Panasonic TC-L42S20BL Schematic

Service ManualORDER NO. PBRAS1103078CE

LCD TV

TC-L42S20BL

Chassis: KM09W

• Design and specifications are subject to change without notice. Mass and dimensions shown are approximate.

CS Division Technical Support

TC-L42S20BL

CONTENTS

1 Safety Precautions................................................................................	3
1.1. General Guidelines...........................................................................	3
1.1.1. Leakage Current Cold Check.........................................................	3
1.1.2. Leakage Current Hot Check (See Figure1.)...................................	3
2 Warning.................................................................................................	4
2.1. Prevention of Electrostatic Discharge (ESD)
to Electrostatically Sensitive (ES) Devices...............................................	4
2.2. About lead free solder (PbF).............................................................	5
3 Service Navigation................................................................................	6
3.1. Service Hint ......................................................................................	6
4 Specifications........................................................................................	7
5 Service Mode........................................................................................	8
5.1. How to enter into Service Mode........................................................	8
5.1.1. Contents of adjustment mode........................................................	8
5.1.2. How to exit.....................................................................................	8
5.2. SRV-TOOL........................................................................................	9
5.2.1. How to access................................................................................	9
5.2.2. Display of SOS History...................................................................	9
5.2.3. POWER ON TIME/COUNT............................................................	9
5.2.4. Exit.................................................................................................	9
5.3. Service Mode Adjustment.................................................................	10
5.3.1. Self Check Mode............................................................................	10
5.3.2. Hotel Mode Adjustment..................................................................	10
5.3.3. Hotel Mode.....................................................................................	10
6 Troubleshooting Guide..........................................................................	11
6.1. Check of the IIC bus lines.................................................................	11
6.1.1. How to access................................................................................	11
6.1.2. Exit.................................................................................................	11
6.1.3. Screen display................................................................................	11
6.1.4. Check Point....................................................................................	11
6.2. Power LED Blinking timing chart.......................................................	12
6.3. No Power..........................................................................................	12
7 Disassembly and Assembly Instructions...............................................	13
7.1. AC Cord Dressing.............................................................................	13
7.2. AC Cord Installation..........................................................................	14
7.3. Control Panel Assembly & Clamper Installation................................	15
7.4. Side AV Preparation & Installation....................................................	16
7.5. Speaker Preparation & Installation....................................................	17
7.6. LCD Panel Assembly Installation......................................................	18
7.7. LED Panel Installation.......................................................................	19
7.8. Felt Sticking at LVDS Wire................................................................	20
7.9. LCD Bracket and MTG Installation ...................................................	21
7.10. Pedestal Assembly..........................................................................	22

8 Measurements and Adjustments...........................................................	24
8.1. Voltage chart of A-board....................................................................	24
8.2. Voltage chart of P-board...................................................................	24
9 Block Diagram.......................................................................................	25
9.1. Main Block Diagram..........................................................................	25
10 Wiring Connection Diagram................................................................	26
11 Schematic Diagram.............................................................................	27
11.1. Schematic Diagram Notes...............................................................	27
11.2. A Board............................................................................................	28
11.2.1. A Board - Sheet : 002 (1 / 3).........................................................	28
11.2.4. A Board - Sheet : 010 (1 / 3).........................................................	31
11.2.7. A Board - Sheet : 011 (1 / 3).........................................................	34
11.2.10. A Board - Sheet : 012 (1 / 3).......................................................	37
11.2.13. A Board - Sheet : 020 (1 / 3).......................................................	40
11.2.16. A Board - Sheet : 031 (1 / 3).......................................................	43
11.2.19. A Board - Sheet : 033 (1 / 2).......................................................	46
11.2.21. A Board - Sheet : 040 (1 / 5).......................................................	48
11.2.26. A Board - Sheet : 050 (1 / 2).......................................................	53
11.2.28. A Board - Sheet : 060 (1 / 2).......................................................	55
11.2.30. A Board - Sheet : 061 (1 / 1).......................................................	57
11.2.31. A Board - Sheet : 090 (1 / 3).......................................................	58
11.2.34. A Board - Sheet : 201 (1 / 3).......................................................	61
11.2.37. A Board - Sheet : 300 (1 / 4).......................................................	64
11.2.41. A Board - Sheet : 700 (1 / 2).......................................................	68
11.2.43. A Board - Sheet : 701 (1 / 2).......................................................	70
11.3. K Board...........................................................................................	72
11.4. P Board...........................................................................................	74
11.5. V Board...........................................................................................	77
12 Printed Circuit Board...........................................................................	80
12.1. A-Board...........................................................................................	80
12.2. A-Board...........................................................................................	81
12.3. P-Board...........................................................................................	82
12.4. P-Board...........................................................................................	83
13 Exploded View and Replacement Parts List.......................................	84
13.1. Exploded View and Mechanical Replacement Parts List................	84
13.2. Electrical Replacement Parts List...................................................	84
13.2.1. Replacement Parts List Notes......................................................	84
13.2.2. Mechanical Parts Location...........................................................	85
13.2.3. Mechanical Replacement Parts List.............................................	85
13.2.4. Assembled Boards.......................................................................	85
13.2.5 Packing Exploded View 1..............................................................	86
13.2.6. Packing Exploded View 2.............................................................	87
13.2.7. Electrical Replacement Parts List................................................	88

