Overview; Introduction; Basic Troubleshooting Steps; Caution - LG 32LG40 Training Manual

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INTRODUCTION

The manual covers two models from the 2008 LCD product line. Each model is an HDTV
with integrated HD tuner. The 32LG40 is a 720p/1080i model, the 42LG60 supports
1080p (Full HD). All models 32" and larger include USB Media Host and SimpLink. USB
Media Host consists of a USB port on the back of the TV that supports USB flash memory
drives loaded with media or firmware for the TV. SimpLink allows for control of other LG
SimpLink products via the HDMI connection.
All LCD TV models are module level repair in and out of warranty. They are covered by a
one year parts and labor warranty. Refer to the last page of the owner's manual for more
warranty information. For models under 30", the Sevice Level is Factory Service Repair.
Larger models are Field Service. Contact the Warranty department for more information.

BASIC TROUBLeSHOOTING STePS

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 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 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.

CAUTION

1) A 20 minute pre-run time is required before any adjustments are performed.
2) Refer to the Voltage Sticker on the Switch Mode Power Supply silk screening. (+/- 1/2
volt).
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2008 LCDS
5
Fall 2008 LCD Training