Xoceco PS-42D8, PH-50D8 Schematic
PDP-TV
PS42D8
PH50D8
Note: This maintenance manual is intended only for the reference of the maintenance people. Please
pay attention to the following points before carrying out the maintenance work.
Safety Instructions
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). 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 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.
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.
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.
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.
8). Considering the module has a glass faceplate, please avoid extrusion by external force lest it
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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 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 static electricity. During maintenance 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 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 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 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.
16). As a digitalized display devise, this module is provided with error diffusion technology and the
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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.
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.
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.
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.
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H
Zone B
Zone A
W/4 W/2
Figure 1 Defective Points
Tabl e 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.
2.2. Model PH－50D8:
There may appear three kinds of defective points for this model as shown in Fig.2 --
bright spot (remain bright); dark spot (non-illuminating); flickering spot (remain flickering).
However they should not exceed the specification as in table 2. Otherwise the product shall
be deemed as sub-standard.
Figure 2 Defective Points
Tabl e 2 Criterion for Three Kinds of Defective Points
H
Zone B
Zone A
W
H/4
H/2
H/4
W/4 W/2 W/4
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Item Kind Area A Area B Remark
1 Dark spots No more than 4 No more than 10
2 Bright spot No more than 1 No more than 3
3 Flickering
spots
No more than 1 No more than 3
Total number of
defective points in A
and B shall not
exceed 14. The
distance between
two defective points
shall not be shorter
than 10mm.
Method of Debugging
For Models PS-42D8 and PH-50D8, the debugging part lies only in the white balance adjustment.
Nothing else should be adjusted and the maintenance software supplied for after-sale purpose has
normally shielded the value of white balance i.e., no more adjustment is needed when upgrading
the software. In case of special circumstances where the main board is replaced following method
can be adopted:
1). The white balance adjustment is made respectively in three ways - TV/AV、VGA、YpbPr. First
adjust TV/AV, then VGA and YpbPr at the last
2). Select corresponding channels respectively. After successively press the keys on the production
plant’s remote control (the key at the right hand lower corner doesn’t show up), go on to press
the left key, right key, confirmation key on the small keyboard one by one and then it’s possible
to enter the menu set up in the plant.
3). Use the right key to select and calibrate the menu. The white balance adjustment and YpbPr
white balance adjustment are for the purpose of white balance adjustment. For the white
balance adjustment of TV/AV and VGA it’s OK just directly adjust the first item whereas for
YpbPr adjust the second item.
4) For the white balance adjustment of TV/AV and VGA: select the item of “white balance
adjustment” from the menu. When it’s entered (as shown in the fig. Below), keep RCUI
immovable and adjust GCUT and BCUT so as to adjust the white balance of the dark area. For
the adjustment of white balance of the bright area, keep RGR immovable and then adjust
GGRV and BGRV. Repeat the above steps several times until the picture is normal in white
balance.
For the white balance adjustment of YpbPr: select the item of “white balance adjustment” from
the menu. When it’s entered (as shown in the fig. Below), adjust RCUT、BCUT and it’s done.
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5).Note: Except for the two items in the plant setup menu as above used for the white
balance adjustment and the items 5,6,7 (for test of pattern, color collocation and
degree of pure gray) in the calibrated menu that can be used to shoot trouble, no
adjustment should be made for the other items. Otherwise it may cause
abnormality to the set. The internal test signal of PW181 can be used for
troubleshooting.
Method of software upgrading
The plasma TV models PS-42D8 and PH-50D8 launched by our company are equipped with RS-232
interface for upgrading that is carried in the steps below:
A. Select a connection wire of serial port (see the figure below) which is required to
have a notch on its both ends and also the pins 2 and 3 on the two ends are
cross-connected.
B. Use the serial port connection wire to connect PC with PDP and set PDP to the off
position.
C. Open the folder of the upgrading software and double click the FlashUpgraderNT
(on condition of window 2000/XP/NT)
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or the FlashUpgrader (on condition of window 98)
After running the programs the following interfaces will appear:
Based on the features of computer set up the serial port (COM Port) and select
corresponding serial port (if it’s not possible to burnt-write other serial port can be used
instead). Baud-select 115200 and then select Reset Target After Download. Hit flash
press button and it’s ready to operate. For the setup of other items please refer to the
figure above (already defaulted by the system so it’s normally unnecessary to alter)
A. Switch on PDP and it begins to run the burnt-write program;
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B. Once it’s over with burnt-write, the cancel pushbutton will become flash. Switch off
the main power and then to switch on the TV set again.
Note: Do not switch the power or the set off in the course of burnt-writing. Otherwise it
may result in the inability of the flash to burnt-write again.
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Briefing on the operation principle of the plasma TV series PS-42D8
Plasma plane screen technology represents the state-of-the-art and it’s also the best choice for high quality picture
and large purely place screen. Plasma display screen PDP is a display unit employing gas discharge. This screen uses
plasma tube as its light emission component. The faceplate (panel)of PDP consists of many image elements (plasma
tubes) for example, the 42”pdp now on the market consists of 852*480 image elements. Each image element in turn
consists of three kinds of image sub-elements. Each image element is actually a plasma tube. These tubes are present
respectively in red, green and blue colors, as shown in fig. I. Each small chamber that corresponds to each plasma tube is
filled with neon and xenon gases. After applying high voltage between the plasma electrodes, the gases in the small
chambers of the plasma tubes sealed in the two layers of glass will produce ultraviolet so as to excite the three basic color
(red, green and blue) fluorescent powder to emit visible light. Each plasma tube acts as an image element. From the
composition of these image elements in different brightness, darkness and colors result the pictures and images of
various grays and colors, which is very similar to the light emission of display tube. Plasma technology is obviously
different form other display methods and is more advanced in structure and formation. Its working principle is similar to
normal daylight lamp. The TV color picture is composed of the light emitted from various independent fluorescent powder
image elements and therefore the picture is fresh and gaily colored, bright, clean and clear. Furthermore the most
outstanding feature of plasma TV is that it can be made super thin and it’s easy to make TV sets of more than 40” with
completely plane big screen but in thickness less than 100 mm (Our Model PS-42D8 is only 79mm thick and it’s the
thinnest in the market at present.)
