LG MCV903 Service Manual page 37

15. PWM MODULATION PART CHECK III (HEAD PHONES)
PWM MODULATION
PART CHECK III
YES
Check the
PWM MODULATOR
NO
output HP:/L40(+)41(-)
HP:/R45(+)46(-)
YES
FL:(-)C859,
NO
FL:(+)C860
FR:(-)C852,
FR:(+)853
YES
P7302 18PIN,16PIN
Check HP output (check
the abnormal operation
of SIG 0.9V)
YES
OK
LGE Internal Use Only
HP/PWM output waveform
Check the
NO
output waveform at both
terminals of HP :R854,
855,865,864
YES
OK
Check the
NO
operation condition
of IC802
YES
Check R857,861
NO
Check Q803 BASE
LOWE
OK
3-16
Check HP/SENS HIGH
YES
Replace the related
part
Check the IC802 ±12V
input power
YES
Check the
NO
power at both terminals
of R859,860
YES
OK
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Only for training and service purposes
Replace the related
part