have to be grounded.
2.10 There are lots of connection wires between parts behind the LCD screen. When servicing or
moving the set please take care not to touch or scratch them. Once they are damaged the screen
1
would be unable to work and no way to get it repaired.
2.11 Special care must be taken in transporting or handling it. Exquisite shock vibration may lead to
breakage of screen glass or damage to driving circuit. Therefore it must be packed in a strong case
before the transportation or handling.
2.12 For the storage make sure to put it in a place where the environment can be controlled so as to
prevent the temperature and humidity from exceeding the limits as specified in the manual. For
prolonged storage, it is necessary to house it in an anti-moisture bag and put them altogether in one
place. The ambient conditions are tabulated as follows:
Temperature Scope for operation 0 ~ +50 oC
Scope for storage -20 ~ +60 oC
Humidity Scope for operation 20% ~ 85%
Scope for storage 10% ~ 90%
2.13 Display of a fixed picture for a long time may result in appearance of picture residue on the
screen, as commonly called "ghost shadow". The extent of the residual picture varies with the
maker of LCD screen. This phenomenon doesn't represent failure. This "ghost shadow" may remain
in the picture for a period of time (several minutes). But when operating it please avoid displaying
still picture in high brightness for a long time.
3. Points for attention during installation
3.1 The front panel of LCD screen is of glass. When installing it please make sure to put it in place.
3.2 For service or installation it's necessary to use specified screw lest it should damage the screen.
3.3 Be sure to take anti dust measures. Any foreign substance that happens to fall down between
the screen and the glass will affect the receiving and viewing effect
3.4 When dismantling or mounting the protective partition plate that is used for anti vibration and
insulation please take care to keep it in intactness so as to avoid hidden trouble.
3.5 Be sure to protect the cabinet from damage or scratch during service, dismantling or mounting.
2
Alignment instructions
1. Test equipment
PM5518 (Video signal generator)
VG-848 (Signal generator)
CA210 (White balancer)
2. The alignment flow chart (see below figure)
Check DDC, HDCP KEY and FLASH
Production of main board and analog board on the line.
Check CPU board and analog board
Combined test for general assembly
Connect to central signal source; check if various
TV functions (station skipping, modulate quantity
control etc), check if the output of earphone and
speaker are normal.
Input AV/S signal and HDTV signal; check various
functions under AV/S terminal
Input VGA signal and check if display is normal in
the state of PC and various functions (analog
quantity control, line/field center etc.)
Input HDMI singal and check if display is normal in
the state of HDMI and various functions (sound
and analog quantity control).
Preset ex-factory
3
Check accessories and then packing
3. The unit adjustment
Enter factory menu method: press the SOURCE 2 580 buttons one by one on the remote
control to factory menu. Press the MENU button to select item. Press the DSP button to exit the
factory menu.
3.1 EEPROM initialization and back light adjustment
Enter the firs page of factory menu, adjust item OPTION-1 to 9, OPTION-2 to 5 and back light to
255(LG PANEL) or 0(SHARP and CMO panel), select the EEPROM initial after, press the VOL+
button, then display the DOING, still the DOING disappear and turn off the unit.
Note: option-1 and option-2 function as follows:
Option-1 Option-2
Bit3 0: No memory function after power off for 10s 0:no signal noise wave of TV
1: memory function after power off for 10s 1:no signal blue screen of TV
Bit2,1 00: STANDBY 00:complexion correction (OFF)
01: turn on 01: complexion correction (WEAK)
10: memory function of turn on 10: complexion correction (MIDDLE)
11: complexion correction (STRONG)
Bit0 0: without LOGO 0: Video and Graphic channel white balance no share
1: With LOGO 1: Video and Graphic channel white balance share
3.2 HDMI channel adjustment
Input the VG-848 TIME854(800X600/60Hz) and PATTERN920 8-LEVEL gray signal, enter the
factory menu2(white balance adjustment menu), adjust the third step and the seventh step.
