LG 50PJ340 Installation guide

Advanced Single Scan Troubleshooting
50" Class HD 720p Plasma TV
(50" diagonally)
Training Manual
50PJ350 Plasma Display
50PJ350 Plasma Display
Published July 12
th
, 2010
Updated August 12
th
, 2010

2July 2010 50PJ350 Plasma
Overview of Topics to be Discussed
• Y-SUS Board Delivers Logic Signals and FG5V to lower Y-Drive board.
• Z-SUS Output Board (Also uses one Z-SUB board for bottom panel connector)
• Y-Drive Boards (1 Upper and 1 Lower).
• Control Board
• X Drive Boards (3)
Troubleshooting:
Circuit Board Operation, Troubleshooting and Alignment of :
• Switch Mode Power Supply No VS On command input to SMPS
• Main Board
Preliminary:
Contact Information, Preliminary Matters, Specifications,
Plasma Overview, General Troubleshooting Steps,
Disassembly Instructions, Voltage and Signal Distribution
OUTLINE
OUTLINE
• No Main Power Switch (Vacation Switch).
• Interconnect Diagram: 11X17 Foldout Section used as a quick reference sheet.
Lower can run separately, but you MUST remove the Upper completely.

3July 2010 50PJ350 Plasma
50PJ350 Plasma Display
The first section will cover Contact Information and 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.
The next section will get the Technician familiar with the Disassembly, Identification
and Layout of the Plasma Display Panel.
At the end of this Section the Technician should be able to Identify the Circuit
Boards and have the ability and knowledge necessary to safely remove and
replace any Circuit Board or Assembly.
Overview of Topics to be Discussed
Overview of Topics to be Discussed

4July 2010 50PJ350 Plasma
Customer Service (and Part Sales) [phone]
Technical Support (and Part Sales) [phone]
USA Website (GSFS) http://gsfs-america.lge.com
Customer Service Website us.lgservice.com
Knowledgebase Website lgtechassist.com
LG Web Training lge.webex.com
LG CS Academy lgcsacademy.com
Published July 2010 by LG Technical Support and Training
LG Electronics Alabama, Inc.
201 James Record Road, Huntsville, AL, 35813.
32LG40, 32LH30, 37LH55, 42LG60, 42LG70, 42LH20, 42LH40, 42LH50, 42LH90, 42SL80,
47LG90, 47LH85, 47LE8500
42PG20, 42PQ20, 42PQ30, 50PG20, 50PJ350, 50PK750, 50PS80, 50PS60, 60PK750,
60PS11, 60PS60, 60PS80
LCD-DV:
PLASMA:
Also available on the Plasma Page:
PDP Panel Alignment Handbook, Schematics with Bookmarks
Plasma Control Board ROM Update (Jig required)
LG Contact Information
LG Contact Information
Presentations with Audio/Video
and Screen Marks
New Training Materials on
New Training Materials on
the Learning Academy site
the Learning Academy site
http://136.166.4.200
New: Software Downloads
Technical Assistance

5July 2010 50PJ350 Plasma
IMPORTANT SAFETY NOTICE
IMPORTANT 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
service, they must be returned to their original positions and properly fastened.
CAUTION
CAUTION
To avoid personal injury, disconnect the power before servicing this product. If electrical power
is required for diagnosis or test purposes, disconnect the power immediately after performing
the necessary checks. Also be 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.
Preliminary Matters (The Fine Print)
Preliminary Matters (The Fine Print)

6July 2010 50PJ350 Plasma
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
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.
Regulatory Information
Regulatory Information
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 designed to provide reasonable protection against harmful
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
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.
ESD Notice
ESD Notice (Electrostatic Static Discharge)
(Electrostatic Static Discharge)

7July 2010 50PJ350 Plasma
Safety & Handling Regulations
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.
3. Check details of defective condition and history. Example: Y-SUS or Y-Drive Board Failure, Mal-discharge on screen, etc.
1. Approximately 10 minute pre-run time is required before any adjustments are performed.
2. Refer to the Voltage Sticker inside the Panel when making adjustments on the Power Supply, Y-SUS and Z-SUS Boards.
3. Always adjust to the specified voltage level (+/- ½ volt) unless otherwise specified.
4. Be cautious of electric shock from the PDP module since the PDP module uses high voltage, check that the Power Supply
and Drive Circuits are completely discharged because of residual current stored before Circuit Board removal.
4. C-MOS circuits are used extensively for processing the Drive Signals and should be protected from static electricity.
5. The PDP Module must be carried by two people. Always carry vertical NOT horizontal.
6. The Plasma television should be transported vertically NOT horizontally.
7. Exercise care when making voltage and waveform checks to prevent costly short circuits from damaging the unit.
8. Be cautious of lost screws and other metal objects to prevent a possible short in the circuitry.
9. New Panels and Frames are much thinner than previous models. Be Careful with flexing these panels. Be careful
with lifting Panels from a horizontal position. Damage to the Frame mounts or panel can occur.
10. New Plasma models have much thinner cabinet assemblies and mounts.
Be extremely careful when moving the set around as damage can occur.
Checking Points to be Considered
Safety and Handling, Checking Points
Safety and Handling, Checking Points

8July 2010 50PJ350 Plasma
Basic Troubleshooting Steps
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
relay closing etc. Observation of the front Power LEDs 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 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.
•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.

9July 2010 50PJ350 Plasma
This section of the manual will discuss the specifications of the
50PJ350 Advanced Single Scan Plasma Display Television.
50PJ350 PRODUCT INFORMATION SECTION
50PJ350 PRODUCT INFORMATION SECTION

10 July 2010 50PJ350 Plasma
50PJ350 Specifications
50PJ350 Specifications
1080P PLASMA HDTV
50" Class (50" diagonal)
•600Hz Sub Field Driving
•High Definition Resolution
•3M:1 Dynamic Contrast Ratio
•TruSlim Frame
•Picture Wizard II (Easy Picture Calibration)
•Smart Energy Saving
•Intelligent Sensor
•Dual XD™ Engine
•AV Mode(Cinema, Sports, Game)
•Clear Voice II
•ISFccc® Ready
•24P Real Cinema
•USB 2.0 (JPEG, MP3)
•3 HDMI™ 1.3 Inputs
•SIMPLINK™ Connectivity
•Dolby® Digital 5.1 Decoder
•Infinite Sound
For Full Specifications
See the Specification Sheet