Panasonic TH-L42U5D User manual

©Panasonic Corporation 2012.
Unauthorized copying and distribution is a
violation of law.
ORDER NO.PAVCI1206036CE
LCD TV
Model No. TH-L42U5D

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CONTENTS
1. Safety precautions .................................................................................................3
2. Alignment instructions and method of software upgrading.....................................5
3. Working principle analysis of the unit ...................................................................15
4. Specifications.......................................................................................................16
5. Block diagram ......................................................................................................17
6. Wiring diagram ...................................................................................................20
7. Troubleshooting guide..........................................................................................25
8. Exploded View .....................................................................................................29
9. Replacement Parts List........................................................................................31
10. Boards Layout....................................................................................................32
11. Disassembly and Assembly Instructions............................................................33

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

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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
~ + 35 o C
Scope for storage
0 ~ + 60o C
Humidity Scope for operation 20% ~ 80 %
Scope for storage 5% ~ 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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2. Alignment instructions
(1) Test equipment
VG-859 (YPbPr, VGA, HDMI signal generator)
CA210 (white balancer)
(2) Power test
Connect main board, power board and IR board according the wiring diagram, connect
the power and press power key (Remote controller or Keypad) button to turn on the TV.
a) Test the pin voltage of P802/power board , the data is shown in table1:
Table1 voltage data of P802
For 42”
P802 Pin1,2 Pin3,4 Pin5,6,7 Pin8,9 Pin10,11
Voltage GND 11.4V~12.6V GND 11.4V~12.6V 4.75V~5.25V
For 42”
Pin12 Pin13 Pin 14 Pin15 Pin16
On:2.5V-5.25V
Off: 0-0.5V
Normal:0V~0.5V
Abnormal :Open drain
On:2.5V-5.25V
Off: 0-0.5V Duty 20%~100% NC

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(3) Alignment flow-chart
The alignment flow-chart is shown as fig-1
Check if DDC, HDCP KEY, FLASH are written
Combined test for general assembly
White balance adjustment
Connect to the center signal source and check each
Function of TV (station leaking, analog control, etc.)
Check the output of earphone and speaker.
Input AV signal and check the function
Input HD signal and check the function of YPbPr
Input VGA signal and check if the display is normal, check
the function (analog control), horizontal/vertical center, etc.
Input USB signal and check if the display is normal, check
the function (analog control), horizontal/vertical center, etc.
Input HDMI signal and check if the display is normal, check
the function (analog control), horizontal/vertical center, etc.
Preset ex-factory
Check the accessories and packing
Fig-1 adjustment flow-chart

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(4) Adjustment instruction
At any input source press the Mute(keep pressing) of Remote control and “Menu” (key pad) to enter factory mode .
During Factory menu, if “EXIT” key of Remote control is pushed, system will exit factory mode.
4-1. Source Calibration
4-1.1. Set the signal generator to input sources Component on LCD-TV;
Signal Format : 720P@60Hz Component 100%Color Bar
Instrument (Recommend) : Astro VG-859 / timing PG2 940
Signal analog level

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4-1.2. Entering factory Mode: Press up or down key of remote control to select “Auto Calibration”, Press 「OK」
key to enter the item.
-> Source calibration performed automatically, and “OK” info. will pop up after finished.
Repeat step 2 to do VGA input sources,
Signal Format : VGA 1024x768@60Hz
Instrument (Recommend) : Astro VG-859 / timing PG2 963

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4-2. Color Temperature Adjustment & Check
4-2.1. Set below items
4-2.3. Adjustment color temperature are min. / typ. / max.
1. Fixed the G Gain and G Offset, adjusts the R Gain, B Gain, R offset, B offset.
4-2.4. Exit Factory Mode:
After finish adjusting color temperature then press [MENU] or [RETURN] to back factory mode.
Press [EXIT] to exit factory mode.
4-2.2. Press up or down key of remote control to select “Cool”, Press 「ENTER」 key to enter the item.
RGAIN, GGAIN, BGAIN, ROFFSET, GOFFSET, BOFFSET, drive values are set for Warm, Normal,
and Cool independently.
2. If R Gain、B Gain and R offset、B offset value are larger the specification, duly change in G Gain or G
Offset at a time , after follow adjustment step 1.

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(5) Items of Factory menu
At any input source press the Mute(keep pressing) of Remote control and “Menu” (key pad) to enter factory mode .
During Factory menu, if “EXIT” key of Remote control is pushed, system will exit factory mode.
Press the up and down key to move high light item from Color Temperature -> Shipping -> NV Clear-> Full Power
-> Auto Calibration -> RF Burn In -> Debug ->Reset -> SoftWare Update(USB) ->Panel Gamma Control.
The NVRAM Clear and Reset to Default items will have a dialog “yes or no” to confirm the action.
Press “Enter” key to select high light item function. (Press left and right to adjust value)
1) Factory Color Temp data edit
Press up or down key to select high light item function
Press enter key to enter the item.
-Color temp default preset No (Warm, Medium, Cool).
-R, G, B data for each preset
Press “Up” or “Down” key to select “R”, “G”, “B” item
Press “Left” or “Right” key to set the “R”, “G”, “B” value
Press “MENU” or “EXIT” item to exit to factory mode
2) Shipping
Select the shipping area to “India” then do "Factory Reset "
After the actions are done, plug out the AC power.
3) NV CLEAR
Initializes TV setting to default values
- Reset settings: Gamma table, Channel table, Model table (H/V Position, Clock, Phase), Source
dependent setting (Contrast, Brightness etc.), Common setting (Volume, Language etc.), OSD
( Picture , Sound , Setup).
This item will have a dialog “yes or no” to confirm the action.
4) Full power
This is for power consumption test.
To measure the maximum power consumption of TV set, we adjust the value of following items to
maximum.
- Video:
Contrast maximum value, Brightness maximum value, Backlight maximum value.
- Audio: Volume maximum value, Bass default value, Treble default value.
Select on/off by left/right key and press Enter key to turn on/off the Full power function.
5) Auto Calibration
Source Calibration (gain/offset) must be adjusted by specific pattern, for VGA, Composite and
Component input source.
This item will have a result dialog “OK” or “NG”.