Panasonic TC-20LB30 Schematic
Specifications
A
A
A
A
ORDER NO. ITD0406015C1
B05 Canada:B07
LCD TV
TC-20LB30
LH32 Chassis
Power Source
Power Consumption
LCD 19.6-inch (499 mm), Diagonal 4 : 3 aspect ratio LCD panel
Screen Size 15.79 " (401 mm) (W) × 11.77 " (299 mm) (H)
Channel Capability VHF-12 : UHF-56 : Cable-125
Sound
Speaker 4 cm × 10 cm, 2 pcs, 16 W
Audio Output 6 W [3 W + 3 W] (10 % THD)
Headphones M3 (3.5 mm) Jack × 1
FEATURES 3D Y/C Digital Comb Filter, CLOSED CAPTION, V-Chip, SD/PC Card slot
Operating Conditions Temperature : 41 °F - 95 °F (5 °C - 35 °C)
Connection Terminals
INPUT VIDEO (RCA PIN Type × 1) × 2 1.0 Vp-p (75 W)
COMPONENT VIDEO INPUT Y×1 1.0 Vp-p (including synchronization)
Dimensions ( W × H × D )
Including TV Stand 24 3/4 “ × 19 51/64 “ × 10 15/64 ”
TV Set Only 24 3/4 “ × 16 29/64 “ × 3 37/64 ”
Mass (Weight) 20.7 lb. (9.4 kg) Net
C 120 V, 60 Hz
verage use : 58 W
Stand-by condition : 0.10 W
Power off : 0.08 W
VGA (640 × 480 pixels)
Humidity : 5 % - 90 % RH (non-condensing)
S-VIDEO (MINI DIN 4pin × 1) × 2 Y : 1 Vp-p (75 W ), C : 0.286 Vp-p (75
W)
UDIO L-R (RCA PIN Type × 2) × 2 0.5 Vrms
PB/PR×1 ± 0.35 Vp-p
UDIO L-R (RCA PIN Type × 2) × 1 0.5 Vrms
(629 mm × 503 mm × 260 mm)
(629 mm × 418 mm × 91 mm)
© 2004 Matsushita Electric Industrial Co., Ltd. All
rights reserved. Unauthorized copying and
distribution is a violation of law.
TC-20LB30
CONTENTS
Page Page
1 Safety Precautions 3
1.1. General Guidelines
2 Prevention of Electro Static Discharge (ESD) to
Electrostatically Sensitive (ES) Devices
3 About lead free solder (PbF)
4 Self-check function
4.1. How to access
4.2. Screen display
5 Chassis Board Layout
6 Disassembly for Service
6.1. Pedestal ass’y
6.2. Rear cover
6.3. TA-Board
6.4. A-Board
6.5. Power unit
6.6. V-Board
6.7. Speaker (left and right)
6.8. JG-Board and JG-Board bracket
6.9. GS-Board
6.10. Main chassis
6.11. LCD panel
7 Location of Lead Wiring
8 Adjustment method
8.1. How to enter into adjustment mode
8.2. Cancellation
8.3. Contents of adjustment mode
10
10
11
11
12
13
13
13
13
3
3
4
5
5
5
6
7
7
7
7
8
8
9
9
8.4. Video Signal Level Adjustment
8.5. LCD GAMMA Adjustment
8.6. MTS Adjustment
9 Conductor Views
9.1. A-Board
9.2. JG-Board
9.3. GS, TA and V-Board
10 Block and Schematic Diagram
10.1. Schematic Diagram Notes
10.2. Power Block Diagram
10.3. Signal Block Diagram
10.4. A-Board (1 of 5) Schematic Diagram
10.5. A-Board (2 of 5) Schematic Diagram
10.6. A-Board (3 of 5) Schematic Diagram
10.7. A-Board (4 of 5) Schematic Diagram
10.8. A-Board (5 of 5) Schematic Diagram
10.9. JG-Board (1 of 2) Schematic Diagram
10.10. JG-Board (2 of 2) Schematic Diagram
10.11. GS, TA and V-Board Schematic Diagram
11 Parts Location & Mech anica l Replacement Parts List
11.1. Parts Location
11.2. Packing Exploded View
11.3. Mechanical Replacement Parts List
12 Repla ceme nt Parts List
12.1. Replacement Parts List Notes
12.2. Electrical Replacement Parts List
14
14
15
17
17
20
22
25
25
26
27
28
29
30
31
32
33
34
35
37
37
38
39
40
40
41
2
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.
TC-20LB30
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
1MW and 5.2MW.
When the exposed metal does not have a return path to the
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 1.5kW, 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.
