Panasonic TX-20LA60F, TX-20LA60P, TX-20LA6F, TX-20LA6P Service manual
ORDER NO. PCZ0610103CE
Service Manual
LCD TV
TX-20LA60F
TX-20LA60P
TX-20LA6F
TX-20LA6P
SL-131PP Chassis
Power Source
AC 220-240V, 50Hz.
Power Consumption
Average use: 41W
Standby condition: 1W
LCD
VGA (640 × 480 pixels)
4:3 aspect ratio LCD panel
Screen Size
408 mm(W) × 306 mm(H)
Sound
Speaker
9 cm × 5cm, 2pcs, 4Ω
Audio Output
4W (2W + 2W), 20% THD
Headphones
M3 (3.5 mm) Jack x 1
Receiving Systems/ Band name
VHF BAND I: CH2-CH4
BAND II: CH5-CH12
UHF HYPER BAND :SI’-S3’, S1-S20
BAND IV, V : CH21-CH68
Operating Conditions
Temperature: -10°C ~ 40°C
Humidity: 0%-90% RH (non-condensing)
Connection Terminals
AV1 (Scart connecter)
21 Pin terminal (Audio/Video in, Audio/Video out, RGB in)
AV2
VIDEO
RCA PIN Type × 1
S-VIDEO
Mini DIN 4-pin
AUDIO L-R
RCA PIN Type × 2
Dimensions (W x H x D)
Including TV Stand
498mm(W) × 260mm(D) × 493mm(H)
TV Set Only
498mm(W) × 95mm(D) × 451mm(H)
Weight
10.9kg Net
Note:
Design and Specifications are subject to change without notice.
Weight and Dimensions shown are approximate.
PAL-B/G, D/K, SECAM-L/L’, NTSC(AV input only)
Aerial-Rear
UHF/VHF
© 2006 Matsushita Electric Industrial Co., Ltd.
All rights reserved. Unauthorized copying and
distribution is a violation of law.
TX-20LA6
TX-20LA60
CONTENTS
Page
1. Safety Precautions ----------------------------------------------- 3
1.1. General Guidelines -------------------------------------- 3
1.2. Touch-Current Check ------------------------------------ 3
2. Prevention of Electro Static Discharge (ESD) to
Electrostatically Sensitive (ES) Devices ------------------ 4
3 About lead free solder (PbF) --------------------------------- 5
4. Self Check ---------------------------------------------------------- 6
5. Chasis Board Layout -------------------------------------------- 7
6. Before servicing -------------------------------------------------- 8
6.1. Wire dressing ---------------------------------------------- 8
7. Disassembly for service --------------------------------------- 9
7.1. Stand ass´y ------------------------------------------------ 9
7.2. Back cover ------------------------------------------------- 9
7.3. CTRL ass´y -----------------------------------------------10
7.4. Power Swith ass´y --------------------------------------10
7.5. LED ass´y -------------------------------------------------10
7.6. Headphone ass’y ----------------------------------------10
7.7. Speaker (left and right) --------------------------------- 11
7.8. TTL ass’y --------------------------------------------------- 11
7.9. Power Module -------------------------------------------- 11
7.10. Main ass´y -----------------------------------------------11
7.11.Panel LCD -------------------------------------------------12
Page
8.Service Mode Function ----------------------------------------13
8.1. How to enter SERVICE --------------------------------13
8.2. How to exit SERVICE ----------------------------------13
8.3. Option Description --------------------------------------14
9. Conduct Views ---------------------------------------------------15
9.1. Foil Side ---------------------------------------------------15
9.2. Component Side -----------------------------------------17
10. Block and Schematic Diagrams --------------------------19
10.1. Schematic Diagram Notes ---------------------------19
10.2. Block Diagram ------------------------------------------20
10.3. Schematic Diagram -----------------------------------21
11. Parts Location & Replacement Parts List -------------28
11.1. Different Part List ---------------------------------------28
11.2. Exploded View ------------------------------------------29
11.3. Stand Assy Exploded View --------------------------30
11.4. Packing Exploded Views -----------------------------30
11.5. Electrical Replacement Parts List ------------------31
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TX-20LA60
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.
1.2. Touch-Current Check
1. Plug the AC cord directly into the AC outlet. Do not use an isolation transformer for this check.
2. Connect a measuring network for touch currents 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 Leakage Current Tester (Simpson 228 or equivalent) to measure the potential across the measuring network.
4. Check each exposed metallic part, and measure the voltage at each point.
5. Reserve the AC plug in the AC outlet and repeat each of the above measure.
6. The potential at any point (TOUGH CURRENT) expressed as voltage U1 and U2, does not exceed the following values:
For a. c.: U
For d. c.: U
Note:
The limit value of U2 = 0.35 V (peak) for a. c. and U1 = 1.0 V for d. c. correspond to the values 0.7 mA (peak) a. c. and 2.0
7. In case a measurement is out 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.
1 = 35 V (peak) and U2 = 0.35 V (peak);
1 = 1.0 V,
mA d. c.
The limit value U1 = 35 V (peak) for a. c. correspond to the value 70 mA (peak) a. c. for frequencies greater than 100 kHz.
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TX-20LA6
TX-20LA60
2. Prevention of Electro Static 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 electro static 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 almi-
num 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, alminum 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 hamless motion such as the brush-
ing 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).
