47LD750, 47LD750N, 47LD751, 47LD780, 47LD790 (CHASSIS:LD03B) - LG TV Service Manual (repair manual)

47ld750, 47ld750n, 47ld751, 47ld780, 47ld790 (chassis:ld03b) service manual
Model
47LD750 47LD750N 47LD751 47LD780 47LD790 (CHASSIS:LD03B)
Pages
40
Size
4.93 MB
Type
PDF
Document
Service Manual
Brand
Device
TV / LCD
File
47ld750-47ld750n-47ld751-47ld780-47ld790-chassis-l.pdf
Date

Read LG 47LD750 / 47LD750N / 47LD751 / 47LD780 / 47LD790 (CHASSIS:LD03B) Service Manual online

LCD TV
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
CHASSIS : LD03B
MODEL : 47LD750/750N
47LD750/750N-ZA
MODEL : 
47LD780/790
47LD780/790-ZA
MODEL : 
47LD751
47LD751-ZB
P/NO : MFL62863020 (1003-REV00)
- 2 -
CONTENTS
CONTENTS .............................................................................................. 2
PRODUCT SAFETY ................................................................................. 3
SPECIFICATION ....................................................................................... 4
ADJUSTMENT INSTRUCTION ................................................................ 7
BLOCK DIAGRAM...................................................................................14
EXPLODED VIEW .................................................................................. 15
SVC. SHEET  ...............................................................................................
- 3 -
SAFETY PRECAUTIONS
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 MΩ 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
1.5 Kohm/10W
To Instrument's
exposed 
METALLIC PARTS
Good Earth Ground
such as WATER PIPE,
CONDUIT etc.
AC Volt-meter
When 25A is impressed between Earth and 2nd Ground
for 1 second, Resistance must be less than 0.1
*Base on Adjustment standard
IMPORTANT SAFETY NOTICE
0.15 uF
- 4 -
SPECIFICATION
NOTE : Specifications and others are subject to change without notice for improvement.
1. Application range
This specification is applied to the LCD TV used LD03B
chassis.
2. Requirement for Test
Each part is tested as below without special appointment.
1) Temperature: 25 ºC ± 5 ºC(77 ºF ± 9 ºF), CST: 40 ºC ± 5 ºC
2) Relative Humidity :  65 % ± 10 %
3) Power Voltage
: Standard input voltage (AC 100-240 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 : CE, IEC specification
- EMC :CE, IEC 
4. Module optical specification
1) Stable for approximately 60 minutes in a dark environment at 25 ºC ± 2 ºC and windless room.
2) Operating Ambient Humidity : Min 10, Max 90 %RH
3) Supply Votage : 24 V
4) Frame Frequency : 120 Hz
No.
Item Specification 
Min.
Typ.
Max.
Remark
1.
Viewing Angle<CR>10> 
Right/Left/Up/Down 
89/89/89/89
CR > 10
2.
Luminance Luminance 
(cd/m
2
)
400
500
Variation 1.3
MAX 
/MIN
3.
Contrast Ratio 
CR
1100
1500
4.
CIE Color Coordinates   
White
Wx
0.279 
All white / All black
Wy 0.292
RED
Xr
0.636
Yr
Typ.
0.335
Typ.
Green Xg
-0.03
0.291
+0.03
Yg
0.603
Blue Xb 
0.146
Yb  
0.061
Page of 40

Download LG 47LD750 / 47LD750N / 47LD751 / 47LD780 / 47LD790 (CHASSIS:LD03B) Service Manual (Repair Manual)

Here you can read online and download LG 47LD750 / 47LD750N / 47LD751 / 47LD780 / 47LD790 (CHASSIS:LD03B) Service Manual in PDF. 47LD750 / 47LD750N / 47LD751 / 47LD780 / 47LD790 (CHASSIS:LD03B) service manual will guide through the process and help you recover, restore, fix, disassemble and repair LG 47LD750 / 47LD750N / 47LD751 / 47LD780 / 47LD790 (CHASSIS:LD03B) LCD. Information contained in service manuals typically includes schematics / circuit diagrams, wiring diagrams, block diagrams, printed wiring boards, exploded views, parts list, disassembly / assembly, pcb.