TC-L42S20BL

1 Safety Precautions

1.1.General Guidelines

1.When servicing, observe the original lead dress. If a short circuit is found, replace all parts which have been overheated or damaged by the short circuit.

2.After servicing, see to it that all the protective devices such as insulation barriers, insulation papers shields are properly installed.

3.After servicing, make the following leakage current checks to prevent the customer from being exposed to shock hazards.

4.When conducting repairs and servicing, do not attempt to modify the equipment, its parts or its materials.

5.When wiring units (with cables, flexible cables or lead wires) are supplied as repair parts and only one wire or some of the wires have been broken or disconnected, do not attempt to repair or re-wire the units. Replace the entire wiring unit instead.

6.When conducting repairs and servicing, do not twist the Faston connectors but plug them straight in or unplug them straight out.

1.1.1.Leakage Current Cold Check

1.Unplug the AC cord and connect a jumper between the two prongs on the plug.

2.Measure the resistance value, with an ohmmeter, between the jumpered AC plug and each exposed metallic cabinet part on the equipment such as screwheads, connectors, control shafts, etc. When the exposed metallic part has a return path to the chassis, the reading should be 100 Mohm and over.

When the exposed metal does not have a return path to the chassis, the reading must be .

1.1.2.Leakage Current Hot Check (See

Figure 1.)

1.Plug the AC cord directly into the AC outlet. Do not use an isolation transformer for this check.

2.Connect a 1.5kohm, 10 watts resistor, in parallel with a 0.15μF capacitors, between each exposed metallic part on the set and a good earth ground such as a water pipe, as shown in Figure 1.

3.Use an AC voltmeter, with 1000 ohms/volt or more sensitivity, to measure the potential across the resistor.

4.Check each exposed metallic part, and measure the voltage at each point.

5.Reverse the AC plug in the AC outlet and repeat each of the above measurements.

6.The potential at any point should not exceed 0.75 volts RMS. A leakage current tester (Simpson Model 229 or equivalent) may be used to make the hot checks, leakage current must not exceed 1/2 milliamp. In case a measurement is outside of the limits specified, there is a possibility of a shock hazard, and the equipment should be repaired and rechecked before it is returned to the customer.

Figure 1

TC-L42S20BL

2 Warning

2.1.Prevention of Electrostatic Discharge (ESD) to Electrostatically

Sensitive (ES) Devices

Some semiconductor (solid state) devices can be damaged easily by static electricity. Such components commonly are called Electrostatically Sensitive (ES) Devices. Examples of typical ES devices are integrated circuits and some field-effect transistors and semiconductor [chip] components. The following techniques should be used to help reduce the incidence of component damage caused by electrostatic discharge (ESD).

1.Immediately before handling any semiconductor component or semiconductor-equipped assembly, drain off any ESD on your body by touching a known earth ground. Alternatively, obtain and wear a commercially available discharging ESD wrist strap, which should be removed for potential shock reasons prior to applying power to the unit under test.

