Panasonic TH42LF20U - 42" HD LCD TV User manual

© Panasonic Corporation 2010
Unauthorized copying and distribution is a violation
of law.
Order Number MTNC100773CE
FULL HD LCD Display
Model No. TH-42LF20U
Model No. TH-47LF20U
TABLE OF CONTENTS
PAGE PAGE
1 Safety Precautions----------------------------------------------- 3
1.1. General Guidelines---------------------------------------- 3
2 Warning -------------------------------------------------------------- 4
2.1. Prevention of Electrostatic Discharge (ESD)
to Electrostatically Sensitive (ES) Devices---------- 4
2.2. About lead free solder (PbF)---------------------------- 5
3 Service Navigation ----------------------------------------------- 6
3.1. Applicable signals ----------------------------------------- 6
4 Specifications ----------------------------------------------------- 8
5 Operating Instructions------------------------------------------ 9
6 Service Mode ----------------------------------------------------- 11
6.1. Service Menu Function (1) ----------------------------- 11
6.2. Service Menu Function (2) -----------------------------12
6.3. Service Mode Function (1) -----------------------------13
6.4. Service Mode Function (2) -----------------------------14
7 Troubleshooting Guide ----------------------------------------15
8 Disassembly and Assembly Instructions ---------------16
8.1. Flowchart for disassembly------------------------------16
8.2. Preparations -----------------------------------------------17
8.3. Pedestal (option) removal------------------------------ 17
8.4. Rear cover removal-------------------------------------- 17
8.5. Replacement method for main board and jack
board -------------------------------------------------------- 18
8.6. Replacement method for Power board ------------- 19
8.7. Replacement method for AC cord bracket -------- 19
8.8. Cabinet back removal (42 type) ---------------------- 20
8.9. Cabinet back removal (47 type) ---------------------- 20
8.10. When removing the cabinet back with the
board connected ----------------------------------------- 20
8.11. Replacement method for speakers ------------------ 20
8.12. Key SW board replacement --------------------------- 20
8.13. Connector board removal ------------------------------ 21
8.14. LCD panel replacement -------------------------------- 21
8.15. Replacement method for RC+LED board---------- 22
8.16. Cabinet front replacement ----------------------------- 22
8.17. Cabinet back replacement ----------------------------- 23
9 Block Diagram --------------------------------------------------- 25
9.1. Block (1 of 2) Diagram ---------------------------------- 25

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9.2. Block (2 of 2) Diagram ---------------------------------- 26
10 Wiring Connection Diagram--------------------------------- 27
10.1. Wiring Connection Diagram (1)----------------------- 27
10.2. Wiring Connection Diagram (2)----------------------- 29
10.3. Wiring Connection Diagram (3)----------------------- 30
10.4. Wiring Connection Diagram (4)----------------------- 31
11 Exploded View and Replacement Parts List ----------- 32
11.1. Exploded View and Mechanical Replacement
Parts List --------------------------------------------------- 32
11.2. Mechanical Replacement Parts List (42 inch) ---- 47
11.3. Mechanical Replacement Parts List (47 inch) ---- 48
11.4. Electrical Replacement Boards list (42 inch) ------ 49
11.5. Electrical Replacement Boards list (47 inch) ------ 49
11.6. Boards Layout--------------------------------------------- 49

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1 Safety Precautions
1.1. General Guidelines
1. When conducting repairs and servicing, do not attempt to modify the equipment, its parts or its materials.
2. When wiring units (with cables, flexible cables or lead wires) are supplied as repair parts and only one wire or some of the
wires have been broken or disconnected, do not attempt to repair or re-wire the units. Replace the entire wiring unit instead.
3. When conducting repairs and servicing, do not twist the Fasten connectors but plug them straight in or unplug them straight
out.
4. 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.
5. After servicing, see to it that all the protective devices such as insulation barriers, insulation papers shields are properly
installed.
6. After servicing, make the following leakage current checks to prevent the customer from being exposed to shock hazards.
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 metal-
lic cabinet part on the equipment such as screwheads,
connectors, control shafts, etc. When the exposed metal-
lic part has a return path to the chassis, the reading
should be between 1Mohm and 5.2Mohm.
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 1.5kohm, 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 sensi-
tivity, to measure the potential across the resistor.
4. Check each exposed metallic part, and measure the volt-
age 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 mea-
surement is outside of the limits specified, there is a pos-
sibility of a shock hazard, and the equipment should be
repaired and rechecked before it is returned to the cus-
tomer.

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2 Warning
2.1. Prevention of Electrostatic Discharge (ESD) to Electrostatically Sensi-
tive (ES) Devices
Some semiconductor (solid state) devices can be damaged easily by static electricity. Such components commonly are called Elec-
trostatically 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.
2. After removing an electrical assembly equipped with ES devices, place the assembly on a conductive surface such as alumi-
num 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, aluminum foil or compara-
ble 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 ham less motion such as the brush-
ing 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).

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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.
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 PbF 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 sol-
der. 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. How-
ever, Sn+Cu (tin, copper), Sn+Zn+Bi (tin, zinc, bismuth) solder can also be used.

