DOWNLOAD LG 42LG80FR (CHASSIS:LP81G) Service Manual ↓ Size: 4.34 MB | Pages: 35 in PDF or view online for FREE

Model
42LG80FR (CHASSIS:LP81G)
Pages
35
Size
4.34 MB
Type
PDF
Document
Service Manual
Brand
Device
TV / LCD
File
42lg80fr-chassis-lp81g.pdf
Date

LG 42LG80FR (CHASSIS:LP81G) Service Manual ▷ View online

- 5 -
IC Remove/Replacement
Some chassis circuit boards have slotted holes (oblong) through
which the IC leads are inserted and then bent flat against the
circuit 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 remaining
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
possible 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 whenever
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
connections).
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
connected 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.
- 6 -
1. Application range
This specification is applied to LP81G chassis.
2. Requirement for Test
Each part is tested as below without special appointment.
(1) Temperature : 25 ± 5°C(77 ± 9°F), CST : 40 ± 5°C
(2) Humidity : 65% ± 10%
(3) Power : Standard input voltage (100-240V~, 50/60Hz)
* 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 20 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
SPECIFICATION
NOTE : Specifications and others are subject to change without notice for improvement.
4. General Specification(LCD Module)
Item
Specification
Measurement
Result
Remark
Display Screen Device
42” wide Color Display Module
Resolution:1366X768(HD)
Aspect Ratio
16:9
LCD Module
42” TFT WXGA LCD
42” HD MAKER :LPL
42” TFT WUXGA LCD
42” FHD MAKER :LPL
Operating Environment
1) Temp.   : 0 ~ 40 deg
LGE SPEC
2) Humidity : 0 ~ 85%
Storage Environment
1) Temp.   : -20 ~ 60 deg
2) Humidity : 0 ~ 85 %
Input Voltage
100-240V~, 50/60Hz
Power Consumption
Power on (Blue) : LG80
Volume: 1/8 volume of sound distortion point 
≤ 250W
42” FHD
≤ 230W
42” HD
St-By (Red) ≤ 1.0 W  (All)
LCD Module
Maker
Inch
(H) x (V) x (D)
unit
Remark
(Maker : AUO, LPL)
LPL(HD)
Outline Dimension
42”
983 x 576 x 51
mm
[with inverter]
Pixel Pitch
42”
0.227 x 0.681
mm
Back Light
42”
LPL(FHD)
Outline Dimension
42”
983 x 576 x 47.3/(51)
mm
[w/o inverter]/[with inverter]
Pixel Pitch
42”
0.4845 x 0.4845
mm
Back Light
42”
- 7 -
5. Model Specification(NON EU)
Remark
China(DK)
Australia(BG)
VHF/UHF
C1~C62
C1~C75
CATV
S1~S41
S2~S44
Rear 1EA, Side 1EA
Rear
Side (S-Video Priority)
Rear
Rear
LG80
L/R Input
Side(1EA)
Specification
NON EU/ CHINA
PAL SECAM B/G/D/K, PAL I/II, NTSC-M
BAND
PAL
NTSC
VHF/UHF
E2~C69
2~78
CATV
S1~S47
1~71
Upper Heterodyne
PAL, SECAM, NTSC
PAL, SECAM, NTSC
PAL, SECAM, NTSC
Y/Cb/Cr, Y/ Pb/Pr
RGB-PC, S/W Upgrade
HDMI-DTV, Only PCM MODE
PC Audio, Component (2EA), AV (2EA)
Divx, MP3, JPEG