Adjust R-OFFSET, G-OFFSET and B-OFFSET item, still the third step and the seventh step color
coordinate to (285, 293). Adjust R-GAIN, G- GAIN and B- GAIN item, still the seventh step color
coordinate to (285, 293). Repeat adjustment R-OFFSET, G-OFFSET and B-OFFSET item and
R-GAIN, G- GAIN and B- GAIN item, still two step gray to (285, 293).
Enter the factory menu3 (cool and warm color temperature difference menu), adjust cool and warm
color temperature difference according the following table:
R-offset-D G-offset-D B-offset-D R-Gain- G-Gain- B-Gain-
elta elta elta Delta Delta Delta
Warm 27CMO 0 -1 1 0 -7 -22
32LG 0 0 0 0 -9 -26
26SHARP -1 -1 1 0 -11 -27
32SHARP 2 3 3 0 -13 -25
Cool 27CMO 0 -1 0 -25 -9 0
32LG -1 1 0 -24 -5 0
26SHARP 0 0 0 -23 -7 0
32SHARP 5 3 2 -30 -11 0
27CMO
TV MODE 32LG 0 -7 0 0 0 0
4
26SHARP 0 -5 0 0 -3 0
32SHARP
Note: R-OFFSET, G-OFFSET and B-OFFSET values must be an item value to 128 at least; R-GAIN,
G- GAIN and B- GAIN values must be an item value to 255 at least.
3.3 VGA channel adjustment
3.3.1 mode pre-set
Input the VGA signal of VG-848 (PATTERN 980:1 dot ON/OFF), select the TIME877 (720x400/70Hz)
signal, press auto-adjust button to all screen or adjust PC setting menu to auto correction. Separate
auto adjust for TIME885 (640x480/60Hz) and TIME854 (800x600/60Hz).
3.3.2 VGA channel auto color adjustment
Input the VG-848 TIME854(800x600/60Hz) and PATTERN920(GRAY 8 STEP(H)), enter the factory
menu1, select the AUTO COLOR after, press the VOL+ button to select AUTO COLOR.
3.4 YPBPR channel adjustment
Input the VG-848 TIME972(1080i/60Hz) and PATTERN976(64 GRAY & Color), enter the factory
menu1, select the AUTO COLOR after, press the VOL+ button to select AUTO COLOR.
3.5 Other setting
Separate Factory Menu 4, Factory Menu 5, Factory Menu 6, Factory Menu 7 adjustment as follows:
Factory Menu 4 Factory Menu 6
Bright Max 148 Picture_Mode Soft Normal Bright
Bright Center 128 Brightness 50 50 55
Bright Min 78 Contrast 35 50 75
Contrast Max 154 Color 40 50 60
Contrast center 118 Sound_Mode Music Movie News
Contrast Min 28 Bass 80 50 30
Color Center 128 treble 60 50 40
Factory Menu 5 Factory Menu 7
27CMO 32LG 26SHARP 32SHARP
Volume_1 48 52 S2310_Color 142
Volume_25 100 102 S2310_Contrast 120
Volume_50 114 116 S2310_Bright 133
Volume_100 123 121
Bright_Cen_Delt 0
Bright_Max_Delt 2
Cont_Cen_Delt 10
Cont_Max_Delt 12
4. Performance check
4.1 TV function
Input center source signal to RF-TV terminal, check if the channel is leak for auto searching.
4.2 AV/S and YPBPR terminal
Input AV/S and HDTV signal, check if the signal is normal.
4.3 VGA terminal
Input 640 x 480 @60Hz VGA format signal, check if the signal is normal.
4.4 HDMI terminal
5
Separate input HDMI and DVI signal; check the picture and sound is normal, check if the HDCP
function is normal.
4.5 check the sound channel
Check the speaker and headphone of each channel.
4.6 ex-factory setting
Enter the first page of factory menu, select the factory out after, press the VOL+ button to display
"doing", then "doing" disappear while it can auto ex-factory setting.
