Xoceco PS42K8 Schematic

COLOR TELEVISION

PS42K8

Note: This maintenance manual is intended only for the reference of the maintenance people.

Please pay attention to the following points before carrying out t he maintenance w ork.

1.Safety Instructions

Please read the “Points for attention for the Maintenance & Repair of PDP”and “Criterion
for Identifying the Defe cts on Scr ee n” as belo w, before inspecting and adjusti ng th e TV set.

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

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

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

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 modu le or metal parts. That’s because within a short time relatively
high voltage still remains on the capacito r of th e driving part even after the power is off.
Make sure to begin relevant maintenance operation at least one minute after the power is
off.

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.

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.

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.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. 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.

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.

9).The complete TV set is designed on the basis of full consideration of thermal dissipation

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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.

10).There are quite a number of circuits in PDP that are integrated ones. Please be on
guard against stati c el ectr i ci ty. During mai nte nance operation be sure to cover yourself with
anti-static bag and before operation make sure to have it sufficiently grounded.

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.

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.

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.

14).Please put it f or 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 storage
Humidity
Scope for storage

Scope for operation

Scope for operation

0～50centigrade

-15～60centigrade
20%～80%
20%～80%

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 d ensity of fluorescen t p owder in the former. On the other hand, ev en 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 tim e during
operation.

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.

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 eletrolyzation.

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.

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.

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H

20). Care must be taken to guard ag ai nst d ust 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.

21). There is piece of i nsulator stuck on the r ear chassis corresp ondi ng to the p ower 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.

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.

<2>. “Criterion for Identifying the Defects on Screen”

The PDP produced by our Company at present uses the following criterion for

identifying the defective points:

2.1,Model PS－42D8:

There may appear three kinds of defective points for this model as shown in Fig.1, i.e.,

bright spot (remain bright); dark spot (non-illuminating); flickering spot (continuously
flickering). However they should not exceed the specification as in table 1. Otherwise the
product shall be deemed as sub-standard.

Zone B

Zone A

W/4 W/2

Figure 1 Defective Points

Table 1 Criterion for Three Kinds of Defective Points

W/4

H/4

H/2

H/4

Kind Area A Area B Remark
Dark spots No more than 2 No more than 8

Bright spot No more than 1 No more than 2
Flickering spot No more than 1 No more than 2

Total number of
defective points in A
and B shall not
exceed 8. The
distance between
two defective points
shall not be shorter
than 15mm.

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2.Method of Debugging

V

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1. Adjustment for MS42K8 excludes 3.1and 3.2

2.Adjustment and calibration Equipment

PM5518(Video signal generator), K-7253(VGA signal generator),CA100 (White

Balancer)

3.Flow process of Adjustment and calibration

For flow process of Adjustment and calibration, see Figure 1

Connect to central signal source, check if various T
functions (station skipping, analog control etc), check i
the output of earphone and speaker is normal

Input VGA sign al (one format) and check if display is
normal in the state of PC and various functions
(analog control, line/field center etc.)

Check if DDC has been FLASH written.

Production of CPU board and AV or TV board on the

line.

Check CPU board

Check AV or TV board

Combined test for general assembly

Input AV/S, HDTV signal and check various
functions under terminals

Check accessories and then packing

Figure 1 Flow process

of Adjustment and

calibration

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4.AV/TV Board adjustment

Adjust the potential meter VR12 on the power supply board, measure the test point
TP1(12VAMP) on the AV/TV board and set the reading at 15±0.05 V.

5. CPU board adjustment

Connect CPU board, push button board and AV or TV board, put power on, and
observe if the display is normal.

Method to enter the factory menu: Continuously push “ VOL+”“Mute” “ Video” keys
to enter the factory menu. Push the “ENTER” key to select different adjustment item when
the first line of each adjustment item is in high brightness. Push “ENTER” key after the
mode is selected with VGA and DV1 input and select three color temperatures
6500K,9300K,and 12000K. Push “MENU” to quit the factory menu.

5.1 EPROM initialization

Enter the first page of factory menu, push “ENTER” key after the selection of Clear

EEPROM, and shut off the power supply after the appearance of “OK”.

5.2 VGA channel adjustment

5.2.1 VGA channel mode preset

Input VGA signal of K-7253(PATTERN 5:Final Test),select TIME301(640*350/70Hz),
push”AUTO”key to automatically set the picture full screen. Likewise, automatically
adjustTIME302(720*400/70Hz), TIME303(640*480/60Hz), TIME311(800*600/60Hz),
TIME313(1024*768/60Hz),TIME315(640*480/75Hz),TIME316(800*600/75Hz),TIME317(10
24*768/75Hz),TIME319(1280*1024/75Hz) ,and TIME339(1280*1024/60Hz ) respectiv ely.

5.2.2 AGC adjustment of VGA channel

Adjust ADC-gain to 15

5.2.3 White balance adjustment of VGA channel

Input K-7253 TIME303(640*480/60Hz),PATTERN471,and the signal of 8 grades of
grey density. Enter the adjustm ent menu of white balance. Use the white balancer to adjust
second and seventh grades.

