Xoceco PH-50HU31S Schematic

PDP TELEVISION

PH-50HU31S

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

Attention: This service manual is only for service personnel to take reference with. Before

servicing please read the following points carefully.

Safety precautions

Please read the “Points for attention for the Maintenance & Repair of PDP” and “Criterion for Identifying the Defects on Screen” as below, before inspecting and adjusting the TV set.

1. “Points for attention for the Maintenance & Repair of PDP”

To avoid possible danger, damage or jeopardy to health and to prevent PDP screen from new damage, the maintenance people must read the following carefully. If they ignore the following warnings, there will be deathful risks:

1.1 Screens vary from one model to another and therefore not interchangeable. Be sure to use the same type of screen in the replacement.

1.2 The operation voltage is approximately 350v for PDP module (including screen, driving circuit, logic circuit and power module). If you want to conduct maintenance work on PDP module when the set is in normal operation or just after the power is off, you must take proper measures to avoid electric shock and never have direct contact or touch with the circuitry of the working module or metal parts. That’s because within a short time relatively high voltage still remains on the capacitor of the driving part even after the power is off. Make sure to begin relevant maintenance operation at least one minute after the power is off.

1.3 Don’t apply on the module any power supply that is higher than the specification. If the power supply used deviates from the value given in the specification, there might be a possibility of leading to fire or damage to the module.

1.4 Never have operation or mounting work under unsuitable environment such as areas in the vicinity of water (bath room, laundry, water chute of kitchen), sources of fire, heat-radiation parts or direct exposure to sunlight. Otherwise there will be kickbacks.

1.5 In case foreign substances such as water, liquid, metal slices or others fall into the module carelessly power must be cut off immediately. Keep the module as it is and do not move anything on the module. Otherwise it might be possible to contact the high voltage or cause shock short circuit so that it may lead to fire or electric shock.

1.6 If there is smoke, abnormal smell or sound from the module, please cut the power off immediately. Likewise in case the screen doesn’t work when the power is on or during the operation, please also cut off the power at once. No more operation in this case.

1.7 Do not remove or plug its connection wire when the module is in operation or right after the power is off. That’s because there remains a relatively high voltage on the capacitor of the driving circuit. If there is a need to remove or plug in the connection wire, please wait at least one minute after the power is off.

1.8 Considering the module has a glass faceplate, please avoid extrusion by external force lest it should cause glass breakage that may get people injured. Two people are needed in cooperation to move this module lest contingency takes place.

1.9 The complete TV set is designed on the basis of full consideration of thermal dissipation by convection, with the round hole on the top for heat emission. To avoid overheat, please do not have any covering on the hole during normal operation and never put it in the place

where the space is narrow and in bad ventilation.

1.10 There are quite a number of circuits in PDP that are integrated ones. Please be on guard against static electricity. During maintenance operation be sure to cover yourself with anti-static bag and before operation make sure to have it sufficiently grounded.

1.11 There are a big number of connection wires distributed around the screen. Please take care not to touch or scuff them during maintenance or removing the screen, because once they are damaged the screen will fail to work and it’s not possible to repair it.

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

damage.

1.12 Connector for the circuit board of the screen part is relatively fine and delicate. Please take care in the replacement operation lest it should get damaged.

1.13 Special care must be taken during transportation and handling because strenuous vibration could lead to screen glass breakage or damage on the driving circuitry. Be sure to use a strong outer case to pack it up before transportation or handling.

1.14 Please put it for storage in an environment in which the conditions are under control so as to prevent the temperature and humidity from exceeding the scope stipulated in the specification. For prolonged storage please cover it with anti-moisture bag and have them piled and stored in one place. The environmental conditions are tabulated as below:

Temperature Scope for operation 0~50centigrade

Scope for storage -15~60centigrade

Humidity Scope for operation 20%~80%

Scope for storage 20%~80%

1.15 If a fixed picture is displayed for a long time, difference in its brightness and color may occur compared with movable pictures. But it doesn’t show any problem and the reason is that there is reduced density of fluorescent powder in the former. On the other hand, even if changes take place in the picture, it can keep its brightness for a period of time (several minutes). It’s a feature inherent with plasma and it’s not abnormal. However please try as much as possible to avoid showing a still picture of high brightness for a long time during operation.

1.16 As a digitalized display devise, this module is provided with error diffusion technology and the gray scale and false enhancement of contour can be displayed by reusing of sub-field. As compared with cathode ray tube, it can be found in the moving picture that at the brim of the face of a person there are some wrong colors.

1.17 During the display of graph (indicating the gradual change in brightness horizontally or vertically) resulting from gray scale test it can be found that the brightness for the two adjacent levels is uneven. This is caused by the reuse of sub-field, the display of load rectification and the electrolysis.

1.18 The screen front plate is of glass. Please make sure that the screen has been put in place during erection. If it is not in place before the erection begins it may lead to screen crack or breakage.

1.19 Make sure the screw used in the mounting of the screen is of the original specs lest it should cause damage to the screen due to mismatch. Special care should be taken not to use too long or

too big screw.

1.20 Care must be taken to guard against dust during assembling or dismantling, especially to avoid dirt from falling in between the screen and the glass lest it should harm the receiving and viewing effect.

1.21 There is piece of insulator stuck on the rear chassis corresponding to the power supply board. It is used to isolate the cool part from the hot part. Please take care to keep it intact lest it should become a potential safety trouble.

1.22 In addition to plasma screen, the glass is a part of high value. It has such functions as anti-radiation, adjustment of color temperature etc. Please handle it carefully.

