Panasonic TX-LR42ET5 / TX-LR47ET5 Service Manual ▷ View online
Safety Precautions
General Guide Lines
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 cover label TBM4GU113 is correctly replaced before returning to customer (see Fig.1).
4. Always ensure cover label TBM4GU113 is correctly replaced before returning to customer (see Fig.1).
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
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,
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. correspond to the value 70 mA (peak) a. c. for frequencies greater than 100
kHz.
2.0 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.
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
TO
APPLIANCES
EXPOSED
METAL PARTS
APPLIANCES
EXPOSED
METAL PARTS
Resistance values in ohms (
)
V
R
0
=500
R
S
=1500
C
S
=0.22
F
10k
0.022
F
COLD
WATER PIPE
(EARTH GROUND)
WATER PIPE
(EARTH GROUND)
V: Voltmetr or oscilloscope
(r.m.s. or peak reading)
(r.m.s. or peak reading)
Measuring network for TOUCH CURRENTS
Input resistance:
1M
Input capacitance:
200pF
Frequency range: 15Hz to 1MHz and d.c.respectively
NOTE – Appropriate measures should be taken to obtain the correct value in case of non-sinusoidal waveforms
U
2
(V)
Fig. 1
U
1
(V)
5
Prevention of Electrostatic Discharge (ESD) to Electrostatically
Sensitive (ES) Devices
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.
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 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
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.
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).
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 harmless 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).
(ESD) sufficient to damage an ES device).
There are special components used in this equipment which are important for safety.
These parts are marked by in schematic diagrams, exploded views and replacement parts list. It is essential that
these critical parts should be replaced with manufacturer’s specified parts to prevent shock, fire, or other hazards. Do
not modify the original design without permission of manufacturer.
These parts are marked by in schematic diagrams, exploded views and replacement parts list. It is essential that
these critical parts should be replaced with manufacturer’s specified parts to prevent shock, fire, or other hazards. Do
not modify the original design without permission of manufacturer.
IMPORTANT SAFETY NOTICE
6
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
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).
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.
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 Fig.3)
flow onto the opposite side. (see Fig.3)
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. (see Fig.4)
However, Sn+Cu (tin, copper), Sn+Zn+Bi (tin, zinc, bismuth) solder can also be used. (see Fig.4)
Fig.3
Fig.4
7
Applicable Signals
Applicable input signal for PC is basically compatible to VESA standard timing.
Signal name
Horizontal frequency (kHz)
Vertical frequency (Hz)
640
480 @60 Hz
31.47 59.94
800
600 @60 Hz
37.88 60.32
852
480 @60Hz
31.44 59.89
1,024
768 @60Hz
48.36 60.00
1,280
768 @60Hz
47.70 60.00
1,280
1,024 @60Hz
63.98 60.02
1,366
768 @60Hz
48.39 60.04
Applicable input signal for PC is basically compatible to HDMI standard timing.
Signal name
Horizontal frequency (kHz)
Vertical frequency (Hz)
640
480 @60 Hz
31.47 60.00
1,280
720 @60 Hz
45.00 60.00
1,920
1,080 @60Hz
67.50 60.00
Note:
Signals other than above may not be displayed properly.
The above signals are reformatted for optimal viewing on your display.
PC signal is magnified or compressed for display, so that it may not be possible to show fine detail
with sufficient clarity.
Signal name
COMPONENT
HDMI
525 (480) / 60i,60p
*
*
625 (576) / 50i, 50p
*
*
750 (720) / 60p, 50p
*
*
1,125 (1,080) / 60i, 50i
*
*
1,125 (1,080) / 60p
*
1,125 (1,080) / 50p
*
1,125 (1,080) / 24p
*
PC
(from D-sub 15P)
PC
(from HDMI terminal)
Component
(Y, Pb, Pr) (from AV2 terminal), HDMI
8
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