LG 42LV5500 User manual

42LV5500
1080P
Direct View LCD
42LV5500
LED Backlights
Training
LCD-DV Troubleshooting
42" Class 1080P 120Hz LED
TV SmartTV (42" diagonally)
Published May 12
th
, 2011

OUTLINE
Preliminar
y
Section:
y
Contact Information, Preliminary Matters, Specifications,
LCD Overview, General Troubleshooting Steps,
Signal Distribution, Disassembly Instructions and Voltages
Troubleshooting Section: Board Operation Troubleshooting of :
Signal
Distribution,
Disassembly
Instructions
and
Voltages
Disassembly Section: Removal of Circuit Boards
•Switch Mode Power Supply with LED Backlight Driver
•Main Board
•Front IR/Intelli
g
ent/Soft Touch Ke
y
Board
•T-CON (TFT Panel Driver Board)
gy
•Speaker
May 2011 LCD TV 42LV5500
2

42LV5500
LCD Direct View Display
Overview of Topics to be Discussed
42LV5500
LCD
Direct
View
Display
Section 1
This Section will cover Contact Information and remind the Technician of Important
Safety Precautions for the Customers Safety as well as the Technician and the
Equipment.
Basic Troubleshooting Techniques which can save time and money sometimes can
be overlooked. These techniques will also be presented.
Thi S ti ill t th T h i i f ili ith th Di bl Id tifi ti d
Thi
s
S
ec
ti
on w
ill
ge
t
th
e
T
ec
h
n
i
c
i
an
f
am
ili
ar w
ith
th
e
Di
sassem
bl
y,
Id
en
tifi
ca
ti
on an
d
Layout of the LCD Display Panel.
fS f C
At the end o
f
this
S
ection the Technician should be able to Identi
f
y the
C
ircuit Boards
and have the ability and knowledge necessary to safely remove and replace any
Circuit Board or Assembly.
May 2011 LCD TV 42LV5500
3

IMPORTANT SAFETY NOTICEIMPORTANT SAFETY NOTICE
Preliminary Matters (The Fine Print)
IMPORTANT
SAFETY
NOTICEIMPORTANT
SAFETY
NOTICE
The information in this training manual is intended for use by persons possessing an adequate background in
electrical equipment, electronic devices, and mechanical systems. In any attempt to repair a major Product,
personal injury and property damage can result. The manufacturer or seller maintains no liability for the
interpretation of this information, nor can it assume any liability in conjunction with its use. When servicing this
product, under no circumstances should the original design be modified or altered without permission from LG
Electronics. Unauthorized modifications will not only void the warranty, but may lead to property damage or
user injury If wires screws clips straps nuts or washers used to complete a ground path are removed for
user
injury
.
If
wires
,
screws
,
clips
,
straps
,
nuts
,
or
washers
used
to
complete
a
ground
path
are
removed
for
service, they must be returned to their original positions and properly fastened.
CAUTIONCAUTION
CAUTIONCAUTION
To avoid personal injury, disconnect the power before servicing this product. If electrical power is required for
dia
g
nosis or test
p
ur
p
oses
,
disconnect the
p
ower immediatel
y
after
p
erformin
g
the necessar
y
checks. Also be
gpp, p ypg y
aware that many household products present a weight hazard. At least two people should be involved in the
installation or servicing of such devices. Failure to consider the weight of an product could result in physical
injury.
May 2011 LCD TV 42LV5500
4

ESD Notice
(Electrostatic Static Discharge)(Electrostatic Static Discharge)
Today’s sophisticated electronics are electrostatic discharge (ESD) sensitive. ESD can weaken or damage
the electronics in a manner that renders them inoperative or reduces the time until their next failure.
Connect an ESD wrist strap to a ground connection point or unpainted metal in the product. Alternatively,
you can touch your finger repeatedly to a ground connection point or unpainted metal in the product. Before
removing a replacement part from its package, touch the anti
-
static bag to a ground connection point or
removing
a
replacement
part
from
its
package,
touch
the
anti
static
bag
to
a
ground
connection
point
or
unpainted metal in the product. Handle the electronic control assembly by its edges only. When
repackaging a failed electronic control assembly in an anti-static bag, observe these same precautions.
lflf
Regu
l
atory In
f
ormationRegu
l
atory In
f
ormation
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to
Part 15 of the FCC Rules. These limits are desi
g
ned to
p
rovide reasonable
p
rotection a
g
ainst harmful
gp p g
interference when the equipment is operated in a residential installation. This equipment generates, uses,
and can radiate radio frequency energy, and, if not installed and used in accordance with the instruction
manual, may cause harmful interference to radio communications. However, there is no guarantee that
interference will not occur in a particular installation. If this equipment does cause harmful interference to
radio or television reception which can be determined by turning the equipment off and on the user is
radio
or
television
reception
,
which
can
be
determined
by
turning
the
equipment
off
and
on
,
the
user
is
encouraged to try to correct the interference by one or more of the following measures: Reorient or relocate
the receiving antenna; Increase the separation between the equipment and the receiver; Connect the
equipment to an outlet on a different circuit than that to which the receiver is connected; or consult the
dealer or an experienced radio/TV technician for help.
May 2011 LCD TV 42LV5500
5

