Sanyo 19XR7, 20XR7 Schematic

FILE NO.

SERVICE MANUAL

LCD TV

LCD-19XR7

PRODUCT CODE No.
1 682 343 87: PAL/SECAM

LCD-20XR7

PRODUCT CODE No.
1 682 343 88: SANYO INDIA

REFERENCE No.: SM0915015

CONTENTS

Safety instructions………………………………………………………………………..…

Adjustment instruction …………………………….…….…………………………….…

working principle analysis……………………………….………….…………………….

block diagram…………………………………..……………………….………………….

IC block diagram………………………………………………………………………..……

Wiring diagram ……………………………………………………………..……………...

Troubleshooting guide ………………………………………………………………..……

Schematic diagram…………………………………………………………………………..

APPENDIX-A: Assembly list

APPENDIX-B: Exploded view

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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

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would be unable to work and no way to get it repaired.
If the connection wires, connectors or components fixed by the thermotropic glue need to disengage
when service, please soak the thermotropic glue into the alcohol and then pull them out in case of
dagame.

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.

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Alignment instructions

1. Test equipment

PM5518 (video signal generator)
VG-848 (VGA and HDMI signal generator)
CA210 (white balancer)

2 Alignment flow-chart

The alignment flow-chart is shown as fig-1

Check DDC, FLASH and POWER control IC

Combined test for general assembly

Factory initialization setup

IF channel AFT voltage of TV and AGC voltage

White balance adjustment

Fig-1 adjustment flow-chart

3 Unit adjustments

Connect all the boards according to wiring diagram, connect with power and observe the display.
Method for entering factory menu: press “INPUT”, “2”, “5”, ”8” and “0” in turn to enter factory menu;
press “CH+” and “CH-” to select adjustment items and press “VOL+” and “VOL-” to adjust value
items, press “MENU” continuously to exit.

3.1 Initialization
Enter factory menu, select “OPTION”, “EEPROM” and “HOTEL OPTION” sub-menu, adjustment of
items to see table1.

Table1 sub-menu adjustment

Items Preset Introduce

HOTEL 0 1: HOTEL OPTION of factory menu is optional

0: HOTEL OPTION of factory menu is not optional

LOGO 1 1: display LOGO in no signal or turn on

0: no LOGO display

ADC PRESCALE 046 Software auto preset according the unit

SIF PRESCALE 02E Software auto preset according the unit

Performance check

Preset ex-factory

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BACK LIGHT FF Software auto preset according the screen

ALL COLOR 1 1: white balance of each channel auto offset based on the HDMI white

balance

0: white balance of each channel adjust the offset base separately

EEPROM-MEMORAY

RECALL

> EEPROM Initialization (operate when EEPROM data chaos)

3.2 Adjustment for AFT voltage and AGC voltage of IF channel in TV

3.2.1 IF AFT adjustment
Disconnect J1(B face), input 38.9MHz PAL signal of 80dB from J1 near L11, Adjust L5 to value

1.25V of TP2. Enter factory menu, adjust TDA4470 from BG to LL, input 33.9MHz SECAM signal of

80dB, adjust R71 to value 1.25V of TP2, then wed J1.

3.2.2 IF AGC adjustment

Input 184.25MHz RF signal (PAL/BG) of 60DBuv from RF terminal, adjust R64 to value 4V of
TP4 and there should be no obvious snowy picture. Increase the signal to 90DBVuv and it should
be display normally and no obvious noise.

3.3 White balance adjustment

3.3.1 VGA white balance check

a. Input VG-848 signal of VGA: TIMING854(800* 600/60Hz) (PATIERN:CROSS) and auto
adjust to full screen, then input PAT948 black/white signal, enter factory menu ADC ADJ, select
AUTOTUNE and wait for OK display. Input PAT920(8 gray levels), check if the white balance is
normal, if not, set ALL COLOR to 0 and fine adjust according the method of 3.3.2

3.3.2 VGA white balance correct

a. Input VG-848 signal to VGA: TIMING854(800*600/60Hz) 8 level gray scale of PAT920,

adjust the balance with CA210.

b. Enter COLOR TEMP sub menu and select color temperature of standard(9300K)

c. Fixed B GAIN, adjust R GAIN, G GAIN to let the color coordinate of the seventh level be
285,293; Fixed B OFF, adjust R OFF, G OFF to let the color coordinate of the second level be
285,293 and the brightness be 3nit ~10nit or so. Repeat adjust R GAIN, G GAIN, R OFF and G OFF,
until the two color coordinate of the level gray scale be 285,293.