2.After removing an electrical assembly equipped with ES devices, place the assembly on a conductive surface such as aluminum foil, to prevent electrostatic charge buildup or exposure of the assembly.

3.Use only a grounded-tip soldering iron to solder or unsolder ES devices.

4.Use only an anti-static solder removal device. Some solder removal devices not classified as [anti-static (ESD protected)] can generate electrical charge sufficient to damage ES devices.

5.Do not use freon-propelled chemicals. These can generate electrical charges sufficient to damage ES devices.

6.Do not remove a replacement ES device from its protective package until immediately before you are ready to install it. (Most replacement ES devices are packaged with leads electrically shorted together by conductive foam, aluminum foil or comparable conductive material).

7.Immediately before removing the protective material from the leads of a replacement ES device, touch the protective material to the chassis or circuit assembly into which the device will be installed.

Caution

Be sure no power is applied to the chassis or circuit, and observe all other safety precautions.

8.Minimize bodily motions when handling unpackaged replacement ES devices. (Otherwise ham less motion such as the brushing together of your clothes fabric or the lifting of your foot from a carpeted floor can generate static electricity (ESD) sufficient to damage an ES device).

TC-L42S20BL

2.2.About lead free solder (PbF)

Note: Lead is listed as (Pb) in the periodic table of elements.

In the information below, Pb will refer to Lead solder, and PbF will refer to Lead Free Solder. The Lead Free Solder used in our manufacturing process and discussed below is (Sn+Ag+Cu). That is Tin (Sn), Silver (Ag) and Copper (Cu) although other types are available.

This model uses Pb Free solder in it’s manufacture due to environmental conservation issues. For service and repair work, we’d suggest the use of Pb free solder as well, although Pb solder may be used.

PCBs manufactured using lead free solder will have the PbF within a leaf Symbol PbF stamped on the back of PCB.

Caution

•Pb free solder has a higher melting point than standard solder. Typically the melting point is 50 ~ 70 °F (30~40 °C) higher. Please use a high temperature soldering iron and set it to 700 ± 20 °F (370 ± 10 °C).

•Pb free solder will tend to splash when heated too high (about 1100 °F or 600 °C).

If you must use Pb solder, please completely remove all of the Pb free solder on the pins or solder area before applying Pb solder. If this is not practical, be sure to heat the Pb free solder until it melts, before applying Pb solder.

•After applying PbF solder to double layered boards, please check the component side for excess solder which may flow onto the opposite side. (see figure below)

Suggested Pb free solder

There are several kinds of Pb free solder available for purchase. This product uses Sn+Ag+Cu (tin, silver, copper) solder.

However, Sn+Cu (tin, copper), Sn+Zn+Bi (tin, zinc, bismuth) solder can also be used.

TC-L42S20BL

3 Service Navigation

3.1.Service Hint

Board	Main Device
A BOARD	AVSW, TUN, OFDM, ADV, P-AVC, GENX, EEP, TEMP
P BOARD	Power Supply
V BOARD	Remote, LED, Luminunce Sensor
K BOARD	KEY, Power SW
TC BOARD	T-CON Board

TC-L42S20BL

Specifications

TC-L42S20A / TC-L42S20P / TC-L42S20BL

Alimentación

110-220 V ~ 50/60 Hz

Consumo

Promedio

193 W

Condición en espera

0,4 W

pantalla

Aspecto

16:9

Tamaño visible de la pantalla

106 cm (diagonal)

930 mm (L) × 523 mm (A)

Número de pixels

2.073.600 (1.980 (L) × 1.080 (A)

sonido

Altavoz

160 mm × 42 mm × 2 pçs, 8 Ω

Salida de audio

20 W (10 W + 10 W), 10% THD

Auriculares

M3 (3,5 mm) mini jack estéreo ×1

VGA, SVGA, XGA

Señales de computadora

SXGA ..... (comprimido)

Frecuencia de lectura horizontal 31 - 69 kHz

Frecuencia de lectura vertical 59 - 86 Hz

1. PAL-M

Sistema de recepción/Nombre

2. PAL-N

Recepción de transmisión y reproducción en videocasete o DVD

de la banda

3. NTSC

Canales de recepción

BANDA VHF

BANDA UHF

CATV

(TV Normal)

