Panasonic TX-LR37G10 / TH-LR37G10 Service Manual ▷ View online
TH-LR37G10
5
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
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 the 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. The potential at any point (touch current) expressed as voltage U
4. Check each exposed metallic part and measure the voltage at each point.
5. The potential at any point (touch current) expressed as voltage U
1
and U
2
, do not exceed the following values:
For AC: U
1
= 35 V (peak) and U
2
= 0.35 V (peak);
For DC: U
1
= 1.0 V,
NOTE :
The limit value of U
The limit value of U
2
= 0.35 V (peak) for AC and U
1
= 1.0 V for DC correspond to the values 0.7 mA (peak) AC and 2.0 mA
DC.
The limit value U
The limit value U
1
= 35 V (peak) for AC correspond to the value 70 mA (peak) AC for frequencies greater than 100 kHz.
6. Should a measurement be 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.
TH-LR37G10
6
1.3.
LH89 Chasis Block Diagram
H
O
T
C
O
L
D
(L
E
D
:5
T
IM
E
S
)
(L
E
D
:9
T
IM
E
S
)
(L
E
D
:8
T
IM
E
S
)
(L
E
D
:1
T
IM
E
S
)
(L
E
D
:7
T
IM
E
S
)
(L
E
D
:3
T
IM
E
S
)
(L
E
D
:6
T
IM
E
S
)
(L
E
D
:4
T
IM
E
S
)
+
A12
A10
STB+5V
L,R
L,R
SD BOOT
ZWEI
PWM
PANEL
INV SOS
DTV+12V
PANEL
A12
HDMI2
A17
IIC3
MAIN Y/U/V
HDMI3
CLOCK
GEN
A11
LED
HDMI3
SUB+1.2V
AV1
DTV-L,R
MONITOR
OUT
HDMI1
SD CARD
DCDC
SUB+5V
STB_RESET
SUB+3.3V
SUB+3.3V
A-BOARD
A03
AUIDO AMP
HDMI Receiver
A/D converter
STB+3.3V
VIDEO
AUDIO
PROCESSOR
HDMI2
LOSD
REMOTE
27MHz
V-BOARD
SUB+3.3V
74MHz
SUB+3.3V
LED
LVDS
AV2
EEPWP
V,C,V
EEPROM
R,G,B
REMOTE
CONTROL
OVP_DET
SD CARD I/F
V,Y,PB,PR
HEADPHONE
GenX8
A01
BACK LIGHT
SUB_ON
RESET
STB Micom
SOUND SOS
27MHz
INV SOS
AV3
SOS
SUB+9V SENSE
SUB+5V SENSE
Serial
FLASH
MEMORY
L,R
SUB+1.8V
HP
V10
INVERTER CIRCUIT
PANEL+12V
FOR
FACTORY
USE
DTV+12V
SUB+5V
REMOTE
RF
CONTROL
OPT OUT
STB+3.3V
IECOUT
AUDIO_RST
SUB+3.3V SENSE
DCDC
L,R
FOR
FACTORY
USE
HDMI1
Tuner
MAIN+3.3V SENSE
DDR2 SDRAM
LED
RF
TV_SOS
SPEAKER
KEY
SUB+1.8V
EEPROM
DTV+12V SENSE
PC
SUB+9V
ZW_PLL3.3V
SUB_ON
RESET
OPT
(MAIN MCU+VIDEO SIGNAL PROCESSOR)
Digital video signal
AV SW
Peaks Lite2p
A07
LCD PANEL
FOR
FACTORY
USE
SBO2
SBI2
DTV Digital Auido
SUB+1.2V
A20
V,Y,PB,PR
MONITOR L,R
ON
+5VS
STB+5V
POWER SW
OPERATION
BUTTON
K-BOARD
AC CORD
PROCESS
VOLTAGE
RECTIFIER
P1
5V
+17V
P5
+5VS
+12V
+17V
DTV+12V
TUNER+6V
P2
FILTER
STB
RELAY
P4
P6
PHOTO
COUPLER
SUB_ON
P-BOARD
K01
MONITOR V
HDMI4
HDMI4
SIF.AM
SIF.AM
DVB CVBS
HOT
COLD
(LED:5 TIMES)
(LED:8 TIMES)
(LED:1 TIMES)
(LED:7 TIMES)
(LED:3 TIMES)
(LED:6 TIMES)
(LED:4 TIMES)
(LED:9 TIMES)
INVERTER CONTROL
INVERTER CONTROL
PWM CONTROL
PWM CONTROL
TH-LR37G10
7
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).
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.
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 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 charges 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 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).
sufficient to damage an ES device).
TH-LR37G10
8
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 (PbF) used in our manufacturing process and discussed below is (Sn+Ag+Cu).
Those are 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 (PbF) used in our manufacturing process and discussed below is (Sn+Ag+Cu).
Those are Tin (Sn), Silver (Ag) and Copper (Cu), although other types are available.
This model uses PbF in its manufacture due to environmental conservation issues. For service and repair work, we would suggest
the use of PbF as well, although Pb may be used.
the use of PbF as well, although Pb may be used.
PCBs manufactured using lead-free will have the “PbF within a leaf Symbol” stamped on their back.
Caution
• PbF has a higher melting point than that of 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).
• PbF 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 PbF on the pins or solder area before applying Pb. If this is not
practical, be sure to heat the PbF until it melts, before applying Pb.
practical, be sure to heat the PbF until it melts, before applying Pb.
• After applying PbF to double layered boards, please check the component side for excess solder which may flow onto the
opposite side (see Figure 2).
Figure 2
Suggested PbF
There are several kinds of PbF available for purchase. This product uses Sn+Ag+Cu (tin, silver, copper) solder. However, Sn+Cu
(tin, copper) and Sn+Zn+Bi (tin, zinc, bismuth) solders can also be used.
There are several kinds of PbF available for purchase. This product uses Sn+Ag+Cu (tin, silver, copper) solder. However, Sn+Cu
(tin, copper) and Sn+Zn+Bi (tin, zinc, bismuth) solders can also be used.
Figure 3
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