6
Working principle analysis of the unit
The RF1 via integrative tuner TUNER1 after, the FBAS VIDEO1 and SIF is generated. The RF2 via
integrative tuner TUNER2 after, the FBAS VIDEO2 and AUDIO is generated. Video signal and
audio signal of VIDEO1,VIDEO2,AV1/SVHS1,AV2,AV3/SVHS2 and audio signal of VGA and so on,
its sent NA3 (CXA2089Q) to switch selection. The output video signal of main picture (Y/V,C) sent
N7 (TVP5160) to decode. The signal via N7 decode after, it sent 8-bit ITU-R656 format signal to
N10 (FLI2310) non-interlaced processing. It sent 24bit YUV signal to main processing control chip
N15(GM1501/1601).
The sub-picture video signal via CXA2089Q selcet after, it sent N8 (TVP5147) to decode. The signal
via N8 decode after, it sent 8-bit ITU-R656 format signal to N10 (FLI2310) non-interlaced
processing. Thereinto, the signal of TUNER2 is sub-picture only.
The main-picture video signal from CXA2089Q is sent to decoder and also AV OUTPUT.
Two ways YPBPR signal via HDTV switch N36(CBT3257C) selection after, it sent RGB switch
N4(CT3257C) and 24bit RGB from pc signal to GM1501/1601.
The HDMI via receiver N34(MST3383MB) processing after, it output RGB signal of 24bit to
GM1501/1601.
They sent to GM1501/1601 picture processing, therein YPBYP or RGB to A/D conversion after, it
and other two signal are switched selection and digital display processing, it include OSD, GAMMA
correction, brightness and contrast processing, then LVDS conversion to LCD panel display.
The SIF of tuner output signal to audio processing NA4(MSP3420),The audio of main-picture and
sub-picture via switch conversion NA3(HEF4052) to MSP3420, the audio of two YPBPR via switch
conversion NA2(HEF4052), the HDMI via MST3383MB decode to audio, it audio via N26(CS4334)
D/A conversion to MSP3420.
The stereo of the SIF with other four ways audio switch conversion selection to volume control and
audio processing. One way output right/left channel audio of main-picture, the signal sent SRS
processing NA5 (M62494) to SRS sound stereo processing. It via sound amplifier NA7(TPA3008D2)
to speaker; one way output right/left channel audio of sub-picture, it sent to earphone, another way
is AV OUT R/L output.
The work of whole unit is controlled by MCU, which includes GM1501/1601.
7
Block diagram
Power_ON,IR,KeyA,KeyB,Led1,Led2
Hs Vs Hs Vs Mute,HP_SW,VGA_CAB,DVI_CAB
EDID SN74AHC14
24C02
YUV/VGA,YUV_SW,YUV/USB
VGA
RGB
RGB Switch RGB
Y Pb/Cb Pr/Cr CBT3257C Y Pb/Cb Pr/Cr
YPbPr 1 HDTV Switch HDTV Switch
YPbPr 2
CBT3257C CBT3257C Frash/ROM DDR
YUV_SW YUV/USB Frame Buffer
YUV/VGA
OPTION
Media Player EEPROM
(USB)
HDMI
HDMI RX PANEL
MST3383
LCD TV Controller
Y_Main/C_main Video Decoder Deinterlacer
HDCP KEY TVP5160 FLI2310 GM1601/GM1501
EDID
24C02 24C04
BK Control
INVERTER
V_PIP Video Decoder
TVP5147
VBL/VCC
SC1_OUT
AV OUT DACM_L/R SRS Audio AMP
AV IN 1
Power_ON,+5V_STB,VCC,VBL
L/R_PIP SC1_L/R
Audio Processor
AV IN 2 AV Switch MSP3420G
AV IN 3 L/R_Main
CXA2089Q SC2_L/R
ANA_IN1
SC4_L/R
SC3_L/R
Tuner 2 SC2_OUT
Head Phone
AMP
HP_SW
Tuner 1 SIF
Power Supply
L/R_HDMI
L/R_VGA
L/R_USB
Audio Switch
L/R_YPbPr1 YUV/USB
TC4052
L/R_YPbPr2 YUV_SW
8
IC block diagram
1.MSP3420
The MSP 34x0G 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 on a single chip. Figure 1◦ Jabse Service Manual Search 2024 ◦ Jabse Pravopis ◦ onTap.bg ◦ Other service manual resources online : Fixya ◦ eServiceinfo