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 ACplugintheACoutlet and repeat eachof 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.
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 asalminum
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.
3
TC-20LB30
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 asthe 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).
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.
4
4 Self-check function
When phenomena like "the power fails from time to time" or "the video/audio fails from time to time" can not be confirmed at the
time of servicing, the self-check function can be used to confirm the occurrence and to limit the scope for the defective circuits.Also,
when "the power fails from time to time", display on the screen can be used to confirm the occurrence and to limit the scope for
the defective circuits.
Any programmed channels, channels caption data and some other user defined settings will be erased and return to factory setting.
4.1. How to access
4.1.1. Access
Produce TV reception screen and, while pressing [VOLUME-] button on the main unit, press [SLEEP] button on the remote
controller unit simultaneously.
4.1.2. Exit
When one of the buttons for channel selection etc. is pressed, the display returns to the normal screen.
4.2. Screen display
TC-20LB30
Display Ref .No. Description P.C.B.
TNR TU001 Tuner TA-Board
SOUND IC2320 Sound control A-Board
AVSW IC3001 AV Switch A-Board
MTS IC2201 Multi Sound Processor TA-Board
GLP IC4014 LCD Processor A-Board
GC3 IC4012 Global Core A-Board
TEMP IC1008 Temperature Sensor A-Board
MEMORY IC1002 EEPROM A-Board
JPEG IC6513 MCU (JPEG) JG-Board
5
TC-20LB30
5 Chassis Board Layout
Board Name Function
A-Board Main (AV Switch, Audio, MCU, Global Core, AV connector )
GS-Board SD card slot
JG-Board JPEG Viewer, PC card slot
V-Board Headphone, Speaker, Remote Reciever, LED
TA-Board Tuner, MTS
Power Unit Power (AC/DC), Switch
None serviceable.
Power Unit should be exchanged for service.
6
6 Disassembly for Service
6.1. Pedestal ass’y
1. Lay down the main unit so thatthe rear cover faces upward.
6.2. Rear cover
1. Remove the pedestal ass´y. (See 6.1.)
2. Remove the fixing screws (12pcs
3. Remove the rear cover.
TC-20LB30
and 2pcs ).
2. Remove the fixing screws (2pcs ) and remove the hinge
cover.
3. Remove the fixing screws (2pcs ).
4. Remove the pedestal ass´y.
6.3. TA-Board
1. Remove the rear cover. (See 6.2.)
2. Remove the fixing screw (1pcs
3. Remove the TA-Board.
).
7
TC-20LB30
6.4. A-Board
1. Remove the rear cover. (See 6.2.)
2. Remove the TA-Board. (See 6.3.)
3. Disconnect the couplers (A5, A7, A8 and A9) and the
flexible cable (A15).
4. Remove the fixing screws (2pcs ).
5. Remove the A-Board shield case.
6. Remove the fixing screws (4pcs
7. Remove the A-Board.
).
Case 1.
Bond is applied to power unit.
Case 2.
Barrier is attached in chassis frame.
6.5. Power unit
1. Remove the rear cover. (See 6.2.)
2. Disconnect the couplers (CN1 and CN2).
3. Remove the fixing screws (6pcs
4. Remove the power unit.
When exchange the power unit, xonfirm the TV unit is case 1
or case2.
If there is no Barrier attachment, Bond should be applied the
same as original power unit (as shown in figure).
).
8
6.6. V-Board
1. Remove the rear cover. (See 6.2.)
2. Remove the fixing screw (3pcs
3. Disconnect the couplers (V1 and V5).
4. Remove the V-Board.
).
6.7. Speaker (left and right)
TC-20LB30
1. Remove the rear cover. (See 6.2.)
2. Disconnect the coupler (V5). (See 6.6.)
3. Remove the fixing screws (8pcs
4. Remove the speaker (left and right).
).
9
TC-20LB30
6.8. JG-Board and JG-Board
bracket
1. Remove the rear cover. (See 6.2.)
2. Remove the fixing screws (4pcs
3. Remove the JG-Board shield case.
4. Disconnect the couplers (JG3 and JG6).
5. Remove the JG-Board.
6. Remove the fixing screws (4pcs
7. Remove the JG-Board bracket.
6.9. GS-Board
1. Remove the rear cover. (See 6.2.)
2. Remove the fixing screws (2pcs
).
).
3. Disconnect the coupler (JG3).
4. Remove the GS-Board shield case.
5. Remove the fixing screws (2pcs ).
6. Remove the GS-Board bracket.
7. Disconnect the coupler (GS4).
8. Remove the GS-Board.
).
10
Loading...