LG 55LS4500 (CHASSIS:LA25C) Service Manual ▷ View online
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Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in the
Schematic Diagram and Exploded View.
It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent
Shock, Fire, or other Hazards.
Do not modify the original design without permission of manufacturer.
General Guidance
An
isolation Transformer should always be used during the
servicing of a receiver whose chassis is not isolated from the AC
power line. Use a transformer of adequate power rating as this
protects the technician from accidents resulting in personal injury
from electrical shocks.
It will also protect the receiver and it's components from being
damaged by accidental shorts of the circuitry that may be
inadvertently introduced during the service operation.
If any fuse (or Fusible Resistor) in this TV receiver is blown,
replace it with the specified.
When replacing a high wattage resistor (Oxide Metal Film Resistor,
over 1 W), keep the resistor 10 mm away from PCB.
Keep wires away from high voltage or high temperature parts.
Before returning the receiver to the customer,
always perform an
AC leakage current check on the exposed
metallic parts of the cabinet, such as antennas, terminals, etc., to
be sure the set is safe to operate without damage of electrical
shock.
Leakage Current Cold Check(Antenna Cold Check)
With the instrument AC plug removed from AC source, connect an
electrical jumper across the two AC plug prongs. Place the AC
switch in the on position, connect one lead of ohm-meter to the AC
plug prongs tied together and touch other ohm-meter lead in turn to
each exposed metallic parts such as antenna terminals, phone
jacks, etc.
If the exposed metallic part has a return path to the chassis, the
measured resistance should be between 1 M
Ω and 5.2 MΩ.
When the exposed metal has no return path to the chassis the
reading must be infinite.
An other abnormality exists that must be corrected before the
receiver is returned to the customer.
Leakage Current Hot Check
(See below Figure)
Plug the AC cord directly into the AC outlet.
Do not use a line Isolation Transformer during this check.
Connect 1.5 K / 10 watt resistor in parallel with a 0.15 uF capacitor
between a known good earth ground (Water Pipe, Conduit, etc.)
and the exposed metallic parts.
Measure the AC voltage across the resistor using AC voltmeter
with 1000 ohms/volt or more sensitivity.
Reverse plug the AC cord into the AC outlet and repeat AC voltage
measurements for each exposed metallic part. Any voltage
measured must not exceed 0.75 volt RMS which is corresponds to
0.5 mA.
In case any measurement is out of the limits specified, there is
possibility of shock hazard and the set must be checked and
repaired before it is returned to the customer.
Leakage Current Hot Check circuit
IMPORTANT SAFETY NOTICE
SAFETY PRECAUTIONS
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SPECIFICATION
NOTE : Specifications and others are subject to change without notice for improvement.
1. Application range
This spec sheet is applied LCD TV with LA25A/B/C chassis
2. Test condition
Each part is tested as below without special notice.
1) Temperature : 25 ºC ± 5 ºC(77 ± 9 ºF), CST : 40 ± 5 ºC
2) Relative Humidity: 65 % ± 10 %
3) Power Voltage
- AC 110-240 V~, 50/60 Hz
* 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 5 minutes prior to
the adjustment.
3. Test method
1) Performance: LGE TV test method followed
2) Demanded other specification
- Safety : UL, CSA, IEC specification
- EMC: FCC, ICES, IEC specification
4. General Specification
No
Item
Specification
Remark
1
Receiving System
1) ATSC / NTSC-M
2
Available Channel
1) VHF : 02~13
2) UHF : 14~69
3) DTV : 02-69
4) CATV : 01~135
5) CADTV : 01~135
2) UHF : 14~69
3) DTV : 02-69
4) CATV : 01~135
5) CADTV : 01~135
3
Input Voltage
1) AC 100 ~ 240V 50/60Hz
120V, 50/60Hz on the label (USA)
4
Market
NORTH AMERICA
5
Screen Size
32/37/42 inch Wide (1920 × 1080)
FHD + 60Hz 42LS3400-UA
22/26/32 inch Wide (1366 × 768)
HD + 60Hz
32LS3400-UA
6
Aspect Ratio
16:9
7
Tuning System
FS
8
Module(Direct LED)
LC320DXN-SER2
LGD
32LS3400-UA
LC420DUN-SER2
LGD
42LS3400-UA
9
Operating Environment
1) Temp : 0 ~ 40 deg
2) Humidity : ~ 80 %
10 Storage Environment
1) Temp : -20 ~ 60 deg
2) Humidity : ~ 85 %
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5. Supported video resolutions
5.1. Component input(Y, CB/PB, CR/PR)
5.2. HDMI Input (DTV)
No.
