Panasonic TX-R20LA80 Service Manual ▷ View online
Power Source :
220-240 V, 50 Hz
Power Consumption :
52 W
Stand-by Power
Consumption :
Consumption :
1 W
Aerial Impedance :
75
Ω unbalanced
Coaxial type
Receiving System :
PAL-B/G/I, D/K,
SECAM B/G, D/K, L/L’
PAL-525/60 (AV only)
M.NTSC (AV only)
NTSC (AV only)
Receiving Channels :
VHF
E2-E12
A-H (ITALY)
R3-R5
H1-H2 (ITALY)
R1-R2
R6-R12
UHF
E21-E69
CATV
S1-S10 (M1-M10)
S21-S41 (Hyperband)
(S01-S05)
S11-S20 (U1-U10)
Operating Conditions :
Temperature:
5°C - 35°C
Humidity:
5% - 90% RH (non-condensing)
TX-R20LA80
GLP21L Chassis
Intermediate Frequency :
Video
38.9MHz, 33.9MHz
Audio
33.4MHz (B/G), 33.16MHz (A2)
33.05MHz (NICAM B/G, D/K, L)
32.4MHz (D/K),
32.66MHz (CZ STEREO)
40.4MHz (L’), 39.75MHz (L’NICAM),
32.35MHz, 32.9MHz (NICAM)
Colour
34.47MHz (PAL)
34.5MHz, 34.65MHz (SECAM)
38.3MHz, 38.15MHz (SECAM L’)
Terminals :
AV1 IN
Video (21 pin)
1V p-p 75
Ω
Audio (21 pin)
500mV rms 10k
Ω
RGB (21 pin)
0.7V p-p 75
Ω AV1
OUT
Video (21 pin)
1V p-p 75
Ω
Audio (21 pin)
500mV rms 1k
Ω
AV2 IN
S-Video IN (4 pin)
Y: 1V p-p 75
Ω
C: 0.3V p-p 75
Ω
Audio (RCA x 2)
500mV rms 10k
Ω
Video (RCA x 1)
1V p-p 75
Ω
AUDIO OUT
Audio (RCA x 2)
500mV rms 1k
Ω
Colour LCD Television
Specifications
ORDER NO. MTV0801650CE
LCD screen :
L5EDD5L00011
640 x 480 VGA, 4:3
Visible Diagonal 508mm
Audio Output :
2 x 3W RMS
8
Ω impedance
Headphones :
3.5mm, 8
Ω Impedance
Accessories supplied :
Remote Control
2 x R6 (UM3) Batteries
Dimensions :
Including TV stand
Height : 484 mm
Width : 498 mm
Depth : 233 mm
1 Safety Precautions
3
1.1.
General Guidelines
3
1.2.
Touch-Current Check
3
2 Prevention of Electrostatic Discharge (ESD) to
Electrostatically Sensitive (ES) Devices
4
3 About Lead Free Solder (PbF)
5
4 Service Hints
6
4.1.
How To Remove The Pedestal Assembly
6
4.2.
How To Remove The Backcover
6
5 Chassis Board Layout
7
6 Setting Inspection
8
6.1.
Voltage Confirmation
8
7 Self Check
9
8 Adjustment Method
10
TV set only
Height : 443 mm
Width : 498 mm
Depth : 98 mm
Mass :
7.5 kg (Net)
Specifications are subject to change without notice.
Weights and dimensions shown are approximate.
8.1.
How to enter Service 1
10
8.2.
Key Command
10
8.3.
White Balance Adjustment
10
9 Block Diagrams
11
10 Schematic Diagrams
14
10.1. Parts Location
14
11 Replacement Parts List
15
12 Schematic Diagram
22
12.1. Schematic Diagram Notes
22
12.2. A Board
23
12.3. P Board
26
12.4. V Board
27
13 Conductor Views
28
CONTENTS
Page
Page
2
TX-R20LA80
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 touch current checks to prevent the customer from being exposed to shock hazards.
4. Always ensure panel TKP0E16001 is correctly replaced before returning to customer (see Fig. 1).
4. Always ensure panel TKP0E16001 is correctly replaced before returning to customer (see Fig. 1).
Fig. 1
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
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 Fig. 2.
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 (TOUCH CURRENT) expressed as voltage U1 and U2, does not exceed the following values:
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 (TOUCH CURRENT) expressed as voltage U1 and U2, does not exceed the following values:
For a. c.: U1 = 35 V (peak) and U2 = 0.35 V (peak);
For d. c.: U1 = 1.0 V,
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 mA
d. c.
The limit value U1 = 35 V (peak) for a. c. corresponds to the value 70 mA (peak) a. c. for frequencies greater than 100kHz.
For d. c.: U1 = 1.0 V,
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 mA
d. c.
The limit value U1 = 35 V (peak) for a. c. corresponds to the value 70 mA (peak) a. c. for frequencies greater than 100kHz.
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.
Fig. 2
3
TX-R20LA80
2 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
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.
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
aluminium foil, to prevent electrostatic charge build up 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, aluminium foil or
comparable conductive material).
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.
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 harmless motions 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).
sufficient to damage an ES device).
4
TX-R20LA80