LG 20HIZ12 (CHASSIS:ML-041F) 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 -
1. Application range
This specification is applied to ML-041F chassis.
2. Requirement for Test
Testing for standard of each part must be followed in below
condition.
condition.
(1) Temperature: 25°C ± 2°C
(2) Humidity: 65% ± 10%
(3) Power: Standard input voltage (AC 100-240V, 50/60Hz)
(4) Measurement must be performed after heat-run more than
(2) Humidity: 65% ± 10%
(3) Power: Standard input voltage (AC 100-240V, 50/60Hz)
(4) Measurement must be performed after heat-run more than
30min.
(5) Adjusting standard for this chassis is followed a special
standard.
SPECIFICATION
NOTE : Specifications and others are subject to change without notice for improvement.
3.General Specification
No.
Item
Content
Remark
1
LCD Module Feature
Maker
LPL
Type
TFT Color LCD Module
Active Display Area
20.1 inches(510.00) duaginal
Pixel Pitch [mm]
0.6375mm(H) x 0.6375mm(V) x RGB
Electrical Interface
TTL
LPL
Color Depth
8bits, 16,777,216 color
Size[mm]
450(H) x 3348.7(V) x 20(D)
Surface Treatment
Glare, Hard Coating (3H)
Operating Mode
Normally Black
Black Light Unit
6CCFL(6 lamps)
R/T Typ.
16ms(R.T : 7/10ms + F.T. : 18/20ms)
- 7 -
4. Feature and Function
5. Mechanical specification
No.
Item
Specification
Remark
1
Teletext
TOP, FLOF
Top(option)
2
REMOCON
NEC Code
PAL/ NTSC
3
AV Input
1
Rear
4
S-Video Input
1
Rear
5
Component input
X
6
PERI TV Connector
Full SCART : 1
Rear
7
Ear-phone output
1
8
RJ-12
1
Only Commercial Model(SI-Box interface)
9
Discrete IR
1
10
2 Carrier Stereo
BG, DK
11
NICAM Stereo
BG, I, LL'
12
2 Carrier Dual
BG, DK
13
NICAM Dual
BG, I, LL'
14
DW(Double Window) Mode
X
15
MW(Multi Window) Mode
X
16
Film Mode
X
17
Noise Reduction
X
18
Progressive Scan
0
19
Motion Detection
X
20
SRS WOW
X
21
Swivel Speaker
X
22
EZ-pip
X
23
ARC
X
24
DRP
X
25
DCDI
X
26
HDCP
X
No
Item
Content
Remark
1
Product
Width (W)
Length (D)
Height (H)
Dimension
Before Packing
597.5
222
460.6
With Stand
After Packing
702
288
547
2
Product
Only SET
9.9kg
Weight
With BOX
12 kg
6. Engineering Specification
No.
ITEM
Specification
Remark
1
ENERGE
SYNC(V/H)
VIDEO
POWER CONSUMPTION
LED COLOR
Normal
On/On
Active
≤ 65W GREEN
Stand By,
Off/Off
Off
≤ 1W
LED
Cut-off Switch off
-
-
0W
OFF
PBP SWAP
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ON/OFF
ITEM
Specification
Remark
- 8 -
7. Outgoing Condition
No
Item
Condition
Remark
1
Power
Off
2
Volume Level
30
3
Main Picture Input
TV
4
Main Last Channel
Pr 01
5
Mute
Off
6
APC
Clear
7
Station
Auto Program
Manual Program
Program Edit
Favorite Program
None
8
Picture
PSM
Dynamic
Dynamic
Contrast
85
Brightness
60
Colour
70
Sharpness
70
Tint
0
NTSC OPTION
9
Sound
SSM
Flat
AVL
Off
Balance
0
10
Special
Input
TV
Child Lock
Off
Auto Sleep
Off
Language
English(Area Management)
8. Optical Character
No
Item
Specification
Remark
LPL
CMO
AUO
1
Viewing Angle
Right / Left
88/88
80/80
80/80
<CR≥10>
Up / Down
88/88
70/70
60/60
2
Luminance
Luminance (cd/m2)
450
450
500
Typical
Variation
1.3
MAX / MIN
3
Contrast Ratio
350
500
500
All white / All black
4
CIE Color Coordinates
White
WX
Typ.
0.289
0.285
0.31
WY
Typ.
0.335
0.293
0.33
RED
Xr
Typ.
0.692
0.692
0.64
Yr
Typ.
0.335
0.332
0.34
Green
Xg
Typ.
0.289
0.276
0.29
Yg
Typ.
0.583
0.601
0.61
Blue
Xb
Typ.
0.143
0.142
0.14
Yb
Typ.
0.909
0.075
0.07
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