Bus
dielectric
clapboard
Magnesia layer
Address
electrod
Front panel
ITO electrode
Fluoresce powder nce
Back board
Figure I Structure of Image Element
Plasma TV model PS-42D8 series of XOCECO is designed and developed by XOCECO itself. In
terms of the main CMOS chip this series of TV set employs PW181 made by Pixelworks Company.
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Among which:video decoder:VPC3230 Non-interlace conversion:PW1230
Ad conversion and DVI interface :AD9887 Audio treatment:MSP3440
Sound power amplification:D type power amplification of TI : Tpa3001
3D Y/C separation:uPD64083
CCD/V-CHIPdecoder:Z86229（For North America only）
Below is a short introduction to the basic work process flow of model PS-42D8series:
This TV model is based on dual MCU control of which the main MCU is PW181（N501, taking care
of the operation of various chips (including image treatment, channel switching, image display etc.), infra
red remote control receiving, the standby control, the control of auxiliary CPU, menu display, debugging
of picture effects and other major functions. The auxiliary CPU is SDA555X（NM5, which is responsible
for sound treatment (including volume adjustment, control of alt and base sound, stereo decode), station
searching control, push button, separation of 3D Y/C (valid only for system N) as well as the
CCD/V-CHIP decoding for the text for oversea sale TV sets etc. Connection between two MCU is made
by means of three pins of X708, i.e., INT (interruption), S1(RXD), S2（TXD）
2.Volume of sound
This model employs double integrated tuner (including high frequency and medium amplification
circuits). The signal received by antenna is fed to the main tuner, TUNER1, which contains a high
frequency distributor, from which RF signal is shunt to supply to TUNER3 for use. Pin 14 of TUNER1
is for the power supply of high frequency distributor (+5v). Tuners are controlled by auxiliary MCU
NM5 （SDA、SCL）to select proper channel and carry out correct switching of systems. After high
amplification and medium amplification decoding, video signal and audio signal are output. The
output signal of TUNER1 is fed into decoder N102 as the display of main picture whereas the output
signal of TUNER3 is fed into decoder N302 as the display of the auxiliary picture for dual picture.
Audio signal is directly fed into audio frequency processor NM2 MSP3440. At the same time dual
way tuners all send their medium frequency signal of the second sound to NM2 for treatment (used
for decoding of stereo or automatic sound volume control). NM2 is provided with the switching over
device for audio frequency channels. Audio input of VGA/DVI/YprPb of the main board, after the
switching-over as selected by N3, is fed together with the audio signal of TV and AV into NM2, where
switching over is selected. The selected audio frequency signal is made use of in the following three
ways. One way is, after being subjected to the control of volume and alt and base sound, fed
separately through left and right sound channels into sound power amplifier TPA3001 for
amplification. Then it is fed into the loudspeaker for sound reproduction. Another way is also fed
separately through left and right sound channels into earphone power amplifier NM9 TDA7053 for
amplification before being output to earphone socket for listening, of which the volume is controlled
by PWM signal produced by pin 50 of NM5.
The remaining way is output through video board as AV out..
The block diagram of MSP3440 is as follows:
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2, 3:SCL、SDA，for the control of IC operation;
27,28:output to the right and left channel of sound power amplifier;
33,34:right and left channel of earphone sound;
36,37:AV OUT right and left channel of sound;
47,48:right and left channel of sound fed from main board;
50,51:AV IN right and left channel of sound;
53,54:right and left sound channel of sub-channel TV;
56,57:right and left sound channel of main channel TV;
67,69:SIF input of main and sub channel TV
Sound power amplifier TPA3001 is an amplification of mono-channel high efficiency D type power.
Under the condition of no heat dissipation its output power can be as high as 20 w. It has the functions of
over current and overheating protection. Automatic protection comes in when the input to the ground is
short-circuited. Then output is stopped. After the removal of short circuit, switch the set again and it
restores to normal. Therefore if the set becomes soundless due to the short circuit caused in carelessly
pulling out or plugging in the audio frequency wire (it is certainly not recommendable to do so), just
switch it on again and no big deal.
3. Picture and image:
Y signal of AV and SVHS shares the same channel. SVHS has priority. Identification of terminal S is
determined by electric level SID fed from SVHS socket to NM5. When the electric level of SID is of high
value, the system is identified as SVHS. Signals from TV or AV and YCRCB are altogether fed into
digital decoder VPC3230 (sent separately in two ways to N102 and N302). Channel switching is carried
out. They are decoded into 16bit CCIR601 signal to be fed into the processor of lower level for treatment.
VPC3230 mainly functions to switch over channels, separate Y/C
of 4 lines, decoding of colors and adjustment of picture effect.
3．1 The block diagram of VPC3230 is shown below:
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