LG 26LC4R (CHASSIS:LP78A) 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
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.
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
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.
melts.
2. Draw away the melted solder with an anti-static suction-type
solder removal device (or with solder braid) before removing the
IC.
IC.
Replacement
1. Carefully insert the replacement IC in the circuit board.
2. Carefully bend each IC lead against the circuit foil pad and
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
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
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.
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
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.
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
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.
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.
necessary, apply additional solder.
Fuse and Conventional Resistor
Removal/Replacement
1. Clip each fuse or resistor lead at top of the circuit board hollow
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.
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.
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).
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.
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.
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.
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.
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.
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 LP78A chassis.
2. Requirement for Test
Testing for standard of each part must be followed in below
condition.
condition.
(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)
(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.
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
(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)
Remark
LCD
MAKER : AUO/CMO/LPL/CPT
LGE SPEC
Volume: 1/8 volume of sound distortion point
(H) x (V) x (D) [with inverter]
(H) x (W)
(H) x (V) x (D) [with inverter]
(H) x (V)
(H) x (V) x (D) [with inverter]
(H) x (V)
(LC260WX2-SLB3)
(LPL 26”)
Specification
26/27/32/37/42” wide Color Display Module
16:9
26/27/32/37/42” TFT WXGA LCD
Temp. : 0 ~ 40 deg, Humidity : 0 ~ 85%
Temp. : -20 ~ 60 deg, Humidity : 0 ~ 85 %
100-240V~, 50/60Hz
Power on (Green)
≤ TBD
(42”)
≤ max
(26”, 27”, 32”, 37”)
St-By (Red) : 1.0 W
AUO
Outline Dimension
26”
32”
37”
Pixel Pitch
26”
32”
37”
Back Light
26”,32”
37”
CMO
Outline Dimension
27”
32”
Pixel Pitch
27”
32”
Back Light
27”
32”
LPL
Outline Dimension
26”
32”
37”
42”
Pixel Pitch
26”
32”
37”
42”
Back Light
26”
32”
37”
42”
Display Colors
Coating
Measurement
626.0 x 373.0 x 47.5
760.0 x 450.0 x 45
877.0 x 514.6 x 54.7
0.4215
0.51075
0.6 x 0.6
8 U-lamp
10 U-lamp
637.55 x 379.8 x 40.7
760 x 450 x 47.53
0.1455 x 0.4365
0.1730 x 0.5190
14 CCFL
16 CCFL
626 x 373 x 44.1
760.0 x 450.0 x 48.0
877.0 x 516.8 x 55.5
1006 x 610 x 56
0.1405 x 0.4215
0.17025 x 0.51075
0.200 x 0.600
0.227 x 0.681
18 EEFL (17 EEFL)
18 EEFL
20 EEFL
20 CCFL
16.7M (16,777,216)
3H, AG
Result
mm
mm
mm
mm
mm
mm
mm
mm
Item
Display Screen Device
Aspect Ratio
LCD Module
Operating Environment
Storage Environment
Input Voltage
Power Consumption
LCD Module
- 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 1EA
Side AV
S-Video Priority
L/R Input(PC 1EA, Component 1EA, Rear 1EA, Side 1EA)
Specification
NON EU, CHINA
PAL BG/DK, PAL I/II, NTSC-M
BAND
PAL
NTSC
VHF/UHF
C1~C69
1~83
CATV
S1~S47
1~71
Upper Heterodyne
PAL, SECAM, NTSC
PAL, SECAM, NTSC
PAL, SECAM, NTSC
Y/Cb/Cr, Y/ Pb/Pr
RGB-PC
HDMI-DTV
PC Audio, Component (2EA), AV (2EA)
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)
Variable Audio out(1EA)
6. Component Video Input (Y, P
B
, P
R
)
V-freq(kHz)
59.94
60.00
50.00
59.94
60.00
50.00
59.94
60.00
50.00
59.94
60.00
50.00
Proposed
SDTV, DVD 480I(525I)
SDTV, DVD 480I(525I)
SDTV, DVD 576I(625I) 50Hz
SDTV 480P
SDTV 480P
SDTV 576P 50Hz
HDTV 720P
HDTV 720P
HDTV 720P 50Hz
HDTV 1080I
HDTV 1080I
HDTV 1080I 50Hz
H-freq(kHz)
15.73
15.75
15.625
31.47
31.50
31.25
44.96
45.00
37.50
33.72
33.75
28.125
Resolution
720*480
720*480
720*576
720*480
720*480
720*576
1280*720
1280*720
1280*720
1920*1080
1920*1080
1920*1080
Pixel clock(MHz)
13.500
13.514
13.500
27.000
27.027
27.000
74.176
74.250
74.25
74.176
74.250
74.250
7. RGB Input (Analog PC)
V-freq(kHz)
70.80
70.80
59.94
60.31
60.00
59.87
59.799
59.799
Proposed
EGA
DOS
VESA(VGA)
VESA(SVGA)
VESA(XGA)
WXGA
WXGA
WXGA
Remark
XGA only
XGA only
XGA only
H-freq(kHz)
31.468
31.469
31.469
37.879
48.363
47.776
47.720
47.720
Resolution
640*350
720*400
640*480
800*600
1024*768
1280*768
1360*768
1366*768
Pixel clock(MHz)
25.17
28.321
25.17
40.00
65.00
79.50
84.75
84.75
- 8 -
8. HDMI input (DTV)
V-freq(kHz)
60.00
59.94
50.00
59.94
60.00
50.00
59.94
60.00
50.00
59.94
60.00
50.00
59.94
60
50
Proposed
SDTV, DVD 480I(525I)
SDTV, DVD 480I(525I)
SDTV, DVD 576I(625I) 50Hz
SDTV 480P
SDTV 480P
SDTV 576P 50Hz
HDTV 720P
HDTV 720P
HDTV 720P 50Hz
HDTV 1080I
HDTV 1080I
HDTV 1080I 50Hz
HDTV 1080P
HDTV 1080P
HDTV 1080P 50Hz
H-freq(kHz)
15.75
15.73
15.625
31.47
31.50
31.25
44.96
45.00
37.50
33.72
33.75
28.125
67.432
67.5
56.250
Resolution
720*480
720*480
720*576
720*480
720*480
720*576
1280*720
1280*720
1280*720
1920*1080
1920*1080
1920*1080
1920*1080
1920*1080
1920*1080
Pixel clock(MHz)
13.514
13.500
13.500
27.000
27.027
27.000
74.176
74.250
74.25
74.176
74.250
74.250
148.350
148.5
148.5
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