Panasonic TH-L42U5D Schematic

ORDER NO.PAVCI1206036CE

LCD TV

Model No. TH-L42U5D

©Panasonic Corporation 2012. Unauthorized copying and distribution is a violation of law.

CONTENTS

1. Safety precautions .................................................................................................

2. Alignment instructions and method of software upgrading.....................................

3. Working principle analysis of the unit ...................................................................15

4. Specifications.......................................................................................................16

5. Block diagram ......................................................................................................17

6. Wiring diagram ...................................................................................................

7. Troubleshooting guide..........................................................................................25

8. Exploded View.....................................................................................................29

9. Replacement Parts List........................................................................................31

10. Boards Layout....................................................................................................32

11. Disassembly and Assembly Instructions............................................................33

Attention:

please read the following points carefully.

Safety precautions

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

servicing

1. Instructions

Be sure to switch off 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.

the power supply before

replacing or welding any components or

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 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

high voltage. Be

sure to take proper measures in

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.

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

~ + 35

Humidity

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.

Scope for storage

Scope for operation

Scope for storage

0 ~

+ 60oC

20% ~

5% ~ 90%

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.

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

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

Pin8,9 Pin10,11

Duty 20%~100% NC

(3) Alignment flow-chart

The alignment flow-chart is shown as fig-1

Connect to the center signal source and check each

Function of TV (station leaking, analog control, etc.)

Check the output of earphone and speaker.

Check if DDC, HDCP KEY, FLASH are written

Combined test for general assembly

White balance adjustment

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 th

e 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 th

e function (analog control), horizontal/vertical center, etc.

Preset ex-factory

Check the accessories and packing

Fig-1 adjustment flow-chart

(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

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

4-2. Color Temperature Adjustment & Check

4-2.1. Set below items

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.

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.

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.

4-2.4. Exit Factory Mode:

After finish adjusting color temperature then press [MENU] or [RETURN] to back factory mode. P

ress [EXIT] to exit factory mode.

(5) Items of Factory menu

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”.

6) RF Burn In Use “snow” pattern for burn in. Selected items are “On” and “Off”. While turn on burn in mode, firmware will automatically turn off “Auto power off” function. If there is no power supply suddenly, firmware will re-enter burn in mode automatically when power

supplied. Pressed the “Power” key (key pad), firmware will automatically turn off burn in mode. Burn in mode: Source is TV.

7) Debug It is for service use only.

8) Reset Reset all settings of OSD menu to default value.

- Reset settings: Channel table, Model table (H/V Position, Clock, Phase), Source dependent setting

(Contrast, Brightness etc.), Common setting (Volume, Language etc.).

9) Software update (USB) Upgrade firmware through USB.

10) Panel Gamma Control For factory test value of gamma.

(6) Performance check

LINE (pixel)

6-1 TV function Connect RF signal, select “auto tuning” to search the channels and mark sure the picture and sound are normally presented after finished.

6-2 AV terminals Input Video signal, make sure the picture and sound are normally presented.

6-3 YPbPr terminal Input YUV signal (VG859 signal generator), listed in table4 and make sure the picture and sound are normally presented.

Table4 YUV signal format

SYNC

POLARITY

LINE

FIELD

MODE

FREQ PERIOD

LINE(kHz)

FRAME

(Hz)

LINE (pixel)

FIELD (lines)

15.734 1716 Negative 27 1440 124 114

59.94Hz 720x480i

31,469 858 Negative 27 720 62 60

59.94Hz 720x480P

45 1650 Positive 74.25 1280 40 220

60Hz 1280x720P 60 750 Positive 720 5 20

50Hz 720x576i 15.734 1716 Negative 27 1440 124 114

59.94 525 Negative 480 3 15

59.94 525 Negative 480 6 30

PIXEL

CLOCK

(MHz)

Display

FRAME

(lines)

SYNC

WIDTH

FRAME

(lines)

BACK

PORCH

FRAME

(lines)

50Hz 720x576P 31.5 858 Negative 27.03 720 62 60

50 525 Negative 480 6 30

50Hz 1920X1080i 33.75 2200 Positive 74.25 1920 44 148

50 1125 Positive 540 5 15

50Hz 1920X1080p

50 1125 Positive 1080 5 15

33.75 2200 Positive 74.25 1920 44 148

60Hz 1920X1080i 60 1125 Positive 1080 5 15

67.5 2200 Positive 148.5 1920 44 148

60Hz 1920X1080P

67.5 2640 Positive 148..5

60 1125 Positive 1080 5 36

1920 44 148

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