2-13 (NTSC M EUA)

14-69 (NTSC M EUA)

1-125 (EUA CATV)

Antena - Trasera

VHF / UHF

Condiciones de operación

Temperatura: 0°C - 40°C

Humedad: 20% - 80% HR (sin condensación)

Entrada

AUDIO L - R

Tipo RCA PIN ×2

0,5 V[rms]

AV1

VIDEO

Tipo RCA PIN ×1

1,0 V[p-p] (75 Ω)

COMPONENT

1,0 V[p-p] (incluyendo sincronía)

conexión

PB/CB, PR/CR

±0,35 V[p-p]

Entrada

AUDIO L - R

Tipo RCA PIN ×2

0,5 V[rms]

AV2

VIDEO

Tipo RCA PIN ×1

1,0 V[p-p] (75 Ω)

Entrada

AUDIO L - R

Tipo RCA PIN ×2

0,5 V[rms]

Terminales

AV3

VIDEO

Tipo RCA PIN ×1

1,0 V[p-p] (75 Ω)

Salida

AUDIO L - R

Tipo RCA PIN ×2

0,5 V[rms] (alta impedáncia)

Monitor

VIDEO

Tipo RCA PIN ×1

1,0 V[p-p] (75 Ω)

Otros

Entrada HDMI1/2/3

Conectores Tipo A

• Este TV soporta la función “HDAVI Control 5”

Entrada PC

HIGH-DENSITY D-SUB 15 PINES R, G, B/0,7 V [p-p] (75 Ω)

HD, VD/TTL Nível 2,0 - 5,0 V[p-p] (alta impedáncia)

Entrada de tarjeta

Entrada SD CARD ×1

Entrada USB

USB 2.0 conector Tipo A ×1, 5V DC, 500 mA máx.

Dimensiones (L × A × P)

1021 mm × 680 mm × 310 mm (con pedestal)

1021 mm × 637 mm × 115 mm (solamente TV)

Peso

21,0 kg (con pedestal)

18,0 kg (solamente TV)

TC-L42S20BL

5 Service Mode

5.1.How to enter into Service Mode

While pressing [VOLUME ( - )] button of the main unit, press [INFO] button of the remote control three times within 2 seconds.

5.1.1.Contents of adjustment mode

•Value is shown as a hexadecimal number.

•Preset value differs depending on models.

•After entering the adjustment mode, take note of the value in each item before starting adjustment.

Main item	Sub item	Sample Data	Remark

ADJUST	CONTRAST	000

	COLOR	4C

	TINT	00

	SUB-BRT	808

	BACKLGT	22E

	B-Y-G	34

	R-Y-A	00

WB-ADJ	R-GAIN	F7

	G-GAIN	FB

	B-GAIN	DB

	R-CENT	82

	G-CENT	80

	B-CENT	86

OPTION	Boot	ROM	Factory Preset.

	STBY-SET	00

	EMERGENCY	ON

	CLK MODE	00

	CLOCK	0E4

RM-SET		00	Fixed.

SRV-TOOL		00	See next.

5.1.2.How to exit

Switch off the power with the [POWER] button on the main unit or the [POWER] button on the remote control.

TC-L42S20BL

5.2.SRV-TOOL

5.2.1.How to access

1.Select [SRV-TOOL] in Service Mode.

2.Press [OK] button on the remote control.

5.2.2.Display of SOS History

SOS History (Number of LED blinking ) indication.

From left side; Last SOS, before Last, three occurrence before, 2nd occurrence after shipment, 1st occurrence after shipment. This indication except 2nd and 1st occurrence after shipment will be cleared by [Self-check indication and forced to factory shipment setting].

5.2.3.POWER ON TIME/COUNT

Note : To display TIME/COUNT menu, highlight position, then press MUTE for 3sec.

Time : Cumulative power on time, indicated hour : minute by decimal

Count : Number of ON times by decimal

Note : This indication will not be cleared by either of the self-checks or any other command.

5.2.4.Exit

1. Disconnect the AC cord from wall outlet.

TC-L42S20BL

5.3.Service Mode Adjustment

Set timer to 30min, press the ‘RECALL’ button on the remote control and press ‘-’ vol button on the LCD panel.

