LG 26LN45XX / 26LN4503 / 26LN450B / 26LN450U / 26LN4573 / 26LN4575 / 26LN457B / 26LN457U (CHASSIS:LC31A / LD31T) Service Manual ▷ View online
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IC Remove/Replacement
Some chassis circuit boards have slotted holes (oblong) through
which the IC leads are inserted and then bent flat against the cir-
cuit foil. When holes are the slotted type, the following technique
should be used to remove and replace the IC. When working with
boards using the familiar round hole, use the standard technique
as outlined in paragraphs 5 and 6 above.
Removal
1. Desolder and straighten each IC lead in one operation by
gently prying up on the lead with the soldering iron tip as the
solder melts.
2. Draw away the melted solder with an anti-static suction-type
solder removal device (or with solder braid) before removing
the IC.
Replacement
1. Carefully insert the replacement IC in the circuit board.
2. Carefully bend each IC lead against the circuit foil pad and
solder it.
3. Clean the soldered areas with a small wire-bristle brush.
(It is not necessary to reapply acrylic coating to the areas).
"Small-Signal" Discrete Transistor
Removal/Replacement
1. Remove the defective transistor by clipping its leads as close
as possible to the component body.
2. Bend into a "U" shape the end of each of three leads remain-
ing on the circuit board.
3. Bend into a "U" shape the replacement transistor leads.
4. Connect the replacement transistor leads to the corresponding
leads extending from the circuit board and crimp the "U" with
long nose pliers to insure metal to metal contact then solder
each connection.
Power Output, Transistor Device
Removal/Replacement
1. Heat and remove all solder from around the transistor leads.
2. Remove the heat sink mounting screw (if so equipped).
3. Carefully remove the transistor from the heat sink of the circuit
board.
4. Insert new transistor in the circuit board.
5. Solder each transistor lead, and clip off excess lead.
6. Replace heat sink.
Diode Removal/Replacement
1. Remove defective diode by clipping its leads as close as pos-
sible to diode body.
2. Bend the two remaining leads perpendicular y to the circuit
board.
3. Observing diode polarity, wrap each lead of the new diode
around the corresponding lead on the circuit board.
4. Securely crimp each connection and solder it.
5. Inspect (on the circuit board copper side) the solder joints of
the two "original" leads. If they are not shiny, reheat them and
if necessary, apply additional solder.
Fuse and Conventional Resistor
Removal/Replacement
1. Clip each fuse or resistor lead at top of the circuit board hollow
stake.
2. Securely crimp the leads of replacement component around
notch at stake top.
3. Solder the connections.
CAUTION: Maintain original spacing between the replaced
component and adjacent components and the circuit board to
prevent excessive component temperatures.
Circuit Board Foil Repair
Excessive heat applied to the copper foil of any printed circuit
board will weaken the adhesive that bonds the foil to the circuit
board causing the foil to separate from or "lift-off" the board. The
following guidelines and procedures should be followed when-
ever this condition is encountered.
At IC Connections
To repair a defective copper pattern at IC connections use the
following procedure to install a jumper wire on the copper pattern
side of the circuit board. (Use this technique only on IC connec-
tions).
1. Carefully remove the damaged copper pattern with a sharp
knife. (Remove only as much copper as absolutely necessary).
2. carefully scratch away the solder resist and acrylic coating (if
used) from the end of the remaining copper pattern.
3. Bend a small "U" in one end of a small gauge jumper wire and
carefully crimp it around the IC pin. Solder the IC connection.
4. Route the jumper wire along the path of the out-away copper
pattern and let it overlap the previously scraped end of the
good copper pattern. Solder the overlapped area and clip off
any excess jumper wire.
At Other Connections
Use the following technique to repair the defective copper pattern
at connections other than IC Pins. This technique involves the
installation of a jumper wire on the component side of the circuit
board.
1. Remove the defective copper pattern with a sharp knife.
Remove at least 1/4 inch of copper, to ensure that a hazardous
condition will not exist if the jumper wire opens.
2. Trace along the copper pattern from both sides of the pattern
break and locate the nearest component that is directly con-
nected to the affected copper pattern.
3. Connect insulated 20-gauge jumper wire from the lead of the
nearest component on one side of the pattern break to the
lead of the nearest component on the other side.
Carefully crimp and solder the connections.
CAUTION: Be sure the insulated jumper wire is dressed so the
it does not touch components or sharp edges.
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SPECIFICATION
NOTE : Specifications and others are subject to change without notice for improvement.
