LG MCV903 - Page 36

3-15
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Only for training and service purposes
LGE Internal Use Only
Check the
IC502,504 ±12V
input power
PWM output waveform
YES
OK
YES
OK
YESYES
NO
OK
YES
OK
NO
Check CN710 3PIN
-12,4PIN +12V
Check the
power at both
terminals of
NO
Replace the related
part
Check the
R554,553,552
output
Check DA-A_MUET
(R539) LOW and
SW-MUTE (R540) LOW
operation
Replace the related
part
NO
Replace the See the
SMPS Ass`y
NO
Check the
PWM MODULATOR
output FL:75(+) 74(-)
FR:59(+) 58(-)
SW 68(+)67(-)
YES
YES
NO
FL:(-)C533,
FL:(+)C516
FR:()C535,
FR:(+)C560
SW:(-)C555,
SW:(+)C556
YES
NO
Check the
operation condition
of IC502,504
NO
FRONT :R530,
518,529,532
SW :Check the output
waveform at both
terminals of
R538,534
NO
Check
PN702 5PIN L-CH ,
7PIN R-CH 14PIN SW
output (Check the abnormal
operation of
SIG 1V)