Text preview for : LG+42PC51+Chassis+PP78A.pdf part of LG LG+42PC51+Chassis+PP78A LG Plasma 42PC51 chassis PP-78A LG+42PC51+Chassis+PP78A.pdf



Back to : LG+42PC51+Chassis+PP78A.p | Home

website:http://biz.LGservice.com




PLASMA TV
SERVICE MANUAL
CHASSIS : PP78A

MODEL : 42PC51 42PC51-ZB



CAUTION
BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.




Downloaded from www.Manualslib.com manuals search engine
CONTENTS



CONTENTS .............................................................................................. 2

SAFETY PRECAUTIONS ..........................................................................3

SPECIFICATION ........................................................................................4

ADJUSTMENT INSTRUCTION .................................................................6

TROUBLE SHOOTING ............................................................................16

BLOCK DIAGRAM...................................................................................24

EXPLODED VIEW .................................................................................. 26

EXPLODED VIEW PARTS LIST ............................................................ 27

REPLACEMENT PARTS LIST ............................................................... 28

SVC. SHEET ...............................................................................................

PRINTED CIRCUIT DIAGRAM ....................................................................




-2-




Downloaded from www.Manualslib.com manuals search engine
SAFETY PRECAUTIONS

IMPORTANT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in the
Schematic Diagram and Replacement Parts List.
It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent
X-RADIATION, Shock, Fire, or other Hazards.
Do not modify the original design without permission of manufacturer.



General Guidance Leakage Current Hot Check (See below Figure)
Plug the AC cord directly into the AC outlet.
An isolation Transformer should always be used during the Do not use a line Isolation Transformer during this check.
servicing of a receiver whose chassis is not isolated from the AC Connect 1.5K/10watt resistor in parallel with a 0.15uF capacitor
power line. Use a transformer of adequate power rating as this between a known good earth ground (Water Pipe, Conduit, etc.)
protects the technician from accidents resulting in personal injury and the exposed metallic parts.
from electrical shocks. Measure the AC voltage across the resistor using AC voltmeter
with 1000 ohms/volt or more sensitivity.
It will also protect the receiver and it's components from being Reverse plug the AC cord into the AC outlet and repeat AC voltage
damaged by accidental shorts of the circuitry that may be measurements for each exposed metallic part. Any voltage
inadvertently introduced during the service operation. measured must not exceed 0.75 volt RMS which is corresponds to
0.5mA.
If any fuse (or Fusible Resistor) in this monitor is blown, replace it In case any measurement is out of the limits specified, there is
with the specified. possibility of shock hazard and the set must be checked and
repaired before it is returned to the customer.
When replacing a high wattage resistor (Oxide Metal Film Resistor,
over 1W), keep the resistor 10mm away from PCB.

Keep wires away from high voltage or high temperature parts. Leakage Current Hot Check circuit

Due to high vacuum and large surface area of picture tube, AC Volt-meter
extreme care should be used in handling the Picture Tube.
Do not lift the Picture tube by it's Neck.


Good Earth Ground
such as WATER PIPE,
Leakage Current Cold Check(Antenna Cold Check) CONDUIT etc.
To Instrument's
With the instrument AC plug removed from AC source, connect an 0.15uF
exposed
electrical jumper across the two AC plug prongs. Place the AC METALLIC PARTS
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 1.5 Kohm/10W
jacks, etc.
If the exposed metallic part has a return path to the chassis, the
measured resistance should be between 1M and 5.2M.
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.




-3-




Downloaded from www.Manualslib.com manuals search engine
SPECIFICATIONS
NOTE : Specifications and others are subject to change without notice for improvement.


V Application Range
This spec is applied to the 42" PLASMA TV used PP78A Chassis.

Chassis Model Name Market Brand Remark
PP78A 42PC51-ZB EU LG




V Specification
Each part is tested as below without special appointment.
1) Temperature : 25