Customer Service (and Part Sales) [phone]
Technical Support (and Part Sales)
(800) 847
7597
LG Contact Information
Technical
Support
(and
Part
Sales)
(800)
847
-
7597
USA Website (GSFS) http://gsfs-america.lge.com
Customer Service Website http://www.us.lgservice.com
Knowledgebase Website http://lgtechassist.com
LG Web Training https://lge.webex.com Presentations with Audio/Video
and Screen Marks
New: 2010 Models Wireless
Ready Software Downloads
LG CS Learning Academy http://ln.lge.com/ilearn http://136.166.4.200
Training Manuals, Schematics with Navigational Bookmarks, Start-Up Sequence, Owner’s Guides,
Int
e
r
co
nn
ec
t Di
ag
r
a
m
s,
Dim
e
n
s
i
o
n
s,
Co
nn
ec
t
o
r ID
s,
Pr
oduc
t Pi
c
t
u
r
es
a
n
d
F
ea
t
u
r
es
.
Also available on the Plasma Page:
PDP Panel Alignment Handbook,
Plasma Control Board ROM Update (Jig required)
e co ec ag a s, e s o s, Co ec o s, oduc c u es a d ea u es
Published May 2011 by LG Technical Support and Training
LG Electronics Alabama
,
Inc.
May 2011 LCD TV 42LV5500
6
,
201 James Record Road, Huntsville, AL, 35813.

Safety and Handling Regulations
LCD Direct View Overview
1. Approximately 20 minute of run time is required before making any picture performance
adjustments from the Menu.
2. Refer to the Voltage/Current silk screening on the Switch Mode Power Supply.
3.
C
-
MOS circuits are sensitive to static electricity.
3.
C
MOS
circuits
are
sensitive
to
static
electricity.
Use caution when dealing with these IC and circuits.
4. Exercise care when making voltage and waveform checks to prevent costly short circuits
from damaging the unit.
5
.B
e
cau
ti
ous
o
f l
os
t
sc
r
e
w
s
a
n
d
o
th
e
r m
e
t
a
l
objec
t
s
t
o
p
r
e
v
e
nt
a
poss
i
b
l
e
s
h
o
rt in th
e
5
e cau ous o os sc e s a d o e e a objec s o p e e a poss b e s o e
circuitry.
Checking Points to be Considered
1. Check the appearance of the Replacement Panel and Circuit Boards for both physical
damage and part number accuracy.
2
Check the model label Verify model names and board model matches
2
.
Check
the
model
label
.
Verify
model
names
and
board
model
matches
.
3. Check details of defective condition and history. Example: Oscillator failure dead set, etc…
May 2011 LCD TV 42LV5500
7

Basic Troubleshooting Steps
Define, Localize, Isolate and Correct
•Define Look at the symptom carefully and determine what circuits could be causing
the failure. Use your senses Sight, Smell, Touch and Hearing. Look for burned parts and
check for possible overheated components. Capacitors will sometimes leak dielectric material
and give off a distinct odor Frequency of power supplies will change with the load or listen for
and
give
off
a
distinct
odor
.
Frequency
of
power
supplies
will
change
with
the
load
,
or
listen
for
relay closing etc. Observation of the front Power LED may give some clues.
•Localize After carefully checking the symptom and determining the circuits to be
checked and after giving a thorough examination using your senses the first check should
checked
and
after
giving
a
thorough
examination
using
your
senses
the
first
check
should
always be the DC Supply Voltages to those circuits under test. Always confirm the supplies
are not only the proper level but be sure they are noise free. If the supplies are missing check
the resistance for possible short circuits.
•Isolate To further isolate the failure, check for the proper waveforms with the
Oscilloscope to make a final determination of the failure. Look for correct Amplitude Phasing
and Timing of the signals also check for the proper Duty Cycle of the signals. Sometimes
“
glitches
”
or
“
road bumps
”
will be an indication of an imminent failure
glitches
or
road
bumps
will
be
an
indication
of
an
imminent
failure
.
•Correct The final step is to correct the problem. Be careful of ESD and make sure to
check the DC Supplies for proper levels. Make all necessary adjustments and lastly always
perform a Safety AC Leakage Test before returning the product back to the Customer
May 2011 LCD TV 42LV5500
8
perform
a
Safety
AC
Leakage
Test
before
returning
the
product
back
to
the
Customer
.

42LV5500 PRODUCT INFORMATION SECTION
This section of the manual will discuss the specifications of the
42LV5500
May 2011 LCD TV 42LV5500
9
LCD Direct View Display

Wireless Media Box (Sold Separately)
Wireless Media Box
The Wireless Media box communicates to the television via a wireless receiver called a
“Dongle”. The Dongle attaches to the Television via two connections:
1. HDMI Cable from the Dongle to the TV to transfer Audio and Video Signals.
2.
Wired Remote cable between the TV and Dongle for Control Functions.
Media Box
2.
Wired
Remote
cable
between
the
TV
and
Dongle
for
Control
Functions.
Wired Remote to control the Media Box
Wi l R i /T itt
TV A/V Inputs
Wi
re
l
ess
R
ece
i
ver
/T
ransm
itt
er
“Dongle”
Attaches via Velcro to
the back of the set
HDMI
May 2011 LCD TV 42LV5500
10
HDMI