Select mode to be 6500K,adjust offset_R, offset_G, offset_B, so that the second grade
color coordinates are 313,329 and the brightness about 2 nit. Adjust gain_R, gain_G,
gain_B so that seventh grade color coordinates are 313,329. Adjust offset_R, offset_G,
offset_B and g ain_R, gain_G, gain_B,again and again unti l tw o g rads of gr ey density are all
set to 313,329.

Select mode to be 9300K,adjust off set_R, offset_G, offset_B,so that the second grade
color coordinates are 285,290 and the brightness about 2 nit. Adjust gain_R, gain_G,
gain_B so that seventh grade color coordinates are 285, 290. Adjust offset_R, offset_G,
offset_B and gain_R, gain_G, gain_B, again and again until two grads grey density are all
set to 285,290.

Select mode to be 12000K.Adjust o ffset _R, of fset_G , of fset_B,so th at the second g rade
color coordinates are 270,283 and the brightness to be about 2 nit. Adjust gain_R, gain_G,
gain_B, so that the sev enth gr ade color coor dinates ar e 270, 283. Adjust offset_R, of fset _G,
offset_B and gain_R, gain_G, gain_B, again and again until two grads grey density are all
set to 270,283.

Note: The value of gain_R, gain_G, gain_B should not exceed 128, and at least one

of them must be guaranteed to be 128.

5.3 AV/TV channel adjustment

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5.3.1 VCO, OPTION, sub-brightness, and sub-contrast adjustment

Input the AV color bar signal (PM5518 COLOUR BAR 100%)to VIDEO terminal, enter
the first page of factory page, select auto color, push “ENTER” key. Two seconds later, OK
appears and shows th e VCD a djust ment i s o ver. Set the value of op tion t o 9, s-br ig ht to 15 0,
s-contrast to 130,max-volume :PS42K8 and 14/MS42K8 to 66.

Enter the adjustment page of VPC3230, adjust the data of the page to be 0,1,3,3,0,1,9

from top to bottom.

5.3.2 White balance adjustment of AVTV channel

Input AV signal (PM 5518, 8 grades of grey density), enter the adjustment menu of
white balance. Use the white balancer to adjust second and seventh grades.
Adjust offset_R, offset_G, offset_B, so that the second grade color coordinates are 255,
245, and the brightness to be 2.5 nit. Fix gain_B to 128,adjust gain_R,gain_G,,so that the
seventh grade color coordinates are 288, 285, Adjust offset_R, offset_G, offset_B and
gain_R, gain_G, again and again until two grads grey density are all set to the specified
value.

5.4 White balance adjustment of D4 channel

Input YPbPr signal o f K-7253 to D4- terminal ,input eig ht grades of grey density sig nal of
TIME380(480i)PATTERN471, adjust s-bright to 120,S-contrast to 130. Enter the
adjustment menu of white balance,adjust second grade with balancer. Adjust offset_R,
offset_G, offset_B so that the second grade color coordinates are 255,245 and the
brightness about 2.5 nit.

Input eight grades of grey density signal of mode T IME392(480p),TIME394(720p)and
TIME396(1080i)separately. Repeat above operation, so that the second grade color
coordinates are 255,245 and the brightness about 2.5 nit.

6. Functional inspection

6.1 TV function

Enter the search menu auto search, connect the central signal source to RF-TV

terminal, check if there is station skipping.

6.2 BS connector

Input BS satellite signal to RF-BS terminal,check BS-5,BS-7,BS-11,if the picture and

sound of three channels are normal. Use oscillograph to check if the terminal output is
normal (Bit Stream is 1 Vpp data flow; Detection Out is 1.34 Vpp detective wave signal).

6.3 AV/S,D4 terminal
Input AV/S, HDTV signal, check if they are normal.

6.4 VGA connector

Insert VGA signal connector, input signal with format 640x480@60 Hz VGA, check if
the display is normal. If there is interfere in picture, push the adjustment key on the remote
control one more time and check if the display is normal.

6.5 Sound channel inspection

Check if the speaker output of each channel is normal.

