LG MCV903 - POWER AMP PART CHECK

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