• Press button R and G for adjustment.

5.3.1.Self Check Mode

1.Press the ‘MENU’ button (on the remote control) and the ‘DOWN’ button on the LCD panel.

2.Press ON/OFF button on the panel to Exit.

5.3.2.Hotel Mode Adjustment

1.Press the ‘VOLUME DOWN’ button on the TV panel and simultaneously press the AV button on the remote control 3 times to enter Hotel Mode.

2.Set Hotel mode ‘on/off’, then press ‘EXIT’ to come out.

5.3.3.Hotel Mode

1.Purpose

Restrict a function for hotels.

2.Access command to the Hotel mode setup menu.

In order to display the Hotel mode setup menu, please enter the following command (within 2 second).

[TV] : Hold Vol [Down] + [Remote] : Press AV button 3 times.

Then, the Hotel mode setup menu is displayed.

Item	Function

Hotel Mode	Select hotel mode ON/OFF

Initial INPUT	Select input signal modes.
	Set the input, when each time power is switched
	on.
	Selection :
	OFF/Analogue TV/Digital TV/AV1/AV2/AV3/PC/
	HDMI1/HDMI2/HDMI3
	• Off: give priority to a last memory.
	• Selectable input is depend on the model.

Initial POS	Select programme number.
	Selection :
	Off/0 to 100
	• Off: give priority to a last memory.

Initial VOL level	Adjust the volume when each time power is
	switched on.
	Selection/Range :
	Off/0 to 100
	• Off: give priority to a last memory.

Maximum VOL	Adjust maximum volume.
level	Range :
	0 to 100

Button lock	Select local key conditions.
	Selection :
	Off/SETUP/MENU/All
	• Off: altogether valid.
	• SETUP: only F-key is invalid.
	(Tuning guide (menu) can not be selected.)
	• MENU: only F-key is invalid.
	(only Volume/Mute can be selected.)
	• ALL: altogether invalid.

Remote lock	Select remote control key conditions.
	Selection :
	Off/SETUP/MENU
	• Off: altogether valid.
	• SETUP: only Setup menu is invalid.
	• MENU: Picture/Sound/Setup menu are invalid.

TC-L42S20BL

6 Troubleshooting Guide

Use the self-check function to test the unit.

1.Checking the IIC bus lines

2.Power LED Blinking timing

6.1.Check of the IIC bus lines

6.1.1.How to access

Self-check indication only:

Produce TV reception screen, and while pressing [VOLUME ( - )] button on the main unit, press [OK] button on the remote control for more than 3 seconds.

Self-check indication and forced to factory shipment setting:

Produce TV reception screen, and while pressing [VOLUME ( - )] button on the main unit, press [MENU] button on the remote control for more than 3 seconds.

6.1.2.Exit

Disconnect the AC cord from wall outlet.

6.1.3.Screen display

6.1.4.Check Point

Confirm the following parts if NG was displayed.

TC-L42S20BL

6.2.Power LED Blinking timing chart

1.Subject

Information of LED Flashing timing chart.

2.Contents

When an abnormality occurs, the protection circuit will operate and reset the unit to stand by mode. During this time, the defective block can be identified by the number of blinking times of the Power LED on the front panel of the unit as follow:

Blinking times	Contents	BOARD

1	Inverter_SOS	P BOARD

2	FAN_SOS	A BOARD

3	SOS	A BOARD

4	DTV_9V	P/A BOARD

5	MAIN_9V	A BOARD

6	SUB_5V	A BOARD

7	SUB_3.3V	A BOARD

8	MAIN_3.3V	A BOARD

9	SOUND_SOS	A BOARD

10	HQ1L_SOS / ZWEI_SOS	A BOARD

13	EMERGENCY SOS	A BOARD

14	Audio PWM SOS	A BOARD

6.3.No Power

First check point

There are following 2 states of No Power indication by power LED.

1.No lit

2.Red is lit then turns red blinking a few seconds later. (See 6.2.)

TC-L42S20BL

7 Disassembly and Assembly Instructions

7.1.AC Cord Dressing

1.Clamp plug with clamper.

2.Insert beads 3 pcs. And slide down to lower hole.

