DOWNLOAD LG 50PJ250-ZC (CHASSIS:PD01A) Service Manual ↓ Size: 6.46 MB | Pages: 35 in PDF or view online for FREE

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

P/NO : MFL62881213(1002-REV00)

- 24 -

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 X-RADIATION, Shock, Fire, or other Hazards. 
Do not modify the original design without permission of manufacturer.

400

602

601

520

900

120

305

300

301

302

303

501

590

200

580

570

205

202

203

208

204

201

206

207

604

240

302

910

A2

A10

A9

LV1

A12

- 2 -

- 3 -

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
X-RADIATION, Shock, Fire, or other Hazards. 
Do not modify the original design without permission of manufacturer.

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 monitor is blown, replace it
with the specified.

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.

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

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 1MΩ and 5.2MΩ. 
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.

Plug the AC cord directly into the AC outlet.
Do not use a line Isolation Transformer during this check. 
Connect  1.5K/10watt  resistor  in  parallel  with  a  0.15uF  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
0.5mA.
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.

1.5 Kohm/10W

To Instrument's
exposed 
METALLIC PARTS

Good Earth Ground
such as WATER PIPE,
CONDUIT etc.

AC Volt-meter

0.15uF