Panasonic TC-20LA5 / TC-20LE5 Service Manual ▷ View online
TC-20LA5
TC-20LE5
TC-20LE5
LH32G Chassis
LCD TV
Specifications
Power Source
AC 120 V, 60 Hz
Power Consumption
Average use : 56 W
Stand-by condition : 0.11 W
Power off : 0.10 W
LCD
20-inch (510 mm), 4 : 3 aspect ratio LCD panel
Screen Size
16.06 " (408.0 mm) (W) × 12.05 " (306.0 mm) (H)
Channel Capability
VHF-12 : UHF-56 : Cable-125
Sound
Speaker
4 cm, 2 pcs, 16
W
Headphones
M3 (3.5 mm) Jack × 1
FEATURES
3D Y/C Digital Comb Filter
CLOSED CAPTION
V-Chip
Operating Conditions
Temperature : 41 °F - 95 °F (5 °C - 35 °C)
Humidity : 5 % - 90 % RH (non-condensing)
ORDER NO. ITD0503008CE
B05
Canada:B07
1 Safety Precautions
3
1.1.
General Guidelines
3
2 Warning
3
2.1.
Prevention of Electro Static Discharge (ESD) to
Electrostatically Sensitive (ES) Devices
3
2.2.
About lead free solder (PbF)
4
3 Location of Controls and Components
5
4 Service Mode
6
4.1.
How to enter into adjustment mode
6
4.2.
Cancellation
6
4.3.
Contents of adjustment mode
6
5 Troubleshooting Guide
7
5.1.
Self-check function
7
6 Disassembly and Assembly Instructions
8
6.1.
Removing the photo stand (TC-20LE5 only)
8
6.2.
Removing the pedestal assembly (TC-20LA5 only)
8
6.3.
Removing the rear cover
8
6.4.
Removing the control button assembly
8
6.5.
Removing the chassis assembly
9
6.6.
Removing the A-Board, TA-Board, and Power unit
9
6.7.
Removing the speaker and the pedestal bracket
9
6.8.
Removing the LCD panel, R-Board, and V-Board
10
6.9.
Removing the LCD mount metal
10
6.10. Location of Lead Wiring
11
7 Measurements and Adjustments
13
7.1.
Video Signal Level Adjustment
13
7.2.
LCD GAMMA Adjustment
13
7.3.
MTS Adjustment
14
8 Block Diagram
15
9 Wiring Connection Diagram
17
10 Schematic Diagrams
19
10.1. Schematic Diagram Notes
19
10.2. A-Board (1 of 5) Schematic Diagram
20
10.3. A-Board (2 of 5) Schematic Diagram
21
10.4. A-Board (3 of 5) Schematic Diagram
22
10.5. A-Board (4 of 5) Schematic Diagram
23
10.6. A-Board (5 of 5) Schematic Diagram
24
10.7. R, TA, and V-Board Diagram
25
11 Printed Circuit Views
27
11.1. A-Board
27
11.2. R, V and TA-Board
30
12 Exploded View and Replacement Parts List
31
12.1. Exploded View
31
12.2. Packing Exploded View
32
12.3. Mechanical Replacement Parts List
33
13 Electrical Parts List
34
13.1. Electrical Parts List Notes
34
13.2. Electrical Replacement Parts List
35
Connection Terminals
INPUT
VIDEO (RCA PIN Type × 1) × 2
1.0 Vp-p (75
W)
S-VIDEO (MINI DIN 4pin × 1) × 2
Y : 1 Vp-p (75
W), C : 0.286 Vp-p (75
W)
AUDIO L-R (RCA PIN Type × 2) × 2
0.5 Vrms
COMPONENT VIDEO INPUT
Y
1.0 Vp-p (including synchronization)
P
B
/ P
R
± 0.35 Vp-p
AUDIO L-R (RCA PIN Type × 2)
0.5 Vrms
Dimensions ( W × H × D )
Including TV Stand
19.61 “ (498 mm) ×
19.61 “ (498 mm) ×
19.93 “ (506.2 mm) ×
17.91 “ (454.8 mm) ×
10.24 “ (260 mm) (TC-20LA5)
7.60 “ (193 mm) (TC-20LE5)
TV Set Only
19.61 “ (498 mm ×
17.72 “ (450.2 mm) ×
3.66 “ (93 mm)
Mass (Weight)
16.8 lb. (7.6 kg) Net (TC-20LA5)
14.1 lb. (6.4 kg) Net (TC-20LE5)
Note:
Design and specifications are subject to change without notice. Weight and dimensions shown are approximate.
CONTENTS
Page
Page
2
TC-20LA5 / TC-20LE5
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 between
1M
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 between
1M
W and 5.2MW.
When the exposed metal does not have a return path to the
chassis, the reading must be
chassis, the reading must be
.
Figure 1
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 1.5k
W, 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.
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.
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.
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.
2 Warning
2.1. 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
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.
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 alminum
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
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
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).
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.
3
TC-20LA5 / TC-20LE5
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 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).
damage an ES device).
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.
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.
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
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.
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.
However, Sn+Cu (tin, copper), Sn+Zn+Bi (tin, zinc, bismuth) solder can also be used.
4
TC-20LA5 / TC-20LE5