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3 Service Navigation
3.1. Applicable signals

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4 Specifications
Power Source 110 - 127 V AC, 50/60Hz
Power Consumption
Rated Power Consumption 250 W (42 inch) 300 W (47 inch)
On mode Average
Power Consumption*
200 W (42 inch) 255 W (47 inch)
Stand-by condition 0.1 W (42 inch) 0.1 W (47 inch)
LCD Display panel 42-inch IPS panel, 16:9 aspect ratio (42 inch) 47-inch IPS panel, 16:9 aspect ratio (47 inch)
Screen size 36.6 " (930 mm) (W) ×20.5 " (523 mm) (H) ×42.0 " (1,067 mm) (diagonal) (42 inch)
40.9 " (1,040 mm) (W) ×23.0 " (585 mm) (H) ×46.9 " (1,193 mm) (diagonal) (47 inch)
(No. of pixels) 2,073,600 (1,920 (W) ×1,080 (H)) (42 inch) 2,073,600 (1,920 (W) ×1,080 (H)) (47 inch)
(No. of pixels) [5,760 ×1,080 dots] [5,760 ×1,080 dots]
Operating condition
Temperature 32 °F - 104 °F (0 °C - 40 °C)
Humidity 20 % - 80 %
Applicable signals
Color System NTSC, PAL, PAL60, SECAM, NTSC 4.43, PAL M, PAL N
Scanning format 525 (480) / 60i 60p, 625 (575) / 50i 50p, 750 (720) / 60p 50p, 1125 (1080) /
60i 60p 50i 50p 24p 25p 30p 24sF, 1250 (1080) / 50i
PC signals VGA, SVGA, XGA, SXGA
UXGA ..... (compressed)
Horizontal scanning frequency 30 - 110 kHz
Vertical scanning frequency 48 - 120 Hz
Connection terminals
AV IN VIDEO BNC 1.0 Vp-p (75-ohm)
S-VIDEO Mini DIN 4PIN Y: 1.0 Vp-p (75-ohm), C: 0.286 Vp-p (75-ohm)
AUDIO L-R RCA Pin jack ×2 0.5 Vrms
HDMI 1/2 TYPE A Connector ×2
COMPONENT / RGB IN
G/Y BNC with sync 1.0 Vp-p (75-ohm)
B/PB/CBBNC 0.7 Vp-p (75-ohm)
R/PR/CRBNC 0.7 Vp-p (75-ohm)
AUDIO L-R RCA PIN JACK ×2 0.5 Vrms
DVI-D IN DVI-D 24 Pin Compliance with DVI Revision 1.0
Content Protection Compatible with HDCP 1.1
AUDIO Stereo mini jack (M3) ×1 0.5 Vrms, Shared with PC IN
PC IN High-Density Mini D-sub 15 Pin G with sync 1.0 Vp-p (75-ohm)
G without sync 0.7 Vp-p (75-ohm)
B:0.7 Vp-p (75-ohm)
R:0.7 Vp-p (75-ohm)
HD / VD:1.0 - 5.0 Vp-p (high impedance)
AUDIO Stereo mini jack (M3) ×1 0.5 Vrms, Shared with PC IN
SERIAL External Control Terminal
D-sub 9 Pin RS-232C compatible
Sound
Speakers 2.0” (50 mm) ×3.6” (90 mm) ×2 pcs
Audio Output 10 W [5 W + 5 W] (10 % THD)
Accessories Supplied
Remote Control Transmitter N2QAYB000535
Batteries AA Size ×2
Clamper TMME289 ×3
Dimensions (W ×H ×D) 38.2" (968 mm) ×22.1" (561 mm) ×4.0" (101 mm)
(42 inch)
38.2" (968 mm) ×22.1" (561 mm) ×4.0" (101 mm)
(47 inch)
Mass (weight) approx. 39.7 lbs (42 inch) approx. 50.7 lbs (47 inch)
* Based on IEC 62087 Ed.2 section 11.6.1 measurement method.
Note:
• Design and specifications are subject to change without notice. Mass and dimensions shown are approximate.

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5 Operating Instructions

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6 Service Mode
6.1. Service Menu Function (1)

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6.2. Service Menu Function (2)

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6.3. Service Mode Function (1)

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6.4. Service Mode Function (2)

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7 Troubleshooting Guide

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8 Disassembly and Assembly Instructions
8.1. Flowchart for disassembly

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8.2. Preparations
To avoid damaging the LCD panel, lay out a soft cloth or towel
and lay down the unit so the front side is facing down.
Precautions when replacing each module
• Always perform the procedure below when replacing each
module.
• Be careful not to overtighten the screws when installing each
module.
8.3. Pedestal (option) removal
If the pedestal (option) is installed, remove the 2 screws for the
pedestal on each side, and then remove the pedestal.
8.4. Rear cover removal
First remove the 10 screws on the rear cover, and then remove
the rear cover. (SCR TPG BRZ 4x10)
Boards & Parts location
This unit is designed so that removing the rear cover reveals
the configuration of the boards.