1. Application range
This specification is applied to the LED TV used LC31A /
LD31T chassis.
2. Requirement for Test
Each part is tested as below without special appointment.
1) Temperature: 25 °C ± 5 °C(77 °F ± 9 °F), CST: 40 °C ± 5 °C
2) Relative Humidity: 65 % ± 10 %
3) Power Voltage
: Standard input voltage (AC 100-240 V~, 50/60 Hz)
* Standard Voltage of each products is marked by models.
4) Specification and performance of each parts are followed
each drawing and specification by part number in
accordance with BOM.
5) The receiver must be operated for about 5 minutes prior to
the adjustment.
3. Test method
1) Performance: LGE TV test method followed
2) Demanded other specification
- Safety : CE, IEC specification
- EMC : CE, IEC
4. Model General Specification
No.
Item
Specification
Remarks
1
Market
EU/CIS(PAL Market-37 Countries)
DTV & Analog (Total 37 countries)
DTV (MPEG2/4, DVB-T) :37 countries
UK/Italy/Germany/France/Spain/Sweden/Finland/Netherlands/
Belgium/Luxemburg/ Greece/Denmark/Czech/Austria/Hungary
/Swiss/Croatia/Turkey/Norway/Slovenia/Poland/Ukraine/Portu-
gal/Ireland/Morocco/Latvia/Estonia/Lithania/Rumania/Bulgaria/
Russia/SlovakiaBosnia/Serbia/Albania/Kazakhstan/Belarus
*4 Country, Nordic option(EU model only)
- Denmark , Finland, Norway, Sweden
DTV (MPEG2/4, DVB-T2): 8 countries
UK/Denmark/Sweden/Finland/Norway/Ireland/Ukraine/Kaza-
khstan
DTV (MPEG2/4, DVB-C): 37 countries
UK/Italy/Germany/France/Spain/Sweden/Finland/Netherlands/
Belgium/Luxemburg/ Greece/Denmark/Czech/Austria /Hun-
gary/Swiss/Croatia/Turkey/Norway/Slovenia/Poland/Ukraine/
Portugal/Ireland/Morocco/Latvia/Estonia/Lithania/Rumania/
Bulgaria/Russia/Slovakia/Bosnia/Serbia/Albania/Kazakhstan/
Belarus
DTV (MPEG2/4,DVB-S): 29 countries
Italy/Germany/France/Spain/Netherlands/ Belgium/Luxemburg/
Greece/ Czech/Austria /Hungary/Swiss/Croatia/Turkey/Slov-
enia/Poland/Portugal/ Morocco/Latvia/Estonia/Lithuania/Ruma-
nia/Bulgaria/Russia/SlovakiaBosnia/Serbia/Albania/ Belarus
Supported satellite : 22 satellites
HISPASAT 1C/1D, ATLANTIC BIRD 2, NILESAT 101/102,
ATLANTIC BIRD 3, AMOS 2/3, THOR 5/6, IRIUS 4, EUTEL-
SAT-W3A, EUROBIRD 9A, EUTELSAT-W2A, HOTBIRD 6/8/9,
EUTELSAT-SESAT, ASTRA 1L/H/M/KR, ASTRA 3A/3B, BADR
4/6, ASTRA 2D, EUROBIRD 3, EUTELSAT-W7, HELLASSAT
2, EXPRESS AM1, TURKSAT 2A/3A, INTERSAT10
- 7 -
No.