Resolution
H-freq(kHz)
V-freq.(kHz)
Pixel clock
Proposed
1.
720*480
15.73
60.00
13.5135
SDTV ,DVD 480I
2.
720*480
15.73
59.94
13.50
SDTV ,DVD 480I
3.
720*480
31.50
60.00
27.027
SDTV 480P
4.
720*480
31.47
59.94
27.00
SDTV 480P
5.
1280*720
45.00
60.00
74.25
HDTV 720P
6.
1280*720
44.96
59.94
74.176
HDTV 720P
7.
1920*1080
33.75
60.00
74.25
HDTV 1080I
8.
1920*1080
33.72
59.94
74.176
HDTV 1080I
9.
1920*1080
67.50
60.00
148.50
HDTV 1080P
10.
1920*1080
67.432
59.94
148.352
HDTV 1080P
11.
1920*1080
27.00
24.00
74.25
HDTV 1080P
12.
1920*1080
26.97
23.94
74.176
HDTV 1080P
13.
1920*1080
33.75
30.00
74.25
HDTV 1080P
14.
1920*1080
33.71
29.97
74.176
HDTV 1080P
No.
Resolution
H-freq(kHz)
V-freq.(kHz)
Pixel clock
Proposed
1.
720*480
31.47
60.00
27.027
SDTV 480P
2.
720*480
31.47
59.94
27.00
SDTV 480P
3.
1280*720
45.00
60.00
74.25
HDTV 720P
4.
1280*720
44.96
59.94
74.176
HDTV 720P
5.
1920*1080
33.75
60.00
74.25
HDTV 1080I
6.
1920*1080
33.72
59.94
74.176
HDTV 1080I
7.
1920*1080
67.50
60.00
148.50
HDTV 1080P
8.
1920*1080
67.432
59.94
148.352
HDTV 1080P
9.
1920*1080
27.00
24.00
74.25
HDTV 1080P
10.
1920*1080
26.97
23.976
74.176
HDTV 1080P
11.
1920*1080
33.75
30.00
74.25
HDTV 1080P
12.
1920*1080
33.71
29.97
74.176
HDTV 1080P
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ADJUSTMENT INSTRUCTION
1. Application Range
This spec. sheet applies to LA25C Chassis applied LCD TV all
models manufactured in TV factory.
2. Specification
(1) Because this is not a hot chassis, it is not necessary to use
an isolation transformer. However, the use of isolation
transformer will help protect test instrument.
(2) Adjustment must be done in the correct order.
(3) The adjustment must be performed in the circumstance of
25 ±5 °C of temperature and 65±10% of relative humidity if
there is no specific designation.
(4) The input voltage of the receiver must keep 100~240V,
50/60Hz.
(5) At first Worker must turn on the SET by using Power Only
key.
(6) The receiver must be operated for about 5 minutes prior to
the adjustment when module is in the circumstance of over
15 °C
In case of keeping module is in the circumstance of 0°C, it
should be placed in the circumstance of above 15°C for 2
hours
In case of keeping module is in the circumstance of below
-20°C, it should be placed in the circumstance of above
15°C for 3 hours
[Caution]
When still image is displayed for a period of 20 minutes or
longer (especially where W/B scale is strong.
Digital pattern 13ch and/or Cross hatch pattern 09ch), there
can some afterimage in the black level area
3. Adjustment items
3.1. Main PCBA Adjustments
(1) ADC adjustment: Component 480i, 1080p / RGB-PC 1080p
(2) EDID downloads for HDMI and RGB-PC
3.2. Final assembly adjustment
(1) White Balance adjustment
(2) RS-232C functionality check
(3) Factory Option setting per destination
(4) Shipment mode setting (IN-STOP)
(5) GND and HI-POT test
3.3. Appendix
(1) Shipment conditions
(2) Tool option menu
(3) USB Download (S/W Update, Option and Service only)
(4) Preset CH Information
4. MAIN PCBA Adjustments
* Download
(1) Execute ISP program “Mstar ISP Utility” and then click
“Config” tab.
(2) Set as below, and then click “Auto Detect” and check “OK”
message. If display “Error”, Check connect computer, jig, and
set.
(3) Click “Connect” tab. If display “Can’t ”, Check connect
computer, jig, and set.
(4) Click “Read” tab, and then load download file(XXXX.bin) by
clicking “Read”
(5) Click “Auto” tab and set as below
(6) Click “Run”.
(7) After downloading, check “OK” message.