LG 32LB9D (CHASSIS:LT73A) 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.
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.
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
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. Inspect (on the circuit board copper side) the solder joints of
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).
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.
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 -
SPECIFICATION
NOTE : Specifications and others are subject to change without notice for improvement.
1. General Specification(TV)
2. General Specification(LCD Module)
No. Item
Specification Remark
1.
Receiving System
Analog : NTSC-M, DTV : DVB-T
2.
Available Channel
1) VHF : 2~13
2) UHF : 14~69
3) CATV : 1 ~ 125
4) DTV : 14~69
3.
Tuner IF
1) NTSC-M : 42.75MHz(Picture),
41.25MHz(Sound)
2) DVB-T : 36.125MHz
4.
Input Voltage
AC 110 V, 60Hz
5.
Market
Taiwan
6.
Picture Size
37 inch
37LC7D
42 inch
42LC7D
7.
Operating Environment
1) Temp : 0 ~ 40 deg
2) Humidity : 10 ~ 90 %
7.
Storage Environment
3) Temp : -20 ~ 50 deg
4) Humidity : 10 ~ 90 %
8.
Display
LCD Module
LPL
NO.
Item
Specification
Unit
Remark
1.
Panel
37" TFT WXGA LCD
37LC7D
42" TFT WXGA LCD
42LC7D
2.
Frequency range
H : 45 ~ 50Khz, V : 47 ~ 63Hz
37 inch
H : 44.65 ~ 50.35Khz, V : 47 ~ 63Hz
42 inch
3.
Power consumption
37 inch
≤ 6 W
42 inch
≤ 8.27 W
4.
LCD Module (37inch)
Type Size
37"
877.0 x 516.8 x 46.9
mm
(H) x (V) x (D)
Pixel Pitch
37"
0.200 x 0.600 x RGB
mm
Pixel Format
1366 horiz. By 768 vert.
Pixels RGB strip arrangement
Coating
Hard coating(3H),
Anti-glare treatment of the front polarizer
Back Light
37"
16 EEFL
5.
LCD Module (42inch)
Type Size
42"
983 x 576 x 47.3
mm
(H) _ (V) _ (D)
Pixel Pitch
42"
0.227 x 0.681 x RGB
mm
Pixel Format
1366 horiz. By 768 vert.
Pixels RGB strip arrangement
Coating
Hard coating(3H),
Anti-glare treatment of the front polarizer
Back Light
42"
18 CCFL
- 7 -
3. Optical Feature(37" LCD Module)
No.
Item
Specification
Min.
Typ.
Max.
Remark
1.
Viewing Angle<CR>10>
R/L, U/D
178, 178
2.
Luminance
Luminance (cd/m2)
300
400
37"
Variation
-
1.3
MAX / MIN
3.
Contrast Ratio
CR(37")
600
800
All white/All black
CRD (With AI)(37")
1200
1600
All white/All black
4.
CIE Color Coordinates
White
WX
Typ
0.279
Typ
LPL(37")
WY
-0.03
0.292
+0.03
RED
Xr
0.640
Yr
0.343
Green
Xg
0.280
Yg
0.605
Blue
Xb
0.145
Yb
0.065
No.
Item
Specification
Min.
Typ.
Max.
Remark
1.
Viewing Angle<CR>10>
R/L, U/D
178, 178
2.
Luminance
Luminance (cd/m2)
350
400
42"
Variation
-
1.3
MAX / MIN
3.
Contrast Ratio
CR(37")
600
800
All white/All black
CRD (With AI)(37")
1200
1600
All white/All black
4.
CIE Color Coordinates
White
WX
Typ
0.281
Typ
LPL(42")
WY
-0.03
0.293
+0.03
RED
Xr
0.630
Yr
0.343
Green
Xg
0.275
Yg
0.607
Blue
Xb
0.147
Yb
0.068
4. Optical Feature(42" LCD Module)
- 8 -
5. Component Video Input (Y, P
B
, P
R
)
No.
Specification
Remark
Resolution H-freq(kHz)
V-freq(Hz)
1.
720*480
15.73
60.00
SDTV, DVD 480i
2.
720*480
15.63
59.94
SDTV, DVD 480i
3. 720*480
31.47
59.94
480p
4. 1280*720
44.96
59.94
HDTV
720p
5. 1920*1080
33.75
60.00
HDTV
1080i
6.
1920*1080
33.72
59.94
HDTV 1080i
No.
Specification
Remark
Resolution H-freq(kHz)
V-freq(Hz)
Pixel clock(MHz)
1.
720*400
31.468
70.08
28.321
2.
640*480
31.469
59.94
25.17
VESA
37.684
75.00
31.50
3.
800*600
37.879
60.31
40.00
VESA
46.875
75.00
49.50
4.
832*624
49.725
74.55
57.283
5.
1024*768
48.363
60.00
65.00
VESA(XGA)
56.470
70.00
75.00
60.123
75.029
78.75
6.
1280*768
47.776
59.870
79.50
VESA(WXGA)
7.
1360*768
47.720
59.799
84.75
VESA(WXGA)
8.
1366*768
47.130
59.65
72.00
Supported
9.
1920*1080
66.587
59.934
138.5
6. RGB PC
- RGB PC INPUT Mode Table
- RGB-PC EDID DATA
C/S
00
20
20
20
20
20
20
0A
00
0E
43
1D
4B
3C
00
0x07
FD
00
00
00
20
20
20
20
20
20
20
0A
56
54
20
47
0x06
4C
00
FC
00
00
00
18
00
00
21
86
BC
04
85
20
50
0x05
40
1F
38
70
A0
80
36
26
1C
00
00
21
86
BC
00
35
0x04
88
48
30
1E
00
51
A0
50
21
1B
01
01
01
01
01
01
0x03
01
01
C0
D1
40
61
40
45
40
31
00
6E
A5
4B
49
11
0x02
25
9C
49
57
A3
B0
D9
EA
78
27
46
01
03
01
Month/Year
0x01
Serial No
Product ID
6D
1E
00
FF
FF
FF
FF
FF
FF
00
0x00
0x0F
0x0E
0x0D
0x0C
0x0B
0x0A
0x09
0x08
0x07
0x06
0x05
0x04
0x03
0x02
0x01
0x00
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