Alignment instructions

1. Test equipment

PM5518 (video signal generator) VG-849 (VGA signal generator) CA210 (white balancer)

2 Alignment flow-chart

The alignment flow-chart is shown as fig-1

Check DDC, HDCP KEY, FLASH and POWER control IC

Combined test for general assembly

Factory initialization setup

IF channel voltage of TV and AGC voltage adjustment

White balance adjustment

Fig-1 adjustment flow-chart

Performance check

Preset ex-factory

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” 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 00A Adjust according different power consumption

SIF PRESCALE 000 Adjust according different power consumption

BACK LIGHT 28 Adjust according different 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

ISP 0 0: no unit upgrade on the assembly line

1: unit upgrade on the assembly line

NO STANDY 00 01: turn on; 00: memory function of turn on; 10: standby

INIT VOLUME 0-100 Volume of turn on

INIT CHANNEL 1-200 Channel of turn on

INIT SRC Source Source of turn on

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 AFC adjustment Disconnect J401(B face), input 38.9MHz PAL signal of 80dB from J401 near the socket, Adjust

L404 to value 0.9V of TP402. Enter factory menu, adjust TDA4470 from BG to LL, input 33.9MHz SECAM signal of 80dB, adjust RP402 to value 0.9V of TP402, then wed J401.

3.2.2 IF AGC adjustment

Input 184.25MHz RF signal of 60DB from RF terminal, adjust RP401 to value 4V of TP404 and there should be no obvious snowy picture. Increase the signal to 90DBV and it should be display normally and no obvious noise.

3.3 White balance adjustment

3.3.1 white balance adjustment of HDMI

a. Input VG-848 signal from HDMI: TIMING854(800* 600/60Hz) and eighth level gray-scale

signal of PAT920. Use color analyzer CA210 to adjust white balance.

b. Enter submenu of COLOR TEMP., Select 9300k of color temperature

c. Fixed value of B GAIN, adjust R GAIN and G GAIN, let the color coordinate of the seventh level be 285 and 293. Fixed value of B OFF, adjust R OFF and G OFF, let the color coordinate of second level be 285 and 293 and the brightness be about 3nit-10nit. Adjustment R GAIN, G GAIN, R OFF and G OFF repeatedly until the value of the two levels gray-scale be 285 and 293.

3.3.2 VGA/YPBPR/AV white balance check and correct

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 3.3.1

b. 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

c. 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

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 J1 of 01S board. Please disconnect J1 again after upgrading.

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/S, 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 HDMI terminal Insert HDMI terminal, input signal of 640 X 480@60 Hz signal and check if the display is normal.

5.5 check sound channel Check the speaker and headphone of each channel.

5.6 RS232 terminal Insert earphone to COM terminal and check if the long-distance control function is normal.

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

5.8 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

Working principle analysis of the unit

The RF signal received by antenna will be sent to tuner TUN401, then IF signal will be obtained through high amplifier and mixed frequency, through pre-intermediate amplified by V408, then it will be sent to acoustic surface-wave Z407 to do IF filter and get better IF characteristics, then it will be sent to N404 (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 Z406 to do filter at the same time, then it will be sent to N404 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 NS4(MST9E88L).

Video signals of AV1/S, VGA, YPbPr and HDMI will be sent to MST9E88L, too.

Video RGB of SCART1 and S-Y, S-C of SCART2 will still be sent to MST9E88L, and the audio signal of them via audio switch N302(HEF4052BT) selection after also sent to MST9E88L.

The main IC NS4(MST9E88L) is a high performance and fully integrated IC, which can realize HDMI processing, 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 selection, processing and MCU.

The video signal via MST9E88L processing, output 4 pairs differential signal and 1 pair clock

signal for PDP panel display. TV-V output from TDA4470 via double video amplifying, it will be sent

to SCART1 for AV-OUT. AV processed by MST9E88L via double video amplifying will be sent to SCART2 for AV-OUT, too.

Audio signal via MST9E88L processing will be sent to sound amplifier N405 (MP7722DF) amplifying to speaker. The audio also sent to earphone amplifier N406(BH3547F) amplifying to earphone. TV audio signal will be sent to D/A converter NS6(DS4344) through I2S bus converting to analog audio signal TV-L/R, then sent to SCART1 for AV-OUT. At the same time, TV-L/R together with AV-L/R processed by MST9E88L will be sent to audio switch NS8(HEF4052BT), after selecting to SCART2 for AV-OUT.

Block diagram

HDMI

VGA

YPbPr

(DTV)

SCART1-RGB

SCART1-AV

SCART1-L/R

SCART2-L/R

SCART2-Y

EDID

24C02

HDTV SW.

PI5V330

AUDIO SW.

HEF4052

EDID

24C02

SCART2-C

Y/AV1

S-C

TUNER

TV-V

TV-SIF

L/R-VGA

L/R-YPbPr

L/R-AV1/S

AV- L / R

SCART1-V OUT TV-IIS

SCART2-L/R OUT

SCART2-V OUT CVBS

SCART1-L/R OUT

SAW

IF AMP

TDA4470

2*AMP

TV-L/R

POWER MEG.

AT M E G8 L

LCD TV

CONTROLLER

MST9X88LD

D/A

CS4334

HP AMP

BH3547F

AUDIO SW.

HEF4052

DDR

FLASH

EEPROM

HDCP KEY

PANEL

AUDIO AMP.

MP7722

SPEAKER

HEAD

PHONE

IC block diagram

1. MST9E88L

The MST9E88L is a high performance and fully integrated IC for multi-function LCD monitor/TV with resolutions up to SXGA/WXGA. 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. With external frame buffer, 3-D video decoding and processing are fulfilled for high-quality TV applications. To further reduce system costs, the MST9E88L also integrates intelligent power management control capability for green-mode requirements and spread-spectrum support for EMI management.

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