SERVICING
PRECAUTIONS
CAUTION
Before
servicing receivers
covered by
this
service
manual
and
its
supplements and
addenda
read
and
follow
the
SAFETY
PRECAUTIONS
on page 3
of
this
publication
NOTE
If
unforeseen circumstances
create
conflict
between
the
following servicing
precautions
and any
of
the
safety
precautions
on page 3
of
this
publication
always
follow
the
safety
precautions
Remember
Safety
First
General
Servicing
Precautions
1
Always
unplug
the
receiver
AC
power
cord
from
the
AC
power
source
before
a
Removing
or reinstalling
any
component
circuit
board
module
or
any
other receiver
assembly
b
Disconnecting
or
reconnecting
any
receiver electrical
plug
or
other electrical
connection
c
Connecting a
test substitute
in
parallel with
an
electrolytic
capacitor
in
the
receiver
CAUTION
A
wrong
part substitution or incorrect polarity
einstallatioxn
of
elpectrolyticlcaopacitorssmay riesuolt
in
ann
hazard
2
Test high voltage
only
by
measuring
it
with
an
appropriate
high voltage
meter
or other
voltage
measuring
device
DVM
FETVOM
etc
equipped
with
a
suitable
high voltage
probe
Do
not
test
high voltage
by
drawing
an
arc
3
Do
not
spray
chemicals
on
or
near
this
receiver or
any
of
its
assemblies
4
Unless
specified
otherwise
in this
service
manual
clean
electrical
contacts
only
by
applying the
following mixture to
the
contacts
with
a
pipe
cleaner cottontipped
stick or
comparable
nonabrasive
applicator
10
by volume
Acetone and 90
by volume
isopropyl
alcohol
90
99
strength
CAUTION
This
is
a
flammable mixture
Unless
specified
otherwise
in this
service
manual
lubrication of
contacts
in
not
required
5
Do
not defeat
any
plugsocket
B
voltage
interlocks with
which
receivers
covered by
this
service
manual
might
be equipped
6
Do
not apply
AC
power
to
this
instrument
andlor
any
of
its
electrical
assemblies
unless
all
solidstate
device heat
sinks
are
correctly installed
7
Always connect
the
test receiver
ground
lead
to
the
receiver
chassis
ground
before
connecting
the
test receiver positive
lead
Always remove
the
test receiver
ground
lead
last
8
Use
with
this
receiver only
the
test fixtures specified
in this
service
manual
CAUTION
Do
not
connect
the
test
fixture
ground
strap to
any
heat
sink
in this
receiver
Electrostatically
Sensitive
ES
Devices
Some
semiconductor
solidstate
devices
can be
damaged
easily
by
static
electricity
Such components
commonly
are
called
Electrostatically Sensitive
ES
Devices
Examples
of typical
ES
devices
are
integrated circuits
and
some
fieldeffect transistors
and
semiconductor
chip
components
The
following
techniques
should
be used
to
help
reduce
the incidence
of
component
damage
caused by
static
by
static
electricity
1
Immediately
before handling
any
semiconductor
component
or
semiconductorequipped assembly
drain
off
any
electrostatic
cAharge
olntyouer bodyrbyntouchinag
a
ktnowinvearthegroundly
obtain
and wear
a
commercially
available
discharging
wrist strap
device
which
should
be removed
to
prevent
potential
shock
reasons
prior
to
applying
power
to
the
unit
under
test
2
After
removing an
electrical
assembly equipped
with
ES
devices
place the
assembly on
a
conductive
surface
such as
aluminum
foil
to
prevent
electrostatic
charge
buildup
or
exposure
of
the
assembly
3
Use
only
a
groundedtip
soldering iron to solder or
unsolder
ES
devices
4
Use
only
an
antistatic
type
solder
removal device
Some
solder
removal devices
not
classified
as
antistatic
can
generate
electrical
charges
sufficient to
damage
ES
devices
5
Do
not
use
freonpropelled chemicals
These can
generate
electrical
charges
sufficient to
damage
ES
devices
6
Do
not
remove
a
replacement
ES
device
from
its
protective
package
until
immediately
before
you
are
ready to
install
it
Meost relplaceementcES
detvicesrareipacckagedawith
leladsly
shorted together
by
conductive
foam
aluminum
foil
or
comparable
conductive
material
7
Immediately
before
removing
the
protective
material
from
the
leads
of
a
replacement
ES
device
touch
the
protective
material
to
the
chassis
or
circuit
assembly
into
which
the
device
will
be
installed
CAUTION
Be
sure
no power
is
applied
to
the
chassis
or
circuit
and observe
all
other safety
precautions
8
Mriniemize
bpodily
lmoations cwhenehandlinmg
unpackaeged
nt
ES
devices Otherwise harmless motion
such as
the
brushing together
of
your
clothes
fabric or
the
lifting
of
your
foot
from
a
carpeted
floor
can
generate
static
electricity
sufficient
to
damage
an
ES
device
General
Soldering Guidelines
1
Use a
groundedtip
lowwattage
soldering iron
and
appropriate
tip
size
and shape
that
will
maintain
tip
temperature
within
the
range
or
500 F
to
600
F
2
Use an
appropriate
gauge
of
RMA
resincore
solder
composed
of
60
parts
tin40
parts
lead
3
Keep
the
soldering iron
tip
clean
and
well
tinned
4
Twhoroughly
icleran
thee surfacbes
to
bersoldieresd
Useta
mlalle
05
inch
or
125
cm
brush
with
a
metal
handle
Do
not
use
freonpropelled sprayon cleaners
5
Use
the
following
unsoldering
technique
a
Allow
the
soldering iron
tip
to
reach
normal temperature
500
F
to
600
F
b
Heat
the
component
lead
until
the
solder
melts
csQuicklyudrawcthe
mteltiedosoldernwith
atn ayntistatipc
e
solder
removal
device
or with solder
braid
CAUTION
Work
quickly
to
avoid overheating the
circuit
board
printed
foil
6
Use
the
following soldering
technique
a
Allow
the
soldering iron
tip
to
reach
a
normal temperature
500
F
to
600
F
b
First
hold the
soldering iron
tip
and
solder
the strand against
the
component
lead
until
the
solder
melts
c
Quickly
move
the
soldering iron
tip
to
the
junction of
the
component
lead
and
the
printed
circuit foil
and
hold
it
there
only
until
the
solder flows
onto
and around
both the
component
lead
and
the
foil
CAUTION
Work
quickly
to
avoid overheating the
circuit
board
printed
foil
d
Closely
inspect the
solder
area
and remove any excess
or
splashed
solder with
a
small wirebristle
brush
Copyright
n
2014
LG
Electronics
Inc
All
rights reserved
Only
for
training
and
service
purposes
4
LGE
Internal
Use
Only
Confidential
Business
Information
LGE910IT000143507
Subject
to Protective
Order