3.3.3 YPbPr/AV white balance check and correct
a. Connect VG-848 signal of YPBPR to YPBPR terminal and input TIMING972(1080i/60HZ)
color bar of PAT908(include black/white bar), Enter submenu of ADC ADJ, Select AUTOTUNE and
wait for OK display. Input PAT920(8 gray levels), check if the white balance is normal, if not, set ALL
COLOR to 0 and fine adjust according the method of 3.3.2 b, c.

b. Input AV signal(PM5518, 8 gray levels) to VIDEO terminal, check if the white balance is
normal, if not, set ALL COLOR to 0 and fine adjust according the method of 3.3.2 b, c.
Note: it can’t set back to 1 once ALL COLOR changes to 0.

4 Software upgrade

When software upgrading please enter factory menu first, enter ISP of OPTION, set ISP to 1 and
you can begin to upgrade. After upgrade finished, it needs to set ISP back to 0. If the picture can’t
display when upgrading, it needs to web JB2 of 01S board. Please disconnect JB2 again after
upgrading.

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5 Performance check

5.1 TV function
Enter searching menu → auto search, connect RF-TV terminal with central signal source and check
if the picture is normal, if there are channels be skipped. Check TXT and parental control.

5.2 AV, YPbPr terminals
Input AV/S, YPbPr/YCbCr HD signal, check if it is normal.

5.3 VGA terminal
Insert VGA terminal, input VGA format signal of 640X480@60 Hz and check if the display is normal.

5.4 check sound channel
Check the speaker of each channel.

5.5 other function check
Check the turn on/turn off timer, asleep timer, picture/sound mode, OSD, freeze/mute, stereo, ect.

5.6 presetting before ex-factory

Item Setting Item Setting Item Setting

PICTURE MODE STANDARD BALANCE 50 OSD LANGUAGE English

COLOR MODE NORMAL VOLUME 50 OSD HPOSITION 50

NR WEAK SLEEP TIMER OFF OSD VPOSITION 50

ZOOM FULL TTX LANGUAGE WEST OSD HALFTONE 50

SOUND MODE STANDARD BLUE SCREEN OFF OSD DURATION 15

AVC OFF WSS OFF

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Working principle analysis of the unit

The RF signal received by antenna will be sent to tuner TUN1, then IF signal will be obtained
through high amplifier and mixed frequency, through pre-intermediate amplified by V15, then it will
be sent to acoustic surface-wave Z17 to do IF filter and get better IF characteristics, then it will be
sent to N3 (TDA4470) to do intermediate amplification, phase-locked loop VCO and synchronous
wave detection to get video signal TV-V; after pre-intermediate amplification IF will also be sent to
acoustic surface-wave Z16 to do filter at the same time, then it will be sent to TDA4470 to do
intermediate amplification and output the second sound intermediate frequency signal (TV-SIF).

The TV-V signal output from TDA4470 together with TV-SIF will be sent to main IC NS2
(MST9E19A).

Video signal and audio signal of VGA will be sent to MST9W19A, too.

Video signal of YPbPr and Video RGB of SCART1 via video switch N5(PI5V330) selection to
MST9E19A

Video V(CVBS) of SCART1 and the audio signal L/R of YPbPr and SCART1 also sent to
MST9E19A.

The main IC NS2(MST9E19A) is a high performance and fully integrated IC, which can realize
video demodulating, video switch selection, A/D and D/A conversion, interlace/de-interlace
processing, modes conversion, OSD and low-voltage differential output, ect. And it also has
functions of audio demodulation, selection, sound effect processing and MCU.

The video signal via MST9E19A processing, output 4 pairs differential signal and 1 pair clock
signal for LCD panel display. TV-V output from TDA4470 via double video amplifying, it will be sent
to SCART1 for AV-OUT.

Audio signal via MST9E19A processing will be sent to operational amplifier NV3(LM358D)
pre-amplifying, then sent to sound amplifier NV1 (R2S15102NP) amplifying to speaker. TV-SIF via
MST9E19A demodulating and sound effect processing after, it output to operational amplifier
NV2(LM358D) amplify, then sent to SCART1 for AV-OUT.

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Block diagram

VGA

YPbPr

SCART1-RGB

SCART1-V

SCART1-L/R

L/R-VGA

L/R-YPbPr

L/R

TUNER

HDTV SW.

PI5V330

PRE AMP

SAW

EDID

24C02

TV-SIF

TV-V

SCART1-V OUT

TV-L/R SCART1-L/R OUT

IF AMP

TDA4470

2*AMP

POWER MEG.

AT M E G8 L

LCD TV

CONTROLLER

MST9E19A

FLASH

EEPROM

PANEL

PRE AMP

LM358D

AUDIO AMP.

R2S15102NP

SPEAKER

PRE AMP

LM358D

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IC block diagram

1. MST9E19A

The MST9E19A is a high performance and fully integrated IC for multi-function LDC monitor/TV with
resolutions up to SXGA(1280X1024)/WXGA+(1440X900). It is configured with an integrated
triple-ADC/PLL, an integrated DVI/HDCP/HDMI receiver, 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
requirements and spread-spectrum support for EMI management.

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