LG 37LC45 (CHASSIS:LD73A) 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
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 -
SPECIFICATION
NOTE : Specifications and others are subject to change without notice for improvement.
1. General Specification(TV)
No. Item
Specification Remark
1.
Video input applicable system
PAL-D/K, B/G, I, SECAM
2.
Receivable Broadcasting System
1) PAL/SECAM B/G
EU(PAL Market)
2) PAL/SECAM D/K
3) PAL I/II
4) SECAM L/L’
5) DVB-T
3.
RF Input Channel
VHF : E2 ~ E12
PAL
UHF : E21 ~ E69
CATV : S1 ~ S20
HYPER : S21~ S47
4.
Input Voltage
AC 100 ~ 240 V/50Hz, 60Hz
5.
Market
UK / France / Spain / German /
Finland / Sweden / Italy
6.
Picture Size
26 inch
26LC45/26LC46/26LC55
32 inch
32LC45/32LC46/32LC55/32LC56
37 inch
37LC45/37LC46/37LC55
42 inch
42LC45/42LC46/42LC55
7.
Tuning System
FVS 100 program
PAL, 200 PR.(Option)
8.
Operating Environment
1) Temp : 0 ~ 40 deg
2) Humidity : 10 ~ 90 %
9.
Storage Environment
3) Temp : -20 ~ 50 deg
4) Humidity : 10 ~ 90 %
10. Display
LCD
Module
LPL
- 7 -
2. General Specification(LCD Module)
No. Item
Specification
Unit
Remark
1.
Panel
26” TFT WXGA LCD
26LC45/26LC46/26LC55
32” TFT WXGA LCD
32LC45/32LC46/32LC55/32LC56
37” TFT WXGA LCD
37LC45/37LC46/37LC55
42” TFT WXGA LCD
42LC45/42LC46/42LC55
2.
Frequency range
H : 45 ~ 50Khz, V : 47 ~ 63Hz
26, 32, 37 inch
H : 44.65 ~ 50.35Khz, V : 47 ~ 63Hz
42 inch
3.
Power consumption
26 inch
≤
4.6 W
32 inch
≤
5.54 W
37 inch
≤
6 W
42 inch
≤
8.27 W
4.
LCD Module-LPL (26inch)
Type Size
26”
626.0 x 373.0 x 44.1
mm (H) x (V) x (D)
Pixel Pitch
26”
140.5 x 421.5 x RGB
um
Pixel Format
1366 horiz. By 768 vert. Pixels
RGB strip arrangement
Coating
Hard coating(3H), Anti-glare
treatment of the front polarizer
Back Light
26”
17 EEFL
5.
LCD Module-CMO (26inch)
Type Size
26”
575.769 x 323.712
mm (H)x (V)x (D)
Pixel Pitch
26”
140.5 x 421.5 um
Pixel Format
1366 x RGB x 768
Coating
Hard coating(3H), Anti-glare
Back Light
26”
12 CCFL
6.
LCD Module (32inch)
Type Size
32”
760.0 x 450.0 x 42.8
mm (H)x (V)x (D)
Pixel Pitch
32”
170.25 x 510.75 x RGB
um
Pixel Format
1366 horiz. By 768 vert. Pixels
RGB strip arrangement
Coating
Hard coating(3H), Anti-glare
treatment of the front polarizer
Back Light
32”
18 EEFL
7.
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
8.
LCD Module (42inch)
Type Size
42”
983 x 576 x 47.3
mm (H) x (V) x (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
- 8 -
3. Optical Feature
3-1. 26” LCD Module-LPL
3-2. 26” LCD Module-CMO
3-3. Optical Feature(32” LCD Module)
No. Item
Specification
Min.
Typ.
Max.
Remark
1.
Viewing Angle<CR>10>
R/L, U/D
178, 178
2. Luminance
Luminance
(cd/m
2
)
350 400
26”
Variation
-
1.3
MAX / MIN
3.
Contrast Ratio
CR(26”)
500
700
All white/All black
CR
D
(With AI)(26”)
1000
1400
All white/All black
4.
CIE Color Coordinates
White
Wx
Typ.
0.275
Typ.
LPL(26”)
Wy
-0.03
0.279
+0.03
RED
Xr
0.630
Yr 0.338
Green Xg
0.283
Yg 0.607
Blue Xb
0.147
Yb
0.064
No. Item
Specification
Min.
Typ.
Max.
Remark
1.
Viewing Angle<CR>10>
R/L, U/D
178, 178
2. Luminance
Luminance
(cd/m
2
)
320 400
32”
Variation
-
1.3
MAX / MIN
3.
Contrast Ratio
CR(32”)
600
800
All white/All black
CR
D
(With AI)(32”)
1200
1600
All white/All black
4.
CIE Color Coordinates
White
Wx
Typ.
0.285
Typ.
32”
Wy
-0.03
0.293
+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
160, 150
2. Luminance
Luminance
(cd/m
2
)
350 400
26”
Variation
-
1.3
MAX / MIN
3.
Contrast Ratio
CR(26”)
500
700
All white/All black
CR
D
(With AI)(26”)
1000
1400
All white/All black
4.
CIE Color Coordinates
White
Wx
Typ.
0.280
Typ.
CMO(26”)
Wy
-0.03
0.285
+0.03
RED
Xr
0.637
Yr 0.332
Green Xg
0.268
Yg 0.590
Blue Xb
0.150
Yb
0.059
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