Item
Market
Broadcasting system
Available Channel
Receiving system
Video Input (2EA)
AV Output (1EA)
S-Video Input (1EA)
Component Input (2EA)
RGB Input (1EA)
HDMI Input (2EA)
Audio Input (5EA)
USB Input
6. Component Video Input (Y, PB, PR)
Resolution
H-freq(kHz)
V-freq.(kHz)
Pixel clock(MHz)
Proposed
720*480
15.73
59.94
13.500
SDTV, DVD 480I(525I)
720*480
15.75
60.00
13.514
SDTV, DVD 480I(525I)
720*576
15.625
50.00
13.500
SDTV, DVD 576I(625I) 50Hz
720*480
31.47
59.94
27.000
SDTV 480P
720*480
31.50
60.00
27.027
SDTV 480P
720*576
31.25
50.00
27.000
SDTV 576P 50Hz
1280*720
44.96
59.94
74.176
HDTV 720P
1280*720
45.00
60.00
74.250
HDTV 720P
1280*720
37.50
50.00
74.25
HDTV 720P 50Hz
1920*1080
28.125
50.00
74.250
HDTV 1080I 50Hz, 
1920*1080
33.72
59.94
74.176
HDTV 1080I
1920*1080
33.75
60.00
74.25
HDTV 1080I
1920*1080
56.25
50
148.5
HDTV 1080P
1920*1080
67.432
59.94
148.350
HDTV 1080P
1920*1080
67.5
60.00
148.5
HDTV 1080P
Resolution
H-freq(kHz)
V-freq.(kHz)
Pixel clock(MHz)
Proposed
Remark
640*350
31.468
70.80
25.17
EGA
720*400
31.469
70.08
28.32
DOS
640*480
31.469
59.94
25.17
VESA(VGA)
800*600
37.879
60.31
40
VESA(SVGA)
1024*768
48.363
60
65
VESA(XGA)
1280*768
47.776
59.87
79.5
VESA(WXGA)
1360*768
47.72
59.799
84.75
VESA(WXGA)
1366*768
47.7
60
84.62
WXGA
1280*1024
63.668
59.895
109.00
SXGA
Only FHD
1920*1080
66.587
59.934
138.50
WUXGA(Reduced Blanking)
Only FHD
Resolution
H-freq(kHz)
V-freq.(kHz)
Pixel clock(MHz)
Proposed
Remark
720x400
31.468
70.08
28.32
640x480
31.469
59.94
25.17
VESA(VGA)
800x600
37.879
60.31
40.00
VESA(SVGA)
1024x768
48.363
60.00
65.00
VESA(XGA)
1280x768
47.776
59.87
79.5
VESA(WXGA)
1360x768
47.72
59.799
84.62
VESA(WXGA)
1366x768
47.7
60
84.62
WXGA
1280x1024
63.595
60.0
108.875
SXGA
Only FHD
1920x1080
66.647
59.988
138.625
WUXGA
Only FHD
- 8 -
8. HDMI input (PC)
- Spec. out but display correctly at only HDMI/DVI IN 1 via DVI to HDMI Cable
Resolution
H-freq(kHz)
V-freq.(kHz)
Pixel clock(MHz)
Proposed
Remark
720*480
15.73
59.94
13.500
SDTV, DVD 480I(525I)
Spec. out but display
720*480
15.75
60.00
13.514
SDTV, DVD 480I(525I)
720*576
15.625
50.00
13.500
SDTV, DVD 576I(625I) 50Hz
720*480
31.47
59.94
27
SDTV 480P
720*480
31.5
60
27.027
SDTV 480P
720*576
31.25
50
27
SDTV 576P
1280*720
44.96
59.94
74.176
HDTV 720P
1280*720
45
60
74.25
HDTV 720P
1280*720
37.5
50
74.25
HDTV 720P
1920*1080
28.125
50
74.25
HDTV 1080I 
1920*1080
33.72
59.94
74.176
HDTV 1080I
1920*1080
33.75
60
74.25
HDTV 1080I
1920*1080
56.25
50
148.5
HDTV 1080P 
1920*1080
67.432
59.94
148.350
HDTV 1080P
1920*1080
67.5
60.00
148.5
HDTV 1080P
1920*1080
27
24
74.25
HDTV 1080P 
1920*1080
33.75
30
74.25
HDTV 1080P 
9. HDMI input (DTV)
7. RGB Input (Analog PC, DTV-NOT SUPPORT)
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