Item
Specification
Remarks
2
Broadcasting system
Analogue TV
1) PAL-BG
2) PAL-DK
3) PAL-I/I’
4) SECAM-BG
5) SECAM-DK
6) SECAM L/L’
Digital TV
1) DVB-T/C/T2
Satellite Digital TV
1) DVB-T/C/S/S2
Analogue TV : (RF) VHF: E2 to E12, UHF : E21 to E69
(CATV) S1 to S20, HYPER: S21 to S47
Digital TV : VHF, UHF
Satellite TV : VHF, UHF,
C-Band, Ku-Band
* DVB-T2 ( T2 model only support )
* DVB-S/S2 (Satellite model only support )
3
Receiving system
Analog : Upper Heterodyne
Digital : COFDM, QAM
► DVB-T
- Guard Interval(Bitrate_Mbit/s)B : 1/4, 1/8, 1/16, 1/32
- Modulation : Code Rate
QPSK
: 1/2, 2/3, 3/4, 5/6, 7/8
16-QAM : 1/2, 2/3, 3/4, 5/6, 7/8
64-QAM : 1/2, 2/3, 3/4, 5/6, 7/8
► DVB-T2
- Guard Interval(Bitrate_Mbit/s)
1/4, 1/8, 1/16, 1/32, 1/128, 19/128, 19/256,
- Modulation : Code Rate
QPSK
: 1/2, 2/5, 2/3, 3/4, 5/6
16-QAM : 1/2, 2/5, 2/3, 3/4, 5/6
64-QAM : 1/2, 2/5, 2/3, 3/4, 5/6
256-QAM : 1/2, 2/5, 2/3, 3/4, 5/6
► DVB-C
- Symbolrate : 4.0Msymbols/s to 7.2Msymbols/s
- Modulation : 16QAM, 64-QAM, 128-QAM and 256-QAM
► DVB-S/S2
- symbolrate
DVB-S2 (8PSK / QPSK) : 2 ~ 45 Msymbol/s
DVB-S (QPSK) : 2 ~ 45 Msymbol/s
- viterbi
DVB-S mode : 1/2, 2/3, 3/4, 5/6, 7/8
DVB-S2 mode : 1/2, 2/3, 3/4, 3/5, 4/5, 5/6, 8/9, 9/10
4
Scart Jack (1EA)
PAL, SECAM
Scart 1 Jack is Full scart and support RF-OUT(analog).
5
Component Input (1EA) Y/Pb/Pr
6
CVBS Input (1EA)
PAL, SECAM, NTSC
4 System(Rear) : PAL, SECAM, NTSC, PAL60
CVBS Video input is used by common port with Component.
7
RGB Input
RGB-PC
Analog(D-SUB 15PIN)
8
HDMI Input (1EA)
HDMI
Rear1EA / HDMI version 1.4/ support PC
Support HDCP/HDMI : MHL Support
9
Audio Input (3EA)
RGB/DVI Audio
Component & CVBS
SCART
L/R Input
CVBS Audio input is used by common port with Component.
10 Headphone out (1EA)
Antenna, AV, Component, RGB, HDMI Side 1EA
11
USB (1EA)
Picture, Music, Movie, SVC
Software Update + Picture + Music + Movie
12 DVB
DVB-T
CI : UK, Finland, Denmark, Norway, Sweden, Russia, Spain,
Ireland, Luxemburg, Belgium, Netherland
CI+ : France(Canal+), Italy(DGTVi)
DVB-C
CI : Switzerland, Austria, Slovenia, Hungary, Bulgaria
CI+: Switzerland(UPC,Cablecom), Netherland(Ziggo),
Germany(KDG,CWB), Finland(labwise)
13 Local Key (Touch)
14 LAN JACK
14 LAN JACK
Modular
Only UK model
- 8 -
5. Timing
5.1. RGB/HDMI (PC)
No.
Specification
Remark
Resolution
H-freq(kHz)
V-freq.(Hz)
Pixel clock(MHz)
1.
720*400
31.468
70.080
28.321
2.
640*480
31.469
59.940
25.175
3.
640*480
37.500
75.000
31.500
4.
800*600
37.879
60.317
40.000
5.
800*600
46.875
75.000
49.500
6.
1024*768
48.363
60.004
65.000
7.
1024*768
60.023
75.029
78.750
8.
1280*720
45.000
60.000
74.250
9.
1280*800
49.702
59.810
83.500
10.
1366*768
47.717
59.79
85.5
5.2. HDMI (DTV)
No.
Specification
Remark
Resolution
H-freq(kHz)
V-freq.(Hz)
Pixel clock(MHz)
1.
720*480
31.469
31.5000
59.940
60.000
27.000
27.030
SDTV 480P
2.
720*576
31.250
50.000
27.864
SDTV 576P
3.
1280*720
37.500
50.000
74.250
HDTV 720P
4.
1280*720
44.960
45.000
59.940
60.000
74.170
74.250
HDTV 720P
5.
1920*1080
33.720
33.750
59.940
60.000
74.170
74.250
HDTV 1080I
6.
1920*1080
28.125
50.000
74.250
HDTV 1080I
7.
1920*1080
27.000
24.000
74.250
HDTV 1080P
8.
1920*1080
33.750
30.000
74.250
HDTV 1080P
9.
1920*1080
56.250
50.000
148.500
HDTV 1080P
10.
1920*1080
67.430
67.500
59.940
60.000
148.350
148.500
HDTV 1080P
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