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8.5. Replacement method for main
board and jack board
1. The terminal section is screwed in from the outside, so
remove the screws as shown in the illustration.
2. Remove 1 screw on the jack board that screws in the
earth terminal which comes off from the left side of the
main board. (SCR PAN+SW+W 3X8)
3. Remove the 7 screws that screw the shield casing onto
the main board. (SCR PAN+SW+W 3X8)
4. Remove the coupler that is connected to the main board,
and then carefully remove the main board. Couplers on
the main board:
K16C, KSPR, KSPL, KLVP, K16B, K16A, K8F, K72E,
K72D
5. Replace the main board with the replacement board.
Precautions when removing and installing
• The lead wire is affixed to the shield casing on the main
board with aluminum foil tape. Re-use the shield casing
with the lead wire affixed as is.
• The gasket is affixed to both sides of the main board.
The gasket is not included on the replacement board, so
replace the gasket at the same time as well.
6. Remove the 4 screws that screw in the jack board.
(SCR PAN+SW+W 3X8)
7. Remove the couplers that is connected to the jack board
and carefully remove the jack board.
Couplers on the jack board: K39H, K39G, K19F, K10E,
K10D
8. Replace the jack board with the replacement board.

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8.6. Replacement method for
Power board
1. Remove the couplers that are connected to the Power
board.
Couplers on the Power board: K601, KIV2, KIV1, K6C,
K6B, K6A
2. Remove the screws (47V type: 9 screws, 42V type: 8
screws) that screw the Power board in place. (SCR
PAN+SW+W 3X8) Pull out the boss (plastic) that holds
the Power board.
3. Remove the Power board carefully and replace it with the
replacement board. (The replacement board is equipped
with a fuse.)
8.7. Replacement method for AC
cord bracket
1. Remove the K601 connector for the AC cord bracket from
the Power board.
2. Remove 1 screw that screws in the earth wire for the AC
cord.
Screw: SCR BIN 4X6
3. Pull out the AC cord bracket from the slit on the cabinet
back.
4. Remove the screws (Qty. 2) and nuts (Qty. 2) shown in
the illustration, and then remove the AC cord component.
Screw: SCR BRZ 3X10, Nut: NUT HEX 3
5. Replace the AC cord.
Precautions when removing and installing
• The lead wire is affixed to the shield casing on the main
board with aluminum foil tape. Re-use the shield casing
with the lead wire affixed as is.
• The gasket is affixed to both sides of the main board.
The gasket is not included on the replacement board, so
replace the gasket at the same time as well.

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8.8. Cabinet back removal (42 type)
Precautions when removing and installing
• Be careful not to strip the screw's thread, etc., as the screws
that screw into the cabinet back's periphery impact the out-
ward appearance.
• When re-installing the rear cover, be careful which holes the
wires come out from. (Refer to the wiring connection dia-
gram)
1. Remove the screws (Qty. 23) on the periphery of the cab-
inet back. (SCR FLT 4X12)
2. Remove the screws (Qty. 4) on the inside part of the rear
cover. (SCR BIN 4X6)
3. Remove the cabinet back carefully.
8.9. Cabinet back removal (47 type)
Precautions when removing and installing
• Be careful not to strip the screw's thread, etc., as the screws
that screw into the cabinet back's periphery impact the out-
ward appearance.
• When re-attaching the cabinet back, be careful which holes
the wires come out from. (Refer to the wiring connection dia-
gram)
1. Remove the screws.
2. Remove the cabinet back carefully.
8.10. When removing the cabinet
back with the board connected
1. Remove the following board couplers.
Jack board: K39H
Main board: KLVP
Power board: KIV1, KIV2
2. Remove according to the previous section "Cabinet back
removal."
8.11. Replacement method for
speakers
1. Remove the cabinet back.
2. Peel off the tape halfway that affixes the speaker lead on
the inside of the cabinet back, and then remove the
speaker lead. (Refer to the wiring connection diagram)
3. Remove the screws (Qty. 4 on each side) that screw in
the speaker unit and then replace it with the repair
speaker unit. (SCR S-TPG BRZ+FLG 3.0X8.0 V)
8.12. Key SW board replacement
1. Remove the cabinet back.
2. Peel off the tape halfway that affixes the lead wire for the
key SW board on the inside of the cabinet back, and then
remove the lead wire. (Refer to the wiring connection dia-
gram)
3. Remove the 4 screws and replace the key SW board.
(SCR S-TPG BRZ+FLG 3.0X8.0 V)
Precautions when installing
• The lead wire is affixed to the shield casing on the main
board with the earth part on the key SW board, do not
forget to install so the key SW board is at a right
angle.minum foil tape. Re-use the shield casing with the
lead wire affixed as is.
• Secure the speaker and key SW board lead wires down
onto the inside of the cabinet back with tape so they do
not pop up.
• When re-attaching the rear cover, be careful which holes
the wires come out from. (Refer to the wiring connection
diagram)