TC-L42S20BL

7.2.AC Cord Installation

1.Put on the AC CORD BRACKET on the CABINET.

2.Fix the AC CORD BRACKET with SCREW.

3.Insert AC CORD connector into P-PCB connector.

4.Clamp the AC CORD.

5.Insert AC CORD bushing into the AC CORD BRACKET.

6.AC CORD is pushed into the bottom of the bracket.

TC-L42S20BL

7.3.Control Panel Assembly & Clamper Installation

1.Put control panel Assy on the cabinet.

2.Fix the control panel with screws.

Fix clamper at bottom mtg.

TC-L42S20BL

7.4.Side AV Preparation & Installation

1.Stick the side av indi. Sheet and felt on the side av bracket.

2.Insert the SIDE AV BRACKET from the side position of the A-PCB.

3.Fix the SCREW with A-PB-MTG METAL.

TC-L42S20BL

7.5.Speaker Preparation & Installation

1.Stick the SP sponge.

2.SP bracket put on cabinet.

3.Fix them with screws.

4.Insert the SP rubber bush into the SP unit.

5.Stick sponge at speaker.

6.Insert the SP unit to SP bracket.

TC-L42S20BL

7.6.LCD Panel Assembly Installation

1.Stick barrier at LCD Panel.

2.Stick Heat Rubber at Barrier.

3.Screw inverter board at LCD panel.

4.Slot mini LVDS wire at LCD panel board and inverter board.

5.Put LCD panel on the cabinet.

TC-L42S20BL

7.7.LED Panel Installation

1.Fix LED PANEL on CABINET.

2.Wire connecting. (V10).

3.Put V-PCB on CABINET.

4.Fix them with SCREW.

5.Insert the CLAMPER.

6.Stick felt at A10-V10 wire.

TC-L42S20BL

7.8.Felt Sticking at LVDS Wire

1.Insert CN1~P4 wire to inverter.

2.Insert CN201~P3 wire to inverter and stick felt.

3.Stick felt at LCD panel (Bottom left side).

4.Fix Top mtg and Bottom Mtg.

5.Fix Chassis frame bracket at Top Mtg and Bottom Mtg.

6.Insert LVDS wire to inverter and stick 3 felt.

7.Stick left at chassis frame to avoid sharp edge.

TC-L42S20BL

7.9.LCD Bracket and MTG Installation

1.Fix MASK BRACKET (SIDE/TOP/BTM) on the cabinet.

2.Fix Vertical Metal Bracket, Metal Support Bracket (R).

3.Fix them with SCREW.

4.Fix Clamper at Vertical Metal Bracket.

TC-L42S20BL

7.10. Pedestal Assembly

1.Fix stand mtg spacer at pedestal cover.

2.Stick felt at front base plate.

3.Fix base plate at stand mtg and pedestal cover and screw.

4.Stick rubber foot at rotation plate.

5.Apply grease at rotation plate and bush (pede).

6.Fix rotation plate and bush (pede) at base plate and screw.

TC-L42S20BL

Put Pedestal Assembly into polybag and fold properly.

TC-L42S20BL

8 Measurements and Adjustments

8.1.Voltage chart of A-board

Set IP-Board to a dummy set and check the satisfaction with the specified voltage as following table.

Power Supply Name	Measurement Point	Specification (V)

SUB1.8V	TP5601	1.74	- 1.90

SUB1.2V	TP5600	1.18	- 1.32

SUB3.3V	TP5602	3.19	- 3.46

SUB5V	TP5200	4.9	- 5.1

SUB9V	TP5220	8.82	- 9.18

STB5V	TP5400	4.9	- 5.1

8.2.Voltage chart of P-board

Set IP-Board to a dummy set or dummy load and check the satisfaction with the specified voltage as following table.

Power Supply	Measurement	Normal Condition	Stby Condition
Name	Point	(V)	(V)

P24V	TP7503	24 ± 1.2 V	NO CARE

17V	TP7502	18 ± 2 V	NO CARE

DTV12V	TP7501	12 ± 0.6 V	NO CARE

TUNER6V	TP7601	6.1 ± 0.3 V	NO CARE
				* HOT
DC390V	TP7201	390 ± 10 V	NO CARE	* HOT