6.6 For factory preset, see table. 1

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Table 1. For factory preset

Item Factory

Preset

Picture

mode

Sound

mode

N/R WEAK SRS ON

SCREEN 16:9 BALANCE ON

NATURE OSD

NEWS VGA color

Item Factory

Preset

Japanese BS POWER ASSOCIATE

language

9300 AV1/DECODER AV

temperature

Item Factory

Preset

3. Introduction of working principle of Plasma TV PS-42K8

The plane screen technology of Plasma is the latest state of art, and it is the best
selection of h igh qua lity p ictu re an d big pu re flat scree n. Th e pla sma dis play PD P is a kind
of display device by means of gas discharging. This kind of screen adopts plasma tube as
light emitting unit. PDP panel consists of many pixel units (plasma tube), such as the
screen of the 42” PDP sold currently, which consists of 852*480 pixel units. Each pixel unit
includes three sub-pixel units. Each pixel unit is a plasma tube, which displays red, green
and blue separately. Each chamber to which each plasma tube co rresponds is filled with
neon or xenon gas. When high voltage is applied between the poles of plasma tubes, the
gas sealed in the chamber of plasma tube between two layers of glass of radiates
ultraviolet light, which in turn excites the fluorescence powder of three base color - red,
green and blue - on the plane screen r adiates visibl e light. Each plasma t ube, as a pixel uni t,
produces different pictures with different color and grey density through various
combinations of its changes in b rightness and color, which is similar to the light emission of
CRT. Compared with other displays, the plasma technology has apparent differences. Its
construction and composition is ahead of other technologies. The working principal is
similar to normal fluorescent lamp. The color picture of the TV is formed of the light
emissions by each pixel unit of fluorescent powder. Thus, the picture looks bright, fresh,
clean and well focused. Besides, The most outstan ding characteri stic of plasm a TV is that it
can be made super thin, and it’s very easy to make the screen as large as over 40 inches
while the thickness is less than 100 mm. (The thickness of our PS-42K8 is 79mm only,
which is the thinnest in the market)

1. For the working principle and process flow of PS42K8, see block diagram

of complete TV set. The signal flow process is described briefly as follows:

By way of TUNA01, the RF signal of sa tellite TV, BS-RF produces color full TV signal
TV-BS and audio frequency signal BS-R/L. By way of TUNA02, the RF signal of broadcast
TV produces full col or TV signal TV-IN2 and second IF sound signal SIF. The VIDEO signal
selected by PI50V330(NA07)through TV-BS and TV-IN2 is sent to video decoder
VPC3230(U29). Video signals AV,SVHS and YcbCr are sent to U29 respectively. After the
selection of above four video signals, one route is as AV OUT, another route is for color
decode. Then the signal in the format of ITU-R656 of 8 bits is sent to FLI2310(U13)for
progressive processing.

D4 is sent to MST9883(U30), where the signal undergoes digit to analog conversion

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and then it is also sent to U13 in YUV format of 24bit.

24bit RGB signal is output and sent to main processing IC JAG-ASM(U12) after the
above two routes of signal are processed in matrix , color density, and tint in U13.. Another
route of RGB signal of computer VGA is also sent to U12, where two routes of signal are
subject to selection and processing for picture format. One route RGB signal of VGA
undergoes A/D conversion before being subject to selection and digit display processing
together with another route of signal, including OSD, GAMMA calibration, brightness and
contrast processing. These signals are changed into the format of 1024*768. The above
RGB signal of 24 bit is output to LVDS converter DS90C385(U31)of; where it is converted
into four pairs of low voltage differential signal acceptable for PDP screen. Then, the signal
is sent to PDP screen for picture display.

The audio R/L of left and right sound channels D4,YCbCr and BS undergoes selection
and is then sent to MSP3420(NA04) . AV,SVHS and R/L of VGA are sent to N AQ04.I n NA0 4,
the second sound IF( SIF) is demodulated into audio signal together with other four routes
of sound signal being switched for selection. The selected R/L after the processing in
volume and sound effect is then output. One route MONO sound is for AV OUT, the other
route is sent to M62494(NA08)of SRS sound field processor for SRS processing. The
signal, after sound power amplification by TPA3001(NA10,NA11), is for driving the speaker.
BS tuner outputs other route BIT/DET. The power is supplied by power supply board on
PDP screen and then transformed into different required power supplies.

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2.BLOCK DIAGRAM

VGA

BS-RF

RF

Y

C

AV

YCbCr

AV-V OUT

D4

BIT/DET

TUNA01

TUNA02

SIF

VPC3230

V

U30

ADC

MST9883

TV-BS

TV-IN2

NA07

PI5V330

TV

VIDEO DECODER

U29

RGB

ITU-R656

8bit

24bit
YUV

U13

DEINTER

LACER

FLI2310

U14

SDRAM

2

I C BUS

U3

EEPROM

RGB
24bit

U12

SCALER

JAG-ASM

U19

SDRAM

U20

SDRAM

U2

MICRO-CONTRLER

TSC80251G2D

RGB
24bit

U31

LVDS

DRIVER

DS90C385MTD

KEY BOARD

U4

FLASHMEMORY

IR

PANEL

SIF
D4

YCbCr

BS

VGA
AV

S

AV-MONO OUT

HEF4052

NA03

MONO

NA04

AUDIO

PROCESSOR

MSP3420

R/L

NA08

SRS 3D STEREO

CONTROLLER

M62494

R/L

NA10

NA11

AUDIO

AMPLIFIER

TAP3001

9

R/L

SPEAKER

4.IC BLOCK

1． MSP3420

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2．VPC3230

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3． JAG-ASM

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