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TX-20LA6
TX-20LA60
3. 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
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.
stamped on the back of PCB.
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TX-20LA6
TX-20LA60
4. Self Check
1. Self-Check is used to automatically check the bus lines and hexadecimal code of the TV set.
2. To get into the Self -Check mode press the Down (
button on the remote control, and the screen will show when the self Check is finished:
SEDNA VERSION
3. Turn off the TV to reset after SELF-CHECK menu.
) button on the TV set, at the same time pressing the Recall ( )
Programm number
Software Type
When Self Check is
finished you have this line
within the option definition.
6
5. Chassis Board Layout
TX-20LA6
TX-20LA60
HEADPHONE ASSY POWER SWITCH
TTL ASSY
ASSY
POWER
MAIN ASSY
MODULE
LED ASSY
Board Name Function
MAIN ASSY Main Board
CTRL ASSY Select Switch
HEADPHONE ASSY Headphone socket
LED ASSY Remote Receiver, LED
POWER SWITCH ASSY Main power switch
TTL ASSY Adapter of FFC cable
POWER MODULE Power Module
CTRL ASSY
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TX-20LA6
TX-20LA60
6. Before servicing
6.1. Wire dressing
Check a wire dressing is same as illustrated below;
CN2
K
Fix by tape
G
D
3
4
P905
2
C
P902
P803
P504
P601
PA0 9
P405
P401
P408
P404
P500
P502
P801
B
P502
I
P602
P501
1
Fix by tape
H
J
A
5
F
6
7
E
6.1.1 Connection
1. Connect every connector surely as ilustrated above photo (
2. Manage wires not to touch any sharp edge of the metal parts.
3. Manage wires not to have too much tension.
6.1.2 Clamping
Wire
A
B
C
D
E
F
G
H
I
J
K
P501 - P501A
connection wire 4850705S30
P502 - P502 on Power Module
connection wire 4850705N39
P902 - P905 on TTL Ass’y
cable FFC 4859006560
P504 - P504A
connection wire 4850704S84
P601 - (L)SPEAKER
connection wire 4850703S77
P602 - (R)SPEAKER
connection wire 4850703S77
P803 - P801 on Power Module
connection wire 4850710S32
PA0 9 - PA09B
connection wire 4850705S28
CN2 - P500 on Power Module
connection wire 4850703N47
P401 and P404 on Power Module
LCD panel connection wire
„P405 and P408 on Power Module
LCD panel connection wire
8
A
~ K).
Clamp wire
4956800200
7
32
71
5,6
3,4 2
4,5,6
Clamp wire
4856815900
1
Loop wire
TX-20LA6
TX-20LA60
7. Disassembly for service
7.1 Stand Ass’y
1. Lay down the main unit so that the back cover faces
upward.
2. Remove the fixing screws (4pcs
3. Remove the stand ass’y
)
7.2. Back cover
1. Remove stand ass’y (see 7.1.)
2. Remove the fixing screws (9pcs
3. Take out the Terminal Cover (
4. Release the Cord Holder (
5. Pull Power Cord plug throgh Back Cover hole.
)
)
)
6. Remove Back Cover.
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TX-20LA60
7.3. CTRL Ass’y
1. Remove the back cover (see. 7.2.).
2. Disconnect wires: CN2 and P504.
3. Remove CTRL Panel Ass’y.
4. Remove screws (2 pcs
5. Remove CTRL PCB.
).
7.5. LED Ass’y
1. Remove the back cover (see. 7.2.).
2. Disconnect wire: P501
3. Remove screw (1 pcs
4. Remove LED PCB.
)
P501
7.4. Power Switch Ass’y
1. Remove the back cover (see. 7.2.).
2. Disconnect wires: CN2 and P504.
3. Remove CTRL Panel Ass’y.
4. Remove screws (3 pcs
5. Remove Button CTRL Ass’y.
6. Remove Button Power and fixing screws (2 pcs
).
7.6. Headphone Ass’y
1. Remove the back cover (see. 7.2.).
2. Disconnect wire: PA09
3. Remove screw (1 pcs
).
4. Remove Headphone PCB
)
PA0 9
7. Remove Power Switch Ass’y.
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TX-20LA60
7.7. Speaker (left and right)
1. Remove the back cover (see. 7.2.)
2. Disconnect wires: P601 and P602
3. Remove screws (8 pcs
P602
4. Remove Speakers.
)
7.8. TTL Ass’y
1. Remove the back cover (see. 7.2.)
2. Unlock P902 connector clip.
3. Disconnect FFC cable.
P902
P601
7.9. Power Module
1. Remove the back cover (see. 7.2.).
2. Disconnect wires: P500, P502, P801
3. Disconnect LCD panel wires: P401, P404, P405, P408
4. Remove screws (4 pcs
P405
5. Remove Power Module.
P408
P401
P502
P404
).
P801
P500
7.10. Main Ass’y
1. Remove the back cover (see. 7.2.)
2. Disconnect wires: P501, P502, P504, P601, P602,
P803, P902, PA09
4. Remove TTL PCB from LCD panel.
5. Unlock P905 connector clip.
6. Remove FFC cable.
P905
3. Remove screws (4 pcs
P602P501
4. Remove Main PCB Ass’y.
).
P502 P902
PA0 9
P601P504P803
11
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