Read LG 47LD750 / 47LD750N / 47LD751 / 47LD780 / 47LD790 (CHASSIS:LD03B) Service Manual online
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
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.
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.
damaged by accidental shorts of the circuitry that may be
inadvertently introduced during the service operation.
replace it with the specified.
over 1 W), keep the resistor 10 mm away from PCB.
metallic parts of the cabinet, such as antennas, terminals, etc., to
be sure the set is safe to operate without damage of electrical
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
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.
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
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.
such as WATER PIPE,
2) Relative Humidity : 65 % ± 10 %
3) Power Voltage
* Standard Voltage of each products is marked by models.
accordance with BOM.
2) Demanded other specification
- EMC :CE, IEC
2) Operating Ambient Humidity : Min 10, Max 90 %RH
3) Supply Votage : 24 V
4) Frame Frequency : 120 Hz